0203.02.002 

December 18, 2006 

Mr. John Mueller 

Office of Transportation and Air Quality 

2000 Traverwood Drive 

Ann Arbor, MI 48105 

Dear John: 

Enclosed for your review is the Updated Draft Category 2 Vessel Census and Activity Report. 

Please give me a call at (919) 468-7812 with any questions or comments you may have about 

this report. 

Sincerely, 

Richard Billings 

Project Manager 

RSB/jt 

Enclosures 

cc: Penny Carey, EPA/OTAQ 

Leigh Roller, ERG/ Chantilly 

Sam Wells, Consultant 

Roger Chang, ERG/Morrisville 

WA 2-02 File/Category 2 Vessel Census Activity Reportrv1.wpd 
CATEGORY 2 VESSEL CENSUS AND ACTIVITY 

DRAFT REPORT 

Prepared for: 

John Mueller and Penny Carey 

Office of Transportation and Air Quality 

U.S. Environmental Protection Agency 

Ann Arbor, MI 48105 

Prepared by: 

Eastern Research Group, Inc. 

1600 Perimeter Park Drive 

Morrisville, NC 27560 

December 18, 2006
0203.02.002.001\Category 2 Vessel Census-Activity Report i 

Table of Contents 

Section Page

1.0 OVERVIEW .................................................................................................................... 1-1 

2.0 CATEGORY 2 VESSEL CENSUS EVALUATION...................................................... 2-1 

2.1 Tugboat ................................................................................................................ 2-1 

2.1.1 Tugboat Data Sources.............................................................................. 2-1 

2.1.2 Initial Coding of WTLUS Data................................................................ 2-2 

2.1.3 Determination of EPA Category.............................................................. 2-5 

2.1.4 Analysis of Tugboat Data ........................................................................ 2-8 

2.1.5 Tugboat References ................................................................................. 2-9 

2.2 Commercial Fishing Vessels................................................................................ 2-9 

2.2.1 Commercial Fishing Vessel Data Sources............................................... 2-9 

2.2.2 Analysis of Commercial Fishing Vessel Data ....................................... 2-12 

2.2.3 Commercial Fishing Vessel References ................................................ 2-15 

2.3 Coast Guard Vessels .......................................................................................... 2-15 

2.3.1 Coast Guard Data Source....................................................................... 2-16 

2.3.2 Analysis of Coast Guard Data................................................................ 2-16 

2.3.3 Coast Guard Reference .......................................................................... 2-16 

2.4 Ferry Vessels...................................................................................................... 2-16 

2.4.1 Ferry Vessel Data Sources..................................................................... 2-16 

2.4.2 Analysis of Ferry Data........................................................................... 2-17 

2.4.3 Ferry References .................................................................................... 2-18 

2.5 Deep Water Cargo Vessels ................................................................................ 2-19 

2.5.1 Deep Water Carbon Vessel Data Sources.............................................. 2-19 

2.5.2 Analysis of Deep Water Cargo Vessel Data.......................................... 2-19 

2.5.3 Deep Water Cargo Vessel References ................................................... 2-19 

2.6 Research Vessels................................................................................................ 2-19 

2.6.1 Research Vessel Data Sources............................................................... 2-20 

2.6.2 Analysis of Research Vessel Data ......................................................... 2-20 

2.6.3 Research Vessel References .................................................................. 2-20 

2.7 Offshore Support Vessels .................................................................................. 2-20 

2.7.1 Offshore Support Vessel Data Sources.................................................. 2-21 

2.7.2 Support Vessel Analysis ........................................................................ 2-21 

2.7.3 Offshore Support Vessel References ..................................................... 2-27 
0203.02.002.001\Category 2 Vessel Census-Activity Report ii 

Table of Contents (Continued) 

Section Page

2.8 Great Lake Vessels and Vessels Not Otherwise Included................................. 2-28 

2.8.1 Remaining Vessel Data Sources ............................................................ 2-28 

2.8.2 Analysis of Remaining Vessel Data ...................................................... 2-29 

2.8.3 Remaining Vessels References.............................................................. 2-31 

3.0 CATEGORY 2 VESSEL ACTIVITY ASSESSMENT................................................... 3-1 

3.1 Vessel Population and Characteristics................................................................. 3-1 

3.2 Operating Days and Load Factors........................................................................ 3-3 

3.3 Horsepower Hours ............................................................................................... 3-7 

3.4 Vessel Activity References................................................................................ 3-12 

4.0 IN-PORT / AT-SEA SPLITS........................................................................................... 4-1 

4.1 Introduction.......................................................................................................... 4-1 

4.2 In-Port / At-Sea Methodology ............................................................................. 4-1 

4.3 Vessel Type Overview......................................................................................... 4-2 

4.3.1 Tugs/Towboats......................................................................................... 4-2 

4.3.2 Commercial Fishing................................................................................. 4-3 

4.3.3 Offshore Support Vessels ........................................................................ 4-3 

4.3.4 Ferries ...................................................................................................... 4-3 

4.3.5 Deep Water Vessels ................................................................................. 4-3 

4.3.6 Research................................................................................................... 4-4 

4.3.7 Great Lakes and Other Vessels................................................................ 4-4 

4.3.8 Government Vessels ................................................................................ 4-4 

4.4 Summary.............................................................................................................. 4-5 

4.5 References............................................................................................................ 4-6 

5.0 CATEGORY 2 SPATIAL ALLOCATIONS .................................................................. 5-1 

5.1 Vessel Type Overview......................................................................................... 5-3 

5.1.1 Tugs/Towboats......................................................................................... 5-3 

5.1.2 Commercial Fishing................................................................................. 5-5 

5.1.3 Offshore Support Vessels ........................................................................ 5-7 

5.1.4 Ferries .................................................................................................... 5-10 
0203.02.002.001\Category 2 Vessel Census-Activity Report iii 

Table of Contents (Continued) 

Section Page

5.1.5 Deep Water Vessels ............................................................................... 5-11 

5.1.6 Research Vessels.................................................................................... 5-13 

5.1.7 Great Lakes and Other Vessels.............................................................. 5-16 

5.1.8 Government Vessels .............................................................................. 5-18 

5.2 Summary............................................................................................................ 5-20 

5.3 References.......................................................................................................... 5-23 

6.0 CATEGORY 2 VESSEL DATABASE........................................................................... 6-1 

6.1 Data Matching...................................................................................................... 6-1 

6.2 Data Augmentation and Assurance...................................................................... 6-3 

6.3 Compiled Database Structure .............................................................................. 6-4 

Appendix A – Identified Category 2 Marine Diesel Engines 

Appendix B – Summary of Monte Carlo Input and Output Data 

Appendix C – Category 2 In-Port / At-Sea Splits 

Appendix D – Category 1 In-Port / At-Sea Splits 
0203.02.002.001\Category 2 Vessel Census-Activity Report iv 

List of Tables and Figures 

Tables Page

1-1 Vessel Type Base Year .................................................................................................... 1-3 

1-2 Category 2 Summary ....................................................................................................... 1-4 

1-3 Category 2 Propulsion Horsepower Hours by Vessel Type ............................................ 1-5 

1-4 Average In-Port and At-Sea Fraction by Vessel Type for Vessels Equipped with 2 

 Propulsion Engines .......................................................................................................... 1-5 

2-1 Available Databases......................................................................................................... 2-1 

2-2 Industry and Region Query of the Operator Database..................................................... 2-3 

2-3 Regional Breakdown Using Port District Codes ............................................................. 2-5 

2-4 Vessel Matching............................................................................................................... 2-7 

2-5 Category 1 and 2 Hulls and Engines................................................................................ 2-8 

2-6 State Fishing Vessel Registration Comparisons ............................................................ 2-10 

2-7 Commercial Fishing Vessel Category Assumptions...................................................... 2-11 

2-8 Summary of Commercial Fishing Vessel Data Sources................................................ 2-11 

2-9 Summary of Commercial Fishing Vessel Categories .................................................... 2-12 

2-10 Commercial Fishing Vessels Sorted by Length and Horsepower Groupings................ 2-13 

2-11 Commercial Fishing Vessels by Horsepower................................................................ 2-14 

2-12 Ferry Population by Engine Category............................................................................ 2-17 

2-13 Distribution of Ferries by State...................................................................................... 2-18

2-14 OMSA U.S. Flagged Vessel Population by Offshore Vessel Type for the 

 Gulf of Mexico............................................................................................................... 2-22 

2-15 OMSA U.S. Vessel Population by Offshore Vessel Type for the 

 Gulf of Mexico............................................................................................................... 2-23 

2-16 Results from Matching Vessels to Engine Characteristics ............................................ 2-25 

2-17 Support Vessel Category Mix........................................................................................ 2-25 

2-18 Category Mix of Support Vessel Type .......................................................................... 2-26 

2-19 U.S. Flagged Category 2 Vessel Population.................................................................. 2-27 

2-20 Summary of Remaining Vessel Engine Classification .................................................. 2-29 

2-21 Average HP for Missing Boats ...................................................................................... 2-30 

2-22 Allocation of Missing Vessels ....................................................................................... 2-30 

3-1 Vessel Population and Characteristics............................................................................. 3-2 

3-2 Operating Days and Load Factors.................................................................................... 3-5 

3-3 Category 2 Propulsion Horsepower Hours by Vessel Type ............................................ 3-7 

4-1 Average In-Port and At-Sea Fraction by Vessel Type for Vessels Equipped 

 with Category 1 and 2 Propulsion Engines...................................................................... 4-5 

5-1 Summary of Spatial Allocation Approaches Used .......................................................... 5-1 

5-2 List of Ferry Ports .......................................................................................................... 5-10 

6-1 Mapping of Database Field Names by Vessel Type........................................................ 6-2 
0203.02.002.001\Category 2 Vessel Census-Activity Report v 

Figures Page

1-1 Project Overview ............................................................................................................. 1-2 

1-2 Combined In-Port and At-Sea Activities for Category 2 Vessels.................................... 1-6 

2-1 Organization of Towboat Data......................................................................................... 2-6 

2-2 Distribution of Test Matched by Count and HP-Tonnage............................................... 2-8 

2-3 Vessel Sale Data ............................................................................................................ 2-14 

3-1 Underway, Idling, and In Port Fractions by Vessel Type ............................................... 3-6 

3-2 Deep Water Vessel HP-HR Calculation Frequency Chart ............................................. 3-8 

3-3 Tow Vessel HP-HR Calculation Frequency Chart ......................................................... 3-9 

3-4 Ferry Vessel HP-HR Calculation Frequency Chart ........................................................ 3-9 

3-5 Commercial Fishing Vessel HP-HR Calculation Frequency Chart .............................. 3-10 

3-6 Great Lakes Vessel HP-HR Calculation Frequency Chart ........................................... 3-10 

3-7 Coast Guard Vessel HP-HR Calculation Frequency Chart ........................................... 3-11 

3-8 Offshore Vessel HP-HR Calculation Frequency Chart ................................................ 3-11 

3-9 Research Vessel HP-HR Calculation Frequency Chart ................................................ 3-12 

5-1 Overview of Approach Used to Develop and Spatially Allocate Annual Activity of 

Vessels Equipped with Category 2 Engines ................................................................... 5-2 

5-2 Tug/Towboat In-Port Activity ......................................................................................... 5-4 

5-3 Tug/Towboat At-Sea Activity.......................................................................................... 5-4 

5-4 Commercial Fishing In-Port Activity .............................................................................. 5-6 

5-5 Commercial Fishing At-Sea Activity............................................................................... 5-7 

5-6 Offshore Support Vessel In-Port Activity........................................................................ 5-8 

5-7 Offshore Support Vessel At-Sea Activity........................................................................ 5-9 

5-8 Ferry In-Port and At-Sea Activity.................................................................................. 5-11 

5-9 Deep Water Vessel In-Port Activity .............................................................................. 5-12 

5-10 Deep Water Vessel At-Sea Activity .............................................................................. 5-13 

5-11 Research Vessel In-Port Activity................................................................................... 5-14 

5-12 Research Vessel At-Sea Activity................................................................................... 5-15 

5-13 Great Lake and Other Vessel In-Port Activity............................................................... 5-17 

5-14 Great Lake and Other Vessel At-Sea Activity............................................................... 5-18 

5-15 Coast Guard In-Port Activity......................................................................................... 5-19 

5-16 Coast Guard At-Sea Activity ......................................................................................... 5-20 

5-17 Combined Category 2 In-Port Activities ....................................................................... 5-21 

5-18 Combined Category 2 At-Sea Activities........................................................................ 5-22 

5-19 Combined In-Port and At-Sea Activities for Category 2 Vessels.................................. 5-22 
0203.02.002.001\Category 2 Vessel Census-Activity Report 1-1 

1.0 OVERVIEW 

For this project, data were compiled from a variety of sources to identify vessels equipped with 

Category 2 propulsion engines. Initially, the project focused on Category 2 vessels operating 

within port areas, but the project objectives changed to encompass all navigable waterways in the 

U.S. 

