National 

Transportation

Safety Board

Washington, D.C.

National Transportation

Safety Board

Washington, D.C. 20594

OFFICIAL BUSINESS

Penalty for Private Use, $300

PRSRT STD

Postage & Fees Paid

NTSB

Permit No. G-200

Marine Accident Report

Capsizing of U.S. Small Passenger Vessel Lady D

Northwest Harbor, Baltimore, Maryland

March 6, 2004

NTSB/MAR-06/01

PB2006-916401 National Transportation Safety Board

Notation 7679A 490 L’Enfant Plaza, S.W.

Adopted March 7, 2006 Washington, D.C. 20594
National Transportation Safety Board. 2006. Capsizing of U.S. Small Passenger Vessel Lady D, 

Northwest Harbor, Baltimore, Maryland March 6, 2004. Marine Accident Report NTSB/MAR-06/01. 

Washington, DC.

Abstract: On March 6, 2004, the small passenger vessel Lady D, a pontoon water taxi with 2 

crewmembers and 23 passengers on board, was en route from Fort McHenry to Fells Point, Maryland, 

when it encountered a rapidly developing storm with high winds. The pontoon vessel began to roll in the 

waves and eventually continued over onto its starboard side and capsized. Responders were able to rescue 

or recover all but 3 occupants of the Lady D and transport them to area hospitals within an hour of the 

accident. The bodies of the remaining victims were recovered from the waterway on March 14 and 15. As 

a result of this accident, 5 passengers died; 4 passengers suffered serious injuries; and 12 people sustained 

minor injuries.

Major safety issues discussed in this report include passenger weight criteria for stability assessment; 

pontoon vessel stability standards; and policies and procedures pertaining to weather operations.

As a result of its investigation of this accident, the Safety Board made safety recommendations to the U. S. 

Coast Guard.

The National Transportation Safety Board is an independent Federal agency dedicated to promoting aviation, railroad, highway, marine, 

pipeline, and hazardous materials safety. Established in 1967, the agency is mandated by Congress through the Independent Safety Board 

Act of 1974 to investigate transportation accidents, determine the probable causes of the accidents, issue safety recommendations, study 

transportation safety issues, and evaluate the safety effectiveness of government agencies involved in transportation. The Safety Board 

makes public its actions and decisions through accident reports, safety studies, special investigation reports, safety recommendations, and 

statistical reviews.

Recent publications are available in their entirety on the Web at <http://www.ntsb.gov>. Other information about available publications also 

may be obtained from the Web site or by contacting:

National Transportation Safety Board

Records Management Division, CIO-40

490 L’Enfant Plaza, S.W.

Washington, D.C. 20594

(800) 877-6799 or (202) 314-6551

Safety Board publications may be purchased, by individual copy or by subscription, from the National Technical Information Service. To 

purchase this publication, order report number PB2006-916401 from:

National Technical Information Service

5285 Port Royal Road

Springfield, Virginia 22161

(800) 553-6847 or (703) 605-6000

The Independent Safety Board Act, as codified at 49 U.S.C. Section 1154(b), precludes the admission into evidence or use of Board reports 

related to an incident or accident in a civil action for damages resulting from a matter mentioned in the report. 
iii Marine Accident Report

Contents

Abbreviations and Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii

Factual Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Accident Narrative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Taxi Operations at Baltimore Harbor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Events On Board the Lady D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Escape and Rescue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Injuries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Damages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Crew Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Regulatory Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Master . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Mate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Vessel Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Regulatory Requirements for Small Passenger Vessels . . . . . . . . . . . . . . . . . . . . . . . . . 10

The Lady D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Safety Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Stability Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Wreckage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Waterway Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Management Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Parent Organization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Management Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Other Seaport Taxi Employees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Operational Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Docking Agreements with City . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Daily Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Passenger Accountability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Weather Policies and Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Meteorological Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

National Weather Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

National Weather Service Postaccident Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Digiwx System Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Weatherbug Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Medical and Pathological Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Medical Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Toxicological Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Survival Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Aspects of Survival in Cold Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

City of Baltimore Consolidated Communication Center . . . . . . . . . . . . . . . . . . . . . . . 35

Response Assets for Marine Incidents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Response of Assets to Lady D Capsizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Contents iv Marine Accident Report

Tests and Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Safety Board’s Stability Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Vehicle Performance Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Other Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Postaccident Actions by the Coast Guard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Accidents Involving Pontoon Passenger Vessel Stability. . . . . . . . . . . . . . . . . . . . . . . 47

Previously Issued Safety Recommendation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Status of Sister Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Exclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Accident Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Cause of the Capsizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Certification Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Erroneous Sister Vessel Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Passenger Overloading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Influence of Weight and Wind on Intact Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Passenger Weight Criteria for Stability Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Pontoon Vessel Stability Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Policies and Procedures Pertaining to Weather Operations . . . . . . . . . . . . . . . . . . . . . . . . . 63

NWS Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Seaport Taxi’s Weather Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Adequacy of Propulsive Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Survivability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Construction and Arrangement of the Accident Vessel . . . . . . . . . . . . . . . . . . . . . . . . . 67

Safety Briefing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Lifejacket Use in Enclosed Deckhouses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Response Effort . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Probable Cause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

New Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Previously Issued Recommendation Classified in This Report . . . . . . . . . . . . . . . . . . . . . . 76

Appendixes

A: Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

B: Intact Stability Study of Lady D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

C: U.S. Coast Guard Policy Letter 04-10, Evaluation of Stability 

and Subdivision Requirements for Small Passenger Vessels Inspected 

Under 46 CFR Subchapter T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
v Marine Accident Report

Abbreviations and Acronyms

ASOS Automated Surface Observing System

AWOS Automated Weather Observing System

BCFD Baltimore City Fire Department

BCPD Baltimore City Police Department

BWI Baltimore-Washington International Airport

CAMI Civil Aerospace Medical Institute

CESM Cold Exposure Survival Model

CFR Code of Federal Regulations

COI certificate of inspection

dBZ decibels of Z (where Z = energy reflected back to radar)

EMS emergency medical service

ICAO International Civil Aviation Organization

ISO International Organization for Standardization

LCM-8 mechanized landing craft

LWX Sterling weather radar station

MSC Marine Safety Center

MSO Marine Safety Office

NCEP National Centers for Environmental Prediction

NHS National Historic Seaport of Baltimore

nm nautical mile

NOAA National Oceanic and Atmospheric Administration

NPRM notice of proposed rulemaking

NVIC navigation and vessel inspection circular

NWR NOAA Weather Radio

NWS National Weather Service

OCMI Officer-in-Charge, Marine Inspection

PSST pontoon simplified stability test

SAR search and rescue

SST simplified stability test

TDWR terminal Doppler weather radar

UHF ultrahigh frequency

VHF very high frequency
Abbreviations and Acronyms vi Marine Accident Report

WFO weather forecast office

WSR-88D weather surveillance radar-88 Doppler
vii Marine Accident Report

Executive Summary

On March 6, 2004, the small passenger vessel Lady D, a pontoon water taxi with 2 

crewmembers and 23 passengers on board, was en route from Fort McHenry to Fells 

Point, Maryland, when it encountered a rapidly developing storm with high winds. The 

pontoon vessel began to roll in the waves and eventually continued over onto its starboard 

side and capsized. Personnel from the Naval Reserve Center Baltimore, a Navy training 

installation adjacent to Fort McHenry, witnessed the capsizing, called 911 to report the 

accident, and then launched a vessel to the scene to render assistance. Responders were 

able to rescue or recover all but 3 occupants of the Lady D within an hour of the accident. 

The bodies of the remaining victims were recovered from the waterway on March 14 and 

15. As a result of this accident, 5 passengers died; 4 passengers suffered serious injuries; 

and 12 people sustained minor injuries. Vessel damage was estimated at $35,000.

The Safety Board’s investigation of this accident identified major safety issues in 

the following areas: 

• Passenger weight criteria for stability assessment;

• Pontoon vessel stability standards; and 

• Policies and procedures pertaining to weather operations.

The National Transportation Safety Board determines that the probable cause of 

the capsizing of the pontoon-style small passenger vessel Lady D was its lack of intact 

stability, which was insufficient to withstand the strong winds and waves that the boat 

encountered. The lack of intact stability was caused by overloading, which resulted from a 

combination of the following:

• The Lady D was erroneously granted sister status by the U.S. Coast Guard to a 

pontoon vessel with different design characteristics;

• The Coast Guard certificated the Lady D to carry too many people as a result of 

an inappropriate stability test on the vessel to which it was granted sister status; 

and 

• The Coast Guard’s regulatory stability test standards on which the Lady D’s 

passenger allowance was based use an out-of-date average passenger weight.

As a result of this investigation, the Safety Board makes recommendations to the 

U.S. Coast Guard.

1 Marine Accident Report

Factual Information

Accident Narrative

Taxi Operations at Baltimore Harbor

In March 2004, Seaport Taxi was one of two water taxi companies servicing the 

harbor area in Baltimore, Maryland. Depending on the weather and time of year, the 

company activated the number of vessels in its fleet necessary to handle anticipated 

customer demand and assigned them to one of two established routes: an inner loop, 

which was between Harbor Place and Fells Point, Maryland, and an outer loop, which was 

between Fells Point and Fort McHenry. (See figure 1.) The water taxis, all pontoon-style 

vessels, transported passengers to local maritime attractions and to other points authorized 

by the City of Baltimore.1

According to the office manager for Seaport Taxi, when she arrived at work on 

March 6, “the weather was very nasty; it was raining a lot.” A small craft advisory, issued 

the previous day by the National Weather Service (NWS) Baltimore-Washington forecast 

office, was still in effect for all of Chesapeake Bay, including Baltimore’s Inner Harbor.2

Throughout the day, the Seaport Taxi office manager had her radios on to monitor 

message traffic from the company taxis and to listen for National Oceanic and 

Atmospheric Administration (NOAA) weather alerts. 

Seaport Taxi was also a subscriber to WeatherBug®, a Web-based source of 

neighborhood weather, severe storm alerts, and radar and camera images. The office 

manager said she listened throughout the day for the distinctive “beep” emitted by her 

office computer when WeatherBug® issued a bulletin, but heard none. She stated that, by 

about 1400, the sun had come out, and it was “pretty nice.” Later that afternoon, however, 

she started hearing raindrops striking a sign in the marina and looked north out her 

window. She said that she noticed that the sky was “very black” and that there was 

lightning to the north. 

1 At the time of this accident, Living Classrooms Foundation (Living Classrooms), a nonprofit 

organization headquartered at Baltimore’s Inner Harbor, owned Seaport Taxi. Information related to 

operating policies and practices appears later in this report, under “Operational Information.”

2 A small craft advisory for mariners is issued by the NWS when sustained winds and frequent gusts of 

18 to 33 knots (21 to 38 miles per hour) persist for 3 or more hours.
Figure 1. Each Seaport Taxi vessel followed one of two round-trip routes unless passenger traffic warranted otherw

between the Inner Harbor complex and Fells Point included two regular stops and two “request” stops, meaning pas

to disembark at these sites or customers on shore could telephone or radio to be picked up there. The outer originated at Fells Point, had one regular stop at Fort McHenry and six request stops in the Canton area.

INNER 

HARBOR

Harbor Place

Science

Center

Rusty

Scupper

Museum

of Industry

Tide Point

Fells

Point

Captain James

Landing

Harris Creek

Tindeco Wharf

Canton 

Waterfront

Park

Fort

McHenry

DH

WEST CHANNEL

MarriottWaterfront (Pier 7)

Aquarium

Pier 5

CANTON

KEY Outer loop, regular route Outer loop, “request” route Inner loop, regular route Inner loop, “request” route Capsize location Search area

N

O

R T H W E S T

H

A

R

B

O

R

Bay Cafe

Henderson’s

Wharf

EAST CHANNEL E

TURNING

BASIN

(Baltimore Marine Center)

Lighthouse Point
Factual Information 3 Marine Accident Report

About 1555, the office manager overheard a radio communication from the 

company’s senior captain on the water (senior captain) alerting the vessel operators on 

duty that a storm was coming through and to “use their discretion about tying up.” She 

said that she then checked the Doppler weather radar images on her computer, which 

indicated that a storm north of the area was moving south-southeast.3 She then radioed the 

fleet to advise the masters that Doppler images showed that the heaviest parts of the storm 

were north and south of their area and that it looked as if their area “might see a little 

sprinkle”; however, “All of a sudden, it was a torrential downpour.”

Events On Board the Lady D

About 1100 on March 6, Seaport Taxi had placed the Lady D (figure 2) into routine 

service, shuttling passengers back and forth on the outer loop between Fells Point and Fort 

McHenry.

Figure 2. The U.S. small passenger vessel Lady D (above), an 8-foot-wide by 36-footlong commercial pontoon boat, was certificated by the U.S. Coast Guard to carry 25 

people. The process by which the Lady D’s allowable load was determined is discussed 

in the “Vessel Information” section of this report.

3 Various news and weather websites obtain Doppler image and other information from the NWS to 

provide to their customers; however, because of the time taken to capture and display the images on the 

websites, typically from 3 to 10 minutes, the information displayed on the office manager’s computer did 

not reflect current conditions.
Factual Information 4 Marine Accident Report

About 1545, the Lady D, with an operating crew of a master and a mate, arrived at 

fireboat pier 1 next to Fort McHenry4 for the express purpose of transporting visitors at the 

fort back to Fells Point. As soon as the water taxi docked, Seaport Taxi’s fort coordinator, 

an employee responsible for managing the embarkation and debarkation of visitors, said 

that he opened the gate at the end of the pier, permitting waiting passengers to proceed to 

the boarding area. The Lady D’s certificate of inspection (COI), issued by the Coast 

Guard,5 limited the vessel’s occupancy to 25 persons. The mate counted the people as they 

sat down on one of the two benches that lined either side of the vessel until 23 passengers 

had boarded. Two couples were not permitted to board after the vessel was at maximum 

capacity. The master said that he verified the mate’s passenger count before departing. As 

the commercial pontoon taxi backed away from the fireboat pier about 1554, the master 

sent out a broadcast message to the fleet and to the fort coordinator that the Lady D was 

departing for Fells Point with 25 persons on board.6 The passengers included 3 children, 

ages 6, 7, and 8, and 20 adults, ages 23 to 60.7

The master and the mate indicated that the mate gave a safety briefing as they were 

departing.8 Most passengers indicated that they had received a safety briefing on previous 

voyages that day; however, none recalled receiving a safety briefing at the onset of the 

return voyage from the fort to Fells Point.

The master said that earlier that afternoon, about 1400, the winds were about 10 to 

15 knots, an estimate that he had based on “the way flags appeared on their poles.” He 

noted that as he was backing away from the pier, “the wind really started picking up.” He 

also observed some dark clouds west of the city. Neither the master nor the mate stated 

that he observed lightning. According to passengers and shore witnesses, it began to rain 

as the boat was departing, and then the weather began to deteriorate rapidly, with 

increasing winds and lightning. Shortly thereafter, the Lady D master received a radio 

communication from the senior captain who had heard thunder9 and whose boat began to 

4 The Fort McHenry pier was damaged, and Seaport Taxi had arranged with the Baltimore City Fire 

Department (BCFD) to permit fort visitors to embark and disembark at the nearby fireboat pier.

5 The Coast Guard certificates passenger vessels for commercial operation, documenting operating 

requirements and restrictions in the vessel’s COI.

6 Federal regulations at Title 46 Code of Federal Regulations (CFR) Part 185.504, “Passenger Count,” 

require, in part, that a vessel master keep a correct, written count of all passengers that embark on the vessel 

and that, before the vessel sails, this count be communicated verbally or in writing, and available ashore at 

the vessel’s normal berthing location or with a representative of the owner or operator of the vessel. In this 

instance, the Seaport Taxi fort coordinator maintained the passenger count.

7 From interviews and hospital records, the Safety Board determined that the average weight of the 

children was 55 pounds and the average weight of the adults was 184 pounds, which equated to an average 

occupant weight of 168.4 pounds.

8 Federal regulations at 46 CFR 185.506 require, in part, that, before getting underway on a voyage or as 

soon as practicable thereafter, the master will ensure that “suitable public announcements are made informing 

all passengers” where emergency exits and lifejackets are located and how lifejackets should be donned.

9 No area witnesses who were interviewed, including Seaport Taxi personnel, passengers, and 

Baltimore police, recalled seeing lightning before 1600. Reports issued by StrikeNet, an online lightning 

verification service, indicate that a lightning strike was recorded 6.6 miles north-northwest of Baltimore at 

1551. After that, multiple lightning strikes were recorded at 1555, including one 5.5 miles west of the 

accident site; one 8.5 miles northwest of the area; and one 8.1 miles west-northwest of the area.
Factual Information 5 Marine Accident Report

be buffeted by winds while en route from Harbor Place to Fells Point. The senior captain 

advised all vessels in service to tie up until the storm passed. The Lady D master next 

received a radio report from the Seaport Taxi office manager advising that radar indicated 

that the heaviest precipitation probably would not affect their area. The Lady D master 

then radioed the senior captain advising that he had already left Fort McHenry. Upon 

learning that the Lady D had departed, the senior captain suggested that its master divert to 

the Baltimore Marine Center or Henderson’s Wharf. (See figure 1.) 

Meanwhile, as the pontoon vessel moved farther out into the channel, occupants 

said that the boat began to roll in the waves. Safety Board investigators received varying 

accounts of how the Lady D handled in the wind. Some passengers reported that the wind 

was initially off the pontoon vessel’s port side but that the wind direction began to shift 

counterclockwise. The mate stated that the master initially held the boat into the wind as 

the gusts intensified; however, “The wind then picked up even stronger and blew him off, 

threw him like in a spiral.” The master also stated that he had difficulty handling the boat 

once the wind picked up and the waves increased. He said that he could not even turn in 

the direction of the Baltimore Marine Center and that he was “almost pushed out” to an 

area “opposite the Bay Cafe”; however, “I couldn’t even get there.” 

Personnel at Naval Reserve Center Baltimore, located near Fort McHenry, were 

watching the Lady D as the water taxi was attempting its transit and was being buffeted by 

the wind and waves. They said that, at one point, the vessel appeared to be heading south.

One passenger sitting on the port side of the Lady D said, “The wind came across 

our back, and keeled us up...[and] the people on the starboard side immediately, out of 

instinct, came over to try and right the boat, and it helped some. The [master] brought the 

boat around into the wind, to level the boat out.” Meanwhile, the mate asked the 

passengers on the starboard side to return to their bench. Passengers said that he nervously 

joked that the lifejackets were under the benches. Moments later, the vessel heeled to 

starboard again, continued over onto its starboard side, and capsized. Some passengers 

estimated that the capsizing sequence took only a few seconds. 

Escape and Rescue

Immediately after the capsizing at 1558, the personnel at the Naval Reserve Center 

Baltimore who had been watching the Lady D called 911 to report the accident. 

Detachment 106, Fleet and Industrial Supply Center Norfolk, which was on drill status at 

the center, then launched a mechanized landing craft (LCM-8) with 19 reservists on board 

to the accident site. The LCM-8 was the first vessel on scene to render assistance, arriving 

about 1606. Meanwhile, the 911 call was relayed to the BCFD; however, a marine 

firefighter at the BCFD fireboat station had witnessed the accident and already alerted 

personnel at the station. The BCFD dispatched a 30-foot fire rescue boat to the scene to 

render assistance. Soon after, Baltimore City Police Department (BCPD) boats joined the 

other rescue vessels at the site of the capsizing. By 1603, the BCFD dispatcher had 

ordered various marine and shore-based assets totaling 43 rescue and medical personnel to 

respond during the initial response. In addition, upon determining where the accident 
Factual Information 6 Marine Accident Report

voyage had originated, the BCPD dispatched patrol officers to Fort McHenry to determine 

from Seaport Taxi’s fort coordinator how many people had been on board the Lady D.

Seaport Taxi sent its fleet captain and the senior captain to the area to assist. In 

addition, the water taxi company contacted Coast Guard Sector Baltimore, which had 

learned of the capsizing when watchstanders overheard message traffic about the accident 

while monitoring VHF (very high frequency) channel 16. The Coast Guard contacted the 

BCFD and, after being briefed about the capsizing, dispatched search and rescue (SAR) 

assets to the scene. 

Meanwhile, the Lady D’s survivors said that after the pontoon boat overturned, 

water quickly began to fill the cabin. Several survivors said that they had problems getting 

out of the vessel. The Lady D had two doors: a sliding door at the bow that slid to the side 

and a hinged door at the stern that swung open. A passenger seated near the bow said that 

he tried to exit the door there; however, he could not get it to slide open. Another 

passenger who was seated near the stern door said that he thought that he exited through 

the back door because while swimming to the water’s surface, he struck the outboard 

engine. One passenger who was seated amidships was able to escape through a window 

opening. He later stated, however, that it never occurred to him to use a door, which 

should have been “an obvious choice.”

The Lady D had 12 slider windows, six along the port side of the vessel and six 

along the starboard side. (See figure 2.) Each slider window had one 24-inch-wide fixed 

sash and one 24-inch-wide sliding sash. One passenger said that he kicked on the window 

to get it to open. Another passenger said that he tried to open a window, but it seemed to 

be locked.10 He then noticed that the man next to him slid a window to the side to open it, 

whereupon he slid open his own window. He said that by this time, he could not see 

anything in the murky water. He felt a “sensation,” but was not sure whether it was water 

pushing against him or whether “the window just ... caved in....” He then felt his way out 

of the boat. A female passenger also stated that while swimming down in the overturned 

deckhouse to find an exit, she felt and pushed on a window, only to have it “float away,” 

which led her to believe that it was no longer attached to the boat.

Navy reservists said that once the LCM-8 reached the water taxi, which was 

floating upside down, they observed a “lot of lifejackets” floating around the boat. All but 

two survivors had climbed atop the pontoons or the underside of the deck. The remaining 

two survivors were still in the water but holding onto the pontoon vessel. None of the Lady 

D occupants had donned a lifejacket; however, one of the people in the water had grabbed 

hold of one. The Lady D’s master later told investigators that he thought he was not going 

to be able to escape the vessel; however, when he saw a lifejacket floating inside the 

deckhouse, he grabbed it and held onto it as he pushed toward “a light.” He said that as he 

exited the boat, the lifejacket pulled him up to the water’s surface.

10 The Seaport Taxi director said that originally locks had been on the windows; however, over time and 

with continued use, the locks had broken off, and at the time of the accident, no window on the Lady D could 

be locked.
Factual Information 7 Marine Accident Report

A few reservists, wearing their own lifejackets, jumped into the water to assist the 

accident victims. One reservist who entered the water without his lifejacket subsequently 

donned one of the Lady D’s lifejackets during the rescue effort to ensure that he remained 

afloat in the cold water. The reservists tied their craft to the water taxi and escorted the 

survivors onto the LCM-8. Upon learning that passengers were still trapped inside the 

water taxi, reservists untied the lines holding the vessels together and lowered the 

LCM-8’s loading ramp into the water and used it as a lever to raise one side of the 

capsized water taxi. Witnesses said that this action freed three trapped passengers, 

including two adult women and a little girl. 

Responders to the capsizing retrieved and transported 22 vessel occupants to shore 

within 30 minutes of the Lady D’s overturning. Of the recovered passengers, 2 died at the 

hospital: the first victim within 2 hours of the capsizing and the second victim within 72 

hours. A third passenger continues to be under long-term medical care. The remaining 

survivors were treated by local hospitals for minor injuries and released.

Three passengers were not found on the day of the accident. Their bodies were 

located and recovered from the bottom of the harbor about 1 week after the accident. 

Injuries

The injuries sustained by the Lady D’s crew and passengers, shown in table 1, are 

categorized according to the injury criteria of the International Civil Aviation 

Organization (ICAO). The Safety Board uses the ICAO injury criteria in most of its 

accident reports. A discussion of the injuries appears later in this report, under “Medical 

and Pathological Information.”

Table 1. Injuries sustained by the Lady D occupants

Injury Type Crew Passengers Total

Fatal 0 5 5

Serious 0 4 4

Minor 2 10 12

None 0 4 4

Total 2 23 25

Title 49 CFR section 830.2 defines a fatal injury as: any injury that results in death within 30 days of the accident. 

It defines serious injury as that which requires hospitalization for more than 48 hours, commencing within 7 days 

from the date the injury was received; results in a fracture of any bone (except simple fractures of fingers, toes, 

or nose); causes severe hemorrhages, nerve, muscle, or tendon damage; involves any internal organ; or 

involves second or third degree burns, or any burn affecting more than 5 percent of the body surface.

Damages

Seaport Taxi elected not to repair and return the Lady D to service following this 

accident. A company spokesperson estimated the value of the pontoon-style small 

passenger vessel at $35,000. Additional information about the damage to the Lady D

appears later in this report, under “Wreckage.”
Factual Information 8 Marine Accident Report

Crew Information

Regulatory Requirements

In certificating a small passenger vessel for commercial operation, the Coast 

Guard determines the number of crewmembers needed and their required competencies by 

considering, among other things, the size of the vessel, its route, the type and horsepower 

of the vessel’s propulsion machinery, the number of passengers the vessel may carry, the 

type and location of lifesaving equipment installed on the vessel, and the hazards specific 

to the route and service. In the case of the Lady D, its COI stipulated that the pontoon taxi 

have one licensed crewmember: the master. According to Seaport Taxi officials, they 

usually assigned two crewmembers to each vessel, a licensed master and an unlicensed 

mate. On the day of the accident, the Lady D had two licensed masters on board, one 

serving as captain and the other serving as mate.

Master

General. The master, age 74, had taken up boating in 1995. The following year, he 

bought his first boat, a diesel-powered 46-foot Bayliner. In July 2001, he purchased a 

gasoline-powered 34-foot Sea Ray. Concurrently, he took several courses in maritime 

education, including a 48-hour boating course conducted by the U.S. Coast Guard 

Auxiliary, several courses conducted at the Virginia Maritime Institute, a course on twinengine boat handling conducted by the Power Boat Division of the Annapolis Sailing 

School, and courses conducted at the Baltimore Community College.

On April 30, 2002, the Coast Guard issued him a U.S. Merchant Marine Officer 

license authorizing him to serve for 5 years as a master of steam or motor vessels of not 

more than 50 gross registered tons (domestic tonnage) upon inland waters. The license 

also authorized him to engage in commercial assistance towing.

In July 2002, he was hired by Seaport Taxi to work as a part-time captain, his first 

job in the maritime industry. After completing Seaport Taxi’s orientation training and 

boat-handling exercise,11 he was assigned to the Lady D and operated that vessel 

thereafter, generally on weekends but sometimes full-time during the peak season.

The Seaport Taxi director indicated that the master was “very, very good at 

handling” a vessel the size of the Lady D, particularly when maneuvering in tight quarters 

such as the 20-foot fairway,12 which can be “a little bit of a challenge in the wind.” 

Company officials indicated that they had not trained the Lady D master to operate the 

larger vessels in Seaport Taxi’s fleet. The fleet captain stated that the decision not to 

qualify the Lady D master on larger boats had to do with staffing needs and the expense of 

training. He said that the company had plenty of masters to drive the larger boats and that 

qualifying the Lady D master on the larger vessels meant that the company would have to 

11 For additional information about the Seaport Taxi training program, see “Operational Information.”

12 In nautical terms, “fairway” refers to either the navigable channel or the usual course that a vessel 

travels through a harbor or coastal waters. In this case, the Seaport Taxi director is referring to the waterway 

between the piers that the pontoon vessel traveled to reach its docking place.
Factual Information 9 Marine Accident Report

take a large boat out of commercial service when the master was available, which was 

usually the weekends when passenger traffic was greater. The fleet captain also stressed that 

the Lady D master operated his boat well. 

Medical. The master told Safety Board investigators that he took no prescription 

drugs. He said, however, that he had completed taking a prescribed course of antibiotics 

about 10 to 12 days before the day of the accident. He indicated that he had worn a hearing 

aid to discriminate sounds for about 3 years. Medical records indicate that his eyesight 

was 20/38, corrected to 20/20. 

Work/Rest History. The master indicated that he normally awoke each day at 

0600 and went to bed at 2230. As noted earlier, he typically worked weekends. He 

indicated that he did not change his routine before the accident. He said that he went to 

bed on Thursday and Friday, March 4 and 5, about 2215. On Saturday, March 6, the day of 

the accident, he awoke at 0645 and reported to work at 0930, a half hour before his shift 

was scheduled to begin.

Mate

General. The mate, age 55, had completed a November 4, 1997, boating course 

conducted by United States Power Squadrons, a nonprofit educational organization whose 

districts teach sail and power boating classes. In May 2003, Seaport Taxi hired him as a 

mate in a “seasonal/contractual hire” status, and he originally worked about 15 hours per 

week. In mid-2003, Seaport Taxi granted the mate limited authorization to learn boathandling skills while he studied for his master’s license. The company form, 

“Authorization to Operate Seaport Taxi Vessels While in Training for Captains License,” 

required the master of the respective vessel to supervise the mate and be responsible for 

his actions. The mate was not allowed to operate the vessel with passengers on board until 

the master considered him competent to do so.

When the mate applied for his master’s license, Seaport Taxi forwarded to the 

Coast Guard Regional Examination Center in Baltimore a “Sea Time Letter,” which 

indicated that the mate had operated a vessel13 for 52 underway days of approximately 8 

hours each between May and October 2003 on five vessels in the company fleet. 

On November 20, 2003, the Coast Guard issued the mate a U.S. Merchant Marine 

Officer license authorizing him to serve for 5 years as a master of steam, motor, or auxiliary 

sail vessels of not more than 50 gross registered tons (domestic tonnage) upon inland 

waters. He was also authorized to engage in commercial assistance towing. The license 

carried a vision waiver: “Corrective lenses to be worn with spare glasses carried on board.”

Medical. The mate told Safety Board investigators that he took cymetadine 

(Zantac type) for acid reflux disease. 

13 Until the Coast Guard issued the mate a master’s license, he could operate a vessel only under the 

supervision of a licensed master. 
Factual Information 10 Marine Accident Report

Work/Rest History. The mate said that he awoke at 0730 on Thursday, March 4, 

performed maintenance from 0930 to 1730, and was asleep by 2400. The following day, 

he did not work and was at home attending to his own boat. The night before the accident, 

he was asleep by 2300. On Saturday, he awoke at 0730 and was at work by 0915.

Vessel Information

Regulatory Requirements for Small Passenger Vessels

Federal regulations pertaining to commercial pontoon vessels are contained in 46 

CFR Subchapter T, “Small Passenger Vessels (Under 100 Gross Tons).”14 Subchapter T 

stipulates that to operate a small passenger vessel, the owner/operator must have various 

programs and policies, maintain various documents, and install and maintain various 

navigation and radio equipment, lifesaving equipment, and firefighting equipment on that 

vessel. The Federal regulations also stipulate that an existing vessel must comply with the 

intact stability15 regulations applicable to it as of March 10, 1996. 

The Coast Guard official with the oversight responsibility for ensuring compliance 

with marine safety standards, including the requirements in Subchapter T, is the Officerin-Charge, Marine Inspection (OCMI) at each Marine Safety Office (MSO), which is a 

local Coast Guard office having jurisdictional authority for a specific area. Any restriction 

or contingency that the OCMI deems necessary for the safe operation of a vessel is listed 

on its COI.

The Lady D

Vessel History. The Lady D was built in 1996 for Baltimore Harbor Shuttle, LLC, 

by the boat builder formerly known as Susquehanna Santee Boatworks,16 headquartered in 

Pennsylvania. The vessel was the third in a design series of four commercial pontoon 

boats measuring 36 feet long by 8 feet wide. Because the Lady D’s date of build was 

March 18, the pontoon boat was required to comply with Subchapter T regulations for 

new vessels that were effective on March 10, 1996.

The first boat in the series, the Fells Point Princess, was built by an individual in 

his backyard, and the following three in the series—the Raven, the Lady D, and the Misty 

Harbor II—were built by Susquehanna Santee Boatworks. After the Lady D was launched 

14 Subchapter T was promulgated in 1957 as a result of Public Law 519, which was enacted by the U.S. 

Congress following the capsizing of the M/V Pelican off Long Island, New York. The small commercial 

fishing vessel, which was designed to safely accommodate 30 persons, was carrying 64 people when it 

capsized in heavy seas. Because of the vessel’s overloaded condition, the sea state, and the failure of the 

boat’s occupants to don lifejackets, 45 people died. 

15 Stability is the tendency of a vessel to remain upright or its ability to return to the normal upright 

position when heeled by the action of weight movements, waves, wind, and so forth.

16 In October 1998, Susquehanna Santee Boatworks was purchased by another company, which 

assumed its name and assets, including files on the Lady D. Thus, the company named as a party in this 

investigation was not the builder of the Lady D. 
Factual Information 11 Marine Accident Report

in March 1996, Baltimore Harbor Shuttle operated it as a water taxi in Baltimore Harbor. 

In 2000, Living Classrooms, the parent company of Seaport Taxi, purchased the Baltimore 

Harbor Shuttle fleet, and the Lady D continued to operate in the Baltimore Harbor area, 

primarily on Seaport Taxi’s outer loop between Fells Point and Fort McHenry. 

Vessel Construction and Design. The vessel’s pontoons, hull, and deckhouse 

(figure 2) were constructed of marine-grade aluminum. The hull consisted of two 

cylindrical pontoons connected by an I-beam framework and deck structure. The pontoons 

were constructed in seven sections, with a transverse bulkhead between each section. The 

deckhouse structure measured 24 feet 1/2 inch long and 7 feet 8 inches wide and had a 

canopy that measured 7 feet high at the sides and 7 feet 6 inches at the peak.17 The sides of 

the deckhouse each had a waist-high bulkhead, above which were six slider windows 

having one fixed sash and one sliding sash. Each window sash measured 42 inches high 

and 24 inches wide. 

The vessel had two doors, located at either end of the deckhouse. Passengers and 

crew embarked on and disembarked from the vessel at the bow (figure 2) by using a ladder 

attached to the forward area of the vessel. They entered or exited the deckhouse through 

its forward door, which slid to the side. The door at the aft end of the deckhouse swung 

outward. The aft door provided the crew with ready access to the outboard motor; 

however, the aft door could also be used for egress in an emergency. A passenger bench 

extended along each side of the vessel. The operator’s console was forward of the bench 

seat on the starboard side of the vessel. The mate normally stood to the port of and slightly 

aft of the master. Vessel particulars are listed below.

Vessel type Pontoon, small passenger

Maximum capacity 25 persons

Gross tons 2

Length 36 feet

Beam 8 feet

Pontoons (2) 2-foot-diameter circular cross-sectioned structures 

constructed of marine-grade aluminum 

Propulsion type Single, 4-stroke outboard, gasoline fuel, 90-

horsepower Honda motor

Electrical power 12-volt d.c. engine-driven alternator and single battery

Fuel capacity About 40 gallons (Lady D was constructed with one 

20-gallon fuel tank; Seaport Taxi added a second fuel 

tank)

Steering system Hydraulic

Throttle/clutch control Independent, 2 cable

Communication system 1 VHF radio, Standard Horizon Eclipse+, model 

GX1250SA, fitted with a NOAA weather alert feature

17 Estimated measurements of the deckhouse and its elements are based on a portion of the Lady D’s 

bulkhead that was recovered after the accident and on photographs of the Misty Harbor II, the fourth boat in 

the series and a pontoon vessel of comparable design.
Factual Information 12 Marine Accident Report

Normal cruising speed for the Lady D was 6 to 7 knots; maximum speed was about 

12 knots.

Safety Equipment

Based on regulatory requirements,18 the Lady D’s COI indicated that the vessel 

was required to carry the following equipment for a load of 25 persons:

Lifejackets (adult) 25

Lifejackets (child) 3

Ring buoys (total) 1 

With lights 1

With line attached 1

The COI indicated, “The minimum number of child-size life preservers required is 

three. If more than three children (or persons weighing 90 pounds or less) are carried, 

additional child-size life preservers shall be carried so that the vessel has an approved life 

preserver suitable for each child onboard.”

According to the Seaport Taxi fleet captain, the Lady D carried 25 adult-size 

lifejackets and 10 to 11 child-size lifejackets. The adult-size lifejackets were stowed under 

benches along the starboard side and most of the port side. The child-size lifejackets were 

stowed forward under the portside bench. A placard showing how to don a lifejacket was 

posted on a bulkhead inside the deckhouse.

In addition to the lifejackets, the Lady D was equipped with a ring buoy that had a 

50-foot-long attached throw-line and a strobe light on a 9-foot-long detachable line. The 

vessel also carried two equipment boxes: one for the master and the other for the mate. 

The master’s box contained, in part, several items for minor emergencies, including two 

flashlights, a first aid kit, and an air horn. 

Stability Certification

Evolution of Regulatory Stability Standards. The original stability rules for 

small passenger vessels in 46 CFR Subchapter T were based, in part, on Subchapter H, 

“Passenger Vessels,” which contained the standards for passenger ships that were over 65 

feet in length or carried more than 150 passengers. The regulations for evaluating the 

stability of large passenger vessels stipulated that a ship undergo an inclining experiment to 

determine the vertical and longitudinal location of the vessel’s center of gravity and 

displacement in an unloaded condition and to verify its intact stability. This process involves 

deliberately heeling the vessel to varying angles and performing a series of calculations. The 

vessel owner typically has to hire a naval architect to conduct an inclining experiment.

18 Federal regulations at 46 CFR 180 stipulate the lifesaving equipment and arrangements required for 

passenger vessels. Regarding the provision for lifejackets, the regulation states that an adult-size lifejacket 

must be provided for each person carried on board and that the number of child-size lifejackets must equal at 

least 10 percent of the persons permitted on board or such greater number as necessary to provide a 

lifejacket for each person who is smaller than the lower size limit of an adult-size lifejacket. 
Factual Information 13 Marine Accident Report

The promulgation of Subchapter T in 1957 resulted in a large number of existing 

small passenger vessels being required to meet the stability standards contained in 46 CFR 

Part 179. Recognizing that the design of most small passenger vessels was far simpler than 

that of large passenger vessels, the Coast Guard supplemented Subchapter T with a 

navigation and vessel inspection circular (NVIC) containing a simplified stability test 

(SST) that could be used in lieu of an inclining experiment to certificate the allowable 

passenger load for “T-boats,” as vessels covered by Subchapter T are termed. The NVIC 

included passenger weight criteria for determining the allowable load used to calculate the 

vessel’s stability. The assumed weight per passenger was 160 pounds, except that if the 

vessel was to operate on protected waters, the assumed weight per passenger was 140 

pounds, based on a passenger mix of men, women, and children. (Further discussion of the 

SST protocol appears in the following section.) The 1957 version of Subchapter T also 

established limiting factors for determining the maximum number of passengers permitted 

on any vessel, including the length-of-rail criterion, the deck-area criterion, and the fixedseating criterion.19

The Coast Guard’s 1960 revision to Subchapter T included the SST for monohull 

vessels carrying more than 49 but not more than 150 persons. Subchapter T as revised did 

not contain stability standards for small passenger vessels carrying fewer than 50 

passengers; however, if an OCMI questioned the stability of a vessel carrying more than 6 

but fewer than 50 passengers, the Coast Guard could require that the vessel undergo a 

stability test. The stability rules gave an OCMI the discretionary authority to accept 

alternatives, equivalents, or departures from the standards when it could be shown that 

special circumstances warranted such actions, especially for existing vessels. In addition, 

departure from the stability requirements was permitted if, in the OCMI’s judgment, the 

vessel was “of a type and structure which experience has demonstrated is safe for the 

proposed service.”

At this time, pontoon vessels were categorized as passenger vessels of “unusual 

design” and if their stability was questioned, they typically were required to meet the 

stability standards in Subchapter H. Upon recognizing that more pontoon vessels were 

being used for commercial passenger service, in the late 1960s, Coast Guard headquarters 

revised Volume 4 (“Technical”) of its Marine Safety Manual to provide the OCMIs with a 

pontoon (passenger vessel) simplified stability test (PSST). The policy in the manual 

outlined the recommended test protocol for pontoon-type small passenger vessels under 

65 feet in length with operations restricted to protected waters. The PSST protocol, in 

general, followed that of the SST; however, because of the design differences between 

monohull and pontoon vessels, the formula and procedure for verifying the allowable load 

differed. (See following section on test protocols.)

The Coast Guard continued in its rulemaking efforts for small passenger vessels 

and on January 30, 1989, issued a notice of proposed rulemaking (NPRM) proposing that, 

except for those vessels that had to undergo an inclining experiment, all small passenger 

vessels carrying more than 6 passengers be required to pass a stability test. The NPRM 

19 The limiting factors are contained in 46 CFR 176.
Factual Information 14 Marine Accident Report

proposed including in the regulations a PSST that was substantially the same as the 

version in the Marine Safety Manual. The NPRM addressed all pontoon vessels that were 

not more than 65 feet in length, did not carry more than 150 passengers, and operated only 

in protected waters. On September 24, 1990, the PSST test proposed for Subchapter T was 

revised to limit its applicability to vessels with two pontoons. This rule pertaining to 

pontoon vessel stability testing was included in the revision of Subchapter T that was 

finalized on January 10, 1996.

Testing Protocols. The purpose of a simplified stability test is to verify a vessel’s 

intact stability for the carriage of passengers. The conduct of either an SST or a PSST is 

the responsibility of vessel owners or their representatives. A Coast Guard inspector is 

present to oversee and verify the validity of the test. Generally speaking, the protocols for 

both tests are similar, except as noted in the following discussion. 

Pretest Actions. In advance of the actual test, a determination is made of the 

passenger allowance. The estimated number of passenger that a vessel can carry is 

calculated based on a review of the vessel’s drawings or physical measurements using one 

of the following criteria:

• Length-of-rail criterion: One passenger for each 30 inches of rail at the sides 

and stern.

• Deck-area criterion: One passenger per 10 square feet of deck area, excluding 

spaces listed in 46 CFR 176.113, which include, among other areas, concession 

stands, toilets, lifesaving gear storage spaces, required aisle area, and fixed 

seating areas.

• Fixed-seating criterion: One passenger per 18-inch width of fixed seating.

Calculation of Heeling Moment(s). The SST protocol has always included 

calculations for wind heeling moment20 and passenger heeling moment to determine 

whether a vessel, as built and proposed to be operated, has a minimum level of stability. 

Before the Lady D accident, the PSST protocol included a calculation only for passenger 

moment. The Coast Guard has since issued a policy letter changing the PSST to include a 

wind heeling moment calculation.21

In the test protocols, the passenger heeling moment is calculated based on the 

beam of the vessel and the number of passengers carried. A wind heeling moment is 

calculated based on the projected lateral surface of the vessel exposed to wind pressure. 

Stability Proof Test. The heeling moment calculations are used to physically 

conduct a stability proof test on the vessel. The calculated moment that is greater (wind or 

20 In physics, a “moment” is the product of a quantity (such as a force) and the distance to a particular 

axis or point.

21 “Other Information” discusses the postaccident actions taken by the Coast Guard as a result of the 

Lady D accident. One measure was the development of a job aid for conducting a stability test, which 

appears in appendix B of this report. 
Factual Information 15 Marine Accident Report

passenger) is applied to the vessel, and the vessel’s loss of freeboard22 is measured. The 

physical proof test simulates a full load using the number of passengers allowed by the 

vessel design and the required crew multiplied by the weight standard (140 pounds per 

person on protected waters). The SST standard allows for only one-half of the freeboard 

(or 14° of heel, whichever is less) to be submerged during the proof test. If the vessel’s 

loss of freeboard from heel is greater than stipulated in the standard, it fails the test. 

The PSST in effect before 2005 used only a calculation for passenger heel in the 

proof test. The physical proof test involves moving a simulated full load test weight based 

on the estimated number of occupants multiplied by the weight standard (140 pounds per 

person on protected waters). The test weight is first centered on the vessel and then moved 

to the extreme outboard transverse and longitudinal edges of the vessel. The vessel must 

pass a deck edge immersion test for longitudinal weight movements and a reserve 

buoyancy test for transverse weight movements. If the deck edge of the pontoon vessel 

submerges during the longitudinal immersion test or the vessel loses more than 50 percent 

reserve buoyancy during the transverse reserve buoyancy test, the pontoon vessel fails the 

test.

If a vessel fails the physical proof test in the SST or PSST protocol, the owner 

must then elect to make one or more of the following changes to reduce the heeling 

moment so that the vessel can pass the proof test: carry fewer passengers, ballast the 

vessel, or reduce the vessel’s wind profile area, if applicable. The SST and PSST 

calculations and proof tests ultimately determine the number of occupants permitted on a 

vessel, unless it has physical characteristics (fixed seating, rail length, or deck area) that 

further limit passenger capacity. Table 2 compares the two tests.

Table 2. Comparison of simplified stability test and pontoon simplified stability test

Test Component SST PSST

Condition of vessel Specified in job aid Specified in new PSST job aid

Test weight Equivalent to total passenger load Same

Wind heel moment 

calculations

Based on lateral area affected by 

wind

Before Lady D accident: none

After Lady D accident: 

 (a) 300 x length

 (b) same as SST if wind heel > 

passenger heel 

Passenger heel moment Function of beam ÷ 6 Function of beam ÷ 2*

Pass/fail

Transverse 14° of heel or 1⁄2 freeboard, 

whichever is less

Loss of reserve buoyancy** 

cannot be more than 50% 

Longitudinal None Deck edge cannot submerge

* Passenger heel for PSST is 3 times the requirement for the SST. Total test weight must be moved from centerline to 

deck edge at side of vessel.

**In the case of the PSST, reserve buoyancy is the nonsubmerged internal volume of the pontoon over which the test 

weight is moved.

22 Freeboard is the distance from the vessel’s deck to the surface of the water.
Factual Information 16 Marine Accident Report

Lady D Certification. As noted earlier, the Lady D was the third in a series of 

vessels built for Baltimore Harbor Shuttle. On August 12, 1992, the first vessel in the 

series, the Fells Point Princess, was subjected to a stability proof test to establish the 

maximum number of persons that could be carried on board. 

According to Coast Guard officials, field notes indicate that the test was not 

conducted in accordance with the PSST protocol contained in the Marine Safety Manual, 

but rather in accordance with CG-4006, a simplified stability test form, or job aid, that was 

applicable to monohull vessels. In the SST for monohull vessels, both a wind heeling 

moment and a passenger heeling moment are calculated. The larger of the two moments is 

then applied to the vessel by shifting weights a distance necessary to achieve that moment. 

A review of the test form shows that during the stability proof test of the Fells Point 

Princess, the passenger heeling moment was not properly calculated, and, as a result, the 

calculated wind heeling moment exceeded the passenger heeling moment. The calculated 

wind heeling moment was then applied to the vessel during the test.23

Based on the results of the 1992 stability proof test, the Coast Guard issued a 

stability letter and COI allowing 25 persons to be carried aboard the Fells Point Princess. 

Over the next 4 years, Susquehanna Santee Boatworks constructed the Raven, the Lady D,

and the Misty Harbor II. Although the four vessels were the same general size and had the 

same configuration, their deckhouse enclosures differed. The first two vessels (the Fells 

Point Princess and the Raven) had open sides in the deckhouse and no windows. The next 

two vessels (the Lady D and the Misty Harbor II) were fitted with glass windows.24

Despite the design differences, none of the three subsequent vessels was subjected to a 

stability proof test. Rather, they were granted sister vessel status,25 and each was allowed 

to carry the same maximum number of persons (25) as the Fells Point Princess. 

Before the capsizing, the Lady D had last received a COI, good for 5 years, from 

the Coast Guard on February 28, 2002. The COI specified that the vessel carry no more 

than 25 persons “not more than 1,000 feet from shore under reasonable operating 

conditions.” Following the accident, the Coast Guard conducted tests of the sister vessel 

Patricia P (formerly the Fells Point Princess) and identified that the maximum passenger 

load permitted by the Lady D’s COI was in error. Additional information about the Coast 

Guard postaccident actions appears later in this report, under “Other Information.”

23 Review of the test form after the Lady D accident showed that if the passenger heeling moment had 

been being properly calculated, it would have exceeded the calculated wind heeling moment, which means 

that it should have been applied during the test.

24 In a postaccident study contracted by the Safety Board, the weight of the Lady D’s windows and 

doors was estimated to be in excess of 400 pounds. See “Tests and Research.”

25 The Coast Guard Marine Safety Manual provided guidance on when a vessel could be deemed to be 

a sister vessel. In chapter 6 D, the manual states “The following general guidelines have been developed to 

provide guidance and to help keep the determination of ‘sister vessel’ as uniform as possible: the previously 

inclined vessel and the proposed sister vessel should have been built within approximately 2 years from one 

another; the vessels must be built by the same shipyard; and the same basic drawings should have been used 

in the construction of both vessels.” Additional Coast Guard guidance on waiving of stability tests based on 

sister vessel status was provided by NVIC No. 14-81 and stability regulations for inspected vessels at 46 

CFR 170.175. 
Factual Information 17 Marine Accident Report

Wreckage

During rescue efforts, the crew of the responding Navy vessel lifted one side of the 

Lady D by positioning the bow gate of the LCB-8 under one of the Lady D’s pontoons. As 

a result, investigators could not readily distinguish what damage to the vessel might have 

been caused before or during the capsizing and what might have been caused by the 

recovery efforts.

When the Lady D was righted on March 7, the day after the accident, investigators 

found that the wreckage comprised only the deck, pontoons, engine, fuel tanks, operator’s 

console, and boarding ladder (figure 3). Part of the bulkhead from the aft end of the 

deckhouse was partially attached to the aft deck. To right the vessel, divers cut this partial 

piece loose. The rest of the deckhouse was missing and never recovered. 

Figure 3. Lady D after being righted the day after the accident. Attached to the deck are 

airbags that were used to help right the vessel. Most of the deckhouse was missing and 

never recovered. 

The port passenger bench was still attached to the deck of the wreckage. The 

starboard passenger bench was missing and was never recovered. The canopy section of 

the deckhouse was discovered during sonar searches of the harbor but was not recovered. 

During a wreckage survey performed on March 9, investigators found the master’s 

chair nearly detached from its mounting base and tilted to the starboard side. The 

starboard pontoon had damage on its aft outboard side (a dent and a hole). The steering 
Factual Information 18 Marine Accident Report

system was found to operate satisfactorily, but the cover from the throttle/clutch control 

mechanism was missing. Investigators did not test the vessel’s engine or VHF radio 

because they had been submerged about 24 hours. 

Two months after the accident, on May 11, 2004, the Safety Board contracted with 

an engineering consulting firm, John J. McMullen Associates, Inc. (JJMA),26 to perform 

an additional survey of the Lady D wreckage. The contractor began by suspending the 

Lady D in a travel lift, visually examining the vessel, and measuring the various 

components. Damage to the starboard pontoon was observed, with water leaking from the 

damaged area. The Seaport Taxi director stated that the damage had occurred during 

rescue operations after the capsizing. Both pontoons were checked, but only the aftmost 

section of the starboard pontoon showed evidence of water. 

To drain all the water out of the pontoon, a small hole was drilled in the hull. (The 

vessel was hanging in the travel lift with the stern lower than the bow.) The hole was then 

plugged with a screw and gasket, and the damaged areas were sealed with epoxy. When 

the epoxy had set, the boat was launched and freeboard readings were taken at the bow, 

amidships, and stern of the vessel and at the aft ends of both pontoons. 

Waterway Information

The Baltimore Harbor areas, located at the head of the Patapsco River, are 

accessed through a series of channels. The accident occurred in the Northwest Harbor near 

a floating aid to navigation (“NH”) marking the entrance to the West Channel from the 

East Channel. The West Channel extends 0.8 mile in a northwesterly direction to a turning 

basin near the Inner Harbor, Baltimore’s central tourist location and the terminus of the 

Patapsco River. In the Northwest Harbor area, the operating depth for vessels is 21 to 25 

feet.27 According to NOAA chart 12281, the East Channel turning basin, located close to 

the accident site, has a depth of 49 feet at mean lower low water. The area just northeast of 

the navigation aid marking the entrance to the West Channel has a water depth decreasing 

to 15 feet along the west side of the turning basin.

The mean range of tide is 1.1 feet at Baltimore. Prolonged winds of constant 

direction may cause substantial variation in the tide. Currents in the harbor are 0.8 knot on 

the flood and ebb. The verified water level at 1600 for Fort McHenry was 1.12 feet above 

26 On April 1, 2005, JJMA was acquired by Alion Science and Technology, another engineering firm 

that provides support services to the government and the commercial maritime industry. The Safety Board 

subsequently tasked Alion Science and Technology, JJMA Maritime Sector, to evaluate the intact static and 

dynamic stability of the Lady D, which is discussed later in “Tests and Research.”

27 National Oceanic and Atmospheric Administration, National Ocean Service, United States Coast 

Pilot, Vol. 3 (Atlantic Coast: Sandy Hook, NJ, to Cape Henry, VA), 38th ed., 2005, p. 358.
Factual Information 19 Marine Accident Report

mean lower low water.28 Currents near Fort McHenry and the Northwest Harbor entrance 

are described as weak and variable.29

Management Information 

Parent Organization.

At the time of the accident, Seaport Taxi operated under the auspices of the Living 

Classrooms Foundation (Living Classrooms), a nonprofit organization whose mission is to 

provide experienced-based training, with emphasis on serving at-risk youth. In 1999, 

Living Classrooms created the National Historic Seaport of Baltimore (NHS) to oversee 

the foundation’s maritime assets and to partner with the owners of other maritime 

attractions in and around Baltimore’s Inner Harbor. (See table 3.) According to a 

spokesman, the following year, the NHS purchased Baltimore Harbor Shuttle, an existing 

water taxi company servicing the area, as a way to link all the partnership sites. The NHS 

then renamed the shuttle service Seaport Taxi.

Table 3. Organization of National Historic Seaport of Baltimore

NHS Assets NHS Affiliates

Baltimore Marine Museum and its historical 

vessels and structures as follows:

U.S. Coast Guard Cutter Taney, 

Lightship LV#116 Chesapeake,

U.S. Submarine Torsk,

Seven Foot Knoll Lighthouse

Baltimore Museum of Industry 

Top of the World

Fort McHenry National Monument and Historic Shrine 

(National Park Service)*

U.S.S. Constellation Museum Star-Spangled Banner Flag House

Seaport Taxi Civil War Museum (Maryland Historical Society)

Sail Baltimore/Visiting Ships Program

*NHS manages the Patriots of Fort McHenry, a community group that helps with educational activities and funds 

miscellaneous activities such as fireworks displays not paid for by the Federal government.

Following the accident, Living Classrooms ceased its Seaport Taxi operation and 

entered into a partnership agreement with Ed Kane’s Watertaxi Service to provide shuttle 

service. 

28 NOAA-National Ocean Service Center for Operational Oceanographic Products and Services, “Tides 

Online” <http://tidesonline.nos.noaa.gov>, “Historical Data Retrieval,” verified 6-minute water level data 

for Baltimore, Fort McHenry, Patapsco River, Maryland, collected on March 6, 2004.

29 NOAA-National Ocean Service Center for Operational Oceanographic Products and Services, tidal 

current secondary station prediction adjustments for Patapsco River: Fort McHenry, NW Harbor entrance 

<http://140.90.121.76/currents05/tab2ac5.html>.
Factual Information 20 Marine Accident Report

Management Hierarchy

Living Classrooms officials were not involved in the day-to-day operations of the 

water taxi service. The officers who established the vessel operating policies and 

procedures for Seaport Taxi were the NHS director, the Seaport Taxi director, and the fleet 

captain. 

Director, National Historic Seaport of Baltimore. The NHS director oversaw 

planning for seven entities: Seaport Taxi, Baltimore Maritime, the U.S.S. Constellation, 

Paddle Boats, Patriots of Fort McHenry, the Baltimore Waterfront Promenade, and 

National Historic Seaport Administration. 

Director, Seaport Taxi. The Seaport Taxi director told Safety Board investigators 

that, because of his interest in boats and motors, he had taken Peterbilt Motors Company 

and General Motors Corporation training classes that dealt with vessel mechanics. In 

1986, he qualified for his first Coast Guard master’s license, which authorized him to 

operate passenger vessels up to 25 tons. While fully employed with R. J. Reynolds, he 

worked part time operating six-passenger charter boats in the Long Island, New York, 

area, and then water shuttle vessels for Baltimore Harbor Shuttle, primarily during the 

summer. By this time, his license had been upgraded to 100-ton vessels, master of inland and 

coastal waterways. He said that, in 1993 and 1994, he bought two vessels and worked as an 

owner/operator for Baltimore Harbor Shuttle until mid-1995. He then sold the vessels and 

served occasionally as a captain for the water shuttle service.

In 2001, after Living Classrooms bought and renamed the water shuttle service 

Seaport Taxi, he was hired as the Seaport Taxi fleet captain. After 2 months, he was 

promoted to Director, Seaport Taxi, the position he held at the time of the accident. As 

director, he said that he oversaw the taxi operation “pretty much in its entirety from fiscal 

issues, marketing issues, operations and maintenance, delegating maintenance as required, 

scheduling, reviewing who’s hired, and overseeing performance.” He oversaw 2 permanent 

employees (the fleet captain and the office manager) and the vessel crews, which numbered 

5 or 6 full-time and 5 or 6 part-time employees during the off-season (such as the master of 

the Lady D, who worked on weekends) and more than 60 employees during peak season. 

During normal daily operations, he sometimes served as master of one of the boats in 

operation and provided guidance and information to other vessels in the fleet. 

Fleet Captain, Seaport Taxi. The fleet captain told Safety Board investigators 

that he was involved in social work for about 20 years before entering the marine industry. 

After purchasing a 40-foot sailing yacht, he outfitted it as a charter boat and obtained his 

first Coast Guard license. Before he was hired as one of Seaport Taxi’s first captains in 

2001, he operated his own vessel and charter vessels of various designs (sailboats, yachts, 

riverboats, gambling boats, and so forth) for a number of companies. 