U.S. Environmental Protection Agency (EPA) defines the three engine categories for commercial 

marine vessels’ main propulsion engines and auxiliary engines as: 

• Category 1: 1-5 liters per cylinder displacement 

• Category 2: 5-30 liters per cylinder displacement 

• Category 3: over 30 liters per cylinder displacement 

Category 2 is a transitional engine category between Category 1 engines (used by most harbor 

and fishing vessels) and Category 3 engines (used by larger ocean going vessels). Previous 

studies have accounted for vessels with Category 1 and 3 engines nationwide, but vessels with 

Category 2 engines have not been studied as thoroughly. 

One of the first tasks for this study is to identify databases and sources that will help identify the 

vessels with Category 2 marine diesel propulsion engines in the contiguous states as well as 

Alaska, and Hawaii. It was discovered early in the project that there is no single data base that 

tracks vessels that are equipped with these engines. In order to capture the Category 2 vessel 

population, multiple data sources needed to be reviewed, compiled, and analyzed. 

As the available data for the different vessel types can be significantly different, the project 

evaluated the available data for the following eight vessel types separately: 

• Towboats; 

• Offshore Support Vessels; 

• Commercial Fishing Vessels; 

• Coast Guard Vessels; 

• Ferry Vessels; 

• Deep Water Cargo Vessels; 

• Research Vessels; and 

• Great Lakes Vessels and Vessels Not Otherwise Included. 

Most of these vessels are not ocean going vessels (except the deep water cargo vessels) as 

defined in the EPA’s Current Methodologies and Best Management Practices in Preparing Port 

Emission Inventories. Most of these vessel types would be considered harbor craft as defined in 

the above report. Tow boats include push boats and tug boats that operate within and outside the 

port. Coast Guard vessels are a subset of government vessels. In this study, offshore vessels 

include both crew boats and work boats. Research vessels discussed in this Category 2 study are 

a subset of workboats. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 1-2 

The first objective of this project is to implement a Census of Category 2 vessels operating in 

U.S. waters. As noted in Section 2 of this report, estimates of activity for each vessel type are 

developed in Section 3 of this study. The in-port / at-sea splits developed in Section 4 will be 

used to apportion the estimated hours of operation developed in Section 3 to port and underway 

activities as noted in Figure 1-1. 

Figure 1-1. Project Overview 

The port activities will be spatially allocated in Section 5 to individual ports base on an 

appropriate surrogate such as the amount of cargo handled (for tow boats, deepwater cargo 

vessels and Great Lakes vessels), fish catch processed (for commercial fishing boats) and the 

vessel’s home port (for offshore, research and government vessels and ferries). 

Underway activities will be spatially allocated to shipping lanes (for tow boats, deepwater 

vessels, Great Lakes vessels), fishing zones (for commercial fishing), coast guard districts (for 

Activity by 

Vessel Type

In- Port At -Sea

Allocated to 

Individual Ports 

Based on: 

• Cargo Handled 

• Fish Catch 

 Processed 

• Vessel Home 

 Port

Allocate to:

• Shipping Lane 

• Fishing Zone 

• Coast Guard 

 District 

• Offshore Oil 

 Platforms 

• Research Area

Applied to GIS Map 

Overlaid with 

County/Federal 

Boundary Shape 

County Level 

Activity by 

Vessel Type
0203.02.002.001\Category 2 Vessel Census-Activity Report 1-3 

government vessels), offshore oil platforms (for offshore support vessels) and research areas (for 

research vessels). 

The port and underway activities will be mapped using Geographic Information Systems tools. 

County and Federal boundaries will be mapped on top of the port and underway activities to 

allow for aggregation of activity estimates to the county level. 

Where ever possible, vessel specific data such as the make and model number of the propulsion 

engines were evaluated individually to accurately identify Category 2 vessels. Unfortunately, for 

most vessels such data proved to be difficult to identify. Instead information was pieced together 

by appropriately linking the different data sets that were compiled. For example, when vessel 

identification data were provided, these data were linked to the Lloyd’s Registry of Ships (ROS), 

American Bureau of Ships (ABS), or Bureau Veritas vessel classification data files to get vessel 

characteristics data. These vessel characteristics were either used directly to calculate the 

cylinder volume or they could be linked up to a dataset of Category 2 propulsion engines that 

was developed for this project and is included in Appendix A of this report. 

To implement this study, data from a variety of sources were used. Through every attempt was 

made to obtain the most recent data available, the compiled data represents different base years 

as noted in Table 1-1. 

Table 1-1. Vessel Type Base Year 

Vessel Type 

Base Year of Population and 

Activity Data 

Towboats 2002-2004 

Offshore Support Vessels 2005 

Commercial Fishing Vessels 2000-2004 

Coast Guard 2004 

Ferry 2000-2004 

Deep Water Cargo Vessels 2005 

Research Vessels 2004 

Great Lake Vessels and Others 2004 

Where engine displacement data were not readily available, several different methods were used 

to estimate the engine category of a vessel. This included evaluating the relationship of a variety 

of variables such as engine horsepower, vessel gross ton weight (GTW), and vessel length so as 

to identify correlations what would help categorize the vessel’s propulsion engine classification. 

Table 1-2 summarizes the Category 2 vessel population based on this compilation and analysis of 

available data. Towboats and Offshore vessels represent the most significant Category 2 vessel 

groups and as such considerable resources were applied to these components of the study to 

develop the most accurate vessel inventory possible with publicly available data. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 1-4 

Table 1-2. Category 2 Summary 

Vessel Type 

Category 2 

Vessel Count 

Percent of 

Total 

Towboats 1,057 42.6 

Offshore Support Vessels 603 24.3 

Commercial Fishing Vessels 333 13.4 

Coast Guard Vessels 157 6.3 

Ferry Vessels 99 4.0 

Deep water cargo vessels 89 3.6 

Research Vessels 31 1.3 

Great Lake Vessels and Vessels Not Otherwise Included 112 4.5 

Total 2,481 100 

Identification of Category 2 fishing vessels was particularly challenging. The data sources for 

this fleet are difficult to evaluate due to limited information available to characterize fishing 

vessels and the fact that there are over 30,000 U.S. flagged fishing ships currently in operation. 

For some of the vessel type categories, there were national databases of vessels, such as for deep 

water cargo vessels, ferries, research ships, offshore support vessels, and Coast Guard vessels, 

which made a good starting point to identify vessels that are potentially equipped with 

Category 2 propulsion engines. 

Section 2 of this report summarizes the data sources analyzed in this study, the methods used, 

and population estimates developed for each vessel type. Some of these summaries are brief, as 

the data to perform this analysis were readily available and the methods used to identify 

Category 2 powered vessels were reasonably simple. 

Section 3 of this study compiles the vessel census and characteristics data into a Monte Carlo 

simulation to estimate activity for each vessel type. Activity in this report is defined as 

horsepower hours of operation for the Category 2 propulsion engines. 

Results from this analysis are noted in Table 1-3. As Table 1-3 indicates, offshore vessels 

account for a large portion of Category 2 vessel activity. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 1-5 

Table 1-3. Category 2 Propulsion Horsepower Hours by Vessel Type 

Vessel Type 

Mean Values 

(million hp-hrs) 

Standard Deviation 

(million hp-hrs) 

Deep Water 1,300 339 

Towboat 7,920 3,020 

Ferry 1,464 443 

Fishing 3,413 1,143 

Great Lakes 1,393 405 

Coast Guard 1,441 496 

Offshore 27,810 11,933 

Research 654 217 

This activity data were split for each vessel type into in-port and at sea components. The splits 

developed for this study are presented in Table 1-4. The in-port time for some of these vessel 

types is relatively small, as the propulsion engines for these vessels are shut off while dockside. 

Section 4 discusses how these in-port and at-sea splits were developed. 

Table 1-4. Average In-Port and At-Sea Fraction by Vessel Type for 

Vessels Equipped with 2 Propulsion Engines 

Vessel Type In-Port At-Sea 

Towboats 17% 83% 

Fishing 5% 95% 

Offshore 4% 96% 

Ferries 65% 35% 

Deepwater 1% 99% 

Research 1% 99% 

Great Lakes 1% 99% 

Government 59% 41% 

Weighted Average 10% 90% 

Once activity data could be disaggregated into the in-port and at-sea components, then the 

activity data were further disaggregated into county and federal lease blocks. Section 5 discusses 

the techniques and surrogate data used to spatially allocate Category 2 activity by vessel type to 

individual counties and federal lease blocks as presented in Figure 1-2. This figure shows total 

Category 2 activity for in-port and at-sea operations. It should be noted that county waters in the 

Great Lakes represent significant larger areas than coastal county blocks which only extend three 

to seven miles to the state/federal water boundary. This difference in the block size makes it 

difficult to visually compare activity levels in the Great Lakes with activity levels in coastal 

areas. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 1-6 

Figure 1-2. Combined In-Port and At-Sea Activities for Category 2 Vessels 

In addition to this report, this project produced a set of data files that contain the compiled 

county and federal lease block activity data developed for this project. The database structure 

used for this study is discussed in Section 6 of this report. Note that the data included in the 

database are vessel specific. Because the EPA’s category determinations are based on the volume 

of the marine diesel engine cylinder, and such data are generally not readily available for all U.S. 

flagged vessels, assumptions had to be made based on statistical review of the compiled data and 

engineering judgment. Given that detailed engine data were not always available, some of the 

individual vessels included in this data base may not actual be equipped with Category 2 engines. 

Some vessels which do have Category 2 engines may be missing. This vessel listing should be 

considered a preliminary census, which should be validated in the future with a detailed 

commercial marine vessel survey. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-1 

2.0 VESSEL TYPE EVALUATION

2.1 Tugboat 

One of the objectives of this project was to identify the population of all tugboats registered in 

the U.S. and estimate the number of Category 2 engines. Previous inventories of tug-related 

emissions were mainly based on fuel consumption, a ton-mile method, or other surrogates that 

did not relate very well to identifying tugboat emissions. 

Technically, there are two kinds of towboats that are commonly referred to as tugboats. One type 

has a rounded bow at the front of the vessel (towboat) and the other a square bow used 

exclusively for pushing barges (pushboat). The terms tugboat and towboat are often used 

interchangeably. Specialized types of towboats, such as the integrated tug-barge (ITB), are not 

considered to be true towboats, but rather ocean-going vessels as they carry cargo on the open 

seas. 

According to the American Waterways Operators (AWO), the main industry group, towboats 

and barges moved 20 percent of America’s coal, 60 percent of U.S. gain exports, and most of the 

heating oil in the Northeast. 

Statistics from the AWO indicate approximately 4,000 line-haul vessels. A line haul vessel is one 

that pushes or pulls barges. There are a smaller, but significant number of towboats engaged in 

ship maneuvering, channel dredging, and construction activities. 

The EPA categorizes towboats as being harbor vessels so as to distinguish them from oceangoing ships. Although most of the traffic is restricted to U.S. territorial waters, it should be noted 

that towboats can travel hundreds of miles, and some are considered to be more similar to ships 

such as the ITB or ocean-going salvage tugs. 

2.1.1 Tugboat Data Sources 

Most of the key data is from the U.S. Army Corps of Engineers and is available on their Internet 

site. Other sources include the U.S. Coast Guard’s Merchant Vessels of the U.S. Lloyd’s 

Register of Ships. Available data used in this study are summarized below in Table 2-1 and 

discussed in greater detail below. 

Table 2-1. Available Databases 

Data Source Records Notes 

Merchant Vessels of the U.S. 6,619 2004 data may contain workboats 

Waterborne Transportation Lines of the U.S. 5,180 2002 baseline 

Merged WTLUS Operators File 4,711 397 did not match 

Inland River Record 3,280 Mississippi and Gulf Intracoastal 

Lloyd’s Register of Ships 864 International vessel records 

American Bureau of Shipping 414 Mainly U.S. vessel records 

Bureau Veritas < 20 Mostly foreign ships 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-2 

• Merchant Vessels of the U.S. (MVUS) – This reference is prepared by the U.S. Coast 

Guard (USCG) and reflects all documented vessels in the U.S., excluding any foreign or 

non-documented vessels, in accordance with U.S. laws. The database contains some 

limited horsepower data, but is mainly oriented towards hull specifications and owner 

information. It is thought that the code for “towing vessels” used in this database may 

include more than CMV towboats and pushboats. 

• Waterborne Transportation Lines of the U.S. (WTLUS) – This reference serves as the 

basis for documenting the number of active and inactive towboats and pushboats in the 

U.S., as compiled by the U.S. Army Corps of Engineers. Once the vessel file was merged 

with the operator/owner file there was a slight loss of information, but the merge proved 

useful to assign tugboats to industry types and geographic area. 

• Inland River Record (IRR) – This reference contains all towboats and pushboats 

operating on the waterways of the Mississippi, its tributaries, and the Gulf Intracoastal 

Waterway. This accounts for approximately half of the tug population in the U.S. It has 

very good records, but the text format was a challenge to convert into in a database 

format. 

• Lloyd’s Register of Ships (ROS) – Tugboats flagged in the U.S. were queried from a very 

large file containing over 70,000 international vessels. Lloyd’s is a marine research 

company as well as a vessel classification, similar to the next two entries. 

• American Bureau of Shipping (ABS) – Similar to the ROS although this data only 

includes those vessels classified by its company standards. 

• Bureau Veritas (BV) – This database was purchased in order to develop a comprehensive 

dataset of vessel characteristics. Unfortunately, very few U.S. tugboats were found in this 

data set. 

2.1.2 Initial Coding of WTLUS Data 

Initially, the WTLUS was coded by visually inspecting the data and creating separate data fields 

for industry type and geographical area of operation. This was a subjective task. Since there were 

many empty (or “null”) values for industry type, the default was set to all boats being engaged in 

towing, a generic term used in the industry for pulling or pushing barges over long stretches of 

water. The following industry types were used in this study: 

• Assisting – pushing large ocean-going ships to or from the dock; 

• Bunkering – providing fuel barge service to refuel large, ocean-going ships; 

• Charter – these are towboats that are for rent by the day, week, month, or year; 

• Construction – engaged in hauling construction materials and machinery; 

• Dredging – related to assisting non-propelled dredges; 

• Fleeting – moving around barges within a harbor or short waterway segment; 

• Idle – not working; 

• Logging – more common to the Northwest and Alaska, includes shifting log rafts; 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-3 

• Oil and Gas – services inland or offshore oil and gas production platforms; 

• Passenger – tugs that push passengers on barges; and 

• Towing – called “line haul barge units,” these are by far the most common. 

While all companies tend to have a preferred market such as hauling petrochemicals, grain, or 

coal, the industry type assignments should be viewed with a certain caution: a line haul towboat 

can also be used for ship assisting, salvage work, shipyard work, or a number of other duties. 

Geographic variables were also included in our data set. Assigning vessels to geographic areas 

was a cumbersome task because the WTLUS has three separate data sources that had to be 

integrated into our data set. These data sources included: 

1. WTLUS of the Great Lakes 

2. WTLUS of the Mississippi River System and the Gulf Intracoastal Waterway 

3. WTLUS of the Atlantic, Gulf, and Pacific coasts 

The Great Lakes data included a small number of towboats in a relatively small domain. The 

Mississippi and Intracoastal waterways had the highest number of towboats, but all operated on 

known shipping channels. The third section was far more complex, since the terms “offshore” or 

“coastwise” simply do not fit. Many of these boats were in fact in-shore towboats or even river 

pushboats (e.g., Delaware Bay in the east or the Columbia/Snake rivers in the west). What was 

missing was a descriptor for inland versus offshore Atlantic/Gulf/Pacific towboats, which is 

important because the offshore vessels tended to have larger engines and with presumably more 

EPA Category 2 engines relative to the in-shore towboats. 

To get a sense of the magnitude of where tugboats are operating and what they are doing, an 

initial pass was taken from the WTLUS towboat data, stratifying boats into industry and 

geographical types, as shown in Table 2-2. 

Table 2-2. Industry and Region Query of the Operator Database 

JOB Lakers Inland Coastwise Total

ASSIST 0 25 66 91

BUNKERING 0 16 16 32

CHARTER 1 71 43 115

CONSTRUCTION 22 115 114 251

DREDGING 5 9 41 55

FLEETING 1 153 8 162

IDLE 0 28 19 47

LOGGING 0 0 73 73

OIL_GAS 0 144 29 173

PASSENGER 0 34 6 40

TOWING 102 2691 1348 4141

131 3,286 1,763 5,180
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-4 

It is evident that the majority of the tugboats are involved in line-haul barge transportation in the 

inland and coastal regions. According to the U.S. ACE, there were 5,180 towboats and pushboats 

operating in 2002 in the U.S. that were tracked for the purposes of regulatory compliance. As is 

also indicated by the “IDLE” entry, some companies have vessels which were inactive. 

Further evaluation of the WTLUS data identified an additional 400 vessels that could be 

undocumented, working overseas, or were coded with invalid codes. As is recorded in Table 2-1, 

397 vessels did not match with the WTLUS towboat data which lists each specific towboat or 

pushboat. This is probably due to the reporting of incorrect operator identification codes. It 

should be noted that many of these 397 vessels are engaged in oceanic traffic such as moving 

cargo to and from Hawaii, Puerto Rico, and other U.S. territories. 

These tugboat estimates are consistent with estimates developed by the American Waterway 

Operators (AWO). The AWO estimates that there are 4,000 to 5,000 towboats operating in U.S. 

waters. 

Additional geographic differentiations are summarized in Table 5 for the following geographic 

areas: 

• Lakers – The Great Lakes. No Canadian towboats are included here. Some boats operate 

on inland waterways connected to the Ohio and Mississippi rivers, the Erie canal, etc. 

• Inland – Mainly the Mississippi River and Ohio River, the largest concentration of 

towboats in the U.S. 

• Atlantic – The entire seaboard between Key West, Florida and upper Maine. The U.S. 

ACE database was not coded to determine inland versus offshore towboats. 

• Gulf Inland – These are mainly towboats operating on the Gulf Intracoastal Waterway 

(GIWW) between Brownsville, Texas and Mobile, Alabama. 

• Gulf Offshore – The U.S. ACE dataset did allow us to distinguish between “inland” and 

“offshore” where the primary area was “Gulf of Mexico.” 

• Pacific – This region covers the area between San Diego and the Puget Sound; again, 

there is no available code for “inland” operations such as on the Columbia-Snake River 

waterways. 

The statistics shown in Table 2-3 should be viewed with caution because the industry type code 

is related to the entire towboat company, not individual towboats. For example, we know that 

bunkering occurs very often in the harbors near Los Angeles and New York, but the companies 

involved with bunkering were primarily engaged in assisting or harbor towing. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-5 

Table 2-3. Regional Breakdown Using Port District Codes 

JOB Lakers Inland Atlantic Gulf_Inland Gulf_Offshore Pacific Total

ASSIST 0 27 39 20 0 5 91

BUNKERING 0 15 1 16 0 0 32

CHARTER 1 61 25 14 11 3 115

CONSTRUCTION 22 119 47 39 3 21 251

DREDGING 5 25 15 1 6 3 55

FLEETING 1 129 0 32 0 0 162

IDLE 0 20 1 15 0 11 47

LOGGING 0 0 0 0 0 73 73

OIL_GAS 0 2 0 142 29 0 173

PASSENGER 0 32 3 5 0 0 40

TOWING 102 1804 277 1360 106 492 4141

131 2234 408 1644 155 608 5180

2.1.3 Determination of EPA Category 

Significant work was required to determine the engine category of identified towboats. After 

combining the U.S. ACE operator and vessel files, vessel identifying codes such as Coast Guard 

number or IMO number were used to match vessel characteristics data to individual vessels. For 

example, both the ROS and ABS data sets had engine make and model information, which was 

useful in determining the EPA category. The ROS data also contained valid cylinder bore and 

stroke information in case the engine make and model could not be matched to engines in the 

Category 2 engine database. Figure 2-1 shows how the different data elements were linked. 

The method to determine a vessel’s EPA engine category is based on cylinder displacement, 

which requires specifications for bore (piston diameter) and stroke (piston travel). The equation 

for estimating the volume of a cylinder was used to calculate cylinder displacement: 

π r

2

 h 

Disp = π x (bore/2)2

 x stroke 

In the cases where this information was not available from ROS, engine specifications were 

obtained over the Internet and bore and stroke values were applied to the spreadsheet. It became 

evident that one could identify estimate engine characteristics by collecting data on an engine 

family rather than each variant of the engine model. For example, all Caterpillar engines were 

Category 1 with the exception of the 3600 series (3606, 3608, and 3612). 

An attempt was made to use horsepower (HP) to help make engine category determinations 

about towboats that did not have a known engine make and model, but this approach was not 

always accurate. The California Air Resource Board uses a cut-point of 750 HP, below which 

engines are classified as Category 1. This approach misidentifies many large Category 1 engines, 

such as the larger engines in the Caterpillar 3500 series, as being Category 2 engines. Using a 

cut-off such as 2,000 HP would be similarly inaccurate because there are many Category 2 

engines below 2,000 HP, including popular models such as: 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-6 

Inland River

Record

USACE

Operator File

USACE 

Vessel File

American 

Bureau of

Shipping

Lloyd’s of

London 

Register of

Ships

Matched

Engine Make

Category Type

Developed 

Category 

Surrogate

(HP-Tonnage)

Tow Boat Compile Dataset 

with Category Type and 

Geographic Area

USCG Boat Number

or

IMO Identification 

Inland River

Record

Figure 2-1. Organization of Towboat Data 

USACE

Operator File

USACE 

Vessel File

American 

Bureau of

Shipping

Lloyd’s of

London 

Register of

Ships

Matched

Engine Make

Category Type

Developed 

Category 

Surrogate

(HP-Tonnage)

Tow Boat Compile Dataset 

with Category Type and 

Geographic Area

USCG Boat Number

or

IMO Identification 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-7 

• Fairbanks 6-38 and 8-38 series 

• EMD 12-278 and 16-278 series 

• Some EMD 12-645 models 

After concluding that individual cylinder displacement has little relationship to horsepower, it 

was decided that a more complex profiling approach was needed. 

Use of HP and Hull Displacement Metric 

After removing vessels that are included in other vessel categories and then matching engine 

models to known EPA categories there were a significant number of “Unmatched Boats,” as is 

reported in Table 2-4. 

Table 2-4. Vessel Matching 

A new approach was developed to help determine whether a vessel was Category 1 or 2 based on 

total towboat HP and hull displacement (in net registered tons). In this approach, vessel HP is 

multiplied by hull displacement and divided by 1,000. Figure 2-2 shows the results of the 

calculation for matched vessels where the EPA engine category was known. 

The vast majority of boats with HP-Tonnage scores below 250 were Category 1 vessels. Those 

with HP-Tonnage values above 1,000 were mostly Category 2 vessels. The area in between 250 

and 1,000 was problematic, but only seemed to account for 10 percent of the fleet. Efforts to 

further refine the cutpoint based on number of installed engines, hull design (model towboat or 

pushboat), and vessel length were not successful. A preliminary decision to use 250 as the 

cutpoint was made knowing that this could conceivably overestimate the number of Category 2 

engines – although there seemed little basis to apply probability statistics in this case. It should 

be emphasized that the surrogate HP-Tonnage method was only applied to the unmatched boats, 

which represented about 31 percent of the fleet. Thus the gross error was plus or minus 5 percent 

for the unmatched vessels or +/- 2 percent for the matched and unmatched data combined. 

Database preparation also included gap filling. In a limited number of cases inspection of the 

data revealed a few (50-80) duplicate rows. This can be explained in part because a towboat 

could have two different engine models on board, as well as a function of how the data were 

merged. Given the low gross error rate and the fact that it was unclear which records should be 

removed, these few boats were retained in the tugboat database. 