As a Seaport Taxi captain, he operated all the boats in the fleet, including the Lady 

D. He stated that in the first year after Living Classrooms purchased the water taxi 

company, “there was a considerable amount of repair and restoration work necessary on 

the boats. So, consequently, you either ran everything or you didn’t do much....”
Factual Information 21 Marine Accident Report

Within months of being hired as a vessel captain, he was promoted to fleet captain. 

As such, he was responsible for supervision management, boat maintenance, and 

scheduling boat repairs. His immediate supervisor was the Director of Seaport Taxi. Like 

the director, the fleet captain sometimes operated one of the boats in service. If the director 

was not on board a vessel, the fleet captain, as senior company official on the water, 

provided guidance and information to other vessels in the fleet.

Other Seaport Taxi Employees

Three other Seaport Taxi employees with oversight of certain company operations 

interacted with the Lady D’s master on the day of the accident. 

Office Manager. The Seaport Taxi office manager was responsible for day-to-day 

administrative work, including advising the crews as to which vessels would be operating 

and who would be assigned to each boat, preparing the cash boxes for the mates, and 

issuing tickets. She also monitored channel 71 on the VHF radio in the office at all times, 

fielding requests for action from the vessel operators, and listened for weather updates that 

she passed on to the fleet via a hand-held walkie-talkie UHF (ultrahigh frequency) radio.

Senior Captain on the Water. If the Seaport Taxi director and the fleet captain 

were not operating a vessel, typically the master with the most seniority would serve as 

senior captain on the water, relaying advice and information to other vessels. The master 

serving as senior captain on the water on the day of the accident had worked a total of 9 

years for Baltimore Harbor Shuttle and Seaport Taxi.

Fort Coordinator. Seaport Taxi’s fort coordinator was a part-time employee who 

worked weekends managing the embarkation and debarkation of visitors at Fort McHenry. 

His duties included escorting and counting the passengers as they boarded a vessel, 

conferring with the mate who was responsible for recounting the passengers as they took 

their seats, and verifying with the master that he too had done a final count of the people 

on board. The fort coordinator also maintained a log of the people who had visited the fort. 

Operational Information

Docking Agreements with City

The City owned the dock at Fort McHenry where Seaport Taxi landed and leased it 

to NHS. As part of the lease agreement, the company had to maintain the dock. However, 

when the Fort McHenry pier was damaged by a hurricane, NHS obtained permission from 

the fire chief to land at the fireboat base (the command center). The company had an 

access agreement with Fort McHenry that permitted the water taxi passengers to enter the 

fort’s gate.
Factual Information 22 Marine Accident Report

Daily Operations

In 2003, Seaport Taxi transported 200,000 paying customers. As noted earlier, the 

taxis operated on two routes—an inner loop between Harbor Place and Fells Point and an 

outer loop between Fells Point and Fort McHenry (refer to figure 1). Trips usually started 

at Harbor Place. The trip from Harbor Place to Fells Point was nonstop and took 12 to 15 

minutes. On arriving at Fells Point, the water taxis disembarked passengers interested in 

the attractions at that stop or in the sites on the outer loop. Taxis operating on the inner, or 

“local,” loop then returned to the Inner Harbor marina with passengers interested in the 

inner loop stops.

The Seaport Taxi director stated that how often a boat made a loop depended on 

the passenger traffic and the number of requested stops. He indicated that the COIs of all 

vessels in the fleet permitted them to go as far as Fort McHenry and Canton. 

Passenger Accountability

According to the Seaport Taxi director, because of the “caravan” nature of the 

water taxi business, with passengers boarding and disembarking a vessel every 7 to 15 

minutes, the company “had yet to come up with a workable system for constantly 

monitoring how many people [were] on a specific boat” at any given time. Every time a 

taxi left a particular docking point, the operator would issue a fleet-wide broadcast 

advising how many people were on board; however, this company practice was meant to 

provide the working fleet and the office manager with some idea of where the respective 

boats were operating, when they might be expected to dock, and where the greatest 

customer demand was. The only docking site where Seaport Taxi documented an exact 

passenger count was at Fort McHenry, which was a requirement of their partnership 

agreement. Seaport Taxi assigned one employee—the fort coordinator—to the site to 

control the movement of vessel passengers to and from the fort, to prevent unauthorized 

people from entering the fort, and to prevent visitors from becoming stranded at the fort. 

He was required to maintain a log documenting each voyage and the number of 

passengers on the boat, which was turned in to the office each evening and which was later 

used to prepare a monthly report to Fort McHenry officials. 

On the day of the accident, witnesses alerted the BCFD emergency control center 

that the capsized vessel had originated at Fort McHenry. BCPD patrol officers in the area 

stopped at the fort, obtained a count of how many people were on board the Lady D from 

Seaport Taxi’s fort coordinator, and relayed the information to the responders.

Following this accident, after discussions with investigators, Seaport Taxi placed a 

box at each taxi depot in which the vessel crewmembers were required to deposit a manifest 

log indicating how many passengers were onboard before their vessel departed the dock. 

Weather Policies and Procedures

According to the Seaport Taxi director, the company’s standing instruction for 

operating in inclement weather was that if masters encountered an electrical storm, 

restricted visibility, fog, or another condition that in their experience would dictate finding 
Factual Information 23 Marine Accident Report

a safe harbor, they should do so. In classroom and on-the-job training, potential new hires 

were instructed not to wait until they were told to get off the water. The director said that 

he considered it part of “good seamanship and common sense” not to operate in conditions 

in which a Coast Guard-licensed master was not comfortable. He also told investigators 

that he did “not want to hamper independent decisions out there because what’s happening in 

the Inner Harbor may be totally different than what’s happening out at Fort McHenry, or 

conversely.” He indicated that he respected the decisions of licensed mariners, stating, “It’s 

their judgment. It’s their license and I would expect that courtesy when I’m running a boat, 

and that’s the same courtesy I give them.”

The director further said that he advised applicants that windage30 on pontoon 

vessels was significantly greater than on a conventional monohull vessel. He added that 

the masters “learn[ed] quickly” that they would not be able to land a vessel if they did not 

understand the effects of wind on the pontoon boats’ high profile. The company’s fleet 

director added that Seaport Taxi had three criteria in its stated weather policy requiring 

masters to put their vessels “into the bulkhead” and “tie up”: when visibility was 

“dramatically reduced”; when lightning was in the immediate area; or when the wind was 

over 30 to 35 knots, depending on the operating route. 

The master of the Lady D had operated that vessel for most of the time he had been 

employed by Seaport Taxi, repeatedly traversing the Northwest Harbor area. He stated, 

“The water is a little rougher as you go out the [Patapsco] river than when you are staying 

in the Inner Harbor...area.” He said that he had made it a personal practice to check the 

Weather Channel before going to work so that he might be prepared for the conditions that 

day. He said that on March 6, the forecast for the “4 o’clock time frame” did not indicate 

that “this humongous wind” would be coming into the harbor area.

The master stated that he understood the company guidance permitted operating in 

winds that were “35 knots or under” and “that is what I generally go with.” He further 

stated, “If it gets 40 knots or above, that is always a no-go for...going out to Fort 

McHenry.” He indicated that he thought he had been caught out on the water when the 

winds had been 50 knots. He said, “The boat was leaning,” but that he had been able to put 

the vessel into the wind and was “okay.”

Seaport Taxi officials told investigators that in past years, “if the windage was such 

that it was deemed...inappropriate to have [the Lady D] out there [operating on loop 2], 

they would assign a heavier boat with larger engines to the route. The senior captain on the 

water indicated that earlier in 2004, the Lady D’s master had radioed “that he felt 

uncomfortable” in the wind conditions, and had asked that a heavier boat take over the 

route, which company officials arranged to do. 

Following this accident, Seaport Taxi revised its weather operating policy to place 

specific wind and sea state restrictions on vessels as shown in table 4. Company officials 

indicated that they met with their vessel operators to stress safe procedures for operating 

in inclement weather, including when they must suspend operations. The company also 

30 The surface of a vessel that is exposed to the wind.
Factual Information 24 Marine Accident Report

equipped each vessel in its fleet with an emergency alert NOAA weather radio to facilitate 

the crew’s receiving accurate and timely information.

Table 4. Seaport Taxi’s postaccident operating restrictions for wind and wave conditions

Boat Sustained Winds (mph) Wind Gusts (mph)* Sea State (feet)

Raven

a. This vessel is not the Raven that was constructed in series to the Lady D. 

a 30 35 2

Phoenix 30 35 2

Migeni 30 35 2

Patrick Duffy 25 30 2

Eagle 25 30 2

*Wind gusts lasting 15 seconds or longer. 

Maintenance 

Lady D History. According to the Seaport Taxi director, when he joined the water 

taxi company, it had received several CG-835 forms, Notices of Merchant Marine 

Inspection Requirements, from the Coast Guard for deficiencies31 on the Lady D such as a 

cracked hold or cracked steps. He indicated that Seaport Taxi had improved the Lady D’s 

record, and that Coast Guard inspectors had not noted any structural deficiencies during 

the vessel’s last annual examination on February 27, 2003. 

The Seaport Taxi director and the fleet captain both indicated that they were last 

aboard the Lady D on March 2, 2004. The fleet captain said that he had operated the Lady 

D less than a week before the accident and noted no problems. The director indicated that 

the last time he operated the Lady D was on February 25, when he took it to attend a 

meeting at the Constellation. He said, “As far as the operational systems, [the vessel] 

seemed fine. Radio was working.” 

The Seaport Taxi director said that in summer 2003, there had been a “little problem” 

with the Lady D’s steering system, but greasing the points solved the problem. Since then, he 

had not received any reports about steering problems until 3 or 4 weeks before the accident, 

when one captain submitted a log report complaining about “a little glitch in the steering.” 

The director found an accumulation of salt and corrected the problem.

Officials indicated that the Lady D was the only vessel in the fleet with a fourstroke Honda engine and “the engine mount on the vessel constantly develops cracks that 

need to be attended to.” The company director stated that shortly before Hurricane Isabel, 

in September 2003, Seaport Taxi had the engine replaced with a new Honda engine that 

was “reinforced better than it was from the factory.” He indicated that as far as structural 

work was concerned, the front deck had been reconstructed, reinforced, and strengthened 

and that the pontoons had been welded and repaired. 

Seaport Taxi provided investigators with 11 bills submitted from contractors to 

Living Classrooms for various repairs made to the Lady D between November 8, 2000, and 

October 4, 2003. According to the bills, repairs to the pontoons were made in 2001 and 2002.

31 A “deficiency” is any failure to meet minimum requirements of vessel inspection laws.

a
Factual Information 25 Marine Accident Report

Maintenance Program. According to the NHS director, about 10 percent of the 

Seaport Taxi annual operating budget, or $50,000 to $60,000, was spent on maintaining 

the fleet. The Seaport Taxi director said that he did not keep records of routine 

maintenance performed by company personnel. However, bills from contractors for 

repairs and examinations that necessitated removing a vessel from the water had to be 

submitted on a purchase order to Living Classrooms for payment, meaning that the 

accounting department of Seaport Taxi’s parent company maintained documentation on 

extensive maintenance.

The Seaport Taxi director stated that the company did not require personnel to do 

prescheduled daily, weekly, monthly, or annual checks and upkeep of the fleet’s vessels 

and their components. He said that the pontoon vessels themselves were “very simple”; 

the operating equipment included a self-lubricating hydraulic steering system and either a 

two-cylinder or a four-cylinder engine. Most routine maintenance, therefore, was limited 

to checking for leaks, replacing seals, adding oil, greasing engine parts, and changing 

spark plugs, tasks that were affected, in large part, by the number of hours a vessel was in 

use.

The director indicated that Seaport Taxi had developed what he termed a 

“proactive” vessel maintenance program for the company’s fleet. He said the captains 

were required to check all systems, lights, horns, and steering each time they were 

assigned to a vessel and to make sure everything was operating properly and to their 

satisfaction before they put the boat in service. In addition, the masters were required to 

maintain a captain’s shift log on which they provided line-item information such as the 

time of day they began operating a particular vessel, how long they were on duty, and how 

much gas or engine oil they added during their shift, as well as any problems or limiting 

conditions they encountered. At the end of every shift, the logs went to the Seaport Taxi 

office for review by the office manager and fleet captain. Seaport Taxi provided the Safety 

Board with 153 shift logs representing 130 days of operation between May 2003 and 

February 2004. On November 19, 2003, the master who operated the Lady D that day 

noted that conditions were “windy”; however, his log does not indicate that he tied up as a 

result of the weather conditions.

Meteorological Information

Many Federal, State, and private entities have installed automated weather 

observation sites independently of one another. The format of data and frequency of 

collection vary. The Safety Board obtained and reviewed recorded meteorological 

information from a variety of sources, including the NWS and privately held mesonet32

systems throughout the area. A summary of the operations of several weather sources and 

the report data captured by their equipment follows.

32 Mesonet is a regional network of observing stations (usually surface stations) designed to diagnose 

the features in a mesoscale weather system, that is, a system whose dimensions generally range from several 

miles to several hundred miles. 
Factual Information 26 Marine Accident Report

National Weather Service

Forecasters at the NWS weather forecast offices use a variety of observational data 

to diagnose and assess current meteorological conditions and the state of the atmosphere. 

They merge this assessment with output from computer models run at the National 

Centers for Environmental Prediction (NCEP), and they collaborate on forecast decisions 

with forecasters at neighboring weather forecast offices and the NCEP Storm Prediction 

Center. According to agency officials, the NWS routinely broadcasts advisories, warnings, 

and other meteorological data to mariners throughout the Chesapeake Bay area via NOAA 

Weather Radio (NWR) All Hazards. NWR coverage is complete over the entire 

Washington-Baltimore-Chesapeake Bay area, and, according to agency officials, the 

NWR was fully operational on the day of the accident.

Standard observational data that are integrated and displayed on the forecasters’ 

workstations include basic surface observations from Automated Surface Observing 

System (ASOS) and similar Automated Weather Observing System (AWOS) sites33 at 

airports; data from weather surveillance radar 88 Doppler (WSR-88D) systems34; basic 

parameters measured through the upper atmosphere by balloon soundings; temperature 

and wind recorded by aircraft; and satellite imagery. 

The weather forecast office having primary responsibility for monitoring the area 

that includes Baltimore Harbor is the Baltimore-Washington site near Sterling, Virginia. 

On the afternoon of March 5, 2004, the Baltimore-Washington forecast office had issued a 

small craft advisory for all of Chesapeake Bay, including the Inner Harbor at Baltimore. 

The small craft advisory remained in effect throughout the following day.

On March 6, a radar operator and a lead forecaster arrived at 1350 and 1500 

respectively for their evening shift at the Baltimore-Washington forecast office. They said 

that they received briefings from the day-shift meteorologists they relieved, who both 

advised them that a cold front between the Appalachian Mountains and the Atlantic Coast 

had generated showers and thunderstorms; however, as was typically the case for that time 

of year, the storm conditions were expected to diminish in intensity and coverage as they 

moved east due to dry air aloft and to westerly blowing winds.35

The night shift meteorologists said that they reviewed the available data and 

agreed with this assessment.

The NWS nightshift personnel indicated they followed their usual routines. The 

radar operator primarily was responsible for monitoring the WSR-88D. The lead 

forecaster was responsible for maintaining a continuous weather watch by reviewing 

33 The ASOS program is a joint program between the Departments of Commerce, Transportation, and 

Defense. AWOS is primarily a Department of Transportation program.

34 The WSR-88D is a short-range weather radar system. 

35 A postaccident review of the storm environment analyses performed by the day-shift meteorologists 

at Sterling revealed that they did not include anticipated environmental changes in their analysis of 

soundings, which resulted in the observation that the chances for convective instability were small for the 

rest of the day. 
Factual Information 27 Marine Accident Report

model data, forecast soundings, observations, and radar and for issuing products and 

forecasts (aviation and marine), as needed. 

The WSR-88D radar sites nearest Baltimore Harbor monitored by the radar operator 

at the Baltimore-Washington weather forecast office included the installation at his own 

office (Sterling, or LWX), the Dover Air Force Base site, and the central Pennsylvania site 

just northwest of State College. These radars are 52, 70, and 135 miles, respectively, from 

the accident site. In addition, the radar operator could access data from neighboring sites at 

his own workstation and monitor multiple sites concurrently and through mosaic images. 

Figure 4 shows selected LWX WSR-88D images displayed shortly after 1500. 

Figure 4. WSR-88D, or Doppler weather radar, shows detailed images of precipitation 

(snow, rain, hail) and other phenomena, including air motions within a storm. The images 

above show weather radar echoes, some of which are intense to extreme, moving to the 

east. The colors noted on the bottom of the images relate to weather radar echo 

intensities (in decibels of Z [dBZ], where Z = energy reflected back to radar). The colors 

blue to yellow indicate intensity ranges from weak, moderate, to strong, and the colors 

orange to red indicate ranges from very strong, intense, to extreme.

About 50 minutes before the Lady D boards passengers 

at Fort McHenry. Intense weather echoes (storms) are 

seen about 40 miles north-northeast of the accident site.

Six minutes later, the storms have moved about 5 miles 

to the east.

According to the radar operator at the Baltimore-Washington weather forecast 

office, he was receiving few aircraft soundings to the west of the cold front, which might 

have alerted him to increasingly unstable conditions. In addition, he did not recall his 

office’s weather processing system generating a “meaningful” radar alarm that might have 

alerted him to a significant change. He later advised NWS officials who conducted an 

independent investigation that he had expected the storm to dissipate as area spring storms 

had typically done in the past. 
Factual Information 28 Marine Accident Report

In the meantime, the lead forecaster said that he was routinely monitoring various 

systems. Data transmitted to the forecasters’ workstations included wind gust data 

captured at various weather observation sites. Table 5 shows the wind gusts recorded by 

weather observation systems west of Baltimore Harbor on March 6.

Table 5. Recorded winds gusts within about 85 miles of accident site

Time

Wind Direction

(degrees true) Station

Wind Gusts

(knots)

1440 270 Martinsburg 36.9

1453 290 Martinsburg 35.9

1520 300 Frederick 32.1

1520 300 Culpepper 33.0

1544 310 Reagan National 46.0

The lead forecaster said that based on “isolated thunderstorm activity” and “after 

noticing some gusts in observations around 30 knots,” he began work on issuing a shortterm forecast for isolated thunderstorms with wind gusts to 35 mph. As the lead forecaster 

was working on verifying the conditions for the short-term forecast, he observed a storm 

cell passing over nearby Reagan Washington National Airport, producing a wind gust 

measuring 46 knots at 1544. He said he immediately alerted the radar operator about his 

observation and disseminated the short-term forecast at 1549. The Doppler radar images 

in figure 5 show the progress of the intense weather radar echoes between 1531:46 and the 

time the short-term forecast was issued.

The radar operator said that he immediately interrogated the cell using the WSR88D at his location. The forecasters at the Baltimore-Washington weather forecast office 

also had access to radar data from other agencies’ observing systems but not through their 

NWS workstations. At the time of this accident, for example, the forecasters could obtain 

radar data from the terminal Doppler weather radars (TDWRs) that the Federal Aviation 

Administration has installed at various airports. To do so, however, the radar operator had 

to switch to a personal computer to access and review the TDWR data.36

In this case, the radar operator accessed the TDWR at Baltimore-Washington 

International Airport to verify that the observation was legitimate and to determine where 

and when the storm posed a threat. He said that interrogating the storm and preparing the 

special marine warning to include Baltimore and a larger portion of Chesapeake Bay took 

about 8 minutes. The special marine warning was issued to area vessel operators at 1605, 

about 7 minutes after the Lady D had capsized.

36 The NWS has since initiated a project to integrate TDWR data into its workstation systems. 

Information about additional measures the NWS has taken as a result of the Lady D accident appears in the 

following section.
Figure 5. LWX Doppler weather radar images showing the movement of storms from west 

to east toward the Baltimore Inner Harbor during the period 1532 to 1549. When the Seaport Taxi office manager radioed the fleet at 1558 that the worst parts of the storms were 

going to miss their area, she described conditions similar to those shown at 1549:11.

LWX Doppler weather radar image about 1532. LWX Doppler weather radar image about 1538.

LWX Doppler weather radar image about 1543. LWX Doppler weather radar image about 1549.

Factual Information 29 Marine Accident Report

National Weather Service Postaccident Assessment 

Following the Lady D capsizing, the NWS conducted its own service assessment 

of events and conditions preceding the accident to address questions related to its 

operations: In particular, did the NWS have sufficient capabilities to provide adequate 
Factual Information 30 Marine Accident Report

warnings to mariners within the Baltimore Harbor and the greater Chesapeake Bay areas, 

and what meteorological data collected by private and public agencies in the Baltimore 

area could be readily collected and used by the NWS?

The NWS assessment team determined that the performance by the forecasters on 

duty was adversely affected by their preconceptions about the environmental conditions, 

which ultimately forced the meteorologists to operate in a reactive mode. The team further 

found that a more aggressive and more efficient approach by forecasters in analyzing the 

evolving weather conditions could have increased their concern about the potential for 

high winds. This, in turn, could have resulted in timelier and more complete information 

being provided in forecast and warning services.

The assessment team also found that the forecasters did not make optimum use of 

available equipment. Equally important, the mesonet and TDWR system data that could 

have alerted the forecasters sooner to deteriorating conditions were either not available at 

all or not available in a format that they could use. As a result, the Sterling forecasters 

updated products to reflect thunderstorms and higher wind speeds only after 

thunderstorms intensified and higher-than-expected winds became apparent in surface 

observations. 

In June 2005, the NWS issued its final report, which discusses the findings of the 

service assessment and identifies recommended actions for improved performance. (See 

table 6.) According to an NWS official, the agency’s assessment report was made 

available to weather forecast offices (WFOs) nationwide by means of the NWS website. 

The training exercises developed by and for the Sterling weather forecast office will be 

disseminated throughout the eastern region and then to other regions. In addition, the 

Sterling weather forecast office may create a weather event simulator scenario or distance 

training session that will be made available to interested offices. The NWS spokesperson 

indicated that the training developed is optional for WFOs; however, agency officials 

anticipate that weather field offices with marine forecast responsibilities will very likely 

access and use the training.

Digiwx System Sensors

Belfort Instrument Company, a Baltimore-based manufacturer of environmental 

measurement systems, provided data logged from two of its Digiwx (digital weather) 

System sensors located near the accident area. One Digiwx sensor is installed at a field 

elevation of 10 feet on the end of the dock at the Baltimore Marine Center, about 0.54 

nautical mile (nm) north of the accident site. The second system sensor is installed at a 

field elevation of 181 feet on the University of Maryland’s Shock Trauma Center in 

downtown Baltimore, about 2.7 nm west-northwest of the site. The captured data from the 

Baltimore Marine Center sensor indicate that about 1555, the wind speeds were 12 knots 

with gusts to 18 knots. Between 1555 and about 1559, the winds increased to 21 knots 

with gusts to 37 knots (1558:58 observation). By about 1600, the sustained winds 

measured 25 knots, and the maximum wind gusts were 41 knots. During these times, the 

wind direction captured from the Shock Trauma Center’s sensor was from the west.
Factual Information 31 Marine Accident Report

Table 6. Results of National Weather Service’s postaccident assessment

NWS Finding Recommendation

1. Atmospheric conditions evolved rapidly during the 

early to mid-afternoon hours over central Maryland, 

becoming more unstable than forecasters expected. 

This supported development of showers and 

thunderstorms, which moved east-southeast into the 

Baltimore area.

1a. The WFO Baltimore-Washington Meteorologistin-Charge and Science and Operations Officer 

should engage all WFO forecasters in a detailed 

analysis of the evolution of atmospheric conditions 

on March 6, 2004, related to events of the day at 

the start of the 2005 convective season. This effort 

should be conducted as a local training 

exercise/workshop.

1b. A related local exercise during or after the 

activity in recommendation (a) is for WFO 

management to document local techniques to 

facilitate operational analysis at the WFO 

throughout the process of routine forecast 

development and formulation.

2a. During this event, forecasters relied mainly on 

data available in their workstations. New data sources 

take time and resources to integrate into the 

workstations. Accessing and integrating data from an 

adjacent computer can be cumbersome and 

precludes optimum use of data during fast-breaking 

events.

2b. Forecasters were able to make only limited use of 

the complementary surface observations along the 

Interstate 70 corridor as thunderstorms moved 

through that area. Even though observations from 

these private and non-Federal sites were taken every 

15 minutes, only half-hourly data were available to 

NWS forecasters through their workstations. Also, 

forecasters have noticed issues with the accuracy, 

availability, and reliability of data from some 

complementary data sources.

2a. NOAA’s NWS should review its procedures and 

capabilities for integrating complementary data into 

workstations to achieve optimum use of the data 

available. Special efforts should be made to 

incorporate all available data and information, 

including data from government (Federal, State, 

and local), private sector and academic networks.

2b. NOAA’s NWS should explore ways to make 

maximum use of complementary data sources 

during high-impact, especially hazardous events, 

and to work with potential partners to improve the 

quality and availability of such data.

3. Forecasters were unable to validate velocities 

observed on radar with groundtruth reports. The 

impact of high winds along the Interstate 70 corridor 

was minimal, resulting in no damage reports from 

spotters or law enforcement officials. Timely wind 

gust information from complementary data sources 

was not available to forecasters.

3. WFO Baltimore-Washington management should 

plan a local training program/workshop for WFO 

staff focused on improving integration of 

groundtruth in short-term forecast and warning 

operations.

4. Forecasters relied mainly on data from their 

collocated WSR-88D at the WFO BaltimoreWashington. While they did interrogate some TDWR 

data on a separate computer, they worked less with 

the Dover Air Force Base WSR-88D. The Dover 88D 

was farther away, but in this specific set of 

circumstances, it was better situated to depict base 

velocity data.

4. Eastern Region Headquarters should support a 

local training exercise for WFO BaltimoreWashington staff between the WFO Meteorologistin-Charge, the Science and Operations Officer, and 

the NWS Warning Decision Training Branch based 

on this event to address optimum use of data from 

multiple radars.

5. In spite of display limitations, TDWR data showed 

excellent potential for integration into WFO short-term 

forecast and warning operations.

5. NOAA/NWS should consider ways to accelerate 

the current NWS-Federal Aviation Administration 

TDWR data integration project, providing WFOs 

data from TDWRs within their areas of 

responsibility.

6. Complementary data from non-NOAA/NWS 

observation networks could help in the forecasting 

and warning process.

6. NWS should explore options for getting timely, 

accurate complementary data from nonGovernment sources.
Factual Information 32 Marine Accident Report

Weatherbug Network

Seaport Taxi was a subscriber to WeatherBug®, a Web-based source of 

neighborhood weather, severe storm alerts, and radar and camera images available to 

personal computer users. Headquartered in Gaithersburg, Maryland, WeatherBug® has 

over 7,000 tracking stations and more than 1,000 cameras networked together nationwide 

via high-speed Internet. In Maryland, WeatherBug® has more than 300 sensor locations. 

NWS forecasters can access WeatherBug® data on their workstations; however, officials 

indicated that because of timeliness and quality control issues with the data, its use is 

limited. The Seaport Taxi office manager indicated that on the day of the accident, she did 

not hear the distinctive beep emitted by her computer when WeatherBug® issues a 

weather announcement.

7. While staffing was at normal levels for a Saturday 

and sufficient to manage events of the day, had dayshift forecasters been more concerned about the 

potential impact of the advancing storms and 

remained on duty, the additional staff might have 

been able to retrieve additional groundtruth 

information.

7. WFO Baltimore-Washington should investigate 

slight adjustments in shift times, especially focused 

on midday workload during the convective season 

and when indicated by specific environmental 

conditions.

8a. Prior to 1549, there was no forecast of 

thunderstorms or wind gusts exceeding 25 mph for 

the Baltimore area. Forecasts were based on the 

expectation that showers would not intensify in an air 

mass characterized by a drying trend and downslope 

winds.

8b. Beginning with a short-term forecast at 3.49 p.m. 

through the special marine warning at 4.05 p.m., 

forecasters were in a reactive mode, working from 

radar data and observations from ASOS sites at 

Baltimore-Washington International Airport and 

Reagan Washington National Airport.

8c. Even with automated dissemination of forecast 

and warning information and excellent NWR 

coverage of the Baltimore area, short-term forecasts 

of 45 mph gusts, and a special marine warning were 

not available to mariners before winds exceeded 45 

mph in the harbor. A small craft advisory had been in 

effect since the previous day.

8. As part of local training exercises/workshops 

relative to this event contained in recommendations 

1, 3, and 4, the WFO Meteorologist-in-Charge, and 

the Science and Operations Officer should engage 

WFO staff in establishing operational practices 

aimed at improved and more frequent event-driven 

products and information.

9. Rebroadcast of NWS marine forecast and warning 

information via local U.S. Coast Guard radio can take 

up to an hour.