Data Count Percent

Matched 2,883 68%

Remaining 1,338 32%

4,221
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-8 

H P * T o n n a g e M e tric

0

100

200

300

400

500

600

700

800

900

5 0

1 0 0

150

2 0 0

350

3 0 0

350

400

450

5 0 0

1 0 0 0

999 9 9

Raw Count

C a t1

C a t2

Figure 2-2. Distribution of Test Matched by Count and HP-Tonnage 

2.1.4 Analysis of Tugboat Data 

Table 2-5 below summarizes the commercial towboat fleet in the U.S., stratified by operating 

area. 

Table 2-5. Category 1 and 2 Hulls and Engines 

Area C1Boats C2Boats Total Towboats 

Atlantic 247 103 350 

Great Lakes 88 21 109 

Gulf Inland 1,281 251 1,532 

Inland 1,135 441 1,576 

Offshore Gulf 69 70 139 

Pacific 344 171 515 

Total 3,164 1,057 4,221 

The last two columns sum up Category 1 and 2 towboats and engines, respectively. 

Approximately 27 percent of the fleet of towboats was classified as having Category 2 main 

propulsion engines. Note that no Category 3 engines were found. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-9 

The authors wish to acknowledge Mr. Doug Scheffler of the AWO for his suggestions regarding 

use of the U.S. ACE databases. Our finding of 4,221 active towboats, of which 1,057 are 

identified as being Category 2 equipped, is consistent with AWO projections for the U.S. 

towboat fleet. 

2.1.5 Tugboat References 

American Bureau of Shipping Bureau – 2004 Data query available by negotiation only, 

http://www.eagle.org/. 

American Waterways Operators, call with Mr. Sam Wells and Mr. Doug Scheffler, 2004. 

Bureau Veritas – 2004 Data query available by negotiation only, Paris, France, 2004. 

California Air Resource Board, call with Sam Wells of Starcrest and Kirk Rosenkranz of ARB 

June 6, 2004. 

Inland River Record – The Waterways Journal, Inc., 319 N. Fourth Street, Suite 650, St. Louis, 

MO, 2004. 

Lloyd’s Register of Ships, Fairplay, Ltd. 8410 N.W. 53rd Terrace, Suite 207, Miami, FL, 2004. 

U.S. Coast Guard, Merchant Vessels of the U.S., NTIS, (CG 408), 2004. 

U.S. Army Corps of Engineers, Waterborne Statistics Division, Waterborne Transportation Lines 

of the U.S., New Orleans, LA. 2004 http://www.iwr.usace.army.mil/ndc/wcsc/wcsc.htm

2.2 Commercial Fishing Vessels 

Commercial fishing vessels are self-propelled ships dedicated to procuring fish for the purpose 

of sale at a market. There are various kinds of fishing vessels that use different types of fishing 

gear. The main kinds of gear include seine nets, crab pots, trolling lines, otter net trawling, gill 

netting, and long-lines. The main distinction between fishing vessels is whether the boat tows a 

net or is engaged in “hook and line” fisheries, or falls into a miscellaneous category that can 

include dive boats, clam dredges, and even aquaculture support vessels. Gear type is not a good 

predictor of horsepower requirements or the category classification of the propulsion engine. In 

fact, many fishing boats are “multi-purpose” so as to be able to participate in as many different 

fishing activities as possible. In addition to smaller fishing vessels, there are a number of large, 

ocean-going vessels that serve as factory ships and are equipped with blast freezers, some of 

which are capable of processing over a hundred metric tons of fish per day. The fishing vessel 

fleet varies from port to port in size, design, and targeted fish species. 

2.2.1 Commercial Fishing Vessel Data Sources 

The principal data source for the commercial fishing vessels is the MVUS database. By law, the 

vessels need to be registered with the U.S. Coast Guard. The database was queried for 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-10 

“commercial fishing vessels” and this file was used as the starting point. Out of a total 29,679 

commercial fishing vessels found in the file, roughly 3,000 vessels had horsepower data. If we 

assume that the port of registry is a surrogate for where the boat is based, the states with the most 

commercial fishing vessels are listed in Table 2-6. Because fishing boats move seasonally with 

fish populations, their area of operation are typically large areas and they visit several different 

ports. 

Table 2-6. State Fishing Vessel Registration Comparisons 

State 

Percentage of National 

Registered Fishing 

Vessels Fleet 

Alaska 18% 

Washington 8% 

Texas 8% 

California 7% 

Florida 7% 

Louisiana 7% 

Maine 7% 

Massachusetts 6% 

Maryland 4% 

Oregon 4% 

Virginia 4% 

North Carolina 3% 

Mississippi 2% 

New York 2% 

Others 13% 

The MVUS database documented U.S. commercial fishing vessels, but it could not be used 

solely to identify vessels with EPA Category 2 propulsion engines since it has limited 

horsepower data and no engine make and model data. In fact, no data source was identified that 

included engine make and model for registered commercial fishing vessels. Therefore, the engine 

category identification could not be based on engine specific data. Instead, horsepower, vessel 

length, geographic area, and type of fishing activities were considered in determining the engine 

category. 

In evaluating the approximately 30,000 rows of data, the vessels were given category codes 

based on classifications noted in Table 2-7. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-11 

Table 2-7. Commercial Fishing Vessel Category Assumptions 

Category Description Vessel Count 

0 0 HP 101 

1 Rated HP less than 1,000 2,818 

Possible 1 HP not given; length less than 100’ length 26,103 

2 Rated HP greater than 1,000 301 

Possible 2 HP not given; length greater than 100’ 356 

Total 29,679 

The 1,000 HP and 100 foot length break-points were used to help sort the data and divide it into 

manageable groups. From previous experience with commercial fishing vessel surveys, it was 

assumed that vessels with less than 1,000 HP and less than 100 foot in length were generally 

Category 1 vessels. 

Alternative data sources were identified to address the data gap for the horsepower field. The 

databases that have detailed commercial fishing vessel data and were used in this study are 

summarized in Table 2-8, and are discussed in great detail below. 

Table 2-8. Summary of Commercial Fishing Vessel Data Sources 

Data Source Vessel Count Comments 

Merchant Vessels of the 

U.S. 

Approximately 30,000 

vessels 

Used as primary file 

American Bureau Shipping Matched 10 vessels Vessel classification 

database 

California Commercial 

Fishing File 

Approximately 300 fishing 

vessels identified of which 

25 to 30 had horsepower 

data that could be used to 

evaluate engine category 

Matched for Los Angeles 

area 

Alaska CFEC 2003 Permits 23,000 permits matched to 

5,000 vessels 

Matched for Alaska and 

Pacific NW 

Washington Department 

Fish and Wildlife 

Matched approximately 700 

vessels 

Matched for Washington 

Coastal fishing operations 

An internet search was done for the main fishing states to find usable vessel data files. A 

downloadable file from the State of Alaska’s Commercial Fisheries Entry Commission (CFEC) 

was found and matched to the existing commercial fishing vessel file. The CFEC keeps track of 

individual permits and vessel information by year for the state of Alaska and has downloadable 

comma separated data files that can be used in spreadsheets. The 2003 year data were 

downloaded and approximately 23,000 permits for resident and non-residents were compared to 

the project’s commercial fishing vessel database. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-12 

The Washington Department of Fish and Wildlife (WDFW) was contacted for information on 

their commercial fishing permits since the state of Washington had the highest percentage of 

vessels with possible Category 2 engines. The WDFW provided us with a list of commercial 

fishing vessels that had applied for permits. The commercial fishing vessel project database was 

compared to the WDFW file to append the missing horsepower data and determine whether the 

vessel was equipped with a gas or diesel engine. These data were used to help fill in the missing 

horsepower data for over 700 vessels. A total of 431 vessels with known gasoline engines were 

deleted from the project database and a new “Excluded” code was added for vessels from 

territories outside the project’s area of interest (e.g., Guam, Samoa, U.S. Virgin Islands). 

This matching of vessels of data from the MVUS with local state and vessel classification data 

was continued on a smaller scale by incorporating data from the ABS and the Los Angeles 

inventories. The final vessel matching is summarized in Table 2-9 below: 

Table 2-9. Summary of Commercial Fishing Vessel Categories 

Category Vessel Count 

HP 0 110 

Definite 1 8,130 

Possible 1 21,328 

Definite 2 412 

Possible 2 227 

Excluded 48 

Total 30,255 

It is unclear what the “HP 0” represents in these databases. Initially it was assumed that the 

vessels were not self-propelled, but further study revealed that this was not the case. Given that 

the HP 0 group is such a small portion of the fleet and the Category 2 vessels represent the 

largest vessels in the fishing fleet, it was assumed that these HP 0 vessel were probably 

Category 1 ships and were not included in this analysis. 

Even after removing the gasoline powered vessels, the total number of vessels went up by about 

500 because commercial fishing vessels with valid permits from the states of Alaska and 

Washington were added to the project database. It is unclear if these were foreign boats such as 

ones from Canada or if the (USCG) database was missing some vessels that should have been 

classified as “fishing” instead of another vessel type, such as “recreational.” 

2.2.2 Analysis of Commercial Fishing Vessel Data 

After further review of the data, the definite Category 2 and possible Category 2 vessels were 

separated from the rest of the file for further study. This separate list contained about 

639 vessels. Table 2-10 shows the vessels sorted by the length and horsepower groups. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-13 

Table 2-10. Commercial Fishing Vessels Sorted by Length and Horsepower Groupings 

Total HP under 100’ 100-124’ 125-149’ 150-199’ 200+ 

1000-2000 137 79 52 51 5 

2000-3000 2 0 4 24 8 

3000-4000 2 0 0 8 5 

4000-5000 0 0 1 3 6 

5000+ 0 0 0 6 12 

Blank 0 78 41 86 24 

Total 141 157 98 178 60 

In order to make a better determination of which of the above vessels had Category 2 engines, 

the national brokerage websites that post commercial fishing vessels for sale were researched for 

vessels with known engine make and model data. These websites post vessel specifications such 

as length, main engine make and model, and sometimes horsepower. They do not list names of 

vessel or any Coast Guard or IMO number that could be linked to a particular vessel 

characteristic. Numerous national and international websites were reviewed to see if the 

information provided could help in determining engine categories based on vessel characteristics. 

Some websites contained vessels from around the world, which showed the difference in engine 

manufacturers between U.S. and foreign flagged vessels. American commercial fishing vessels 

tend to have main engines manufactured in the United States, such as Caterpillar, Cummins, 

Detroit Diesel, and Perkin Engines. 

The brokerage website data verified the assumption that vessels equipped with engines rated 

with less than 1,000 HP were Category 1 engines. A spreadsheet of U.S. vessels for sale that had 

a total engine horsepower of 1,000 HP or greater was compiled. The 103 vessels for sale with 

known engine make and model data found in the web search were sorted into engine category, 

vessel length, and horsepower. The results showed that U.S. commercial fishing vessels under 

100 feet in length typically contained one main Category 1 engine. Vessels with lengths between 

100 and 125 feet are generally equipped with one or two Category 1 engines. In the 125 to 

200 feet length range, the vessels were equipped mostly with one or more Category 2 engines. 

There were a few exceptions for larger vessels that were equipped with twin Category 1 engines 

in the 1,000-2,000 total horsepower range. All vessels over 200 feet long were Category 2 

engines with more than 1 engine per vessel. The vessels over 200 feet in length found for sale 

were mostly fish processors, while the vessels with lengths between 125 and 200 feet were 

mostly trawlers. 

Figure 2-3 summarizes the results from the 103 vessels for sale with know engine make and 

model: 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-14 

0

5

10

15

20

25

30

35

50 100 125 150 200

Length Group

Vessel Count

Cat 1

Cat 2

Figure 2-3. Vessel Sale Data 

From the main engine information gathered about the vessels from brokerage websites, it was 

assumed that the 144 vessels with lengths under 100 feet and the 157 vessels with lengths 

between 100 and 124 feet (noted in Table 12) have Category 1 engines. The 333 vessels with 

lengths greater than 125 feet are likely to have Category 2 engines. These assumptions are not 

inconsistent with the horsepower data reported in Table 2-10 and summarized in Table 2-11. 