9. Baltimore-Washington WFO staff should work 

with local Coast Guard officials to develop 

techniques to improve timely delivery of marine 

advisory and warning information on Coast Guard 

radio in the Baltimore Harbor area.
Factual Information 33 Marine Accident Report

Medical and Pathological Information

Medical Findings

After the Lady D capsized, most of the vessel’s occupants were in the water 

between 5 to 15 minutes, based, in part, on survivor interviews and a reconstructed 

timeline. The three victims (2 adult women and 1 child) freed by the LCM-8 were 

recovered at 1617, about 19 minutes after the capsizing. According to the Coast Guard 

situation report, the area water temperature in the Patapsco River was 44° F and the air 

temperature was 66° F.37

Twenty-two of the Lady D’s occupants recovered on March 6 were transported by 

ambulances to local hospitals in Baltimore, including Johns Hopkins Bayview Medical 

Center, Johns Hopkins Hospital, Mercy Medical Center, and the University of Maryland 

Medical Center.

Five passengers, ages 6 to 62, suffered fatal injuries. Two people died in the 

hospital, and divers retrieved the bodies of three accident victims from the river on March 

14 and 15. Records of the general postmortem examinations performed by the Office of 

the Chief Medical Examiner, State of Maryland, indicate that all deaths resulted from 

drowning complicated by hypothermia.

The four serious injury victims were passengers who required hospitalization 

because of injuries suffered at the accident scene or medical complications that occurred at 

the medical facility. Three adults, ages 55 to 59, were transported to Johns Hopkins 

Hospital, where one woman required surgery for a shoulder fracture and dislocation. Her 

husband, also a passenger on the water taxi, experienced chest pains while at her bedside 

and was admitted for observation. Another woman suffered palpitations while in the 

emergency room and subsequently spent 3 days in the hospital. An 8-year-old child who 

almost drowned and went into cardiac arrest was transported to the University of 

Maryland Medical Center–Pediatrics, where she was admitted for 25 days before being 

transferred to a rehabilitation center in Virginia.

Twelve people, including the 2 crewmembers and 10 passengers, sustained minor

injuries, mostly abrasions, lacerations, and contusions. The vessel master sustained a 

contusion on his left leg requiring evaluation for fracture and minor cuts on his palms. The 

mate was treated for hypothermia and diagnosed with pneumonitis. He was discharged 

after an uneventful night of observation. One passenger suffered a muscle strain pulling 

other accident victims out of the water onto the overturned boat. Another passenger 

sprained his ankle when it became caught on something in the boat and he pulled it free.

Toxicological Testing

Regulatory Requirements. Title 46 CFR Part 4 stipulates that the marine 

employer shall ensure that toxicological specimens are collected as soon as practical from 

37 The aspects of cold exposure survival appear in the “Survival Factors” section of this report.
Factual Information 34 Marine Accident Report

an individual on board the vessel “who is determined to be directly involved in a serious 

marine incident.”

Postaccident Testing. The University of Maryland Medical Center took blood 

samples from the Lady D’s crew and passengers for analysis as a matter of routine 

emergency treatment. When the master was admitted to the emergency room, at 1759, he 

informed the medical technicians that because of the accident, he had to submit samples 

for toxicology screening. He provided both urine and blood samples at 1841. The medical 

center laboratory analysis indicated that the master’s screens were negative for drugs and 

alcohol. The medical center obtained a blood sample but no urine sample for testing from 

the mate at 1754. His blood was not screened for drugs.

The Safety Board subpoenaed the specimens taken from the master and the mate 

by the medical center for further testing. The medical center, pursuant to the subpoena, 

provided the master’s blood and urine specimens and the mate’s blood specimen to the 

Federal Aviation Administration’s Civil Aerospace Medical Institute (CAMI) in 

Okalahoma City, Oklahoma, for testing. The CAMI report indicated no positive results for 

alcohol or legal or illegal drugs, including amphetamine, opiates, marijuana, cocaine, 

phencyclidine, benzodiazepines, barbiturates, antidepressants, antihistamines, 

meprobamate, methaqualone, and nicotine.

At the request of the Coast Guard, the mate and the master provided samples for 

drug testing on March 8 and March 10, respectively, at the Concentra Medical Center in 

Baltimore. The samples were sent to the American Toxicology Network laboratory in 

Memphis, Tennessee, for analysis. The results of the drug tests were negative.

Survival Factors

Aspects of Survival in Cold Water

The latest update to the U.S. Coast Guard Addendum to the National Search and 

Rescue Supplement, issued January 5, 2006, includes guidance for identifying the four 

stages of cold-water immersion in which death can occur. The guidance is based on the 

Cold Exposure Survival Model (CESM) developed by Canada’s Defense and Civil 

Institute for Environmental Medicine for use in predicting survival times for cold air 

exposure and cold water immersion. The CESM predicts functional time and survival 

times based on cooling of the body’s core,38 and on an individual’s physical 

characteristics, clothing, and weather and sea conditions. The stages are listed below. 

38 CESM is strictly a hypothermia model and does not include the effects of dehydration, injuries, 

medications, drugs, alcohol, sleeplessness, and circadian hormonal cycles.
Factual Information 35 Marine Accident Report

• Initial Immersion Cold Shock: Death occurs within 1 to 3 minutes of 

immersion. Sudden immersion in water colder than 59° F stimulates a large 

gasp response that may be followed by hyperventilation plus an increase in 

blood pressure and heart rate, which ultimately causes respiratory or cardiac 

problems.

• Cold Incapacitation: Death occurs within 5 to 30 minutes of immersion. The 

body’s natural attempt to preserve core body temperature by diverting blood 

from the limbs causes muscular failure, which in turn, causes the person to lose 

the ability to swim, maintain position, or use his hands. 

• Hypothermia: Occurs within 20 to 30 minutes of immersion. Continued heat 

loss eventually results in a decrease in core temperature that adversely affects 

the heart, lung, and brain. The rate of cooling depends on water temperature, 

body metabolism and fatness, and external insulation. Hypothermia will 

progress until shivering stops and unconsciousness occurs.

• Circum-Rescue Collapse: Can occur immediately before, during, or from 

minutes to several hours after the rescue effort. The anticipation of imminent 

rescue causes a decrease in the output of stress hormones, which may result in 

a drop in blood pressure that results in fainting and drowning. Also, pulling a 

victim out of the water in a vertical position removes the “hydrostatic 

squeeze”39 on the extremities, which results in decreased blood pressure that 

causes stress that may induce cardiac arrest.

At the time and in the area of the capsizing, the water temperature was 44° F. As 

noted earlier, all fatalities resulted from drowning complicated by hypothermia. Three 

accident victims were trapped inside the overturned vessel about 20 minutes and floated 

free when the LCM-8 lifted the side of the Lady D. Of these, one was pronounced dead 

upon arrival at the hospital, one died within 72 hours, and the third, a child, almost 

drowned and suffered cardiac arrest. 

City of Baltimore Consolidated Communication Center 

According to information provided by the BCFD, in 1995, the City of Baltimore 

contracted the design, construction, and installation of a state-of-the-art radio and 

computer-aided dispatch system to better coordinate the response to major emergencies. 

The consolidated communications system, located at the BCFD’s Emergency 

Communications Center, links the fire department, the police, and the public works 

department, permitting a single call to 911 to generate a multiagency response. The shared 

system ensures communication compatibility among all City public safety agencies, 

which, in the event of a major emergency, permits an incident commander to share 

39 Hydrostatic squeeze refers to the pressure exerted by an external fluid, in this case, the water in 

which a person is submerged. For example, at 3 feet below the surface, the external pressure is equivalent to 

nearly 80 millimeters of mercury, which is the typical pressure in the blood vessels of the extremities during 

the relaxation phase of the heart cycle. Once the water pressure is removed, there is substantially increased 

blood flow out to the extremities, decreasing core blood pressure.
Factual Information 36 Marine Accident Report

information with other response agencies, track the dispatch and location of assets such as 

emergency medical service (EMS) units, and so forth. 

Response Assets for Marine Incidents

The Coast Guard has Federal jurisdiction over the Patapsco River because it is a 

navigational waterway and is used for interstate and international commerce. The State of 

Maryland has granted jurisdictional authority over the waters surrounding the City of 

Baltimore, including the Baltimore Harbor waterways, to the BCFD and the BCPD. 

The BCFD’s Marine Division consists of 37 officers and crewmembers and four 

vessels, which operate out of the fireboat station at Fort McHenry. The BCPD’s marine 

unit has five vessels to accomplish its missions. 

Response of Assets to Lady D Capsizing

At 1558, Navy reservists and others witnessed the Lady D overturn and 

immediately notified 911 (the Emergency Communications Center) of the accident via 

cellular and landline telephones. The communications center’s system dispatcher, in turn, 

alerted the BCPD and then the BCFD of the accident. Before the BCFD dispatcher could 

order that agency’s marine assets to respond, a BCFD marine pilot on duty at the fireboat 

station notified the dispatcher that he had witnessed the capsizing. Meanwhile, the Navy 

reservists had assembled a rescue team and launched an LCM-8, which was the first to 

arrive at the accident site. By 1603, the BCFD dispatcher had ordered various marine and 

shore-based assets totaling 43 rescue and medical personnel to respond. Shortly thereafter, 

the BCFD battalion chief had established a shoreside incident command site and assumed 

control of the operation. Other State and County assets from Maryland subsequently 

responded, including a State police search helicopter.

BCFD fire/rescue [boat] No. 1 reached the scene immediately after the Navy 

Reserve LCM-8, and the BCPD vessel arrived shortly thereafter. The crews on the BCFD 

and BCPD marine vessels coordinated the rescue effort with the Naval reservists, who had 

already begun to transfer passengers and crewmembers to the LCM-8. Five reservists had 

entered the water to rescue those trapped in the deckhouse. The reservists transferred two 

passengers, one of whom appeared to be in cardiac arrest, to the BCFD boat, which took the 

accident victims to paramedics waiting shoreside. Meanwhile, the BCPD marine unit crew 

was successful in extricating an unconscious passenger from the water taxi, whereupon 

they immediately proceeded toward the pier to turn the passenger over to waiting 

paramedics. While en route to shore, the police marine crew performed CPR on the victim. 

Meanwhile, about 1616, watchstanders at Coast Guard Sector Baltimore, located 

about 5 1/2 nm from the accident site, learned of the capsizing while routinely monitoring 

radio traffic on VHF channel 16. Shortly thereafter, at 1617, Seaport Taxi notified the 

Coast Guard of the accident after company officials determined that the Lady D had 

capsized.40 Coast Guard personnel then activated the SAR alarm and contacted the BCFD 

dispatcher, who advised them that four rescue vessels were already on scene. The BCFD 

advised the Coast Guard of the recovery progress, and the Coast Guard immediately 
Factual Information 37 Marine Accident Report

ordered a muster for the dispatch of three utility boats and one helicopter to assist. The 

first vessel was underway by 1625. 

By 1633, the Navy reservists had retrieved the remaining survivors from the 

overturned pontoon vessel and were transporting them to Naval Reserve Center 

Baltimore, where a triage team had been assembled to administer aid. From the center, the 

accident victims were transferred to EMS personnel who transported them by ambulances 

to local hospitals for further examination and treatment, as necessary. 

The first Coast Guard vessel arrived on scene at 1637, and its personnel received 

an update on the status of the Lady D’s occupants from the rescuers already at the scene. 

Responders accounted for 22 victims within an hour of the accident. 

On-scene personnel then established a search for the three remaining passengers, 

aided by the Coast Guard’s second and third utility boats, which arrived at 1657 and 1916 

respectively. The search helicopter arrived at 1725. According to BCFD logs, the incident 

commander relegated the search effort to a recovery operation on March 7. The bodies of 

two victims were subsequently recovered on March 14 and the body of the last victim was 

recovered on March 15. 

Tests and Research

Safety Board’s Stability Study

Following the accident, the Safety Board contracted with Alion Science and 

Technology, JJMA Maritime Sector, to conduct a study evaluating the intact static and 

dynamic stability of the Lady D.

41 This section first summarizes some basic concepts 

related to intact vessel stability and then discusses the tasks and modeling variables in the 

Safety Board’s contract study. For a more detailed and illustrative description of vessel 

intact stability, refer to appendix B.

Stability Concepts. For almost every type of vessel, the vertical center of gravity 

(center of mass) of the vessel is directly above the vertical center of buoyancy (center of 

water volume displaced). When the center of gravity and the center of buoyancy are 

vertically aligned, the vessel is in static equilibrium, typically without any angle of heel. 

As the vessel heels to one side, the center of gravity shifts to the side as a function of the 

angle of heel. During the heeling action, the center of buoyancy moves to the side more 

rapidly than the center of gravity does. The resulting difference in vertical alignment, 

called the “righting arm” (usually expressed as GZ), creates an imbalance that gives the 

40 Federal regulations at 46 CFR 4.04, “Notice of Potential Vessel Casualty,” require that a vessel 

owner, charterer, managing operator, or agent immediately notify the Coast Guard (district rescue 

coordinator center or nearest SAR authority) if there is reason to believe a vessel is lost or imperiled.

41 Intact stability assumes no damage or flooding to a vessel. Static stability is a measure of a vessel’s 

stability characteristics in calm water. Dynamic stability refers to a vessel’s motions and response to external 

forces such as wind and waves.
Factual Information 38 Marine Accident Report

vessel the tendency to right itself. The GZ times the vessel displacement is the righting 

moment that resists whatever moments work to heel the vessel over, such as passenger 

movement or wind forces.

A family of righting arm curves can be developed to analyze the stability of a 

vessel. Typically, GZ is equal to zero at zero heel, and it increases as the heel angle 

increases. However, the rate of increase in GZ with heel angle gradually diminishes until it 

reaches a maximum value at some angle. This is called the angle of maximum righting 

arm. As the angle of heel increases beyond that point, the GZ decreases until at some point 

it becomes zero. This point, called the angle of vanishing stability, is the angle at which 

the center of gravity becomes outboard of the center of buoyancy. After that point, the 

vessel will continue to heel under its own weight until it capsizes. 

A righting arm curve represents a single draft (displacement), so it is usually 

expressed as a distance (GZ) rather than a moment, because the force component 

(displacement) of the righting moment is constant. From a physical perspective, it is the 

moment that provides the righting force. The area under the righting arm curve (footdegrees) is called “righting energy” in naval architecture convention. The energy 

expressed by the righting arm curve is reserve energy that gives an indication of the 

vessel’s ability to resist overturning forces and moments such as the effects of waves, 

steady winds, wind gusts, and other dynamic influences.

Study Tasks. The Safety Board’s contract study involved the following seven 

tasks:

• Task 1: Assess the stability calculations for the Lady D and sister vessels 

performed to show compliance with Coast Guard passenger vessel stability 

regulations. Determine the adequacy of relevant data to successfully complete 

a more rigorous analysis of the static and dynamic stability. 

• Task 2: Perform a static stability analysis of the Lady D at the time of the 

capsizing using current regulations.

• Task 3: Evaluate the dynamic effects of wind (steady state and gusting), 

passenger and crew loading and movement, wave action, and any other 

relevant conditions, and the interrelationships of these dynamic effects on the 

stability of the Lady D that may have contributed to its capsizing.

• Task 4: Prepare a 3- to 5-minute computer animation video showing the 

capsizing event.

• Task 5: Examine the dynamic response of the vessel Lady D when loaded to its 

maximum safe number of passengers, as determined by applying current 

stability criteria under similar environmental conditions, to provide some 

measure of assurance that the static stability criteria provided in Federal 

regulations is adequate.

• Task 6: Evaluate the intact stability for the Lady D as configured on the day of 

the accident using the following loading conditions: 
Factual Information 39 Marine Accident Report

* Meeting the PSST at 46 CFR 178.340 (carrying 14 persons weighing an 

average of 140 pounds).

* Meeting the COI (carrying 25 persons weighing an average of 140 

pounds).

* Meeting the actual capsize condition (carrying 25 persons weighing an 

average of 168.4 pounds).

• Task 7: Evaluate the intact stability of the Lady D as configured and loaded on 

the day of the accident when subjected to 30-, 40-, and 50-knot winds acting on 

the vessel’s beam.42

The absence of reliable mass properties data on the Lady D made it necessary to 

calculate the vessel’s weight and center of gravity. Because neither the owner nor the 

shipbuilder could provide engineering drawings and most of the vessel deckhouse was 

missing, the vessel weights had to be estimated. To establish the weight and center of 

gravity needed to perform the static stability analysis, the boat dimensions were collected 

with the vessel out of water, and freeboards were measured while the vessel was afloat. 

Using Creative System’s “General HydroStatics” computer stability software, the 

static stability analysis of the Lady D (task 2) showed that the vessel did not meet the 

current requirements of 46 CFR 178.340 for pontoon vessels operating in protected 

waters43 with 25 (140-pound) passengers, as shown on the vessel’s stability letter issued 

on March 28, 1996. The vessel failed to meet the minimum criteria for adequate stability 

in both transverse and longitudinal directions. The contractor also performed an analysis 

of the vessel as loaded at the time of the accident, that is, using an average passenger 

weight of 168.4 pounds. Again the vessel failed to meet the stability criteria. 

Current static stability regulations do not address the effects of wind on pontoon 

boats. The stability study evaluated the ability of the Lady D to withstand a 40-knot beam 

wind. The evaluation assumed the load the vessel carried at the time of the accident, using 

passenger weights gathered from witness interviews and hospital records. The average 

passenger weight was 168.4 pounds. Assumptions were made regarding the vessel’s 

profile because the deckhouse was missing. Under the assumed conditions, the pontoon 

boat did not capsize from a 40-knot wind acting directly on the side of the vessel. In the 

simulation, the vessel heeled to about 6°, with slightly less than 2 inches of freeboard 

remaining, but it remained upright. The calculations did not consider the dynamic effects 

of vessel motion, wind gusts, waves, or the movement of passengers aboard the vessel.

42 Wind variables for the contract study were based, in part, on the data captured by Digiwx and TDWR 

systems.

43 According to Federal regulations at 46 CFR 175.400, “Protected waters is a term used in connection 

with stability criteria and means sheltered waters presenting no special hazards such as most rivers, harbors, 

and lakes, and that is not determined to be exposed waters or partially protected waters by the cognizant 

OCMI.” 
Factual Information 40 Marine Accident Report

The motion of a floating vessel subject to the forces of wind and waves can be 

simulated using computer programs that model the physics of the system and calculate the 

response of the vessel to forces applied by the environment. The wind and the waves are 

treated as random variables modeled in terms of energy spectra. In this case, a wind 

spectrum is chosen to establish the limits of the wind conditions at the time of the 

accident, and a wave spectrum is developed based on the wind spectrum and the fetch44

over which the wind generates waves. 

For the Lady D analysis, the wind and waves were assumed to be unidirectional. The 

spectra were used to generate random wind and wave sequences that were applied to a 

computer model of the Lady D’s hull with the mass properties calculated previously. The 

exact motion of the vessel was computed as a response to the unique wind and wave 

profiles, as well as to the initial conditions (position and roll motions) of the vessel that were 

also random variables. The initial motions of the vessel and the exact wind and wave forces 

that led to the capsizing are unknown. The simulation represented what the vessel response 

would have been under the assumed conditions. The analysis produced different results 

even for minor changes in the initial conditions and the random profiles of wind and waves. 

Therefore, to identify a trend, such as the tendency to capsize, the simulation was repeated 

several times to model the variability in the vessel’s response to the random inputs.

To complete task 3, the contractor used naval architecture software and analytic 

methods to simulate the dynamic effects of the wind and wave conditions acting on the 

vessel. The environmental model used in the simulation assumed a 1.25-foot wave chop at 

a peak period of 3.0 seconds and a 25-knot steady wind gusting to 42 knots from 300° 

true.45 The dynamic simulation, using AQUA Drift46 simulation software, was run 20 

times and the vessel capsized in every case. In all simulations, capsizing occurred within 1 

minute. 

Task 5 required additional static stability analysis to determine the maximum safe 

passenger load. The static stability analysis showed that the maximum safe loading 

condition for the vessel was 14 persons based on the Coast Guard stability standards in 46 

CFR 178.340, which assume an average passenger weight of 140 pounds. Dynamic testing 

with the 14-person load showed that the vessel could capsize if the port beam was exposed 

to wind and waves for a substantial period. When the beam was exposed for 30 minutes, the 

vessel in the 14-passenger condition capsized in 9 of 40 cases. In both tasks 3 and 5, the 

calculations did not consider the dynamic effects of passenger movement (voluntary or 

involuntary) on board the vessel or the vessel’s heel during a turn. The simulations did not 

account for corrective action, such as changing heading, that the vessel operator could take.

44 Wave height, length, and period depend upon such factors as wind speed, how long the wind has 

blown, and fetch, that is, the straight distance a wave has traveled over the water’s surface. 

45 The assumed wind and wave conditions were based on witness interviews, photographs taken shortly 

before the accident, and meteorological data from 1550 to 1600.

46 AQUA is a suite of ship dynamics software. AQUA Drift, a subprogram of the suite, is a 

Computational Fluid Dynamics program that solves ship motion problems as a time history by calculating 

the hydrodynamic and aerodynamic response of a moving vessel subjected to waves, wind, and current.
Factual Information 41 Marine Accident Report

Tasks 6 and 7 documented the Lady D’s loss of stability as measured by reduced 

righting energy while total passenger load and wind speed increased. (See table 7.)

Table 7. Lady D righting energy under different loading cases

Loading Case

Total Load

(pounds)

Reserve Righting Energy at Different Wind 

Speeds (foot-degrees)

30 Knots 40 Knots 50 Knots

14 people at 140 pounds each 1,960 37 28 17

25 people at 140 pounds each 3,500 17 10 4

Accident condition 4,210 6 2 None *

* In the actual loading condition at a 50-knot wind speed, the vessel would capsize as the heeling moment exceeds the 

vessel’s static righting moment.

Vehicle Performance Reconstruction

Safety Board engineers amassed evidence from a variety of sources to reconstruct 

the accident timeline and vessel position before and after the capsizing. Two digital 

photographs taken by a passenger were used to estimate vessel position and heading as a 

function of time during the accident voyage. The true camera bearing was reconstructed 

using uniquely aligned landmarks that were visible on the horizon of each photograph. 

Foreground data in each photograph, vessel geometry, and the passenger’s known seating 

location were used to establish the camera bearing relative to the vessel bow. The vessel’s 

heading was then calculated based on the true camera bearing and the camera’s bearing 

relative to the vessel bow. 

Time-encoded data from the digital photographs were used to locate the photo 

sequence on a master event time line and to document the position and heading of the 

vessel before it capsized. Vessel position was estimated using the intersection of the two 

true camera bearing lines. The two source photographs were taken 11 seconds apart; 

however, water taxis are relatively low-speed vessels, so the position could be estimated 

reasonably accurately.

Additional vessel position and heading data were established based on the 

eyewitness accounts of Navy Reservists, digital photographs taken by Navy personnel 

participating in rescue efforts on the LCM-8 vessel, and a digital photograph provided by 

the BCFD.

Other Information

Postaccident Actions by the Coast Guard

Stability Proof Test of Similar Vessels. Following the capsizing, Coast Guard 

Sector Baltimore ordered the Lady D’s sister vessel, the Patricia P, and a pontoon vessel 
Factual Information 42 Marine Accident Report

of similar size, the W. B. Morgan, to cease carrying passengers until a PSST of the vessels 

could be completed. The testing by the Coast Guard marine inspector, conducted on April 

14, 2004, and witnessed by Safety Board investigators, determined that the maximum 

number of people that the Patricia P and the W. B. Morgan could carry was 15 and 16, 

respectively, rather than 25 as indicated on the vessels’ COIs. In both tests, the inspector 

used the testing conditions listed in 46 CFR 178.330, which assume a weight per person of 

140 pounds given that the vessels operated exclusively on protected waters and that the 

passenger load consisted of men, women, and children. Following the test, the Coast 

Guard deactivated the vessels’ COIs at the owner’s request. 

Based on the PSST findings, the MSO for Coast Guard Sector Baltimore ordered a 

review of the COIs for all pontoon passenger vessels in the operating area and, where 

necessary, adjusted the number of passengers permitted. Coast Guard Sector Baltimore 

used the weight criterion of 140 pounds per person specified in the regulations in making 

the adjustments.

In response to questions raised by the Safety Board and concerns about the results 

of the tests conducted by Coast Guard Sector Baltimore, Coast Guard headquarters sent a 

memorandum to the agency’s field units requesting data on all inspected pontoon vessels 

in their areas. After receiving and analyzing the information, Coast Guard headquarters 

provided the field offices with a summary of findings, including comments from the field 

offices. The summary section pertaining to stability tests indicates, among other findings, 

that most units understood and applied the pontoon stability test as appropriate. Several 

field offices had suggested raising the weight allotted per passenger in the stability test to 

160 pounds for protected waters to more accurately reflect the current size of an average 

American. 

Coast Guard headquarters subsequently issued a memorandum to the field offices 

containing guidance addressing some of their concerns and questions. The memorandum 

conceded that Americans are heavier today, but stated that the weight allowance 

was derived for vessels operating exclusively on protected waters and assumes a 

mix of women, children, and...men. It’s what we have in the regs [regulations]; 

it’s what we have to use. Remember, the simplified tests (conventional or 

pontoon) are conservative in nature. Some of the conservative factor will “make 

up” for a weight per passenger that doesn’t seem to accurately represent the 

average American. 

Pontoon Vessel Stability Project. According to Coast Guard officials, the 

headquarters memorandum issued to field offices after the Lady D capsizing became the first 

phase in a multiphase action plan designed to evaluate and improve the current pontoon 

vessel stability process. (See table 8.) A discussion of several completed action items follows. 
Factual Information 43 Marine Accident Report

Table 8. Action items in Coast Guard pontoon stability project

Action Item

1. Query field to determine size of pontoon vessel fleet.

2. Review casualty data to identify other casualties involving pontoon vessels. Include analysis of 

recreational vessels if data is available....

3. Provide support and document activities to field units as requested and necessary to ensure 

appropriate tests are conducted and correct procedures followed.

4. Evaluate current pontoon stability process, including determination of limitations of the current test, a 

comparison of righting arms/energy vs. a conventional hull (classic naval architecture and challenge to 

the assumption that initial stability predicts adequate dynamic sea keeping) and a validation of “checks” 

put out to the field in the feedback/“interim guidance.”

5. Analyze alternate stability tests for pontoon vessels (American Boat and Yacht Council, International 

Organization for Standardization) to provide comparison with current pontoon stability test and include 

pros and cons of use of these alternate tests.

6. Suggest/recommend appropriate use of current (or other) test with more guidance on handling vessels 

of unusual proportion and form, of a particular length to beam ratio (if appropriate), or calculation of the 

number of passengers.

7. Report out on items 4, 5 & 6 above to include recommendations for implementation (such as NVIC, 

regulatory change).

8. Review and advise on other discontinuities noted during the review of current processes.

9. Sharing of report (item 7 above) as a basis for a process action team or other chartered industry/Coast 

Guard working group (including pontoon manufacturers, designers, American Boat and Yacht Council 

technical committee) to review results and obtain industry peer review.

10. Design job aid for appropriate pontoon stability test.

11. Analyze subdivision requirements for vessels that carry more than 49 passengers. Compare 

requirements to current build practices in industry.

12. Review guidance on seasonal restrictions and egress (NVIC 7-91 and NVIC 1-01) for application to 

pontoon vessels.

13. Review processes at Sector Baltimore.

Policy Letter 04-10. On October 4, 2004, Coast Guard headquarters issued policy 

letter 04-10 to OCMIs providing guidance for evaluating stability and subdivision 

requirements of small passenger vessels inspected under 46 CFR Subchapter T. Included 

with the guidance was a job aid47 for Coast Guard inspectors to use when witnessing 

stability proof tests for pontoon vessels operating on protected waters (action item 10). 

The notes on the job aid state that, for purposes of testing, the weight per passenger should 

equal 160 pounds, “except when passenger loads consist of men, women, and children.” 

In such cases, the job aid indicates a weight per passenger of 140 pounds “may be used.” 

The job aid required that the inspector include a separate line item for the weight of 

crewmembers, with the assumed crew test weight equal to 160 pounds per person.

Based on Coast Guard correspondence and the weight standard contained in the 

job aid for pontoon stability testing, on December 20, 2005, the Safety Board issued 

Safety Recommendation M-04-4 regarding passenger weight calculations. A full 

discussion of the recommendation appears later in this section.

47 A copy of the job aid appears in appendix C.
Factual Information 44 Marine Accident Report

Pontoon Vessel Stability and Subdivision Study. In February 2005, a study 

team of Coast Guard personnel initiated an internal study to determine whether the Lady 

D, in a full load condition and operating in protected waters, could meet alternate stability 

requirements contained in 46 CFR Subchapter S, “Subdivision and Stability.”48 The 

modeling software49 calculated the stability of the Lady D under two assumed loading 

conditions: 25 passengers weighing an average of 140 pounds each and 25 passengers 

weighing an average of 168 pounds each. The alternate stability requirements considered 

in the project included 

• 46 CFR 170.170, “Calculations Required” minimum GM with wind heeling 

moment [weather criterion],

• 46 CFR 170.173(e)(2), “Criterion for Vessels of Unusual Proportion and 

Form” (weather criterion), and

• 46 CFR 171.050, “Intact Stability Requirements for a Mechanically Propelled 

or a Nonself-propelled Vessel” minimum GM with passenger heeling moment 

[passenger loading criteria for large vessels].