Table 2-11. Commercial Fishing Vessels by Horsepower 

Total HP Category 1 Category 2

1000-2000 219 105 

2000-3000 2 36 

3000-4000 2 13 

4000-5000 0 10 

5000+ 0 18 

Unknown 78 151 

Total 301 333 

This analysis shows that approximately 1 percent of the total commercial fishing vessels are 

equipped with Category 2 engines. The possible Category 2 list was also sorted by state and 

region. The state of Washington had the most commercial fishing vessels with Category 2 

engines (46%), followed by the states of Louisiana (14%), Alaska (8%), and California (6%). 

The Pacific Coast accounts for 64 percent of the Category 2 commercial fishing vessels, 

followed by the Gulf region with 19 percent, and the Atlantic coast with 14 percent. 

Our data did not allow us to investigate foreign ships that may be fishing within the U.S. 

territorial waters, legally or otherwise. It is common for vessels within the U.S. water to be U.S.-

flagged, but this is not always true; for example, it is possible to obtain permits to fish in the 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-15 

waters of Mexico, which typically occurs when U.S. waters are closed (e.g., charter boat snapper 

fishery). 

In conclusion, a few commercial fishing vessels that resemble factory processors were identified 

as having Category 2 main engines. However, the typical fishing vessel in the U.S. is quite small, 

generally 30 to 50 feet in length and powered by Category 1 diesel engines. 

2.2.3 Commercial Fishing Vessel References 

American Bureau of Shipping (ABS) database. 

Eastern Research Group (ERG) (2004), Update to the Commercial Marine Inventory for Texas to 

Review Emissions Factors, Consider a Ton-Mile EI Method, and Revise Emissions for the 

Beaumont-Port Arthur Non-Attainment Area. 

Research Fishing Vessels website. 

Starcrest (2000), Houston-Galveston Area Vessel Emissions Inventory (HGAVEI). 

Starcrest (2004), Port of Los Angeles Port-Wide Baseline Air Emissions Inventory (PWBAEI). 

State of Alaska, Commercial Fisheries Entry Commission, 2003 permit database, see 

www.cfec.state.ak.us/veslist. 

State of Washington, Department of Fish and Wildlife commercial fishing license database. 

U.S. Coast Guard, Merchant Vessels of the U.S. database. 

Websites used: 

Alaskan Leader 

National Fisherman 

Ocean Marine 

Ships USA 

Trident Seafoods 

Tidewater Brokerage 

2.3 Coast Guard Vessels 

To account for all Category 2 military vessels, it is necessary to include all branches of the 

military service that operate marine vessels. This would include the U.S. Navy and Coast Guard. 

To include naval data is particularly challenging as it is necessary to consider only those vessels 

that are operating in navigable waters of the U.S., which requires detailed information about 

vessels and their location. Unfortunately, details concerning the Naval fleet are currently not 

publicly available and therefore can not be included in this analysis. Only data from the U.S. 

Coast Guard could be considered in this report. The actual military fleet of vessels equipped with 

Category 2 engines operating in U.S. waters is underestimated in this study. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-16 

The U.S. Coast Guard uses a variety of vessels throughout the United States to conduct its daily 

business. The vessels can be separated into cutters and small boats. 

The 1,400 small boats that range in length from 12’ to 64’ and operate close to shore were 

determined to be equipped with Category 1 engines and therefore were not included in the list of 

vessels that required more detailed research. These small boats include motor lifeboats and surf 

boats, utility, rescue, and Port security boats. 

A cutter is a Coast Guard vessel that is at least 65’ in length. For this study, the cutters were 

researched to determine their engine category. Cutters include icebreakers, river, inland, coastal, 

and seagoing buoy tenders, construction tenders, large patrol boats, and harbor tugs. Twelve 

Coast Guard vessels that are equipped with gas turbine engines were removed from this analysis 

as they do not meet the Category 2 definition. 

2.3.1 Coast Guard Data Source 

The main source of information for this U.S. Coast Guard fleet was the U.S. Coast Guard 

webpage (www.uscg.mil/datasheet/dataindx.htm) which lists its fleet of cutters, small boats and 

airplanes. The cutters are presented individually grouped by their vessel class. Many had their 

own websites that provided information needed to make an engine category determination. The 

websites also provided other vessel characteristics data including vessel horsepower and the 

districts where they patrol. Where data were missing, vessel characteristics were estimated by 

matching the vessels to other vessels in the same class which did report vessel characteristics. 

2.3.2 Analysis of Coast Guard Data 

Approximately 158 of the 235 cutters currently in service had Category 2 engines. 

2.3.3 Coast Guard Reference 

Coast Guard official website - www.uscg.mil/datasheet/dataindx.htm. 

2.4 Ferry Vessels 

Ferries are self-propelled vessels that carry passengers from one location to another. Some ferries 

have the capability to also carry motor vehicles. These vessels are owned and operated by both 

State Agencies, usually State Department of Transportation, and private firms. 

2.4.1 Ferry Vessel Data Sources 

The main data source for ferries was the 2000 Bureau of Transportation Statistics (BTS) National 

Ferry Database. There were a total of 680 vessels included in the National Ferry Database. The 

database provided vessel horsepower, the name of the vessel, and the city and state were the 

vessel operates. Main engine make and model data for individual ferries were not included in the 

BTS database, and so a number of other sources were used to determine the engine category. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-17 

The data sources used to determine engine category included the IRR that listed passenger 

vessels operating along the Mississippi River and Gulf Coast, and the ABS dataset that listed 

registered ferries. Appropriate websites were also identified and lists of ferries with engine 

specifications were downloaded. Information about ferries at several of the major ports was 

obtained from published studies. To address the remaining data gaps, it was necessary to contact 

individual ferry operators to obtain readily available information about their vessels. New ferries 

built and operated since 2000 and containing Category 2 main engines were added to the 

project’s ferry database. 

2.4.2 Analysis of Ferry Data 

The original BTS database included 685 ferries. The non-Category 2 vessels were identified and 

flagged based on knowledge of the ferry fleet obtained from work performed at major ports. 

Where engine make and model data were identified, these engine data were compared with the 

engine database developed for this project. Vessels were also flagged that are not self-propelled 

or do not use diesel fuel. Lastly vessels operating in the Virgin Islands, Puerto Rico, and other 

U.S. protectorates were noted as they were not included in the project’s scope of work. For 

53 vessels there was insufficient data to determine the engine category. For these vessels, calls 

were made to the operators which revealed that 16 of the 53 remaining ferries were equipped 

with Category 2 engines. 

Table 2-12 summarizes the vessel category profile for ferries. Note that “0” represents ferries 

that are not self-propelled and “excluded” represents ferries operating outside the study area, 

such as the U.S. Virgin Islands and Mariana Islands, or were duplicates with vessels reported in 

the deep water vessel category. 

Table 2-12. Ferry Population by Engine Category 

Engine Category No. of Vessels 

Not self-propelled 44

1 508 

2 99 

Excluded 34 

Total 685 

Out of the 685 ferries, 99 ferries (14%) had Category 2 engines. The states with the most 

Category 2 ferries are summarized in Table 2-13. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-18 

Table 2-13. Distribution of Ferries by State 

State Percentage

Washington 19 

California 12 

New York 11 

Connecticut 10 

Massachusetts 9 

Alaska 8 

Delaware 5 

Texas 5 

2.4.3 Ferry References 

American Bureau of Shipping (ABS) database.

Bureau of Transportation (2000), National Ferry Database. 

Corbett, J.J. et al (2003), Air Pollution from Passenger Ferries in New York Harbor. 

Inland River Record (IRR) (2004). 

Starcrest (2003), New York, Northern New Jersey, Long Island Nonattainment Area Commercial 

Marine Vessel Emissions Inventory (PANYNJ CMVEI), Volume 1. 

Starcrest (2000), Houston-Galveston Area Vessel Emissions Inventory (HGAVEI). 

Starcrest (2004), Port of Los Angeles Port-Wide Baseline Air Emissions Inventory (PWBAEI). 

Cities and States contacted:

City of Vallejo 

State of Alaska 

State of North Carolina 

State of Washington 

Companies contacted:

Cross Sound Ferries 

Bridgeport & Port Jefferson Steamboat Company 

Catalina Clipper 

Blue & Gold Fleet 

Miller Boat Line 

Hydrolines Express, Inc. 

Jet Express 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-19 

2.5 Deep Water Cargo Vessels 

Ocean going vessels carry international cargo and passengers to and from major ports around the 

world. Category 2 vessels account for approximately 8 percent of international ship trips. 

2.5.1 Deep Water Cargo Vessel Data Sources 

In an earlier project, vessels included in the U.S. ACE Clearance and Entrance (C&E) data set 

were matched to vessel characteristics from the ROS, ABS, and Bureau Veritas databases. These 

files include data flags for the different engine categories as derived from cylinder displacement 

data as discussed in the tugboat section of this memorandum. All deep water cargo vessels that 

have been identified as being equipped with Category 2 engines have been extracted from the 

U.S. ACE C&E data set and pulled into this project’s database. 

2.5.2 Analysis of Deep Water Cargo Vessel Data 

The matching of the C&E data with vessel characteristic data from vessel classification 

companies identified 520 deep water cargo vessels that are equipped with Category 2 Engines. 

300 foreign flagged vessels were removed when the data for each of the vessels types were 

combined into the database discussed in Section 3 of this report, the deep water vessel listing 

was compared with the other vessel data to ensure that no vessels were double counted in this 

project. Special attention was given to vessel types such as tugs and Great Lakes Vessels as they 

were likely to have duplicate vessel data. When duplicates were removed, 89 vessels were 

remaining. Because the data provided by the U.S. ACE is vessel specific, additional analysis of 

the engine category was not necessary. 

2.5.3 Deep Water Cargo Vessel References 

American Bureau of Shipping Bureau – 2004 Data query available by negotiation only, 

http://www.eagle.org/. 

Bureau Veritas – 2004 Data query available by negotiation only, Paris, France, 2004. 

Lloyd’s Register of Ships, Fairplay, Ltd. 8410 N.W. 53rd Terrace, Suite 207, Miami, FL, 2004. 

U.S. Army Corps of Engineers, Vessel Clearance and Entrance Data, Waterborne Statistics 

Division, New Orleans, LA. 2006 

2.6 Research Vessels 

A variety of marine research vessels ply the coastal waters of the United States. These vessels 

are equipped with a wide range of scientific equipment used to track marine wildlife, map 

geographic formations, monitor coastal coral reefs, investigate changing meteorological 

conditions, and test water quality parameters. Some of these vessels are fairly large and would be 

equipped with Category 2 propulsion engines. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-20 

2.6.1 Research Vessel Data Sources 

The University of Delaware maintains an inventory of U.S. flagged research vessels operating in 

the U.S. This University of Delaware database was an excellent starting point as it includes 

many, though not all, research vessels. The vessels that were included in the database were 

matched with research vessels included in the ROS and ABS databases. For the matched 

research ships engine specific data were associated with these vessels to accurately flag the 

Category 2 vessel population. 

These data were supplemented with data obtained from internet web searches. The UniversityNational Oceanographic Laboratory System (UNOLS) website was particularly useful as it listed 

other research vessels besides those included in the University of Delaware’s database. Many 

smaller research vessels were identified but not included in the database as the focus of this 

project is Category 2 powered vessels. Vessels were also evaluated to ensure only active ships 

are included, this led to the Removal of Vessels that have been decommissional or are in cold 

storage. An addition research vessel was also removed as it spend all of its time in antartica and 

is outside U.S. waters. 

2.6.2 Analysis of Research Vessel Data 

Through this effort 31 research vessels were identified as equipped with Category 2 engines. 

2.6.3 Research Vessel References 

The UNOLS website is found at www.unols.org. It has a research vessel index found at 

www.unols.org/info/vessels.htm

2.7 Offshore Support Vessels 

Most offshore vessels represent a variety of boats that provided different support services to the 

offshore oil platforms. These services include geophysical surveys, exploratory drilling, platform 

construction and removal, pipeline construction and maintenance, and continuous transfer of 

people, equipment and supplies to and from the platforms. These activities use the following 

vessel types: 

• Anchor handling tugs; 

• Crew boats; 

• Drilling rigs; 

• Lightering escort vessels; 

• General purpose tugs; 

• Liftboats; 

• Pipe laying vessels; 

• Supply boats; 

• Support vessels; and 

• Survey vessels. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-21 

Because offshore oil platform needs vary, the support vessel fleet composition includes boats 

with a wide range of propulsion engine sizes and operating speeds with approximately half of 

fleet equipped with Category 2 propulsion engines. 

2.7.1 Offshore Support Vessel Data Sources 

As with the other vessel types included in previous Category 2 studies, there is no single 

comprehensive database that includes a complete listing of all active support vessels and their 

engine characteristics. The Offshore Marine Service Association (OMSA), which is the trade 

organization for offshore support vessel operators, maintain records of the number of American 

flagged vessels currently operating the Gulf of Mexico, unfortunately, they do not have detailed 

data about the propulsion engines for each vessel. The Oilfield Publications Limited’s (OPL) A-Z 

Offshore Support Vessels of the World Data Set, contain detailed data on specific offshore 

vessels; but unfortunately, this data set did not identify which vessels are actually operating in 

U.S. waters. 

A two phase approach was developed that used these complementary data sets to quantify the 

population of U.S. flagged Category 2 offshore vessels operating in U.S. waters. In the first 

phase, national estimates were developed for each vessel type for U.S. flagged support vessels by 

extrapolating the OMSA Gulf of Mexico data. In the second phase, detailed vessel specific data 

were obtained from the OPL and evaluated to develop estimates of the proportion of each 

offshore vessel type that is equipped with Category 2 propulsion engines. These Category 2 

ratios were applied to the offshore vessel population data providing reasonable estimates of the 

Category 2 offshore vessels. The following sections of this memorandum discusses in greater 

detail the approaches used in this study. 

2.7.2 Support Vessel Analysis 

During the course of this study two offshore vessel types were investigated and discovered to not 

be equipped with Category 2 propulsion engines and were not included in this study. These two 

non-Category 2 vessel types included drilling rigs and escort vessels. 

Once a survey vessel has identified an area that may have oil bearing strata, a drilling rig is 

commissioned and sent to the site. Drilling rigs are sometimes considered to be offshore vessels 

as they operate in shallow as well as deep waters. Some drilling rigs are self-propelled, while 

others are towable. Drilling rigs were not included in any of the other Category 2 vessel groups, 

but were considered in this study due to their involvement with offshore oil exploration. There 

are several different types of drilling rigs, from drill barges that operate in shallow waters, jackups that operate in waters with depths less than 100 meters, semi-submersibles that operate in 

water depths greater than 300 meters, and drill ships that operate in waters with depths up to 

1,200 meters. Though all drilling rigs are equipped with large diesel engines, only 

semisubmersibles and drilling ships are self-propelled, all of the others are towed to the site 

using oceangoing support tugs. 

The self-propelled drilling rig population for the Gulf of Mexico, Alaska, and California was 

obtained from RigZone, which is a trade group that monitors global activity of individual drilling 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-22 

rigs. It should be noted that no self-propelled drilling rigs were identified operating in 

Californian or Alaskan waters and 16 drill ships and semisubmersible rigs were identified as 

operating in the Gulf of Mexico. Upon further study of the propulsion engines associated with 

the self propelled drilling rigs, three of these vessels could be match to propulsion engine 

characteristics and all three used Category 3 diesel engines for propulsion; therefore it was 

decided to exclude drilling rigs as a vessel type from this offshore assessment. 

Similarly, escort vessels were also excluded from this study as all identified escort vessels were 

equipped with Category 3 propulsion engines. Escort vessels are offshore vessels that shuttle 

products to and from tankers afloat in the Coast Guard monitored lightering zones. These tankers 

may be too large to safely operate in a port area or they may chose to offload their product to 

escort vessels in a lighter zone to avoid congested harbors. Such escort vessels tend to have 

Category 3 engines in order to quickly move product to shore and return to the tanker for 

additional transfers. 

As noted earlier, the OMSA provided an estimate of U.S. flagged vessels currently operating in 

the Gulf of Mexico. Crew boats, supply and support vessels, and utility boats were combined in 

this report as these vessels often provide multiple overlapping services and needed to be match to 

the vessel categories used in the OPL dataset. The OMSA vessel population data are summarized 

in Table 2-14. 

Table 2-14. OMSA U.S. Flagged Vessel Population by Offshore Vessel Type for the 

Gulf of Mexico 

Offshore Vessel Type 

Minimum 

Horsepower 

Maximum 

Horsepower 

Vessel 

Count 

Anchor Handling Vessels 10,000 14,000 25 

Crew/Supply/ Support/Utility Boats 900 6,000 660 

Lift Boats 1,000 1,500 113 

Tugs/Towing 1,000 5,000 200 

Total 998 

These OMSA offshore vessel population estimates only cover the Gulf of Mexico. Though more 

than 90% of the offshore oil and gas comes from platforms in the Gulf, there are active platforms 

in Alaskan waters and off the coast of California. Offshore oil production data for each region 

were obtained from the Department of Interior’s Mineral Management Services’ Offshore Oil 

Program. These oil production values were compared to the Gulf’s U.S. flagged offshore vessel 

fleet estimates to approximate the U.S. flagged vessel population in each region using the 

following equation: 

VPij = OPi/OPg ×VTgj
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-23 

Where: 

VPij = Population for vessel type j in geographic area i 

OPi = Offshore oil production for geographic area i (millions of barrels) 

OPg = Offshore oil production for the Gulf of Mexico (millions of barrels) 

VTgj = the population of vessel type j in the Gulf of Mexico – Table 2-14 

i = Geographic area (i.e., Pacific or Alaska) 

j = Vessel type (i.e., anchor handling vessels, crew boats, lift boats, supply 

vessels, tugs, utility boats) 

g = Gulf of Mexico 

Result of these vessel population equations are summarized in Table 2-15. 

Table 2-15. OMSA U.S. Vessel Population by Offshore Vessel Type for the Gulf of Mexico 

Vessel Count 

Offshore Vessel Type 

Gulf of 

Mexico Pacific Alaska

U.S. Waters

(Unknown 

Location) Total 

2004 Oil Production 

(Million of Barrels) 534.969 27.510 25.078 --- 585.557 

Anchor Handling Vessels 25 1 1 --- 27 

Crew/Supply/ Support/Utility Boats 660 33 31 --- 724 

Lift Boats 113 6 5 --- 124 

Tugs/Towing 200 10 9 --- 219 

Survey --- --- --- 62 62 

Pipe/Cable laying --- --- --- 24 24 

Total 998 50 46 86 1,180 

Survey vessels and pipe laying vessels were handled differently than the other offshore vessel 

types. The survey vessels include geotechnical, hydrographic, and seismic vessels, therefore the 

survey vessels are not limited to the oil and gas industry activities and can be found in many 

navigable waters. The vessel population data for survey vessels were obtained from the OPL 

database. 

Similarly for pipe laying vessels, research concerning the design and uses of pipe laying vessels 

indicated that pipe laying and cable laying vessels are essentially the same type of vessels and 

can be quickly modified to perform any laying activity. Basically only the material being laid has 

to be changed out and most of the remaining equipment stays the same. Because of this, pipe 

laying and cable-laying vessels are considered together. The vessel population data for 

pipe/cable laying vessels was obtained from the OPL database. As the survey vessel and pipe 

laying categories may operate outside the areas where offshore oil platforms operate, only 

national total numbers were used for this study. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-24 

During Work Assignment 4-02 under Contract 68-C-00-112 entitled Category 2 Commercial 

Marine Propulsion Engine Population Estimation, ERG ordered a copy of the OPL data set to 

help quantify the Category 2 offshore vessel populations. Unfortunately, the OPL data did not 

arrive during the project’s period of performance. Upon reviewing the OPL data set, 

1,407 vessels were identified that may operate in U.S. waters. This determination was based on 

vessels that were flagged as U.S. vessels or listed the vessel manager’s address as being in the 

United States. This data set may over represent U.S. flagged vessels as it includes vessels that 

may not necessarily be operating in U.S. waters. 

Offshore vessels use a large number of tugs to tow drilling rigs and components of the platforms 

for construction or removal. Tugs and barges also are used to carry supplies and equipment to the 

offshore platforms. The vessels included in the OPL listing were matched with vessels in the 

Category 2 tug data set, developed under Work Assignment 4-02. Nineteen vessels were 

identified as being in both data sets and were removed from Towboat dataset to eliminate any 

double counting of vessels. 

After drilling rigs, and escort vessels were removed from the OPL data, the offshore vessel 

population was 1,254, which is similar to, but slightly higher than the adjusted OMSA vessel 

population data. The difference between these two values represent the uncertainty associated 

with the number of U.S vessels operating overseas. 

The remaining OPL offshore vessels were compared to the Coast Guard’s Marine Vessel 

Register to pull in as many vessel ID codes as possible and obtain any available engine 

propulsion data to identify those vessels equipped with Category 2 propulsion engines. The 

primary engine data that were sought were the engine’s bore and stroke dimensions. These data 

were used to calculate the cylinder displacement. 

If engine bore and stroke data were not available, engine make and model information was 

compared to records in the Category 2 engine database developed for Work Assignment 4-02. 

This database lists all known Category 2 engines. 

The vessels were matched by name, gross tonnage, and year of construction or modification. Of 

the 1,254 OPL vessels, 205 had engine data in the Marine Vessel Registry. 

The vessels identification codes obtained from the OPL data set and the Marine Vessel Registry 

were used to link the vessels to data obtained in Work Assignment 4-02, from the American 

Bureau of Shipping, Bureau Vertas, and Lloyds Register of Ships to get bore and stroke data or 

engine make and model information. 

Table 2-16 summarizes the vessel engine data compiled for offshore support vessels. As this 

table indicates, approximately half of the vessels could be matched to their propulsion engine 

characteristics. Most (>80%) of the matched vessels were matched to data in the Marine Vessel 

Registry and the American Bureau of Shipping’s data. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-25 

Table 2-16. Results from Matching Vessels to Engine Characteristics 

Data Source 

Vessel Count with 

Engine Data 

Percentage of 

Total 

Percentage of 

Total Excluding 

Blanks 

Unknown Engines 609 48.6 --- 

Marine Vessel 

Registry 

205 16.3 31.8 

American Bureau of 

Shipping 

318 25.4 49.3 

Lloyds Registry of 

Ships 

121 9.6 18.8 

Bureau Veritas 1 0.1 0.2 

Total Excluding 

Tug Data Set 

1,254 100 --- 

Total Excluding 

Unknown Engines 

645 --- 100 

Based on the compiled engine characteristic data, the split between Category 1, 2, and 3 engines 

can be summarized in Table 2-17. 

Table 2-17. Support Vessel Category Mix 

Vessel Count 

Percentage of 

Total 

Percentage of 

Total Excluding 

Blank or Invalid 

Unknown Categories 812 64.8 --- 

Category 1 198 15.8 44.8 

Category 2 226 18 51.1 

Category 3 18 1.4 4.1 

Total 1,254 100 --- 

Total Excluding 

Unknown Categories 442 --- 100 

As Table 2-17 indicates approximately half of the offshore vessel fleet is composed of vessels 

equipped with Category 2 engines. It should be noted that this value is based on matching of 35.2 

percent of the vessels. For the purpose of this study it is assumed that he unmatched vessels have 

the same category profile as the matched vessels. Alternatively, the unmatched vessels may 

include a larger fraction of smaller boats, that may not be Category 2 vessels, and are not insured 

through the three larger vessel classification companies, which was the data source for this 

component of the study. Additional data could not be obtained that would validate or negate the 

assumption used in this study. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-26 

The larger value was not seen as surprising as many of these offshore support vessels are 

designed to carry large loads and travel up to two hundred miles offshore for extended periods of 

time. Instead of using the aggregated value, a somewhat more accurate estimate was developed 

by disaggregating the data by offshore vessel types as noted in Table 2-18. 