The study team found50 that with an assumed load equal to 25 persons weighing 

140 pounds each, the Lady D met the minimum stability criteria in Subchapter S. 

However, using an assumed load equal to 25 persons weighing 168 pounds each—the 

actual per-person weight average on the day of the accident—the vessel failed to meet 

Subchapter S stability criteria, 46 CFR 170.173(e)(2).51 The criterion not met was 

minimum energy requirements because the Lady D had only 70 percent of the required 10 

foot-degrees under the righting arm curve between 0° and the angle of maximum righting 

arm. The study team concluded that

[t]he difference between the assumed and actual passenger weight equates to a 

one-inch change in static freeboard. Given the dynamic environmental factors that 

affected this casualty, we cannot determine whether this small gain in 

freeboard/buoyancy would have changed the response of the vessel to the adverse 

weather and sea conditions reported at the time of the casualty.

The study team further noted

There are several dynamic factors that affect stability, not all of which are 

precisely known for the time of this casualty. They are at varying times 

48 Small passenger vessel regulations (Subchapter T) require that pontoon boats be subjected to a 

simplified stability proof test specified at 46 CFR 178.340. Alternatively, the vessel owner can perform more 

detailed stability calculations specified in Subchapter S, which applies to all inspected vessels. Regulations 

in Subchapter T state that failure of the proof test does not necessarily mean that the vessel lacks stability for 

the intended route, service, and operating condition, but that calculations or other methods must be used to 

evaluate the vessel’s stability.

49 Creative System’s “General Hydrostatics” stability software.

50 Note that the study findings of the internal staff team are subject to review and may not represent the 

final position of the Coast Guard. 

51 This weather criterion was developed to better assess overall stability of these types of vessels because 

their hull forms produce large initial stability but a small range of stability and small righting energy. 
Factual Information 45 Marine Accident Report

cumulative or canceling, and their effects relative to the vessel’s interdependent 

stability characteristics (i.e., maximum righting arm, area under the righting arm 

curve, range of stability, and heeling angle) result in an infinite and complex 

matrix of vessel reactions. Accordingly, we cannot reliably assess the stability 

required to survive the actual conditions due to the complexity of the calculations 

and the wide range of introduced error. 

April 2005 Analysis of Comparative Stability Standards. On April 28, 2005, the 

study team completed an analysis of the independent variables affecting pontoon vessel 

stability that are found in existing regulatory and industry stability standards (action items 4 

and 5).52 The study team reviewed the pontoon vessel simplified stability test variables 

contained in Subchapter T, Subchapter S, the American Boat and Yacht Council consensus 

standards, and the International Organization for Standardization (ISO) standards.

The PSST was designed in the late 1960s. At that time, pontoon vessels were fairly 

simple structures with two pontoons, an open deck, and handrails. The PSST assumed that 

passenger heeling moments would always be larger than any wind heeling moments. 

Since the development of the test, pontoon-style passenger vessels have evolved into more 

complicated structures, sometimes incorporating completely enclosed deckhouses. These 

modifications raise the center of gravity and dramatically increase the windage area of the 

vessels. In recognition of this change, the Coast Guard sought to determine whether the 

pontoon vessel simplified stability study in 46 CFR 178.340 was still appropriate, given 

the changes in the CFR and modern pontoon vessel design. The April 2005 study therefore 

addressed the following questions:

• Is the PSST conservative? Do vessels that pass the PSST also meet the other 

requirements in the 46 CFR Subchapter S? (46 CFR 170.173, 170.170, and 

171.050)

• How do the PSST and CFR requirements compare to other standards, such as 

those of the American Boat and Yacht Council53 and the ISO54?

• Because the PSST only calculates for passenger heel, were wind heeling 

moments considered negligible when the PSST was developed? If so, should 

wind heel now be considered in the PSST?

• Has the envelope of pontoon vessel construction been expanded such that 

pontoon vessels with certain characteristics (small beam/length ratio, initial 

submergence, or pontoon diameter) are less safe? 

• Should the PSST be modified or changed due to modern construction methods 

and changes in the regulations since the PSST was developed?

52 “Study on the U.S. Domestic Intact Stability and Subdivision Requirements for Twin Hull Pontoon 

Passenger Boats Less Than 65 Feet in Length,” April 28, 2005.

53 American Boat and Yacht Council Standard H-35, “Powering and Load Capacity of Pontoon Boats.”

54 ISO Standard 12217-1: 2002, “Small Craft—Stability and Buoyancy and Categorization—Part 1: 

Non-Sailing Boats of Hull Length Greater Than or Equal to 6m [meters].”
Factual Information 46 Marine Accident Report

The parameters examined in the study were as follows:

• Pontoon diameter;

• Distance between pontoon centers;

• Height of center of gravity; and

• Depth of pontoon submergence at full load.

The results of the study showed that pontoon vessels with certain geometries could 

pass the PSST in 46 CFR 178.340 and still fail other alternative CFR criteria in Subchapter 

S. That is because wind heel is not negligible for some pontoon vessels, and multihull 

vessel stability is sensitive to hull dimensions and draft. The existing PSST does not 

adequately account for these factors. The study recommended restricting the applicability 

of the PSST to pontoon boats within defined parameters.55 (See table 9.) This restriction is 

further supported by analysis of the ISO standard, which shows that vessels with 

parameters outside these recommendations have difficulty passing ISO criteria for Beaufort 

4 conditions56 (1.5-foot wave heights and wind gusts to 29 mph). The results of the study 

also show that, under these recommendations, the PSST outlined in 46 CFR 178.340 is the 

most stringent of the three standards (CFR, American Boat and Yacht Council, and ISO).

Table 9. Boundary conditions for application of pontoon simplified stability test

Parameter Criteria Reason

Full load submergence

(as a percentage of 

displaced volume of the 

pontoons)

Not greater than 50% Rapid loss of righting energy for vessels 

with deeper submergence (reduced by 

5% due to weight creep)

Full load submergence Greater than 33% PSST not applicable to vessels with 

shallower submergence

Pontoon diameter Not less than 24 inches Low overall stability for vessels with 

smaller pontoons

Distance between pontoon 

centers

Not less than 6 feet This minimum value needed to meet 

protected waters criteria

The study team observed that protected waters are defined in the CFR as sheltered 

waters presenting no special hazards, such as most rivers, harbors, and lakes. This 

definition includes no wind or wave restrictions. The study recommended establishing a 

maximum allowable wind speed of 16 knots (Beaufort 4) in which pontoon vessels can 

operate or restricting vessels from operating when small craft advisories or warnings are 

in effect.

55 The Lady D’s pontoons were 24 inches in diameter and spaced 6.1 feet apart. Full load submergence 

calculations based on the Safety Board contract were as follows: 14 persons at 140 pounds each was 46 

percent; 25 persons at 140 pounds each was 53 percent; 25 persons at 168 pounds each was 56 percent.

56 In 1805, Sir Francis Beaufort developed the Beaufort Scale, which is a method for estimating wind 

strengths without the use of instruments. It is still used for this purpose as well as for tying various 

components of weather (wind strength, sea state, and observable effects) into a unified picture.
Factual Information 47 Marine Accident Report

The study team also found the calculation at 46 CFR 171.050 (minimum GM 

required for passenger heel) is not relevant to pontoon passenger vessel stability because 

the passenger weight movements are only half the required weight movements in the 

PSST. The calculation produces values (numbers of passengers) well beyond the safe 

carrying capacity of pontoon passenger vessels.

Coast Guard Impact Study. In October 2005, the Coast Guard issued a notice in 

the Federal Register57 advising that it was conducting a 1-year impact study to determine 

the effect on the marine industry of increasing the standard allowance for passenger 

weight and size used to calculate the intact stability of domestic passenger vessels. The 

impact study resulted, in part, from the Safety Board’s Safety Recommendation M-04-4, 

and from preliminary findings of the Coast Guard’s pontoon boat stability study. The 

notice states that because current passenger weight standards apply to all types of vessels, 

the evaluation should not be limited to pontoon boats but extend to all small passenger 

vessels. The Coast Guard engaged a consultant to perform the impact study, which will be 

completed in two phases and will include the following actions: 

• Evaluate potential impacts to the domestic passenger vessel fleet caused by an 

increase in average passenger weight and size;

• Identify the degree of impact on fleet segments;

• Identify and suggest changes to existing regulations;

• Develop efficient implementation strategies; and

• Provide assistance for the development of draft regulatory changes and 

associated regulatory analyses, including economic and environmental 

analyses. 

Once the impact study is completed, the Coast Guard will publish a notice in the 

Federal Register advising the public that the study’s results are available and requesting 

comment.

Accidents Involving Pontoon Passenger Vessel Stability. 

As part of this accident investigation, the Safety Board asked the Coast Guard to 

review its casualty records for the purpose of identifying previous pontoon vessel 

capsizings. The Coast Guard responded that a review of its electronic records indicated 

that, since 1981, the Lady D is the only capsizing casualty involving a commercial 

pontoon-style passenger vessel. 

Previously Issued Safety Recommendation

Recognizing the negative effect of overloading on pontoon vessel stability, in 

December 2004, the Safety Board issued the following safety recommendation to the 

Coast Guard:

57 Vol. 70, No. 207 (October 27, 2005), pp. 61987-61988.
Factual Information 48 Marine Accident Report

M-04-4 

Revise your guidance to Officers in Charge, Marine Inspection, to determine the 

maximum occupant capacity of small passenger pontoon vessels either (1) by 

dividing the vessel’s simplified stability proof test weight by the per-person 

weight allowance for an average adult stipulated in Federal Aviation 

Administration Advisory Circular 120-27D (174 pounds per person, assuming 

summer clothing and a 50-50 gender mix), or (2) by restricting (at the time of 

loading) the actual cumulative weight of passengers and crew to the vessel’s 

simplified stability proof test weight.

The Board noted, “Vessels operated in an overloaded condition are exposed to a 

higher risk of capsizing,” and suggested ways to ensure that the certificated load for a 

vessel is appropriate. The Board suggested that one way to accomplish this would be to 

increase the average weight used to calculate maximum occupant capacity. The Safety 

Board proposed that, as an alternative, the weight of persons allowed on board could be 

limited to the allowable load resulting from the vessel’s PSST. The Board suggested that 

this could be accomplished by painting a load reference line on the vessel’s pontoons or by 

summing people’s actual weights as they boarded the vessel.

On April 7, 2005, the Coast Guard responded to the recommendation, stating that 

it concurred with the premise behind option (1), that is, the need to update the weight 

standard, but that it did not concur with option (2) “because typical operators of small 

passenger pontoon vessels do not have a means to accurately determine the cumulative 

weight of passengers and crew at the time of loading.” The Coast Guard noted that the 

current weight standards “are set out in regulation at 46 CFR 178.330 and extend to all 

other types of small passenger vessel types”; therefore, necessary changes went beyond a 

revision of OCMI guidance.

The Coast Guard indicated that it had chartered a workgroup to analyze the 

passenger weight issue and to assess the potential impacts of regulatory changes. The 

Safety Board responded on July 26, 2005, stating, “Because the Coast Guard has initiated 

action to revise the guidance as requested, Safety Recommendation M-04-4 is classified 

‘Open—Acceptable Response.’”

Following the notice published in the Federal Register regarding the impact study 

contracted by the Coast Guard to determine the effect on the marine industry of increasing 

the standard allowance for passenger weight and size used to calculate the intact stability 

of domestic passenger vessels, the Safety Board advised the Coast Guard that Safety 

Recommendation M-04-4 is classified “Open—Acceptable Response,” pending the 

outcome of the impact study and subsequent planned actions. 

Status of Sister Vessels

As discussed elsewhere in this report, because of the issues identified by the Coast 

Guard in its review of the Lady D’s stability, the Coast Guard evaluated the stability of the 

three purported sister vessels. In the case of the Patricia P (formerly the Fells Point 

Princess) evaluation, the Coast Guard witnessed a simplified stability test in April 2004 
Factual Information 49 Marine Accident Report

and determined that it could be certificated to carry 15 persons. However, the owner of the 

vessel decided to remove the vessel from service and requested that the Coast Guard 

deactivate the vessel’s COI, which the Coast Guard did. The Coast Guard also evaluated 

the stability of the Patricia P based on calculations demonstrating compliance with 46 

CFR Subchapter S, and determined that the vessel could carry 20 persons and still comply 

with Subchapter S. 

At the time of the Lady D accident, the Raven was in seasonal service on the 

Maumee River in Toledo, Ohio. In June 2004, the Coast Guard performed a PSST on the 

Raven, which resulted in it being certificated to carry 19 persons.58 The vessel remains in 

active commercial passenger service on the Maumee River. 

The Misty Harbor II was removed from active service in August 2001 and put into 

dry storage at the Susquehanna Santee Boatworks boatyard. After the Lady D accident, the 

Coast Guard evaluated the stability of the Misty Harbor II and determined that it could 

carry 15 persons. Calculations according to 46 CFR Subchapter S indicated that the vessel 

could carry 21 persons. As of this date, the vessel does not have a COI and remains out of 

service at the boatyard.

58 The PSST indicated that 19 persons could be carried. Subsequently, the pontoons were filled with 

foam to address corrosion wastage. Because of the additional weight of the foam, the allowable person load 

was reduced to 17.
50 Marine Accident Report

Analysis

General

The analysis first identifies factors that can be eliminated as causal or contributory 

to the accident. It then discusses the following safety issues identified in the accident 

investigation:

• Passenger weight criteria for stability assessment;

• Pontoon vessel stability standards; and

• Policies and procedures pertaining to weather operations.

This analysis also examines the factors affecting survivability in this accident.

Exclusions

The Safety Board considered whether such factors as drug (illegal and prescribed) 

or alcohol use, sleep deficit, or physical impairment might have adversely affected the 

actions of the Lady D’s crewmembers on the day of the accident. The master said that he 

took no prescription drugs, and toxicological tests of blood and urine samples that he 

provided within 3 hours of the capsizing were negative for the presence of drugs and 

alcohol. The mate said that he took Zantac (cymetadine) for acid reflux disease, and 

toxicological tests of blood samples that he provided within 2 hours of the capsizing were 

negative for the presence of alcohol. Both men indicated that they did not change their 

routines in the days before the accident. According to their interviews, the master and the 

mate respectively averaged about 8 hours and 7 1/2 hours of sleep nightly, consistently at 

the same times. Thus, they probably were not experiencing a sleep deficit at the time of 

the accident. The master wore a hearing aid to help discriminate sounds but said he had no 

problem hearing the radio transmissions from both the senior captain and the taxi office 

manager. Based on the information provided, the Safety Board concludes that sleep 

deprivation, alcohol, drugs, and physical impairments were not factors in this accident.

As a matter of routine investigation, the Safety Board examined the Lady D’s 

mechanical systems, principally the steering and propulsion systems, to determine 

whether they showed deficiencies that might have been factors in this accident. The 

master of the Lady D told investigators that he did not experience any problems with the 

vessel’s propulsion and steering systems during his attempt to transit the waterway but 

was not able to make headway because he was buffeted by strong winds. The Safety 

Board’s examination of the vessel’s hydraulic-type steering mechanism found that it 

operated normally and showed no evidence of leaks. Manipulation of the steering wheel 

resulted in it turning smoothly, and operation of the steering control resulted in a full range 
Analysis 51 Marine Accident Report

of movement. The engine motor showed no external indication of failure. The Safety 

Board therefore concludes that the mechanical condition of the Lady D’s propulsion and 

steering systems was not a factor in this accident.

During the general vessel examination, investigators noted that the aft outboard 

side of the starboard pontoon had a dent and a small puncture near the waterline. If the 

damage had existed before the accident, at least some flooding would have occurred in the 

aft portion of the sectioned pontoon. Such flooding would have caused the pontoon to lose 

reserve buoyancy, which, in turn, would have reduced the stability of the vessel. 

From interviews with various individuals, however, the Safety Board received 

accounts that support the finding that the starboard pontoon was not damaged before this 

accident. The water taxi was not operated in a manner that might contribute to damage on 

the side of a pontoon, particularly at the aft end. The door to the cabin through which 

passengers embarked was at the bow; consequently, the vessel was docked bow-side to the 

pier. Seaport Taxi’s fleet captain said that he had checked the Lady D when he arrived at 

the marina that morning and noted no damage to the vessel, including both pontoons. Both 

the master and the mate were required to perform checks listed on a daily log sheet before 

putting the Lady D into operation, and both said that they did not observe any indication 

that the starboard pontoon might be damaged. The responders from the Naval Reserve 

center stated that during the rescue effort, they positioned the bow gate of their LCM-8 

under one of the Lady D’s pontoons and lifted it up in order to free people trapped inside 

the cabin. The impact of a large structure made of steel with a smaller structure made of 

aluminum could have caused the dent and puncture in the pontoon. 

Investigators found no other significant damage to either pontoon on the Lady D. 

In addition, examination of all other vessels in the Seaport Taxi fleet revealed that their 

general condition was good and that their pontoons were free of damage such as that 

found on the hull of the Lady D’s starboard pontoon. Thus, both the postaccident 

interviews and the vessel examinations support the finding that the damage to the 

starboard pontoon most likely occurred after the capsizing. The Safety Board therefore 

concludes that examination of the Lady D’s hull showed no evidence of preaccident 

damage.

Accident Analysis

While en route from Fort McHenry to Fells Point, the commercial pontoon vessel 

Lady D, with 2 crewmembers and 23 passengers on board, encountered gusting westerly 

winds. Despite efforts by the master to maneuver the vessel to a safe haven, he could not 

control the water taxi in the wind, and the vessel ultimately capsized in the Northwest 

Harbor, where the West Channel and the East Channel converge. Responding rescuers, 

including Navy reservists, as well as BCFD and police assets, succeeded in recovering and 

transporting 22 of the vessel’s occupants to local hospitals within less than an hour. The 

bodies of 3 victims were not recovered until the following week. As a result of this 

accident, 5 people died, 4 people suffered serious injuries, and 12 sustained minor injuries. 
Analysis 52 Marine Accident Report

Cause of the Capsizing

The pontoon-style small passenger vessel Lady D was built in 1996 and had only 

been operated in Baltimore Harbor as a water taxi. Its first owner/operator was Baltimore 

Harbor Shuttle. In 2000, Seaport Taxi, through its parent company Living Classrooms, 

obtained the Lady D and operated the vessel primarily on the company’s outer loop route 

between Fells Point and Fort McHenry. Interviews with the original owner and officials of 

Seaport Taxi revealed that in the 8 years during which the Lady D had transported 

passengers, the vessel had never experienced any major incidents. In the year before this 

accident, only one master who had operated the Lady D had submitted a daily log report 

indicating that he had encountered “windy” conditions; however, his report did not 

indicate that he had been forced to tie up because of the winds. Seaport Taxi records show 

that the company transported more than 200,000 passengers annually. Thus, the Lady D

most likely had previously operated with a full load of passengers and crew during both 

fair and inclement weather but not in conditions like those on the day of the capsizing. 

In the case of the master involved in the accident, he had worked for Seaport Taxi 

for 3 years, primarily on weekends and occasionally on weekdays during the peak season. 

He had been assigned almost exclusively to the Lady D during this time. He stated that he 

had operated the Lady D before in inclement weather and thought that on some occasions 

he might have been caught in wind gust conditions of 40 to 50 knots. He said, however, 

that he had never been caught in conditions like those on the day of the accident. In the 

few minutes before the capsizing, no meteorological sensor in the area captured wind 

conditions such as those the Lady D master said he had previously experienced. The 

evidence therefore suggests that the master probably incorrectly estimated the wind 

conditions on previous occasions.

In seeking to determine what on the day of the accident so greatly affected the 

stability of the vessel that it capsized, the Safety Board found that a combination of factors 

contributed to the vessel’s overturning. Some factors stemmed from errors made in 

determining the allowable number of occupants in certificating the vessel. Those errors 

permitted the vessel to operate in an overloaded condition that, when combined with the 

effects of wind and waves, significantly reduced the stability of the pontoon boat. The 

investigation also revealed flaws in the Coast Guard’s granting of sister vessel status to 

three similar boats built after the Fells Point Princess, including the Lady D. These issues 

are discussed in greater detail in the following sections.

Certification Error

The Lady D’s stability problem stemmed from the 1992 simplified stability proof 

test of the Fells Point Princess (later renamed the Patricia P), the first of four vessels built 

over a 10-year period. The test was not conducted in accordance with the PSST protocol 

as it should have been, but rather with the SST protocol for monohull vessels. Pontoon 

vessels and monohull vessels have dramatically different stability characteristics. A 

pontoon vessel’s wide base gives it large initial stability. However, a pontoon vessel’s 

range of stability is generally much less than that of a monohull vessel and vanishes 

quickly as a pontoon begins to submerge when the vessel heels. Consequently, it was 
Analysis 53 Marine Accident Report

inappropriate to use the test protocol for monohull vessels to determine the stability and 

loading capability of a pontoon-style passenger vessel such as the Fells Point Princess.

The test document indicates that passenger heeling moment calculations were 

based on moving the test load weight from the centerline to one-third the distance to the 

extreme outboard side of the vessel (the distance needed to achieve the amount of heeling 

moment specified in the monohull test protocol). The test protocol for the PSST required 

that the test weight be moved from the centerline to the extreme outboard edge of the 

vessel, which in the case of the 8-foot-wide Fells Point Princess was a distance of 4 feet. 

Thus, the test did not provide the appropriate heeling moment for determining the 

maximum number of persons allowed. 

As a result of the inappropriate application of the SST protocol on the Fells Point 

Princess, that pontoon vessel was certificated to carry 25 persons based on the 140-pound 

average weight standard specified in Coast Guard regulations. This average weight 

standard was developed by the Coast Guard in the 1950s and assumed a mix of men, 

women, and children. 

The three vessels subsequently built by Susquehanna Santee Boatworks, which 

included the Lady D, had the same general size (36 feet long by 8 feet wide) and 

arrangement and had a superstructure for the carriage of passengers. The Coast Guard 

granted sister vessel status to these boats because of their similarities and did not subject 

them to their own stability tests. Consequently, the results of the original vessel’s stability 

certification, which was based on an inappropriate test protocol, were carried through to 

the other vessels. The Safety Board concludes that the load for which the pontoon vessel 

Lady D was certificated was based on a monohull simplified stability proof test on the 

Fells Point Princess, which was not appropriate for pontoon vessels.

Erroneous Sister Vessel Status

Although the Fells Point Princess, the Raven, the Lady D, and the Misty Harbor II

were of the same general size, the vessels differed in certain design aspects that affected 

their load-carrying capability and stability. The most notable difference was in the design 

of their deckhouses. The deckhouses of the first two vessels constructed, the Fells Point 

Princess and the Raven, had large side openings with no windows. The third and fourth 

vessels in the series, the Lady D and the Misty Harbor II, were fitted with large glass 

windows and doors. The postaccident stability analysis of the Lady D contracted by the 

Safety Board estimated that the weight of the Lady D’s glass windows and doors exceeded 

400 pounds, nearly equivalent to the weight of 3 passengers [400 pounds divided by 140 

pounds per person = 2.87 people]. 

Following this accident, the Coast Guard retested the Lady D’s sister vessels, the 

Patricia P, the Raven, and the Misty Harbor II. The Coast Guard also evaluated the 

stability of the Lady D by direct calculation. The Coast Guard’s postaccident testing of the 

sister vessels revealed that each had different load-carrying capabilities because of their 

design differences. The first vessel in the series, the Patricia P with its partially enclosed 

superstructure, was found able to carry 15 persons. The Raven, which also had a partially 
Analysis 54 Marine Accident Report

enclosed superstructure, was found able to carry 19 persons. The Misty Harbor II, with a 

fully enclosed superstructure, was found able to carry 15 persons. The differences in the 

vessels, including their occupant capacity, indicates that they were not similar enough to 

be considered sister vessels. 

While researching its records to assist the Safety Board and to conduct its own 

investigation of this accident, the Coast Guard discovered errors in the stability 

certification and sister vessel status assignment for the Lady D and the other three boats in 

the series. Coast Guard files show that the Lady D did not undergo a stability test but was 

granted sister vessel status to the Raven by the OCMI and certificated for the same 

passenger load as that vessel based on the approved results of the Raven’s stability test.

However, Coast Guard personnel could not locate any documentation of a stability test for 

the Raven. They subsequently determined that the Raven had never undergone a stability 

test but had been granted sister vessel status to the Fells Point Princess.

Granting sister vessel status to the Raven, the Lady D, and the Misty Harbor II

precluded the Coast Guard from discovering that the passenger capacity of the Fells Point 

Princess (and the later vessels in the series) was based on the inappropriate application of 

the SST on a pontoon vessel. If the Coast Guard had recognized that the Fells Point 

Princess and the other vessels in the series had not been built by the same builder and that 

the design of the Lady D’s deckhouse differed from that of the Raven and the Fells Point 

Princess, it may have required that a PSST be performed on the Lady D. The results of a 

PSST of the Lady D would have yielded a significantly different allowable occupant load 

from that of the Raven or the Fells Point Princess, to such a degree that the Coast Guard 

probably would have recognized that an error had been made in an earlier test and taken 

corrective measures. The Safety Board concludes that as a result of inappropriate sister 

vessel status to the Fells Point Princess being granted to the Raven, the Lady D, and the 

Misty Harbor II, all four pontoon boats had serious deficiencies in stability as a result of 

the inappropriate stability test used to determine the number of persons allowed on all the 

vessels. Although it was the Lady D that was involved in this accident, the potential risk of 

a capsize event was substantially the same for all four vessels during their years of 

operation.

Coast Guard headquarters, after learning of the errors in the vessel files at Coast 

Guard Sector Baltimore and being informed about the results of the postaccident stability 

testing of the pontoon vessels in series to the Lady D, directed field commanders to 

“assess their risk” as it pertained to pontoon passenger vessels within the field offices’ 

areas of responsibility. Coast Guard field office personnel subsequently reviewed the files 

and documents and analyzed the results of stability tests on file to ensure that the “stability 

conditions” of pontoon passenger vessels were accurate and, where deemed necessary, 

ordered pontoon vessels to undergo new stability tests. Headquarters guidance to the field 

offices also provided some examples of defined “Reasonable Operating Conditions,” a 

common entry that is added to the COI for a vessel when it operates in areas where wind 

and other factors might affect its safe operation. Additional information about 

postaccident measures taken by the Coast Guard appears later in this analysis, under 

“Pontoon Vessel Stability Standards.”
Analysis 55 Marine Accident Report

Passenger Overloading

From interviews and its review of emergency room records, the Safety Board 

found that the average weight of the Lady D’s occupants on the day of the accident was 

168 pounds, significantly more than the per-person weight standard of 140 pounds used to 

verify the allowable number of passengers in stability proof tests. The combination of the 

excessive number of persons permitted in the original certification and the higher-thanassumed average weight of the people on board the Lady D resulted in the vessel being 

significantly overloaded. 

The correctly calculated capacity allowed for 14 persons at 140 pounds each, or 

1,960 pounds total; however, the vessel actually carried 25 persons at 168 pounds each, or 

4,200 pounds total. The additional weight resulted in the vessel’s pontoons being more 

deeply submerged, which, in turn, caused a reduction in the reserve buoyancy available to 

resist overturning moments. The Safety Board concludes that the combination of the use 

of an out-of-date average weight standard for occupants of small passenger vessels and the 

excessive number of persons permitted in the Lady D’s original certification resulted in 

the pontoon boat carrying a load that reduced its reserve buoyancy and compromised its 

stability characteristics, which made it more susceptible to capsizing on the day of the 

accident. The issue of the weight standard is addressed later in this analysis, under

“Passenger Weight Criteria for Stability Assessments.”

Influence of Weight and Wind on Intact Stability

The Safety Board’s stability study examined and charted the effects of load and 

wind on the intact stability of the Lady D. Figure 6 shows the charted righting arm curves 

for the following three load cases, which assume calm waters: 

• The first case—14 persons weighing an average of 140 pounds each (1,960 

pounds total)—represents the maximum safe load condition allowed for the 

Lady D in accordance with the PSST at 46 CFR 178.340, which would be the 

test protocol used today to certificate the Lady D. 

• The second load case—25 persons each weighing 140 pounds (3,500 pounds 

total)—represents the load allowed under the Coast Guard COI for the Lady D, 

which reflects the inappropriate use of the monohull simplified stability proof 

test.59

• The third loading case—25 persons weighing an average of 168.4 pounds 

(4,210 pounds total)—represents the Lady D’s load condition at the time of the 

accident.

The charted values show how increasing the load carried by the vessel 

significantly decreased the maximum righting arm of the vessel and the vessel’s range of 

stability. The maximum righting arm for the vessel in the first load case was 1.9 feet and 

59 The second loading case is somewhat artificial in that it was used only to distinguish between the 

separate effects of first and third cases (the type of stability test and the heavier weight of contemporary 

Americans).
Analysis 56 Marine Accident Report

the vessel’s range of stability was about 48°. In the second load case, the maximum 

righting arm was 1.1 feet and the vessel’s range of stability was about 45°. In the third load 

case, which was the load condition at the time of the capsizing, the maximum righting arm 

was 0.7 feet and the vessel’s range of stability was 33°. Under these conditions, if the 

vessel heels beyond a 33° angle of heel, no righting energy remains to bring it back to an 

even keel, with the result that the vessel will capsize. 