Table 2-18. Category Mix by Support Vessel Type 

Type Count Category Percent

343 Unknown --

Unknown Vessel Type 2 Category 3 --

22 Unknown --

7 Category 1 15.9

34 Category 2 77.3

Anchor Handling 3 Category 3 6.8

98 Unknown --

1 Category 1 33.3

Liftboat 2 Category 2 66.7

18 Unknown --

1 Category 1 20.0

3 Category 2 60.0

Pipe/Cable Laying 1 Category 3 20.0

232 Unknown --

176 Category 1 60.1

116 Category 2 39.6

Crew/Supply/ Support/Utility Boats 1 Category 3 0.3

49 Unknown 

6 Category 1 46.2

5 Category 2 38.5

Survey 2 Category 3 15.4

50 Unknown --

7 Category 1 8.5

66 Category 2 80.5

Tugs/Tow 9 Category 3 11.0

It is appreciated that for some of the categories a large number of vessels could not be matched 

to propulsion engine categories. These vessel categories, such as survey vessels, lift boats, and 

pipelaying vessels, had relatively small vessel populations therefore the overall error in the 

Category 2 fleet population estimate will be relatively small. According to OMSA most of the 

Gulf support vessels are crew/supply/support vessels, where engine matches were somewhat 

better. By disaggregating the fleet into individual vessel types, slightly more accurate Category 2 

vessel population estimates were possible, than if the general Category 2 split noted in Table 2-

17 was used. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-27 

The Category 2 percentages from Table 2-18 were applied to the vessel population data 

summarized in Table 2-15 to estimate the number of Category 2 vessels in each geographic area 

using the following equation: 

OCi = (CPi /100)×VPi

Where: 

OCi = The population of offshore support vessel type i equipped with 

Category 2 propulsion engines 

CPi = The percentage of offshore support vessel type i equipped with 

Category 2 propulsion engines (%) – Table 2-18 

VPi = The population of U.S. flagged offshore support vessels for vessel type 

i – Table 2-15 

i = Offshore support vessel type (e.g., anchor handling, liftboat, pipe 

laying, supply/crew boats, survey vessels, tugs/tow boats 

Results from the application of this equation are presented in Table 2-19. 

Table 2-19. U.S. Flagged Category 2 Vessel Populations 

Vessel Type 

Gulf of 

Mexico California Alaska 

Unknown 

Location Total 

Anchor Handling 19 1 1 --- 21 

Liftboat 75 4 3 --- 82 

Pipe/Cable Laying --- --- --- 14 14 

Crew/Supply/ Support/Utility Boats 261 13 12 --- 286 

Survey --- --- --- 24 24 

Tugs/Tow 161 8 7 --- 176 

Total 516 26 23 38 603 

2.7.3 Offshore Support Vessel References 

American Bureau of Shipping, 2004 Vessel Information, Houston Texas. 

Fairplay, Ltd. 2004, Lloyd’s Register of Ships, Miami, FL. 

Offshore Marine Service Association (OMSA), 2006, 2005 Offshore Vessel Population and 

Activities, Harahan, LA. 

Oilfield Publications Limited (OPL) 2004, A-Z of Offshore Support Vessels of the World – 

Second Edition, Houston, Texas. 

RigZone, 2006 Drilling Rig Regional Summary. Houston, TX, http://www.rigzone.com/data/ 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-28 

U.S. Department of Interior, Minerals Management Service (MMS). 2006. Oil and Gas 

Production. http://www.mms.gov/stats/xlsExcel/OCS%20Production-Sep05.xls 

U.S. Coast Guard/Office of Information Resources, October 2004, Merchant Vessels of the 

United States, NTIS No PB2004-594361, Springfield, Virginia. U.S. DOI, Minerals 

Management Service (MMS). 2004b. Gulfwide Emission Inventory Study for the Regional Haze 

and Ozone Modeling Effort: Final Report. New Orleans, LA. OCS Study MMS 2004-072. 

U.S. Department of Interior, Minerals Management Service (MMS). 1995. Gulf of Mexico Air 

Quality Study: Final Report, Volumes I-III. New Orleans, LA. OCS Study MMS 95-0038, 

95-0039, and 95-0040. 

U.S. Environmental Protection Agency (EPA), December 2004, Category 2 Vessel Census – 

Draft Report, Ann Arbor, MI. 

Workboat Publications, 2006, Mandeville, LA. 

2.8 Great Lake Vessels and Vessels Not Otherwise Included 

The Great Lake Vessels includes a variety of ships that are designed specifically to operate in 

that area and navigate the lochs of the St. Lawrence Seaway, the Welland Canal, and the St. Clair 

River. The “Laker” vessel design is also particularly appropriate for the unique regional products 

that they transport. The Great Lake ship traffic also includes ocean going vessels that are not 

restricted to operating in the Great Lakes. These vessels transport cargo internationally or to 

domestic ports on the East coast of the U.S. Given the diverse population of vessels, it became 

necessary to develop an approach that would capture a wide range of vessel types, several of 

which were not included in the vessel types discussed above. 

• Auto Carriers; 

• Break Bulkers; 

• Containerships; 

• Cruise/Passenger Vessels; 

• General Cargo Ships; 

• Special Carriers; 

• Roll On/Roll Off; and 

• Tankers. 

2.8.1 Remaining Vessel Data Sources 

In order to identify the U.S. flagged vessels operating in the Great Lakes, the U.S. ACE database 

for self-propelled vessels was queried and boats under 100 tons were removed. The 100 tons 

threshold was used so as to reduce the overall impact of smaller, Category 1 harbor craft. 

Fishing, offshore, and self-propelled barges were also filtered out as they are accounted for in 

other components of this study. Yachts (recreational vessels) were also removed. This left over 

500 vessels that have yet to be evaluated to determine their EPA category. Note that this 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-29 

approach not only includes Great Lake vessels, but other vessels that were not captured by the 

other vessel types included in this study. 

This data set of “Remaining Vessels” was merged with ROS by ship name. Matching the vessels 

using IMO numbers was not practical as the vast majority of these vessels are considered to be 

part of the domestic fleet and therefore do not travel in international shipping lanes. As their 

activities are limited to domestic shipping lanes, they would not have an IMO number. 

Conversely, any ship included in this group of vessels that did not have a Coast Guard 

identification number was deleted as they were assumed to be a foreign cargo vessel and would 

have already been included in the U.S. ACE’s E&C data set. Once the foreign cargo vessels have 

been removed the number of Remaining Vessels amounted to 514 ships. 

2.8.2 Analysis of Remaining Vessel Data 

Where the vessels could be matched to the ROS data, the EPA engine category was determined 

for each vessel by the volume of the cylinder in liters as described earlier in this report. There 

were 264 vessels (51%) that could be matched and 250 (49%) that could not be matched. Results 

of this analysis of remaining vessel engine categories are summarized in Table 2-20. Vessel 

characteristics data from ABS were evaluated, but no additional vessel matches were identified. 

Table 2-20. Summary of Remaining Vessel Engine Classification 

Matched Vessels 

Type C1 C2 C3 Steam 

Unmatched 

Vessels Total

Auto 0 0 1 0 0 1

Bulk 1 19 20 18 12 70

Containership 1 2 46 19 7 75

Cruise 0 1 0 0 20 21

General Cargo 5 4 10 3 72 94

RORO 1 1 5 5 20 32

Special Carrier 6 23 7 0 94 130

Tanker 4 6 28 28 25 91

Totals 18 56 117 73 250 514

Percentage of Total 3.5% 10.9% 22.8% 14.2% 48.6% 

Combined total 

Percentage 51.4% 

As is evident in this table, the matching for general cargo and special carriers is especially poor. 

Further investigation revealed that many of these vessels had low horsepower levels, indicating 

that they were more similar to small harbor crafts rather than ocean-going ships. A preliminary 

analysis using average horsepower is presented in Table 2-21. It should be noted the standard 

deviation for these averages would be expected to be reasonably large. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-30 

Table 2-21. Average HP for Missing Boats 

Type Avg_HP

Bulk 1,534

Cruise 1,582

General Cargo 2,087

RORO 1,830

Special Carrier 1,498

Tanker 1,565

1,683

Total horsepower data for each vessel were extracted from the U.S. ACE data set and was used 

to evaluate the vessel engine category for the 250 unmatched vessels. After some analysis, the 

threshold between Category 1 and Category 2 was determined to be 2,000 HP and the threshold 

between Category 2 and Category 3 was established at 7,500 HP. Such values were admittedly 

subjective, as many ships probably had more than one engine and the U.S. ACE did not report 

the number of propulsion engines. 

For the few entries that did have a valid CG Number but no horsepower rating, if deadweight 

tonnage was over 12,000 short tons the vessel was classified as being Category 3; otherwise the 

few (less than 15) remaining vessels were classified as Category 1 vessels. These vessels were 

compared to the other vessel categories and 29 ships were removed because they were duplicates 

with deep water vessels and tow boats. After these fixes, Table 2-22 summarizes the likely 

distribution of commercial marine vessels by EPA engine category: 

Table 2-22. Allocation of Missing Vessels 

Further research is recommended for this category to help refine these estimates as they include a 

very diverse vessel fleet which poorly matches available vessel specific characteristics. 

Type C1 C2 C3 STEAM Total

Auto 0 0101

Bulk 6 18 23 18 65

Containership 1 2 53 19 75

Cruise 14 5 1 0 20

General Cargo 36 35 11 3 85

RORO 6 2 18 5 31

Special Carrier 68 43 8 0 119

Tanker 9 7 45 28 89

140 112 160 73 485

28.8% 23.1% 33.0% 15.1% 100.0%
0203.02.002.001\Category 2 Vessel Census-Activity Report 2-31 

2.8.3 Remaining Vessels References 

Lloyd’s Register of Ships, Fairplay, Ltd. 8410 N.W. 53rd Terrace, Suite 207, Miami, FL, 2004. 

U.S. Army Corps of Engineers, Waterborne Statistics Division, Waterborne Transportation Lines 

of the U.S., New Orleans, LA. 2004 http://www.iwr.usace.army.mil/ndc/wcsc/wcsc.htm
0203.02.002.001\Category 2 Vessel Census-Activity Report 3-1 

3.0 CATEGORY 2 VESSEL ACTIVITY ASSESSMENT 

Category 2 vessel activity is defined as the total horsepower hours associated with each vessel 

type. Total horsepower hours primarily takes into consideration the days of operation, the vessel 

horsepower, and appropriate engine load factors. The basic equation used to estimate total 

horsepower hours for this study is noted below: 

Thp-hrij = VPi ×URi × ENi × HPij ×DOij × 24 × LFij

Where: 

Thp-hrij = Total horsepower hours for vessel type i in mode j 

VPi = Population of vessel type i 

URi = Utilization rate for vessel fleet i 

ENi = Average number of engines on vessel type i 

HPij = Horsepower of vessel type i

DOij = Days of operation for vessel type i in mode j 

24 = hours per day 

LFij = Load factor of vessel type i propulsion engines in mode j 

i = Vessel type (i.e., deep water, tow, ferries commercial fishing, 

Great Lakes, Coast Guard, offshore support, and research) 

j = Mode of operation (i.e, underway cruise, underway idle) 

The following section explains the data sources used to quantify these variables and limitations 

associated with their use. Normal variance is one of the more significant data limitations 

encountered in estimating total horsepower hours for each vessel type. For example, Category 2 

engines can have a horsepower rating from 500 to 8,600. Similarly, engine operating days can 

vary significantly between the different vessel types. To account for the variance intrinsic in this 

calculation, a Monte Carlo simulation was used to define the range of possible total propulsion 

horse power hours. Note, in this Monte Carlo analysis, horsepower and days of operation were 

varied based on the minimum, maximum, and most likely values. Other variables in the above 

equation change by vessel type or mode of operation, but they were held constant for a given 

vessel type in the Monte Carlo analysis. 

3.1 Vessel Population and Characteristics 

To calculate the total horsepower hours, the Category 2 vessel population used in this calculation 

was quantified as described in Section 2 of this report and these vessel population values are 

summarized in Table 3-1. It is recognized that there is some uncertainty associated with these 

population figures, but the estimates provided in this report represent a reasonable approximation 

of the Category 2 vessel population. 