Figure 6. Righting arm curves for three load cases. The top, solid curve is 

for the first loading case of 1,960 pounds. The middle curve is for the 

second case with a 3,500-pound load. The bottom dashed curve is for the 

Lady D as loaded on the day of the accident (4,120 pounds).

LADY D Righting Arm

-0.5

0

0.5

1

1.5

2

0 10 20 30 40 50 60

Angle - degrees

Arm - feet

1960 lbs 3500 lbs 4210 lbs

Maximum Righing Arm = 1.9 feet

Range of Stability 33 deg.

48 deg.

45 deg.

Max. Righting Arm = 1.1 feet

Max. Righting Arm = 0.7 feet

Graphic courtesy of Alion Science and Technology, JJMA Maritime Sector

The passenger load on the Lady D on the day of the accident therefore had a major 

negative effect on the vessel’s intact stability. The weight of the persons on board the 

vessel increased its draft, which reduced the reserve buoyancy of the pontoons. The 

reserve buoyancy of the pontoons, especially of the downwind pontoon, is what produced 

the righting force that could counteract environmental forces that would heel the vessel 

farther over. Therefore, the loss of reserve buoyancy reduced the ability of the Lady D to 

resist environmental factors such as wind and waves on the day of the accident.

The static analysis of the effect on the vessel of wind alone showed that the force 

of a 40-knot wind was not adequate to overturn the vessel. Figure 7 charts the impact of a 

40-knot wind on the intact stability of the Lady D as loaded on the day of the accident. The 

figure shows the vessel’s “residual righting arm,” which is the difference between the 

righting arm for the vessel and the wind-heeling arm. In calm water, a 40-knot wind would 

heel the vessel over to a 6.1° angle. 
Figure 7. Residual righting arm for Lady D in 40-knot wind.

Graphic courtesy of Alion Science and Technology, JJMA Maritime Sector

Analysis 57 Marine Accident Report

In the heeled condition, illustrated by figure 8, the Lady D’s pontoon on the side 

opposite the wind was almost completely submerged and had little reserve buoyancy left 

to counteract additional heeling forces. Thus, considering the Lady D’s load and wind 

conditions on the day of the accident, at an angle of slightly less than 22° of heel, the 

vessel would have had no reserve righting arm and nothing to prevent it from capsizing. 

At a wind speed of 40 knots, very little margin remained in the vessel’s intact stability to 

counteract additional dynamic heeling forces. Any additional external force such as a 

wave hitting the boat, a rapid maneuver by the boat’s master, or a shift in the boat’s center 

of gravity due to passenger movements would have been enough to capsize the vessel. 

The wave height at the time of the capsizing was about 1.25 feet, and the master 

was trying to maneuver the vessel to a safe haven. The Safety Board therefore concludes 

that the Lady D capsized as a result of the combined effects of the excessive load it carried 

and the wind and wave conditions experienced at the time of the accident. 
Figure 8. Sketch of Lady D in the heeled condition.

Graphic courtesy of Alion Science and Technology, JJMA Maritime Sector

Analysis 58 Marine Accident Report

Passenger Weight Criteria for Stability Assessments

Within months of this accident, the Safety Board, after determining the Lady D’s 

total weight load and its detrimental effects on that vessel’s stability, issued a safety 

recommendation to the Coast Guard. That action was warranted because the design of 

most pontoon-style small passenger vessels makes them particularly susceptible to 

capsizing when they operate in an overloaded condition. Safety Recommendation M-04-4 

asked that the Coast Guard take measures to minimize the possibility that occupant weight 

load carried on a pontoon passenger vessel would exceed the stability proof test weight. 

In its letter to the Coast Guard, the Safety Board suggested that as one method to 

ensure that the certificated load is accurate, the average weight used to calculate maximum 

occupant capacity should be increased. The Board cited the per-person weight criterion of 

174 pounds used by the Federal Aviation Administration for aircraft loading. The Board 

suggested that as an alternative measure, the cumulative weight of persons permitted 

could be limited to the allowable weight load calculated in the vessel’s PSST. This 

alternative measure could be accomplished in various ways, including summing the actual 

weights of people as they boarded the vessel, or by placing a load reference line on the 

vessel’s pontoons to indicate the total allowed occupant weight.

The Coast Guard concurred, in part, with the recommendation, and provided the 

Safety Board with an early draft of its multiphase action plan addressing pontoon 

passenger vessel stability. The Coast Guard chartered a workgroup to analyze the 

passenger weight issue and to assess the potential impact of regulatory changes in pontoon 

vessel stability calculations. The workgroup was tasked to review background material 
Analysis 59 Marine Accident Report

and determine the potential impacts of changes to the regulations regarding passenger 

weight, simplified stability proof tests, and other small passenger vessel stability 

requirements. Based on the workgroup’s plan, the Safety Board classified Safety 

Recommendation M-04-4 “Open—Acceptable Response” on July 26, 2005.

The Coast Guard announced in the October 27, 2005, Federal Register that it was 

contracting for a study to determine the potential impact on the marine industry that would 

result from increasing the passenger weight and size standards used when calculating the 

intact stability of all domestic passenger vessels.

The Safety Board’s subsequent investigative work, including preliminary findings 

in the October 2, 2005, capsizing involving the monohull passenger vessel Ethan Allen in 

Lake George, New York, demonstrate that excessive load due to underestimating the 

weight of passengers needs to be addressed in the Coast Guard’s intact stability criteria for 

all domestic passenger vessels. The 140-pound weight standard is used in the PSST (46 

CFR 178.340), the SST (46 CFR 178.330) for monohull small passenger vessels on 

protected routes, and the Subchapter S stability calculations for the minimum GM 

required for passenger heel (46 CFR 171.050). Updating these standards will result in a 

more realistic assessment of the number of passengers a vessel can safely carry. 

Considering that statistically representative average passenger weight is subject to change, 

the Coast Guard should also identify how best to address a test value that may change in 

the future. 

Accordingly, the Safety Board believes that the Coast Guard should revise 

regulations to require that passenger capacity for domestic passenger vessels be calculated 

based on a statistically representative average passenger weight standard that is 

periodically updated. As a result of this recommendation, Safety Recommendation M-04-

4 is classified “Closed—Superseded” in this report.

Updating the average passenger weight standard will be a positive step toward 

ensuring that a vessel is properly certificated for the number of passengers it can safely 

carry. However, even if the number of passengers permitted is based on an increased 

average weight standard, the problem persists that a vessel can become overloaded if 

many of the passengers on board are heavier than the standard. Masters therefore need an 

easy way of identifying whether the passenger load they are preparing to carry will 

compromise the stability of their vessels. If a mark were painted on the hull that 

corresponded to the waterline when the vessel was under maximum approved load, any 

crewmember could easily determine whether the vessel was overloaded simply by 

observing the vessel’s draft in relation to that mark. The Safety Board concludes that 

masters need a simple and ready means such as a mark on the hull to determine whether 

their vessels are overloaded and potentially unsafe. The Safety Board therefore believes 

that the Coast Guard should identify a method for determining the maximum safe load 

condition of a small passenger vessel at the time of loading, such as a mark on the side of 

the hull, and require that the vessel owners implement that method.
Analysis 60 Marine Accident Report

Pontoon Vessel Stability Standards

Following this accident, investigations and tests conducted by both the Coast 

Guard and the Safety Board revealed that some factors affecting pontoon vessel stability 

are not adequately addressed in existing regulatory standards. The Coast Guard’s action 

plan involves several reviews and studies, some of which are summarized later in this 

analysis. Early actions involved querying the field offices regarding the number of small 

passenger pontoon vessels under their purview and advising field commanders to initiate 

quality checks of stability documents on file. Subsequent actions involved evaluating the 

current pontoon stability approval process, including determining limitations of the 

current test and analyzing alternate stability tests for pontoon passenger vessels (American 

Boat and Yacht Council, ISO) for the purpose of identifying whether and how the existing 

PSST should be revised. 

The stability study contracted by the Safety Board showed that if the Lady D had 

been loaded with 14 or fewer 140-pound persons (a maximum load of 1,960 pounds), the 

water taxi would have met the static stability requirements for pontoon passenger vessels 

found in 46 CFR 178.340 (the PSST). However, the PSST does not explicitly address the 

effects of wind and waves. In this accident, as the Lady D proceeded across Baltimore 

Harbor and the master changed course to make for safe haven, the full strength of the 

storm struck the vessel on the port beam. The wind gusts and waves rocked the vessel so 

much that the Lady D could not resist the heeling forces and capsized.

Recognizing that the wind or waves were probably factors in the capsizing, the 

Safety Board tasked its contractor to analyze their role in the Lady D casualty. 

Calculations performed to evaluate the ability of the Lady D to withstand a beam wind 

showed that with a load of 25 persons weighing an average of 168.4 pounds, the vessel 

had adequate righting moment to resist the static force of a 40-knot wind acting directly on 

the side of the vessel. In the simulation, the vessel heeled about 6° and had slightly less 

than 2 inches of freeboard, but it remained upright. The results of the computer simulation 

to evaluate the dynamic effects of wind and waves on the Lady D were dramatically 

different. The environmental model used in the simulation assumed 1.25-foot waves at a 

peak period of 3.0 seconds and a 25-knot steady wind gusting to 42 knots on the beam. 

The dynamic simulation was repeated 20 times to establish a statistical baseline, and the 

vessel capsized in every case. In all simulations, capsizing occurred within 1 minute. Note 

that the computer simulation assumed that the heading of the vessel did not change. In 

reality, a vessel operator would most likely attempt to change the heading of the vessel to 

avoid a beam wind.

Unlike the SST for monohull vessels, the original PSST developed by the Coast 

Guard did not include a wind heel condition. Though the Coast Guard acknowledges that 

it no longer has documentation to explain the genesis of the PSST, officials indicated that 

they thought an exception to the wind heel conditions had been made for pontoon vessels 

because early vessels, as designed, did not carry canopies or deckhouses. Under those 

circumstances, passenger heel, rather than wind heel, was the more critical stability test. 

Today, however, pontoon passenger vessels such as the Lady D have deckhouses that 
Analysis 61 Marine Accident Report

significantly increase a vessel’s wind profile and raise its overall center of gravity to the 

point that its wind heel resistance needs to be evaluated in addition to passenger heeling 

moments.

The Coast Guard has recognized the evolution in design and configuration of 

pontoon passenger vessels and addressed the impact of wind heel by issuing to all OCMIs 

policy letter 04-10, which includes guidance and a job aid for conducting a PSST. The new 

test protocol includes an additional calculation that evaluates wind heel as a potential 

limiting condition on vessel stability. 

The Safety Board acknowledges that the job aid form developed by the Coast 

Guard should be easier to use than previous references. The applicability instructions in 

the job aid should preclude a Coast Guard inspector using the wrong test protocol when 

overseeing a stability proof test. However, the guidance for the job aid still directs Coast 

Guard inspectors to use the 140-pound weight standard for passengers in its calculation 

formulas. As noted earlier in this report, this weight standard is out-of-date and does not 

reflect the weight of average Americans today.

The various tests that the Coast Guard conducted or contracted for in 2005 as part 

of its pontoon vessel stability project corroborated many findings in the stability 

evaluation contracted by the Safety Board. Tests by both the Safety Board and the Coast 

Guard found that the Lady D under a full load condition (25 persons) would not pass the 

PSST in 46 CFR Subchapter T (small passenger vessels). The Coast Guard’s Marine 

Safety Center (MSC) ran calculations to determine whether the Lady D in a full-load 

condition and operating on protected waters could meet the alternate stability 

requirements in Subchapter S, an option for stability compliance available to vessel 

owners. The MSC found that while loaded with 25 140-pound persons, the Lady D could 

meet the minimum stability criteria in Subchapter S. However, under the actual load 

conditions at the time of the accident, or about 710 pounds over the weight load permitted 

by standard, the MSC found that the vessel failed to meet the weather criteria in 46 CFR 

170.173(e)(2) for vessels of unusual proportion and form. The MSC evaluation, like the 

Safety Board’s contract evaluation, found that the overloaded vessel could not meet the 

Coast Guard’s stability criteria for weather. In its summary of findings, the MSC noted 

that the Lady D’s intact stability was unpredictably affected by the weather and sea 

conditions at the time of the accident.

A Coast Guard study team subsequently conducted an analysis to determine 

whether the PSST was still appropriate for modern pontoon vessels, which usually have 

superstructures that add weight and make the vessel more susceptible to the effects of 

wind. The analysis was a parametric review comparing stability standards in Federal 

regulations (the PSST in Subchapter T and criteria in Subchapter S) with those of industry 

(American Boat and Yacht Council and ISO).

The study team’s parametric study observed that the PSST usually produced the 

most conservative results in calculating passenger loading, but not always. A pontoon 

vessel could pass the PSST and fail the alternative criteria found in Subchapter S because 

the effect of wind heel is not negligible for some pontoon vessel designs and because 
Analysis 62 Marine Accident Report

multihull stability is sensitive to vessel dimensions and draft. Some pontoon vessel designs 

that could meet the static stability criteria in Subchapters S and T would have difficulty 

meeting the ISO stability standard for wind and waves. This finding was consistent with 

the results of the Safety Board’s contract evaluation, which found that the Lady D, while 

configured to pass the PSST (14 persons at 140 pounds each), could capsize under the 

dynamic load conditions of wind and waves that existed at the time of the accident.

The study team also found that if certain characteristics in pontoon vessel design 

(full load submergence, pontoon diameter, and distance between pontoon centers) were 

limited, the PSST criteria as revised in Coast Guard policy letter 04-10 would be the most 

stringent of all the pontoon stability standards evaluated. The Lady D would not have met 

the full load submergence criteria in the COI condition (25 persons at 140 pounds each) or 

the accident condition (25 persons at 168 pounds each). In each condition, the full load 

submergence exceeded 50 percent. The study also recommended implementing a 

maximum wind speed under which pontoon vessels could operate in protected waters and 

revising the average passenger weight standards.

The analyses of the stability of pontoon passenger vessels performed by both the 

Safety Board and the Coast Guard as a result of the capsizing of the Lady D raised safety 

issues related to Coast Guard pontoon vessel stability standards that need to be resolved to 

reduce the possibility of this type of accident recurring. The Safety Board concludes that 

existing Coast Guard intact stability standards for pontoon passenger vessels (the PSST in 

Subchapter T, “Small Passenger Vessels,” and/or the alternative criteria in Subchapter S, 

“Subdivision and Stability”) do not adequately account for the dynamic loading from wind 

and waves on a pontoon vessel operating on an unrestricted protected route. The Safety 

Board therefore believes that the Coast Guard should revise the stability criteria for small 

passenger pontoon vessels for all passenger loading conditions to minimize the potential 

for capsizing in wind and waves.

Both the Safety Board and the Coast Guard demonstrated that the Lady D could 

not meet the PSST for the carriage of 25 persons. If a vessel fails a stability proof test, the 

owner must make one or more of the following changes to reduce the heeling moment so 

that the vessel can pass the proof test: carry fewer passengers, ballast the vessel, or reduce 

the vessel’s wind profile area, if applicable. Coast Guard policy letter 04-10 indicates that 

if a pontoon vessel does not pass the physical proof test in the PSST, the vessel owner can 

provide design calculations to the MSC showing that the vessel meets the applicable 

stability criteria of 46 CFR Subchapter S in each condition of loading. The Lady D’s 

owner therefore could have submitted calculations demonstrating compliance with 46 

CFR Subchapter S for 25 persons. The MSC would have approved these calculations for 

the carriage of 25 persons. Yet, the MSC’s February 2005 analysis of the Lady D accident 

indicated that the dynamic factors affecting the Lady D’s stability were not precisely 

known, and, consequently, it could not reliably assess the stability required for the vessel 

to survive the actual conditions encountered. Therefore, the Safety Board recommends 

that until such time as the Coast Guard revises the passenger weight standard and the 

stability criteria used to evaluate small passenger pontoon vessel safety as requested, it 

should develop interim pontoon passenger vessel stability guidance based on static and 

dynamic intact stability considerations.
Analysis 63 Marine Accident Report

Although the CFR defines protected waters as sheltered waters presenting no 

special hazards, the definition includes no wind or wave restrictions. OCMIs will often 

include “Under reasonable operating conditions” as an operating restriction on COIs 

issued by the Coast Guard. This caveat gives no objective operational guidance to vessel 

operators for assessing the ability of a vessel to safely operate in wind and waves. The 

Coast Guard study team in its pontoon vessel stability review recommended that 

operational guidance be provided on COIs restricting operations in wind conditions not 

greater than Beaufort force 4 (16 knots of wind) or using the more familiar small craft 

advisory/warning (observed or forecast winds of 18 to 33 knots). The Safety Board 

therefore concludes that a Coast Guard endorsement on a vessel’s COI restricting a 

pontoon passenger vessel to limiting weather conditions would provide definitive 

operational guidance to a vessel’s operator. The Safety Board believes that the Coast 

Guard should establish limiting environmental conditions such as weather in which 

pontoon vessels may safely operate, and list those limiting conditions on the vessel’s COI.

Policies and Procedures Pertaining to Weather Operations

In this accident, NWS meteorologists failed to identify the developing storm 

conditions in a timely manner and provide the information to mariners in a special marine 

warning. Seaport Taxi’s weather policy also did not ensure maximum safety of operations 

during threatening weather conditions. These problems and factors affecting the decision 

of the Lady D master to leave the Fort McHenry dock are discussed below.

NWS Operations

Data captured by various systems near the accident site, including Baltimore Marine 

Center and BWI airport, showed that at the time of the capsizing (1558 to 1600), the Lady D

encountered westerly winds gusting about 28 knots (32.2 mph) to 41 knots (47.2 mph), with 

a sustained wind speed of about 25 knots around 1600. The winds were generated by a 

thunderstorm moving through the area. Lightning strike data indicated cloud-to-ground 

lightning strikes in the accident area at the time of the accident. The TDWR at BWI recorded 

no data indicating that a microburst or downburst had affected the vessel. 

In this accident, the performance by the NWS forecasters on duty at the BaltimoreWashington forecast office was adversely affected by their preconceptions about the 

environmental conditions, which they had discussed with the forecasters they had relieved 

earlier in the afternoon. The meteorologists’ procedures typically involved monitoring the 

various data systems available and if they had any cause for concern, comparing the data 

captured by their own systems and commercial mesonet systems to analyze evolving 

weather conditions. However, mesonet and TDWR data were not available in a format that 

they could readily use. Comparing the various data took several minutes, and if conditions 

warranted issuing a special marine warning, preparing the message took at least 5 minutes.

The meteorologists at the Baltimore-Washington forecast office were slow to 

respond to evidence of intense storm conditions until the lead forecaster noticed a high 
Analysis 64 Marine Accident Report

wind reading (46 knots) at 1544 at Reagan Washington National Airport. However, their 

own system data that were available at their workstations had provided sufficient 

information to have warranted their issuing a special marine warning before the Lady D

embarked passengers at the dock near Fort McHenry at 1552. 

About 1500, LWX Doppler radar images indicated areas of intense weather echoes 

about 40 miles north/northwest of Baltimore Harbor. The weather radar data also indicated 

cell movement in excess of 40 knots. At 1514, the LWX Doppler weather radar indicated 

that the radial velocities (westerly component) to the west of that NWS office were greater 

than 34 knots at an altitude of 1,500 feet above msl (mean sea level). The forecasters’ 

workstations also displayed surface observations from airport ASOS and AWOS sites, 

which captured wind gusts in excess of 30 knots from the north/northwest for more than 

an hour before the capsizing. For example, Martinsburg, West Virginia, recorded 37 knots 

and 36 knots at 1440 and 1453, respectively. Thus, the meteorologists had the opportunity 

to monitor and compare the data displays and issue a special marine warning in time to 

alert the water taxi services operating in Baltimore Harbor. All the Seaport Taxi vessels in 

operation, including the Lady D, were equipped with VHF radios fitted with a NOAA 

weather alert feature. If Seaport Taxi had received a NOAA alert of a thunderstorm with 

high winds, the company policy would have called for the vessel captains to tie up.

The Safety Board therefore concludes that meteorological data displayed on the 

workstation monitors at the NWS Baltimore-Washington forecast office showed that the 

strong gusty winds and thunderstorm conditions associated with the Lady D accident 

could have been identified by forecasters as early as about 1501, providing opportunity for 

them to verify conditions and issue a special marine warning more than 20 minutes before 

the Lady D left the dock near Fort McHenry.

Following this accident, the NWS examined the various weather system data 

available on March 6 at the Baltimore-Washington weather forecast office and critiqued 

the performance of the meteorologists on duty. The team found that a more aggressive and 

more efficient approach by forecasters in analyzing the evolving weather conditions could 

have increased their concern regarding the potential for high winds. This, in turn, could 

have resulted in timelier and more complete information being provided in forecast and 

warning services. The assessment team also found that the forecasters did not make 

optimum use of available NWS equipment. Further, the team recognized that the NWS 

would benefit from improving the access to mesonet and TDWR system data. 

According to NWS officials, the agency’s report of findings was made available to 

weather forecast offices nationwide by means of the NWS website. The NWS will 

disseminate the training exercises developed by and for the Baltimore-Washington 

weather forecast office first throughout the eastern region and then to other regions. NWS 

officials advised Safety Board investigators that they expect their weather forecast offices 

with marine forecast responsibilities to access and use the training. The Safety Board 

concludes that the agency-wide actions taken by the NWS to correct its system 

deficiencies and performance errors are adequate to address the problems that occurred at 

the Baltimore-Washington weather forecast office.
Analysis 65 Marine Accident Report

Seaport Taxi’s Weather Policy

Seaport Taxi had a stated weather policy with defined operating parameters, 

demonstrating that company officials recognized and attempted to mitigate risks to the 

pontoon-style passenger vessels traversing the harbor in harsh weather. The water taxis 

could operate in rain; however, the company policy stipulated that vessel masters tie up 

when they encountered electrical storms, sustained winds over 15 knots or wind gusts over 

35 knots, restricted visibility, and other conditions. The company advised its masters about 

its weather policy in both introductory and annual refresher training classes. During dayto-day operations, the manager at Seaport Taxi’s shoreside office would radio information 

about the weather either at her own initiative or in response to questions from a master in 

the fleet. In addition, a senior official could advise or order vessel operators to seek a safe 

haven and tie up their boats if he observed weather conditions that warranted such action. 

However, recognizing that weather conditions near the Inner Harbor (operating loop 1) 

and the Canton area (operating loop 2) could differ dramatically, company officials 

usually left the decision regarding operating in bad weather to the Coast Guard-licensed 

master. Seaport Taxi vessel masters who encountered difficult wind and wave conditions 

while operating one of the company’s small, single-engine boats on loop 2 could request 

that a larger boat be assigned to the outer loop route, and the company would arrange a 

switch. 

The Lady D’s master told Safety Board investigators that he was aware of the 

company’s operating policy and generally agreed with it. He also told investigators, 

however, that in the 2 to 3 years that he had worked for Seaport Taxi, he had been caught 

in 40-knot winds while operating the Lady D. He said that he believed that on one 

occasion, he had been in wind conditions approaching 50-knot gusts; however, he said he 

had never been in conditions like those on the day of the accident, which did not reach 50 

knots. He also stated, and company officials confirmed, that he had operated on loop 2 

when conditions were sufficiently bad to warrant his asking that a larger, twin-engine boat 

be assigned to the outer loop. Thus, when he had operated in the past during wind 

conditions that exceeded the parameters established by Seaport Taxi, the Lady D master 

had demonstrated that he recognized the limiting weather conditions for that pontoon boat 

and had alerted the company to make vessel changes for the route.

On the day of the accident, several factors affected the master’s decision-making, 

in particular, his choice to leave the Fort McHenry dock despite evidence of an impending 

storm. Earlier that day, after arising about 0600, he had monitored the forecast on the 

Weather Channel and noted that the prediction for that afternoon was sunny skies, with no 

mention of storms. From the time of his first trip, about 1000, until his last trip to Fort 

McHenry, the weather conditions he encountered were consistent with the forecast. 

When the master docked at Fort McHenry about 1545, he noted the dark clouds 

north-northwest of Baltimore; however, he considered them distant and not an immediate 

threat. He had been directed by the Seaport Taxi office manager to pick up passengers at 

Fort McHenry before it closed at 1600 and return them to Fells Point. He could not 

embark all those who were waiting at the fort, but he picked up 23 passengers, bringing 

the total number of persons on board to the maximum load for which the Lady D was 
Analysis 66 Marine Accident Report

certificated. As the master prepared to leave, he told the fort coordinator that he would 

return as soon as possible “to get the last people off,” demonstrating that he was somewhat 

focused on accomplishing his mission.

When the Lady D master backed away from the dock about 1554, the weather 

conditions that he observed met none of Seaport Taxi’s criteria that precluded making a 

transit. The wind began to pick up and light rain began to fall. Because the Lady D’s 

master had operated previously in wind and rain, the weather conditions would not 

necessarily have affected his decision to proceed to Fells Point. 

Human factors research shows that the cognitive effort required to alter a decision 

once it has been acted upon is more difficult than if the action had not been taken at all.60

In this case, it would have been more difficult for the master to return after leaving the 

dock than if he had decided not to leave the dock in the first place. His course of action to 

proceed to Fells Point was supported by radio communications from company personnel 

who provided him with operating instructions and information. Immediately after the 

senior captain radioed the fleet about potential storm conditions and recommended that 

vessel masters tie up, the Seaport Taxi office manager broadcast that Doppler weather 

radar indicated that the worst of the storm would miss them. Thus, her transmission 

probably negated the effect of the senior captain’s warning and affected the Lady D

master’s decision to proceed to Fells Point. He told Safety Board investigators that, in the 

past, the weather reports from the office had generally given the vessel masters adequate 

warning and enough time to tie up someplace, if necessary.

As noted earlier, the Doppler weather radar image on display at the NWS about the 

time that the Lady D master departed Fort McHenry would have shown a more detailed 

picture of the impending conditions. However, the timeliness of the broadcast Doppler 

weather image depends on how long it takes a weather information provider to upload the 

data feed from the NWS. Based on her description of the Doppler weather radar image on 

her computer screen, the office manager probably was looking at an earlier Doppler image 

when she radioed the fleet that the worst of the storm would miss them. The Safety Board 

concludes that the weather information available to Seaport Taxi at the time of the 

accident did not accurately reflect the impending storm conditions, which compromised 

efforts to adhere to safe operating procedures.

Adequacy of Propulsive Power

As discussed earlier in this analysis, the Safety Board evaluated the vessel’s 

propulsion system and found that its mechanical condition was not a factor in this 

accident. In addition, the Safety Board considered whether the outcome would have been 

different had the master had additional propulsive power available as he was attempting to 

maneuver his vessel in the adverse weather. 

60 C. D Wickens and J. G. Hollands, Engineering Psychology and Human Performance (Upper Saddle 

River, New Jersey: Prentice Hall, 2000).
Analysis 67 Marine Accident Report

The master stated that he operated the vessel at 6 knots, well below its maximum 

operating speed of 12 knots. Vessels in the area in which Lady D operated were in a 

“no-wake zone,” and were limited to a speed of 6 knots. Because the vessel was limited to 

operating at 6 knots and yet had sufficient power to reach 12 knots, the vessel was not 

underpowered for its operations. In addition, according to design standards for small 

vessels, a maximum horsepower is recommended to prevent dangerous overpowering of a 

vessel. In this case, one such standard for pontoon vessels would have limited a vessel of 

the Lady D’s dimensions to about 65 hp.61 The Lady D’s outboard motor was rated at 90 

hp. The Safety Board concludes that the propulsive power of the Lady D was not a factor 

in this accident.

Survivability

Several factors affected the survivability of the Lady D’s occupants in this 

accident. The vessel’s design, specifically the enclosed deckhouse and the windows, 

presented barriers to escape. The cabin’s canopy precluded donning lifejackets because 

wearers of the safety devices would not have been able to overcome their buoyancy and 

would have been trapped in the enclosed cabin. Environmental conditions, in particular 

the water temperature, increased the potential for serious and fatal injuries. The key factor 

that contributed positively to the survivability of the Lady D’s occupants was the 

timeliness and effectiveness of the rescue effort. 

Construction and Arrangement of the Accident Vessel

During inclement weather, the Lady D was one of Seaport Taxi’s preferred vessels 

for operation because the pontoon boat had a fully enclosed deckhouse. However, because 

of its design, the Lady D posed potential egress problems not present on other pontoon 

vessels in the Seaport Taxi fleet. 

The vessel had two doors, which were at opposite ends of the deckhouse. The door 

at the bow was a horizontal sliding model that moved to the side; the door at the stern was 

a hinged model that opened outward. The primary means of emergency egress for 

passengers sitting amidships were the windows along the sides of the Lady D. The 

windows were 42 inches high by 48 inches wide; however, they were combination 

windows with one 24-inch-wide sliding sash and one 24-inch-wide fixed sash. 

Several survivors said that they initially had problems getting out of the capsized 

vessel. Four passengers seated near the forward or the aft doors conceivably should have 

been able to readily exit through them. One passenger said, however, that when he tried to 

open the sliding glass door at the bow as the Lady D started to sink, he was unable to move 

it. The mate later confirmed that he had experienced some difficulty with the front door 

61 American Boat and Yacht Council Standard H-35, “Powering and Load Capacity of Pontoon Boats,” 

July 2003.
Analysis 68 Marine Accident Report

when he had helped prepare the vessel for an upcoming Coast Guard inspection. Contrary 

to the passenger interviewed, the mate recalled that the front door had been easy to open 

but “very difficult” to close.

Another passenger seated next to the aft door said he believed that he had exited 

through that door because he swam into the boat propeller as he surfaced. Fortunately, 

water had already flooded the Lady D’s engine, and the propeller was not moving.

A passenger who had been seated midsection on the starboard side said that, in 

retrospect, exiting through the forward door was an obvious choice; however, in the midst 

of the emergency, it never occurred to him to try to egress through the forward door. He 

said that he was able to escape through a window opening.

In this accident, all the fatality victims, who ranged in age from young to middle 

age and whose physical conditions varied, were seated amidships. The closest means of 

egress for those passengers were the windows, which were closed to protect passengers 

from wind and rain during the voyage. 

Some passengers stated that they were able to slide the windows open and exit. 

One survivor said that after the vessel overturned, he kicked at the windows and felt one 

give way. Several passengers said that they had problems finding an open window 

because the water was so murky. Others said that with the boat upside down, they realized 

they would have to swim downward to find a window exit. One woman stated, “I kicked 

to go down, and I started feeling...I pushed a window and it seemed to just, just to float 

away. I don’t think...it was attached anymore. So, I could...just go out of that window.”

The Safety Board therefore concludes that in the panic situation that ensued after 

the Lady D capsized, the vessel’s normal means of egress from the deckhouse, including 

the differently designed doors and the slider windows, posed evacuation problems for the 

vessel’s occupants.

Safety Briefing

Federal regulations at 46 CFR 185.506 stipulate that a vessel master must ensure 

that before getting underway, suitable public announcements are made informing all 

passengers of the location of emergency exits, ring buoys, instructional placards, and 

lifejackets. In addition, passengers must be informed about how to don a lifejacket. 

Seaport Taxi had installed a placard indicating how to don a lifejacket inside the 

Lady D’s deckhouse and required that operating crews deliver a safety briefing. The 

Safety Board received conflicting accounts about whether a safety briefing was performed 

at the outset of the accident voyage. The master and the mate both told investigators that a 

safety announcement advising passengers about the location of lifejackets was performed. 

However, most of the Lady D’s survivors either could not recall receiving a safety briefing 
Analysis 69 Marine Accident Report

on board the Lady D or stated that the crew did not conduct one. Almost all survivors said 

that they had received a safety briefing on other Seaport Taxi vessels at Harbor Place for 

the trip to Fells Point. 

From postaccident interviews, the Safety Board determined that passengers might 

have benefited from receiving a safety briefing specific to the Lady D’s characteristics 

much like the type of briefing provided to passengers on a particular model of aircraft. The 

door at the bow and the door at the stern opened differently. For passengers sitting 

amidships, the windows were the logical source of egress; however, each window was a 

combination style with one fixed sash and one sliding sash. In this accident, several 

occupants of the deckhouse escaped when some of the windows ultimately gave way, 

either from passengers kicking on them or from the water exerting pressure against them, 

or both. 

The passengers also should have been advised about whether and when it was 

appropriate to don a lifejacket. This subject is discussed in greater detail in the following 

section.

A verbal safety briefing serves several purposes: It refreshes the crew’s 

understanding of emergency procedures, informs passengers, and provides them with the 

opportunity to ask questions if they do not understand recommended emergency 

procedures. Conditions are generally so chaotic during an emergency that individuals need 

to be able to identify an appropriate action and respond quickly. The Safety Board 

concludes that the currently required safety briefing on emergency procedures that 

includes a discussion of lifejacket stowage/donning and egress capabilities would enhance 

small passenger vessel safety.

Lifejacket Use in Enclosed Deckhouses

Because of the suddenness of the vessel’s capsizing and its rapid flooding, 

passengers had little opportunity to retrieve and don lifejackets, which, in this case, 

probably contributed to survivability. Donning a lifejacket inside a rapidly flooding 

enclosed deckhouse could have resulted in the buoyant safety device carrying a wearer 

upward when most people had to swim downward to escape. Wearing a lifejacket inside 

the overturned Lady D would have impeded mobility, made exiting through the windows 

difficult if not impossible for several passengers, and delayed egress. Several young 

children were on board the Lady D. If a parent had taken time to find a child-size lifejacket 

and put it on a youngster, both the parent and the child might not have escaped from the 

vessel. Following this accident, several passengers with past boating experience told 

investigators that they realized wearing a lifejacket inside an enclosed deckhouse was not 

recommended when the vessel threatened to capsize. No passenger on the Lady D donned 

a lifejacket before the vessel turned over.
Analysis 70 Marine Accident Report

Much research has shown the benefits of wearing lifejackets, particularly in waters 

as cold as the Patapsco River on the day of the accident (44° F), and normally the Safety 

Board is a strong proponent of lifejacket use in hazardous conditions and marine 

emergencies. However, in the case of the Lady D capsizing, passengers should have only 

retrieved and held the lifejackets in preparation for possible evacuation while the boat 

rocked in the wind. When the vessel overturned, they could have pushed a lifejacket out a 

window or door to serve as a flotation device after they escaped the boat and swam to the 

surface. 

In this case, the pontoon vessel itself became the best flotation device for vessel 

occupants who found their way out of the deckhouse. The survivors either climbed on the 

overturned boat or pulled others in getting on top of it. Two survivors were still in the 

water, holding onto the boat, when rescuers arrived. Two passengers died as a result of 

being trapped in the vessel. Because the cabin ultimately tore free of the deck, it is not 

known whether the remaining three fatality victims died in the vessel or were able to exit 

the vessel but not reach the water’s surface. The Safety Board therefore concludes that 

donning lifejackets in the Lady D’s enclosed deckhouse before the capsizing could have 

resulted in additional fatalities.

Response Effort

The response to this accident was rapid and effective. People at shoreside 

installations, including personnel at the Naval Reserve Center Baltimore and a BCFD 

marine unit member at the fireboat station, witnessed the capsizing and immediately 

called 911, notifying the dispatcher at the emergency communications center of the 

accident within seconds of the Lady D’s overturning. The calls to the consolidated 

communications system enabled the BCFD to initiate a response from all necessary City 

public safety agencies. More than 40 rescue and medical personnel and various marine 

and shore-based assets were dispatched by 1603, or within about 5 minutes of the water 

taxi’s capsizing at 1558. Thus, timely efforts by witnesses to notify the 911 dispatcher 

contributed to an effective response by City safety agencies.

The Navy reservists also contributed to the prompt rescue of the accident victims. 

The Reserve center pier was about 1/3 nm from the position of the capsized water taxi. 

After witnessing the Lady D overturn, the reservists quickly put together a crew and 

launched an LCM-8. Within 8 minutes of the capsizing (1606), they had arrived at the 

accident site and begun transferring survivors to their vessel. Upon learning that 

passengers were still trapped inside the Lady D’s cabin, the LCM-8 operator lowered the 

ramp on the LCM-8 and used it as a lever to lift one side of the pontoon vessel, which 

freed at least three passengers. The quick thinking of the LCM-8 operator, therefore, 

probably saved the lives of some passengers. 
Analysis 71 Marine Accident Report

The BCFD’s fire/rescue boat and the police department’s vessel arrived at the site 

shortly after the LCM-8. The crews of the three vessels communicated and worked well 

together. As a result, several passengers needing immediate medical attention were 

transferred to either the BCFD rescue boats or the BCPD vessel, all of which carried 

EMTs who could provide life-saving treatment while the passengers were transported to 

ambulances waiting on shore. Because of the combined response efforts of marine and 

shore-based personnel with the Navy Reserve, the BCFD, and the BCPD, 22 occupants of 

the accident vessel were rescued from the water and transported to area hospitals within an 

hour of the capsizing. 

While the volunteer and the City responders were working at the accident site, 

Coast Guard watchstanders monitoring VHF channel 16 overheard radio traffic about the 

capsizing. Immediately thereafter, about 1617, Seaport Taxi notified the Coast Guard of 

the accident, as required by 46 CFR 4.04, after water taxi officials were able to confirm 

that one of their vessels had overturned. Company officers had learned of the accident 

only after they did not receive a response to their radio and cell phone calls to the Lady D

and took another vessel out toward Fort McHenry to determine why. 

Coast Guard officers sounded the SAR alarm and contacted Baltimore’s 

emergency communications center. The BCFD battalion chief, as incident commander, 

effectively briefed Coast Guard personnel about the emergency, advising them that four 

rescue vessels were already on scene. The Coast Guard ordered a crew muster for the 

dispatch of three utility boats and one search helicopter to assist, and the first vessel was 

underway by 1625. By the time the first utility boat arrived on scene at 1637, most of the 

Lady D’s occupants had already been recovered. The incident commander then effectively 

merged the responding Coast Guard assets into a multiagency SAR operation to search for 

the three missing passengers. 

The Safety Board concludes that the rapid response effort by personnel from Naval 

Reserve Center Baltimore to the Lady D’s capsizing probably resulted in fewer lives being 

lost. Moreover, the actions of all City and first responders, including the fire department, 

the police, the emergency medical technicians, and the Coast Guard, were timely and 

effective.
72 Marine Accident Report

Conclusions

Findings

1. Sleep deprivation, alcohol, drugs, and physical impairments were not factors in this 

accident.

2. The mechanical condition of the Lady D’s propulsion and steering systems was not a 

factor in this accident.

3. The propulsive power of the Lady D was not a factor in this accident.

4. Examination of the Lady D’s hull showed no evidence of preaccident damage. 

5. The load for which the pontoon vessel Lady D was certificated was based on a 

monohull simplified stability proof test on the Fells Point Princess, which was not 

appropriate for pontoon vessels.

6. As a result of inappropriate sister vessel status to the Fells Point Princess being 

granted to the Raven, the Lady D, and the Misty Harbor II, all four pontoon boats had 

serious deficiencies in stability as a result of the inappropriate stability test used to 

determine the number of persons allowed on all the vessels. Although it was the Lady D

that was involved in this accident, the potential risk of a capsize event was 

substantially the same for all four vessels during their years of operation. 

7. The combination of the use of an out-of-date average weight standard for occupants of 

small passenger vessels and the excessive number of persons permitted in the Lady D’s

original certification resulted in the pontoon boat carrying a load that reduced its 

reserve buoyancy and compromised its stability characteristics, which made it more 

susceptible to capsizing on the day of the accident. 

8. The Lady D capsized as a result of the combined effects of the excessive load it 

carried and the wind and wave conditions experienced at the time of the accident.

9. Masters need a simple and ready means such as a mark on the hull to determine 

whether their vessels are overloaded and potentially unsafe.

10. Existing Coast Guard intact stability standards for pontoon passenger vessels (the 

pontoon simplified stability test in Subchapter T, “Small Passenger Vessels,” and/or 

the alternative criteria in Subchapter S, “Subdivision and Stability”) do not 

adequately account for the dynamic loading from wind and waves on a pontoon 

vessel operating on an unrestricted protected route.
Conclusions 73 Marine Accident Report

11. A Coast Guard endorsement on a vessel’s certificate of inspection restricting a 

pontoon passenger vessel to limiting weather conditions would provide definitive 

operational guidance to a vessel’s operator.

12. Meteorological data displayed on the workstation monitors at the National Weather 

Service Baltimore-Washington forecast office showed that the strong gusty winds and 

thunderstorm conditions associated with the Lady D accident could have been 

identified by forecasters as early as 1501, providing opportunity for them to verify 

conditions and issue a special marine warning more than 20 minutes before the Lady D

left the dock near Fort McHenry. 

13. The agency-wide actions taken by the National Weather Service to correct its system 

deficiencies and performance errors are adequate to address the problems that 

occurred at the Baltimore-Washington weather forecast office.

14. The weather information available to Seaport Taxi at the time of the accident did not 

accurately reflect the impending storm conditions, which compromised efforts to 

adhere to safe operating procedures. 

15. In the panic situation that ensued after the Lady D capsized, the vessel’s normal 

means of egress from the deckhouse, including the differently designed doors and the 

slider windows, posed evacuation problems for the vessel’s occupants. 

16. The currently required safety briefing on emergency procedures that includes a 

discussion of lifejacket stowage/donning and egress capabilities would enhance small 

passenger vessel safety.

17. Donning lifejackets in the Lady D’s enclosed deckhouse before the capsizing could 

have resulted in additional fatalities.

18. The rapid response effort by personnel from Naval Reserve Center Baltimore to the 

Lady D’s capsizing probably resulted in fewer lives being lost. Moreover, the actions 

of all other City and first responders, including the fire department, the police, the 

emergency medical technicians, and the U.S. Coast Guard, were timely and effective.
Conclusions 74 Marine Accident Report

Probable Cause

The National Transportation Safety Board determines that the probable cause of 

the capsizing of the pontoon-style small passenger vessel Lady D was its lack of intact 

stability, which was insufficient to withstand the strong winds and waves that the boat 

encountered. The lack of intact stability was caused by overloading, which resulted from a 

combination of the following:

• The Lady D was erroneously granted sister status by the U.S. Coast Guard to a 

pontoon vessel with different design characteristics;

• The Coast Guard certificated the Lady D to carry too many people as a result of 

an inappropriate stability test on the vessel to which it was granted sister status; 

and 

• The Coast Guard’s regulatory stability test standards on which the Lady D’s 

passenger allowance was based use an out-of-date average passenger weight.
75 Marine Accident Report

Recommendations 

As a result of its investigation of the Lady D accident, the National Transportation 

Safety Board makes the following recommendations.

New Recommendations

To the U.S. Coast Guard:

Revise regulations to require that passenger capacity for domestic 

passenger vessels be calculated based on a statistically representative 

average passenger weight standard that is periodically updated. (M-06-5)

Identify a method for determining the maximum safe load condition of a 

small passenger vessel at the time of loading, such as a mark on the side of 

the hull, and require that the vessel owners implement that method. (M-06-

6)

Revise the stability criteria for small passenger pontoon vessels for all 

passenger loading conditions to minimize the potential for capsizing in 

wind and waves. (M-06-7)

Until such time as you revise the passenger weight standard as requested in 

Safety Recommendation M-06-5 and the stability criteria used to evaluate 

small passenger pontoon vessel safety as requested in Safety 

Recommendation M-06-7, develop interim pontoon passenger vessel 

stability guidance based on static and dynamic intact stability 

considerations. (M-06-8)

Establish limiting environmental conditions such as weather in which 

pontoon vessels may safely operate, and list those limiting conditions on 

the vessel’s certificate of inspection. (M-06-9)
Recommendations 76 Marine Accident Report

Previously Issued Recommendation Classified in This Report

M-04-4

Revise your guidance to Officers in Charge, Marine Inspection, to 

determine the maximum occupant capacity of small passenger pontoon 

vessels either (1) by dividing the vessel’s simplified stability proof test 

weight by the per-person weight allowance for an average adult stipulated 

in Federal Aviation Administration Advisory Circular 120-27D (174 

pounds per person, assuming summer clothing and a 50-50 gender mix), or 

(2) by restricting (at the time of loading) the actual cumulative weight of 

passengers and crew to the vessel’s simplified stability proof test weight. 

Safety Recommendation M-04-4 (previously classified “Open—Acceptable 

Response”) is classified “Closed—Superseded” by Safety Recommendation M-06-5 as 

discussed in the “Passenger Weight Criteria for Stability Assessments” section of this 

report.

BY THE NATIONAL TRANSPORTATION SAFETY BOARD

MARK V. ROSENKER

Acting Chairman

DEBORAH A. P. HERSMAN

Member

ELLEN ENGLEMAN CONNERS

Member

KATHRYN O’LEARY HIGGINS

Member

Adopted: March 7, 2006
77 Marine Accident Report

Appendix A 

Investigation

The National Transportation Safety Board learned of this accident from media 

accounts about 1700 on March 6, 2004, and launched a four-person investigative team 

consisting of an investigator-in-charge and specialists in human performance, operations, 

and survival factors. The team was joined by the then Chairman, her assistant, and 

representatives from the Safety Board’s offices of Public Affairs and Transportation 

Disaster Assistance. The investigative team conducted on-scene interviews between 

March 6 and March 14. On March 10, 2004, a vehicle performance specialist joined the 

investigative team.

On May 11, 2004, the Safety Board assisted in the survey of the Lady D wreckage. 

Members of the team subsequently conducted follow-up interviews on October 26, 2004.

The Safety Board investigated the accident under the authority of the Independent 

Safety Board Act of 1974, according to the Board’s rules. The parties to the investigation 

were the U.S. Coast Guard, the Living Classrooms Foundation (the owner of the Lady D), 

the National Weather Service, the City of Baltimore Fire Department, and Susquehanna 

Santee Boatworks, Inc. (the holder of construction records on the Lady D).
78 Marine Accident Report

Appendix B

Intact Stability Study of Lady D 

Conducted by Alion Science and Technology, JJMA Maritime Sector
DELIVERABLES 1 & 2 

MV LADY D INTACT STABILITY WITH WIND

Purchase Order No. NTSBF060005 

December 15, 2005 

Prepared for: 

National Transportation Safety Board 

Office of Marine Safety 

Prepared by: 

Alion Science and Technology 

JJMA Maritime Sector 

4300 King Street, Suite 400 

Alexandria, VA 22302

Appendix B 79 Marine Accident Report
1. INTRODUCTION

This report presents the results of Task 1 and Task 2 of NTSB Purchase Order 

NTSBF060005. It combines Deliverables 1 and 2 into a single report since the two 

tasks are very closely related. This report summarizes the basics of intact stability 

as they apply to pontoon vessels. It also describes the static intact stability of 

the MV LADY D that was analyzed for three loading cases and three wind 

speeds. 

2. ASSESSING INTACT STABILITY OF VESSELS 

Intact stability is the naval architect’s term that describes how a vessel that is 

intact, or undamaged, responds when heeled (tipped) over. How a vessel 

responds when it is damaged is called damaged stability and that subject is 

outside the scope of this report. There are a number of forces that act on 

vessels that can cause the vessel to heel over. Some of the common heeling 

forces are: wind, waves, and the movement of passengers or cargo. Heeling 

forces are counteracted by the buoyancy of the hull of the vessel. As a vessel is 

heeled over the location of the buoyant forces shifts which produces a righting 

moment. If the righting moment is equal to the heeling moment, the vessel is in 

equilibrium and will remain in that position until the equilibrium is disturbed. If the 

heeling moment is greater the righting moment the vessel will continue to heel 

over and will turn completely over, or capsize. 

The shape of the vessel’s hull determines its buoyancy and how much 

righting energy is produced. In the case of a pontoon boat, see Figure 1, the 

two pontoons both produce buoyancy that counteracts heeling forces. The 

force of buoyancy of the two hulls can be turned into a single, (combined) 

buoyancy force. The distance measured perpendicular to the line of the 

combined buoyancy and the line of the weight of the boat is the “righting arm” 

of the boat. The greater the righting arm of the vessel, the more heeling force 

the vessel can resist. 

Righting arm changes as a vessel is heeled over. When a vessel is floating 

level, with a heel angle of 0 degrees, the righting arm is zero because the force 

of buoyancy and weight are aligned. As a vessel is heeled over the center of 

buoyancy shifts outboard, creating a “righting arm” that tends to push the boat 

back to the upright position. As the vessel heels over further, the righting arm 

increases, see Figure 2, until it reaches a maximum. This point is called the 

vessel’s maximum righting arm. Beyond the point of maximum righting arm, the 

righting arm decreases until it reaches zero, which is called the point of 

Appendix B 80 Marine Accident Report
vanishing stability. The distance from 0 degrees heel and the point of vanishing 

stability is called the vessel’s “range of stability”. At heel angles beyond the 

point of vanishing stability the vessel’s center of gravity has shifted further 

outboard than the center of buoyancy and so the righting arm becomes 

negative, creating a moment that forces the vessel to heel more, eventually 

leading to capsize. 

The area under the righting arm curve is a measure of the vessel’s righting 

energy. The righting energy is important because this is the energy that is 

available to counteract forces that would heel the vessel over. This righting 

energy resists environmental forces that affect the vessel such as wind and 

waves. The vessel must have sufficient righting energy to counteract the 

environmental forces that the vessel is expected to encounter during its lifetime. 

Figure 1 Intact Stability of a Pontoon Boat 

Buoyancy Buoyancy Weight

Of Boat

Heeling Force 

Combined Buoyancy

Appendix B 81 Marine Accident Report
Figure 2 Righting Arm over a Range of Heeling Angles 

 The calculation of righting arm for any vessel is usually performed using 

computer programs. The hull form of the vessel is entered into the program for 

use in calculating a number of different properties of the vessel. These 

properties are referred to as the vessel’s “hydrostatics”. To calculate righting arm 

for the vessel, the program systematically changes the angle of heel of the hull. 

As the vessel is heeled, the program calculates the shift in the hull’s center of 

buoyancy. The program adjusts the mean of the draft of the hull to keep the 

volume of water displaced by the hull (buoyancy) equal to the vessel’s weight. 

Once the position of the hull’s center of buoyancy (B) is calculated, the 

perpendicular distance from the vessel’s center of gravity (G) to a line 

extending vertically from the center of buoyancy is measured. This is the vessel’s 

righting arm, which naval architects refer to as GZ (see Figure 3). The 

intersection of the vertical line from the center of buoyancy (B) to the vessel’s 

center line is called the ship’s metacenter (M). The distance from the ship’s 

center of gravity (G) to the metacenter (M) is referred to by naval architects as 

the vessel’s metacentric height, also known as GM. 

L A D Y D R ig h t in g A r m

- 0 .5

0

0 .5

1

1 .5

2

0 10 2 0 30 40 50 6 0

A n g le - d e g r e e s

Arm - feet

1 9 6 0 lb s

B G B

G

W B

GB

W

Boat in Balance 

No Righting Arm B & G Aligned 

No Righting Arm

B & G farthest apart 

Maximum Righting Arm

Range of positive stability 

Point of Vanishing 

Stability 

Maximum Righting Arm 

Appendix B 82 Marine Accident Report
Figure 3 Calculation of Righting Arm 

A vessel’s GM is frequently used by naval architects as a measure of a 

vessel’s stability. It is a good indication of the vessel’s stability at small angles of 

heel (“initial stability”). The vessel’s initial GM is the slope of the righting arm 

curve at zero degrees of heel angle (Figure 4). If the initial GM is high, the 

righting arm curve increases rapidly giving large righting arms for only small 

angles of heel. If initial GM is low, then the righting arm curve goes up slowly 

allowing the vessel to heel over farther. Vessels with positive GM when they are 

heeled to one side will resist the force and return themselves to a central upright 

position when the heeling force is removed. A vessel with negative GM is 

unstable and any upsetting force will cause the vessel to move away from its 

initial position. Vessels with two hulls, also called catamarans, such as a pontoon 

vessel, tend to have a very high initial GM, unless their center of gravity is very 

high or they are very heavily loaded. 

G

B

Z

M

Appendix B 83 Marine Accident Report
Inital GM

-2

0

2

4

6

8

10

12

0 10 20 30 40 50 60 70

Heel Angle - Degrees

Arm - feet

Intial GM = 9.73 feet

57.3 deg.

Figure 4 Initial GM 

3. WIND HEELING FORCES 

As mentioned in the last section, there are a number of common heeling 

forces that act on vessels: wind, waves, and passenger/cargo loads. Wind 

forces can be a major influence on any vessel. The major factors in calculating 

these forces are the area of the vessel that is exposed to the wind, also called 

sail area, and the wind speed. As a vessel heels over the sail area decreases so 

the heeling forces decrease. A sample graph showing wind heeling forces 

versus heeling angle is shown in Figure 5. 

Appendix B 84 Marine Accident Report
Wind Heeling

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 5 10 15 20 25 30 35 40

Angle - degrees

Arm - feet

Figure 5 Winding Heeling Forces versus Heel Angle 

Wind heeling arm curves are usually plotted on the same graph as a 

vessel’s righting arm curve (Figure 6). The righting arm and wind heeling curves 

show important information about a vessel’s intact stability in wind. The first 

intersection between the righting arm curve and the wind heeling arm curve is 

the equilibrium point. The angle of this intersection is how far the vessel would 

be heeled by a steady wind. If the wind heeling arm exceeds the vessel’s 

righting arm the vessel will capsize. The second intersection point between the 

two curves is the point of vanishing stability in for the vessel at that wind speed. 

A steady wind heels a vessel over and reduces the amount of righting energy 

that is available to counteract environmental variables such as wind gusts or 

waves. The area between the two curves is called by naval architects the 

vessel’s “residual righting energy”. It is the vessel’s reserve of righting energy that 

is available to counteract dynamic heeling forces. Stability criteria for ships that 

use the concept of righting energy usually do not consider the full area under 

the righting arm curve, but rather use only a portion of it, such as the area to the 

angle of maximum righting arm, the angle of downflooding, or a specified angle 

in degrees. This approach is conservative because it builds in an unspecified 

Appendix B 85 Marine Accident Report
factor of safety. The simplified stability test of 46 CFR 178.349 (PSST), does not 

explicitly require the calculation of wind heeling forces, but environmental 

factors are implicitly taken into account as part of the criteria used in the test. 

Righting Arm vs. Heeling Arm

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 5 10 15 20 25 30 35 40 45 50

Heel Angle - degrees

Arm - feet

Righting Arm Wind Heeling Arm

Equilibrium

Point

Vanishing Stability

Reserve of dynamic 

stability

Figure 6 Righting Arm versus Wind Heeling Arm 

4. INTACT STABILITY OF THE MV LADY D IN 3 LOADING CONDITIONS 

The weight of the passengers carried by the MV LADY D has a significant 

effect on the vessel’s intact stability. Three load cases were examined which 

varied by the number of people on the vessel and their average weight. The 

first case examined was for 14 persons weighing an average of 140 pounds 

each (1960 pounds total). This case represents the maximum safe load 

condition allowed for the MV LADY D in accordance with the simplified stability 

test in 46 CFR 178.340. The second load case examined was for 25 persons each 

weighing 140 pounds (3500 pounds total). This case represents the load that 

Appendix B 86 Marine Accident Report
was allowed under the USCG Certificate of Inspection for the LADY D. The third 

loading case is the vessel loaded with 25 persons weighing an average of 168.4 

pounds (4210 pounds total). This case represents how the LADY D was actually 

loaded at the time of the accident. For each of these three load cases curves 

of righting arm versus heel angle were developed. All three curves are shown 

plotted on one graph in Figure 7. The top, solid curve is for the first loading case 

of 1960 pounds. The middle, line with two dashes curve is for the second case 

with 3500 pound load. The bottom, dashed curve, is for the LADY D as loaded 

on the day of the accident (4120 pounds). 

LADY D Righting Arm

-0.5

0

0.5

1

1.5

2

0 10 20 30 40 50 60

Angle - degrees

Arm - feet

1960 lbs 3500 lbs 4210 lbs

Maximum RighingArm = 1.9 feet

Range of Stability 33 deg.

48 deg.

45 deg.

Max. RighingArm = 1.1 feet

Max. RighingArm = 0.7 feet

Figure 7 Righting Arm Curves for Three Load Cases 

This figure shows how increasing the load carried by the vessel significantly 

decreases the maximum righting arm of the vessel and the range of stability. 

The maximum righting arm for the vessel in the first load case is 1.9 feet and it 

has a range of stability of about 48 degrees. In the second load case the 

maximum righting arm is 1.1 feet and the range of stability is about 45 degrees. 

In the third load case the maximum righting arm is only 0.7 feet and the vessel 

has a range of stability of only 33 degrees. On the day of the accident, once 

the LADY D reached a 33 degree angle of heel, there was no righting arm left to 

Appendix B 87 Marine Accident Report
bring the vessel back to an even keel so she would keep tipping until she was 

completely turned over. 

The passenger load on the LADY D on the day of the accident had a major 

negative effect on the vessel’s intact stability. The weight of the persons 

onboard the vessel increased her draft which reduced the reserve buoyancy of 

the pontoons. The reserve buoyancy of the pontoons, especially of the far side 

pontoon, is what produces the righting force that counteracts environmental 

forces that may heel the vessel farther over. Therefore the loss of the reserve 

buoyancy reduced the ability of the LADY D to resist environmental factors, such 

as wind and waves, on the day of the accident. 

5. WIND HEELING FORCES ON THE DAY OF THE ACCIDENT 

The ability of the LADY D, as loaded on the day of the accident, to resist 

wind heeling forces was examined for three wind speeds acting on the vessel’s 

beam. The three wind speeds examined were 30, 40, and 50 knots. Wind 

heeling curves were generated for each of these wind speeds and they were 

plotted against the vessel’s righting arm, as shown in Figure 8. The figure shows 

that as the wind speed increases the vessel losses “residual righting energy”. In 

the 50-knot wind case, the wind heeling arm exceeds the vessels righting arm 

which would result in the vessel’s capsizing. A steady state wind speed of 40-

knots alone is not sufficient to capsize the vessel outright, but there is little 

“residual righting energy” remaining to counteract any other dynamic heeling 

forces such as wind gusts and waves. 

Appendix B 88 Marine Accident Report
Actual Loading Condition

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

0 5 10 15 20 25 30 35 40 45

Angle (degrees)

Arm - feet

Righting Arm 30 kt heel arm 40 kt heel arm 50 kt heel arm

50 kts

40 kts

30 kts

Figure 8 Righting Arm versus Wind Heeling Arm for 3 Wind Speeds 

The impact of a 40-knot steady wind on the intact stability of the LADY D 

as loaded on the day of the accident is shown in Figure 9. This figure shows the 

“residual righting arm” for the vessel, which is the difference between the 

righting arm for the vessel and the wind heeling arm. The figure shows that a 

steady 40-knot wind would heel the vessel over to a 6.1 degree angle in calm 

water. Figure 10 is a sketch of the vessel looking at the bow in the heeled 

condition. The pontoon on the opposite side from the wind is deeply 

submerged and has little reserve buoyancy left to counteract any additional 

heeling forces. At an angle of slightly less than 22 degrees of heel, the vessel has 

no more righting energy and there is nothing to prevent the vessel from 

capsizing. Any additional external force (such as a gust of wind or a wave 

hitting the boat), a rapid maneuver by the boat’s captain, or a shift in the boat’s 

center of gravity due to passenger movements would be enough to capsize the 

vessel. At this wind speed there is very little margin remaining in the vessel’s 

intact stability to counteract any additional heeling forces. 

Appendix B 89 Marine Accident Report
Residual Righting Arm for MV LADY D - Actual Load Case

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0 5 10 15 20 25 30 35 40 45

Heel Angle - degrees

Residual Righting Arm - feet

Max. Righting

Arm = 0.24 ft

Range of Stability = 15.6 degrees

Angle of heel = 6.1 degrees Angle of Vanishing

Stability = 21.7 degrees

Residual Righting Energy =

2.4 foot - degrees

Figure 9 Residual Righting Arm for LADY D in a 40-Knot Wind 

Appendix B 90 Marine Accident Report
Figure 10 Sketch of LADY D in the Heeled Condition 

Appendix B 91 Marine Accident Report
DELIVERABLE 3 

TABLE OF WIND HEEL VERSUS RIGHTING ENERGY 

FOR THREE LOADING CONDITIONS 

FOR MV LADY D

Purchase Order No. NTSBF060005 

December 8, 2005 

Prepared for: 

National Transportation Safety Board 

Office of Marine Safety 

Prepared by: 

Alion Science and Technology 

JJMA Maritime Sector 

4300 King Street, Suite 400 

Alexandria, VA 22302

Appendix B 92 Marine Accident Report
P.O. NTSBF060005 

DELIVERABLES 1 & 2 

Residual Righting Energy at Different Wind 

Speeds – foot-degrees 

Loading Case Total 

Load - 

pounds

30 Knots 40 Knots 50 Knots 

14 people at 140 lbs 

each

1960 37.32 27.79 16.70 

25 people at 140 lbs 

each

3500 16.95 10.27 3.68 

Actual Condition 4210 6.27 2.40 None 

In the actual loading condition at a 50 knot wind speed, the vessel would 

capsize as the heeling energy is greater than the righting energy. 

Appendix B 93 Marine Accident Report
94 Marine Accident Report

Appendix C

U.S. Coast Guard Policy Letter 04-10,

Evaluation of Stability and Subdivision Requirements for Small 

Passenger Vessels Inspected Under 46 CFR Subchapter T
Appendix C 95 Marine Accident Report
Appendix C 96 Marine Accident Report
Appendix C 97 Marine Accident Report
Revised September 28, 2004

Page 1 of 16

- SMALL PASSENGER VESSELS -

SIMPLIFIED STABILITY TEST PROCEDURE FOR PONTOON VESSELS ON PROTECTED 

WATERS

DEPARTMENT OF (In accordance with 46 CFR 178.340)

HOMELAND SECURITY

U.S. COAST GUARD

Name of Vessel ________________________ Documentation No. _________ Date ______

Owner/Representative ___________________________ Inspector ____________________

Location ____________________________ Wind: Relative Direction _______ Vel ____ mph

Mooring Arrangement _____________________________________ Route: Protected Only

APPLICABILITY:

This form is to be used ONLY if ALL of the following conditions are met, otherwise contact MSC:

 vessel is less than or equal to 65 feet in length

 vessel carries 49 or less passengers

 vessel operates on protected waters

 vessel is a pontoon boat, i.e. fully enclosed pontoons with no machinery or tanks inside

 vessel has only two pontoons

 vessel has outboard engines

 vessel has only one deck and the deck is less than 6 inches above pontoon tops (fd below)

 deck accessible to passengers does not extend beyond pontoons fore/aft and port/stbd

 transverse test moment is greater than minimum test moment (see Section (2))

Indicate on above Sketch Indicate on above Sketch

1) Pontoon length (LOP) 1) Maximum beam (B) to outside of pontoons

2) Distance, from pontoon bow, of furthest 2) Maximum beam (BP) accessible to 

fwd location accessible to passengers (PF) passengers

3) Distance, from pontoon bow, of furthest 3) Distance (fd) between pontoon tops & 

aft location accessible to passengers (PA) top of deck; must be less than 6 inches.

4) Freeboard at bow to pontoon top 4) Pontoon diameter (D) if circular pontoons;

5) Freeboard at stern to pontoon top Pontoon waterline breadth if wall-sided

The measurements above are to be taken in the loaded condition with trim and heel minimized.

Measurements for (LOP) and (B) are to exclude rub rails.

(PA)

(PF)

LWL

(LOP) (B)

(BP)

(D)

fd

Appendix C 98 Marine Accident Report
Revised September 28, 2004

Page 2 of 16

(1) TOTAL TEST WEIGHT REQUIRED:

Total test weight must include the weight of passengers and crew.

_____________ X ____140_____ = _______________ pounds

 # of Pass. Wt/Pass. Pass. Test Wt. (WP)

_____________ X ____160_____ = _______________ pounds

 # of Crew Wt/Crew Crew Test Wt. (WC)

_____________ + ____________ = _______________ pounds

(WP) (WC) Total Test Wt. (W)

Notes: a) “Total Test Weight” defines only the weight to be moved during the test. Weights 

used to represent missing equipment or stores shall be considered part of the 

“loaded condition.”

b) The maximum number of passengers shall not exceed the number computed in 

accordance with 46 CFR 176.113. At no time shall the number of passengers 

exceed 49.

c) Weight per passenger equals 72.6 kg (160 lbs), except when passenger loads 

consist of men, women, and children; weight per passenger of 63.5 kg (140 lbs) 

may be used. Weight per crew member is 72.6 kg (160 lbs).

(2) MINIMUM TEST MOMENT -- SIMPLIFIED:

The calculated test moment (MTest) cannot be less than the simplified minimum test moment

(MMin1) as calculated below:

Simplified Minimum Test Moment (MMin1) = ___300_lb X _____________ = ____________ ft-lb

Vsl Length (LOP) (MMin1)

Calc. Test Moment (MTest) = _____________ X _____________ ÷ __2__ = __________ft-lb

Total Test Wt. (W) Pax. Beam (BP) (MTest)

ft-lb ft-lb

(MMin1) (MTest)

Simplified

Minimum Test Moment Calculated Test Moment

If (MTest) is greater than or equal to (MMin1) then this simplified test is valid. Skip to section (4) and 

continue with this test.

If (MTest) is less than (MMin1) then this simplified test may not be valid. Go to the next section to 

calculate the actual minimum test moment.

Appendix C 99 Marine Accident Report
Revised September 28, 2004

Page 3 of 16

(3) MINIMUM TEST MOMENT -- CALCULATED:

a) If the calculated test moment is less than the simplified minimum test moment 

calculated in section (2) above, the actual minimum test moment must be calculated 

using the wind profile of the vessel.

b) Go to Appendix A to calculate the actual minimum test moment and enter it below.

ft-lb ft-lb

(MMin2) (MTest)

Minimum Test Moment

(from Appendix A)

Calculated Test Moment

(from section (2) above)

If (MTest) is greater than or equal to (MMin2) then this simplified test is valid. Go to the next section 

and continue with this test.

If (MTest) is less than (MMin2) then this simplified test is not valid. Stop the test. The owner has the 

option to conduct a stability test (incline or deadweight survey) and submit calculations to 

MSC. Contact MSC if you have questions.

(4) VESSEL CONDITION PRIOR TO & DURING TESTS:

a) The test shall be conducted with all tanks 3⁄4 full, ballast onboard and in place, and any 

non-return valves or flaps on scuppers or deck drains restrained in the open position.

b) The test shall be conducted with the vessel in the full load condition. Any items, such as 

chairs, coolers, and deck coverings, which are not onboard at the time of the test shall 

be simulated by the use of weights approximating the weight and location of the missing

items. These simulated weights are not to be shifted during any of the following tests.

c) The vessel shall be fully afloat and all mooring lines are to be slack during the test.

d) If the vessel carries passengers on diving excursions, the total weight of diving gear 

must be included in the loaded condition. Diving gear is assumed to be 36 kg (80 lbs) 

person.

e) During the loading and moving of test weights, care should be taken if there is any 

evidence of low stability. This may be assumed to be the case whenever the effect of

any added or shifted weight increment is noted to be more than that of the preceding

increment of the same size, or when one of the pontoons comes out of the water or is 

submerged as a result of the heel.

f) Care is to be exercised that the vessel is not heeled excessively either due to weight 

movement or superimposed roll which could cause the test weights to topple or the 

ship’s gear to become adrift.

g) Before the vessel is heeled, check for open seams, loose hull fittings, etc., which are not 

normally immersed and which could cause flooding of the vessel.

Appendix C 100 Marine Accident Report
Revised September 28, 2004

Page 4 of 16

(5) TRANSVERSE STABILITY TEST – DISTRIBUTION OF TEST WEIGHT:

a) Distribute test weights so as to minimize heel and trim.

b) Arrange the test weight so that its vertical center of gravity (VCG) is approximately 76.2

cm (30 inches) above the deck

c) The vertical distribution of the test weight shall be such as to simulate the most

unfavorable VCG likely to occur in service.

(6) TRANSVERSE STABILITY TEST – DETERMINATION OF METHOD:

a) If the pontoons have a circular cross section, proceed to Appendix B.

b) If the pontoons are wall-sided, proceed to Appendix C.

c) For all other pontoon shapes, this test may not be applicable – please contact the 

Marine Safety Center for further guidance.

(7) TRANSVERSE STABILITY TEST – TEST RESULTS:

The vessel passes this test if the vessel meets the requirements of Appendix B or C as applicable.

 This vessel PASSED the transverse stability test. Continue with Longitudinal Stability Test.

OR

 This vessel FAILED the transverse stability test. Stop the test. Remove a few passengers 

(test weight), print a new test form and start the form over, beginning with page 1 of the form.

If the vessel cannot pass this simplified test, the owner has the option to conduct a stability test 

(incline or deadweight survey) and submit calculations to MSC.

Contact MSC if you have questions.

Appendix C 101 Marine Accident Report
Revised September 28, 2004

Page 5 of 16

(8) LONGITUDINAL STABILITY TEST – WEIGHT MOVEMENT:

a) The trimming moment shall be obtained by a longitudinal movement of the test weight 

from Section (1) to the extreme forward or aft position of the deck available to

 passengers and crew, whichever position is further from the initial position of the load.

b) All other notes from Section (4) shall be observed.

Quantity Weight per Unit Subtotal Weight

(Quant. x Wt. per Unit) Distance Moved

Total Weight

Check: This should be equal to or greater than the Test Weight from Section (1)

(9) LONGITUDINAL STABILITY TEST – TEST RESULTS:

The vessel passes this test if the tops of the pontoons are not submerged at any location 

with the weights shifted as indicated above. See the figure below.

 This vessel PASSED the longitudinal stability test.

 This vessel FAILED the longitudinal stability test. Stop the test.

Remove a few passengers (test weight) print a new test form and start the form over, beginning

with page 1 of the form.

If the vessel cannot pass this simplified test, the owner has the option to conduct a stability test 

(incline/deadweight survey) and submit calculations to MSC. Contact MSC if you have questions.

46 CFR Figure 178.340(d)(2)

Appendix C 102 Marine Accident Report
Revised September 28, 2004

Page 6 of 16

(10) GENERAL STABILITY INFORMATION

Tankage:

Aft of Pontoon Bow Above Top of Keel

Approximate Location of CG @ 100% Cap. Tank Capacity

Ballast:

Aft of Pontoon Bow Above Top of Keel

Approximate Location of CG

Material Weight

Appendix C 103 Marine Accident Report
Revised September 28, 2004

Page 7 of 16

APPENDIX A

CALCULATION OF MINIMUM TEST MOMENT BY WIND AREA

(A) HOW TO USE THIS APPENDIX

To determine the calculated minimum test moment, follow the steps below:

a) Block off the profile of the vessel into rectangles using vertical lines starting at the 

waterline, as shown below. Include passenger railings, canopies, and spotting towers.

b) Measure, on the vessel, the length (L) and height (V) of each rectangle and enter into 

the table below.

c) Complete the calculations in the table, add the products in the last column and follow

the calculations to determine if this test is applicable.

Appendix C 104 Marine Accident Report
Revised September 28, 2004

Page 8 of 16

APPENDIX A

CALCULATION OF MINIMUM TEST MOMENT BY WIND AREA

(B) SKETCH OF VESSEL PROFILE

Profile

Load Waterline Scale: 1 square = _________

(C) CALCULATION OF MINIMUM TEST MOMENT

Calculations

A

B

C

D

E

F

Sum of (A x H) = 

H

(1⁄2 V) Section L V A x H A

(L x V)

Minimum Test Moment (MMin2) = 7.5 lbs/ sq. ft. X _____________ = ____________ft-lbs

Wind Pressure (P) Sum (A x H) (MMin2)

Enter (Mmin2) into the appropriate block in section (3) of this test form.

Appendix C 105 Marine Accident Report
Revised September 28, 2004

Page 9 of 16

APPENDIX B

CALCULATION OF AREAS FOR CIRCULAR PONTOONS

46 CFR Figure 178.340(d)(1)

Arc Length

Freeboard

Waterline

Pontoon Diameter

Pontoon Measurement Guide

(A) PONTOON SIZE

Pontoon Diameter = _____________ inches

Pontoon Radius = diameter ÷ 2 = _______________ inches 

Appendix C 106 Marine Accident Report
Revised September 28, 2004

Page 10 of 16

APPENDIX B

CALCULATION OF AREAS FOR CIRCULAR PONTOONS

(B) AREA ABOVE WATERLINE BEFORE WEIGHT MOVEMENT (AREA A+B)

Measured arc length = _____________ inches

Ratio 1 = __________ ÷ ______________ x __57.3__= _______________

(arc length) (Pontoon radius) (Ratio 1)

Enter table (last two pages of this appendix) with this value and find the closest number in the 

column labeled (Ratio 1); read the value to the right in the column labeled (Ratio 2) and enter that 

number below:

Ratio 2 (from table) =_____________

Area = __________ X _____________ X _____________ = ____________ sq in.

 (Ratio 2) (Pontoon Radius) (Pontoon Radius) (Area A+B)

(C) WEIGHT MOVEMENT

The heeling moment shall be obtained by a transverse movement of the test weight from Section 

(1) to the extreme outboard position of the deck available to passengers and crew on the side with 

the least initial freeboard.

Quantity Weight per Unit Subtotal Weight

(Quant. x Wt. per Unit) Distance Moved

Total Weight

Check: This should be equal to or greater than the Test Weight from Section (1)

Appendix C 107 Marine Accident Report
Revised September 28, 2004

Page 11 of 16

APPENDIX B

CALCULATION OF AREAS FOR CIRCULAR PONTOONS

(D) AREA ABOVE WATERLINE AFTER WEIGHT MOVEMENT (AREA A)

Measured arc length = _____________ inches

Ratio 1 = __________ ÷ ______________ x __57.3__= _______________

(arc length) (Pontoon radius) (Ratio 1)

Enter table (last two pages of this appendix) with this value and find the closest number in the 

column labeled (Ratio 1); read the value to the right in the column labeled (Ratio 2) and enter that 

number below:

Ratio 2 (from table) =_____________

Area = __________ X _____________ X _____________ = ____________ sq in.

 (Ratio 2) (Pontoon Radius) (Pontoon Radius) (Area A)

(E) AREA SUBMERGED DUE TO WEIGHT MOVEMENT (AREA B)

Area = __________ - _____________ = ____________ sq in.

(Area A+B) (Area A) (Area B)

(F) TEST RESULTS

sq. in. sq. in.

(Area A) (Area B)

Pontoon area above waterline after 

weight movement from Section (D)

Pontoon area submerged due to 

weight movement from Section (E)

If (Area A) is greater than or equal to (Area B) then vessel passed test. Continue with

Longitudinal Stability Test

If (Area A) is less than (Area B) then stop the test. Remove a few passengers (test weight), print 

a new test form and start the form over, beginning with page 1 of the form.

Return to Test Form – Section (7)

Appendix C 108 Marine Accident Report
Revised September 28, 2004

Page 12 of 16

APPENDIX B

CALCULATION OF AREAS FOR CIRCULAR PONTOONS

Ratio 1 Ratio 2 Ratio 1 Ratio 2 Ratio 1 Ratio 2 Ratio 1 Ratio 2

1 0.00000 46 0.04176 91 0.2942 136 0.8395

2 0.00000 47 0.04448 92 0.3032 137 0.8546

3 0.00001 48 0.04731 93 0.3123 138 0.8697

4 0.00003 49 0.05025 94 0.3215 139 0.8850

5 0.00006 50 0.05331 95 0.3309 140 0.9003

6 0.00010 51 0.05649 96 0.3405 141 0.9158

7 0.00015 52 0.05978 97 0.3502 142 0.9314

8 0.00023 53 0.06319 98 0.3601 143 0.9470

9 0.00032 54 0.06673 99 0.3701 144 0.9627

10 0.00044 55 0.07039 100 0.3803 145 0.9786

11 0.00059 56 0.07417 101 0.3906 146 0.9945

12 0.00076 57 0.07808 102 0.4010 147 1.0105

13 0.00097 58 0.08212 103 0.4117 148 1.0266

14 0.00121 59 0.08629 104 0.4224 149 1.0428

15 0.00149 60 0.09059 105 0.4333 150 1.0590

16 0.00181 61 0.09502 106 0.4444 151 1.0753

17 0.00217 62 0.09958 107 0.4556 152 1.0917

18 0.00257 63 0.10428 108 0.4669 153 1.1082

19 0.00302 64 0.10911 109 0.4784 154 1.1247

20 0.00352 65 0.11408 110 0.4901 155 1.1413

21 0.00408 66 0.11919 111 0.5019 156 1.1580

22 0.00468 67 0.12443 112 0.5138 157 1.1747

23 0.00535 68 0.12982 113 0.5259 158 1.1915

24 0.00607 69 0.13535 114 0.5381 159 1.2084

25 0.00686 70 0.14102 115 0.5504 160 1.2253

26 0.00771 71 0.14683 116 0.5629 161 1.2422

27 0.00862 72 0.15279 117 0.5755 162 1.2592

28 0.00961 73 0.15889 118 0.5883 163 1.2763

29 0.01067 74 0.16514 119 0.6012 164 1.2934

30 0.01180 75 0.17154 120 0.6142 165 1.3105

31 0.01301 76 0.17808 121 0.6273 166 1.3277

32 0.01429 77 0.18477 122 0.6406 167 1.3449

33 0.01566 78 0.19160 123 0.6540 168 1.3621

34 0.01711 79 0.19859 124 0.6676 169 1.3794

35 0.01864 80 0.20573 125 0.6813 170 1.3967

36 0.02027 81 0.21301 126 0.6950 171 1.4140

37 0.02198 82 0.22045 127 0.7090 172 1.4314

38 0.02378 83 0.22804 128 0.7230 173 1.4488

39 0.02568 84 0.23578 129 0.7372 174 1.4662

40 0.02767 85 0.24367 130 0.7514 175 1.4836

41 0.02976 86 0.25171 131 0.7658 176 1.5010

42 0.03195 87 0.25990 132 0.7803 177 1.5184

43 0.03425 88 0.26825 133 0.7950 178 1.5359

44 0.03664 89 0.27675 134 0.8097 179 1.5533

45 0.03915 90 0.28540 135 0.8245 180 1.5708

Appendix C 109 Marine Accident Report
Revised September 28, 2004

Page 13 of 16

APPENDIX B

CALCULATION OF AREAS FOR CIRCULAR PONTOONS

Ratio 1 Ratio 2 Ratio 1 Ratio 2 Ratio 1 Ratio 2 Ratio 1 Ratio 2

181 1.5882 226 2.3319 271 2.86484 316 3.10245

182 1.6057 227 2.3466 272 2.87334 317 3.10495

183 1.6231 228 2.3612 273 2.88169 318 3.10735

184 1.6406 229 2.3758 274 2.88988 319 3.10964

185 1.6580 230 2.3902 275 2.89793 320 3.11183

186 1.6754 231 2.4044 276 2.90582 321 3.11392

187 1.6928 232 2.4186 277 2.91355 322 3.11591

188 1.7102 233 2.4326 278 2.92114 323 3.11781

189 1.7276 234 2.4465 279 2.92858 324 3.11961

190 1.7449 235 2.4603 280 2.93586 325 3.12133

191 1.7622 236 2.4740 281 2.94300 326 3.12295

192 1.7795 237 2.4876 282 2.94999 327 3.12448

193 1.7967 238 2.5010 283 2.95683 328 3.12593

194 1.8139 239 2.5143 284 2.96352 329 3.12730

195 1.8311 240 2.5274 285 2.97006 330 3.12859

196 1.8482 241 2.5404 286 2.97645 331 3.12979

197 1.8653 242 2.5533 287 2.98270 332 3.13092

198 1.8824 243 2.5661 288 2.98880 333 3.13198

199 1.8994 244 2.5787 289 2.99476 334 3.13297

200 1.9163 245 2.5912 290 3.00057 335 3.13389

201 1.9332 246 2.6035 291 3.00624 336 3.13474

202 1.9501 247 2.6157 292 3.01177 337 3.13552

203 1.9669 248 2.6278 293 3.01716 338 3.13625

204 1.9836 249 2.6397 294 3.02241 339 3.13691

205 2.0003 250 2.6515 295 3.02751 340 3.13752

206 2.0169 251 2.6631 296 3.03248 341 3.13807

207 2.0334 252 2.6746 297 3.03732 342 3.13857

208 2.0499 253 2.6860 298 3.04201 343 3.13902

209 2.0663 254 2.6972 299 3.04658 344 3.13943

210 2.0826 255 2.7083 300 3.05101 345 3.13978

211 2.0988 256 2.7192 301 3.05530 346 3.14010

212 2.1150 257 2.7299 302 3.05947 347 3.14038

213 2.1311 258 2.7405 303 3.06351 348 3.14062

214 2.1471 259 2.7510 304 3.06742 349 3.14083

215 2.1630 260 2.7613 305 3.07120 350 3.14100

216 2.1788 261 2.7715 306 3.07486 351 3.14115

217 2.1946 262 2.7815 307 3.07840 352 3.14127

218 2.2102 263 2.7914 308 3.08181 353 3.14137

219 2.2258 264 2.8011 309 3.08511 354 3.14144

220 2.2413 265 2.8107 310 3.08828 355 3.14150

221 2.2566 266 2.8201 311 3.09134 356 3.14154

222 2.2719 267 2.8293 312 3.09429 357 3.14156

223 2.2870 268 2.8384 313 3.09712 358 3.14158

224 2.3021 269 2.8474 314 3.09984 359 3.14159

225 2.3170 270 2.8562 315 3.10245 360 3.14159

Appendix C 110 Marine Accident Report
Revised September 28, 2004

Page 14 of 16

APPENDIX C

CALCULATION OF AREAS FOR WALL-SIDED PONTOONS

(A) APPLICABILITY

This appendix is applicable for the following shapes with the following restrictions:

1) Rectangular/square pontoons: This test is applicable without restriction.

2) Flared pontoons: This test is applicable for pontoons with flared hulls, not those with tumblehome (see pictures below). The width of the pontoon (BPONT) must be measured at the waterline.

Pontoon with flare

This test is APPLICABLE

Pontoon with tumblehome 

This test is NOT APPLICABLE

Submit calculations to MSC

3) Rounded/chine bottoms: This test is applicable as long the chine or turn of the bilge is 

underwater during the entire transverse stability test. If any part of the chine or turn of the bilge 

comes out of the water during the test, stop the test. 

4) Unusually-shaped pontoons: If the pontoon is not similar to those shown above, contact MSC 

to determine applicability of pontoon simplified stability test.

Pontoon Measurement Guide

BPONT

WL WL1 1

BPONT

B

fb2 fb1

BPONT

B1/2

WL2

A

CL

WL1

Appendix C 111 Marine Accident Report
Revised September 28, 2004

Page 15 of 16

APPENDIX C

CALCULATION OF AREAS FOR WALL-SIDED PONTOONS

(B) VESSEL HALF-BEAM

Vessel’s 1⁄2-beam (centerline to outboard edge of pontoon at pontoon top) measured at same 

longitudinal location as freeboard measurement = ____________ inches

(B1/2)

(C) VESSEL CONDITION BEFORE WEIGHT MOVEMENT

Width of pontoon at waterline at same location as freeboard measurement = __________ inches

(BPONT)

Check: BPONT must be less than or equal to B1/2. If not, this test is not valid. Stop the test.

Freeboard; waterline to top of pontoon = ___________ inches

(fb1)

(D) WEIGHT MOVEMENT

The heeling moment shall be obtained by a transverse movement of the test weight from Section 

(1) to the extreme outboard position of the deck available to passengers and crew on the side with 

the least initial freeboard.

Quantity Weight per Unit Subtotal Weight

(Quant. x Wt. per Unit) Distance Moved

Total Weight

Check: This should be equal to or greater than the Test Weight from Section (1)

Appendix C 112 Marine Accident Report
Revised September 28, 2004

Page 16 of 16

APPENDIX C

CALCULATION OF AREAS FOR WALL-SIDED PONTOONS

(E) VESSEL CONDITION AFTER WEIGHT MOVEMENT 

Freeboard; waterline to top of pontoon = ___________ inches 

(fb2)

(F) TEST RESULTS

Width Ratio = __________ ÷ ____________ = ____________ 

(BPONT) (B1/2) (WR)

Line 1 = 1 - ___________ = ______________

(WR) (Ans 1)

Line 2 = 2 - ___________ = ______________

(WR) (Ans 2)

Criteria = __________ X ___________ ÷ __________= ______________ in.

(fb1) (Ans 1) (Ans 2) (Criteria)

in. in.

(fb2) (Criteria)

Freeboard taken after weight 

movement from Section (E)

Result of (Criteria) calculation from

line above 

If (fb2) is greater than or equal to (Criteria) then vessel passed test. Continue with Longitudinal 

Stability Test

If (fb2) is less than (Criteria), then stop the test. Remove a few passengers (test weight), print a

new test form and start the form over, beginning with page 1 of the form.

Return to Test Form – Section (7)

Appendix C 113 Marine Accident Report
Monohull

Simplified

Stability Test 

IAW 46 CFR 

178.3302

Pontoon

Simplified

Stability Test 

IAW 46 CFR 

178.3402

Contact MSC, 

Calculations

Submitted to MSC 

IAW 46 CFR Subchapter S

Length of Vessel Less than 65 Feet

Type of Vessel 

(See Definitions

 in Job Aid)

Pontoon Vessel 

Carrying More 

Than 49 

Passengers?

Monohull

Vessel

Carrying

More Than 49 

Passengers?

Monohull

Simplified

Subdivision

Calculations IAW 

46 CFR 179.2202

Yes

No

Monohull

Other

Yes

No

No Simplified 

Subdivision

CalculationsRequired for 

Stability

Yes No

Pontoon Vessel

START

Stability of all 

Subchapter T vessels 

required to be 

evaluated 1

Flowchart to Determine the Applicability of Simplified Stability Tests & Simplified Subdivision Bulkhead Spacing Calculations 

for Small Passenger Vessels Inspected Under 46 CFR Subchapter T

Note 1: Unless specifically waived by the OCMI in accordance with 46 CFR 178.320(c).

Note 2: If the vessel fails the simplified stability test or bulkhead spacing calculations, the vessel must be shown by design calculations 

submitted to MSC to meet the applicable stability criteria of 46 CFR Subchapter S in each loading and operation.

Sailing Monohull

Sailing Vessel 

Simplified

Stability Test 

IAW 46 CFR 

178.3302

Appendix C 114 Marine Accident Report