Engine horsepower data were compiled into the project database during the data collection phase 

of the project for each vessel type. The horsepower data were reviewed to insure that all data 

were reasonable. A number of values were considered inappropriate for Category 2 engines and 

were removed from this analysis. For example, a number of deep water vessels had engines 
0203.02.002.001\Category 2 Vessel Census-Activity Report 3-2 

Table 3-1. Vessel Population and Characteristics 

Engines Horsepower 

Vessel Type Vessel 

Population 

Utilization 

Rate 

Equivalent 

Vessels Avg 

# Total Min Likely Max 

Displacement 

(cu l/cyl) 

Deep Water Cargo 89 80% 89 2.09 148 1,860 3,603 7,200 10.75 

Tow Boats 1,057 74% 782 1.96 1,533 900 2,207 7,420 

Ferries 99 85% 84 2.2 185 865 2,412 4,400 

Commercial 

Fishing 333 85% 283 1.21 342 1,000 1,924 4,313 10.55 

Great Lake 112 85% 95 2.43 231 518 2,505 3,600 11.16 

Coast Guard 157 100% 157 2.04 320 1,250 2,289 3,650 

Offshore 603 97% 585 2.22 1,299 740 2,016 7,502 12.05 

Research 31 100% 31 1.95 60 600 1,622 3,750 

Total 2,481 2,106 4,118 

Weighted Average 87% 2.08 891 2,227 7,007 11.45 

with a horsepower rating less then 500 horsepower were considered too small for a Category 2 

engine and were probably a data entry error. Deepwater vessel horsepower data was obtained 

from one of the major tow boat companies (as the majority of the Deepwater vessels were 

towboats). Additionally, many of the fishing vessel horsepower ratings pulled into the project 

database were for total vessel horsepower (possibly including auxiliary engines). Where total 

horsepower could not be disaggregated into individual propulsion engines, these horsepower 

ratings were flagged as possibly incorrect values and not used in this analysis. Fishing vessel 

horsepower data from vessel classification databases were extracted for vessels that were 

classified as Category 2 vessels and used to characterize the range of horsepower ratings 

associated with the fishing fleet. 

Vessels equipped with Category 2 propulsion engines could have a horsepower rating from 500 

to 8,600, therefore, horsepower was considered a variable in the Monte Carlo analysis. The 

horsepower profile varied by vessel type. Table 3-1 shows the minimum, maximum, and likely 

values used for each vessel type. The likely values are averages of the valid compiled 

horsepower ratings. 

The number of propulsion engines for different Category 2 vessels were compiled for each vessel 

type during the data collection phase of this project. The number of engines associated with a 

specific vessel was not always provided. Thus, the number of propulsion engines by vessel type 

was evaluated using only the records in the project database that had this data field populated. 

Some large ferries in the Seattle area have four propulsion engines 10 of these ferries were 

identified in this study and are included in the average of engines. Although the numbers of 

propulsion engines varied between individual vessels, most vessels were equipped with two 

propulsion engines, therefore, for the purpose of this project the average number of propulsion 

engines was used, as noted in Table 3-1. Fishing vessels are an exception, for vessels with 

engines with HP rating greater than 1,500 it was assumed that these ships are equipped with two 

propulsion engines. For vessels with engines rated below 1,500 it was assumed that those vessels 

have one engine. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 3-3 

To quantify the total number of annual horsepower hours that Category 2 propulsion engines 

operate, it was necessary to determine the percentage of the fleet that is active—this is often 

referred to as the utilization rate. Utilization rates for the different vessel types were obtained 

from a variety of sources. For example, the publication Workboat reports monthly fleet 

utilization values for a variety of offshore vessel types. For vessels such as ferries, research 

vessels and U.S. Coast Guard ships, the utilization rate was assumed to be high. The data 

collection approach used for deep water vessels used for this study captured only those vessels 

that were actually visiting ports and transferring cargo through customs, vessels that were not 

active were not included in the dataset, therefore the deepwater vessel data were obtained only 

for the utilized portion of the deepwater fleet. For towboats, the utilization rate was provided by 

Doug Schaffer of the American Waterways Operators Association. For fishing vessels and Great 

Lakes and other vessels, data on vessel utilization was not readily available, instead a default 

value of 85 percent was used. This value of 85 percent was considered a conservative value 

because it represents a low utilization rate at which point the fleet is over capitalized and there 

are a surplus of vessels. Actual utilization rates may be higher, particularly for the Great Lakes 

and in water around other vessels category, or lower for fishing vessels operating in restricted 

fishing zones, such as in waters around New England. 

Within a vessel type, utilization rates vary relative to geography, changes in the industry and 

weather events. For example, offshore vessel utilization rates increased significantly between 

2001 and 2004 when some of the larger offshore vessel service providers reduced their fleet size, 

scrapping or putting vessels into storage. Utilization rates further increased in 2005, when two 

major hurricanes swept through the Gulf of Mexico, destroying 115 platforms and damaging 

52 platforms and 183 pipeline segments. These storms increased the demand for offshore support 

vessel, which did not occur in California or Alaska where offshore platforms also exist. The 

utilization rates used in this study are presented in Table 3-1. These rates were applied to the 

vessel population estimates to approximate the number of vessels currently operating, referred to 

in Table 3-1 as the equivalent vessels. 

3.2 Operating Days and Load Factors 

Vessel operators and groups that monitor vessel activities, tend to track the number of days that 

vessels operate rather than actual hours. The days of operation were compiled and later 

converted to hours of operation based on the assumption that a vessel equipped with Category 2 

engines can operate 24 hours per day. The hours of operation should be considered conservative; 

actual hours of operation may be somewhat less. 

Operating days for each vessel type were obtained from a variety of data sources. For example, 

because most of the deepwater vessels equipped with Category 2 propulsion engines were ocean 

going tugs similar to large tow boats, the same operating days value was used for both 

categories. The average value reported in Table 3-2 for deep water tugs and tow boats was 

obtained from one of the larger tug companies. These operation data were adjusted for the Great 

Lakes vessel category to reflect the period of time when the Great Lakes are frozen and vessel 

activity are temporarily stopped. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 3-4 

The annual underway days for ferries was obtained from Corbett, J.J., J.J. Winebrake, and P. 

Woods, An Evaluation of Public-Private Incentives to Reduce Emissions from Regional Ferries: 

Synthesis Report, pp. 15, Rutgers, State University of New Jersey and University of Delaware, 

New Brunswick, NJ, 2005. and Winebrake, J.J., J.J. Corbett, C. Wang, A.E. Farrell, and P. 

Woods, Optimal Fleetwide Emissions Reductions for Passenger Ferries: An Application of a 

Mixed-Integer Nonlinear Programming Model for the New York-New Jersey Harbor, Journal of 

Air and Waste Management, 55 (4), 458–466, 2005. 

Ferries operating in Alaska may have a significantly different schedule than vessels operating in 

the New York harbor area; for example the Alaskan ferries may spend more time at sea than 

New York harbor ferries. At this time there were insufficient data to account for Alaska’s unique 

ferry operations. 

Days of operation for fishing vessels were obtained from a study by Corbett and Koehler, 

Considering Alternative Input Parameters in an Activity-based Ship Fuel Consumption and 

Emissions Model: Reply to Comments by Øyvind Endresen et al. on “Updated Emissions from 

Ocean Shipping” (2004). These fishing vessel values may under-represent the activity levels of 

larger commercial fishing vessels equipped with Category 2 engines as these larger vessels tend 

to remain at sea for longer periods of time. The Coast Guard provided estimates for the number 

of days per year that individual vessels operate at sea for the past 8 years, these vessels were 

matched with the list of Category 2 Coast Guard vessels that was developed as described in 

Section 2.0. Only those vessels that were match to the Category 2 vessel list was used in this 

evaluation of days of operation. 

The estimate for days of operation for offshore support vessels was provided by James Mcgill, 

Coast Guard Technical Representative for the National Offshore Safety Advisory Committee 

(NOSAC). Mr. Mcgill has worked on offshore vessel activities for over 18 years and has 

considerable insight into their operations. In addition, Dr. Tommy Dickey, Dr. Grace Chang and 

Frank Spada of the Ocean Physics Laboratory (OPL) at the University of California – Santa 

Barbara provided the estimates of typical operating schedules for research vessels for which they 

are familiar. Dr. Dickey, Dr. Chang and Mr. Spada are involved with inter-university research 

vessel planning and are very knowledgeable about research vessel operations. These vessel 

operating day data are summarized in Table 3-1. 

Operating days can vary significantly for individual vessels depending upon the activity, market 

force, and local fleet operating characteristics. For these reasons days of operation was 

considered a variable in the Monte Carlo analysis. 

When Category 2 vessels come to port they tend to shut off propulsion engines to reduce cost 

and use only auxiliary engines to generate electricity, run refrigeration units, or assist in loading 

and offloading. Therefore, there are no operating days for the propulsion engines while the 

vessels are hoteling in port. 

Vessels such as offshore support vessels, research vessels, fishing boats, and Coast Guard ships 

spend some time idling at sea. Idling at sea is significant because these vessels operate at lower 

load factors than they do while cruising at sea. Offshore support vessels are not allowed to come 
0203.02.002.001\Category 2 Vessel Census-Activity Report 3-5 

in contact with drilling rigs or platforms. Therefore, they must run their propulsion engines 

during unloading and loading operations, which run from 4 to 6 hours per trip, based on 

information provided by Mr. Mcgill. Research vessels also idle at sea depending on the study 

being implemented. Staff at OPL provided an estimate of the typical period that research vessels 

spend idling at sea. Fishing boats idle at sea when nets or lines are being hauled in and the catch 

is moved to storage. Coast Guard vessels idle at sea while inspecting cargo ships or during 

search and rescue operations. For fishing vessels and Coast Guard ships, idling at sea values 

were not readily available and were developed based on professional judgment. The period of 

time that vessels idle at sea are summarized in Table 3-2 and presented in Figure 3-1. 

Table 3-2. Operating Days and Load Factors 

Activity data for days of operation were also used to quantify the amount of time vessels 

equipped with Category 2 engines spend in port, as presented in Figure 3-1. The time spent in 

port includes seasonal down time, normal maintenance activities, time spent loading or 

discharging cargo, or in-port delays associated with weather or vessel traffic. These values 

should be considered rough approximations; actual time spent underway and in port for specific 

vessels may be significantly more or less than that shown in Figure 3-1. 

Load factors were also derived from a variety of references. In many cases, the data source for 

load factors was the same as the data source for operating days. Load factors for tugs were 

provided by Doug Schaffer of the American Waterways Operators. Load factors for ferries were 

obtained from Corbett, et al (2003). These ferry load factors were considered appropriate for use 

for Great Lakes vessels. Typical load factors for fishing vessels were obtained from Corbett and 

Koehler (2004). The load factor estimates for offshore support vessels were provided by James 

Mcgill and staff at OPL provided load factors for research vessels. In some cases, vessel type 

specific load factors were not readily available, such as for deep water vessels and Coast Guard 

ships. Typical load factors found in other EPA documents were used for this study. These load 

factor estimates should be seen as rough approximations of actual engine loads. It should be 

Annual Underway Underway Idling Load Factor 

Vessel Type 

Min 

Days 

Likely 

Days 

Max 

Days Percentage

Likely 

Days 

Annual 

Port 

Days Min Likely Max 

Deep Water Cargo 219 0 0 146 0.10 0.80 0.90 

Tow Boats 219 0 0 146 0.10 0.44 0.90 

Ferries 152 174 243 0 0 137 0.53 0.68 0.80 

Commercial 

Fishing 250 271 292 30 81 94 0.27 0.70 0.80 

Great Lake 136 0 0 229 0.53 0.84 0.84 

Coast Guard 29 88 157 20 18 277 0.10 0.80 0.90 

Offshore 280 299 317 22 66 31 0.10 0.85 0.87 

Research 220 40 88 145 0.10 0.85 0.90 
0203.02.002.001\Category 2 Vessel Census-Activity Report 3-6 

Figure 3-1. Underway, Idling, and In Port Fractions by Vessel Type 

noted that the California Air Resource Board has developed load factors for a variety of different 

vessels that are significantly lower than the load factors used in this study. The California load 

factors were not used as they include vessels other than Category 2 vessels that have different 

usage and operation patterns. 

As noted earlier, Category 2 vessels do not run their propulsion engines while hoteling in port. 

During the period in port that vessels are maneuvering, their propulsion engines operate under a 

wide variety of loads. The period that these larger Category 2 vessels spend maneuvering is not 

easily documented, and is assumed to be a short period relative to the period of time that 

Category 2 vessels are underway, therefore, the maneuvering period is not included in this 

assessment. It is assumed that amount of in port activity and associated emissions from the 

propulsion engines is small. 

When Category 2 vessels are cruising underway, they tend to operate at the most fuel efficient 

load, which is around 80 percent. Vessels can operate at maximum load levels briefly to 

negotiate a difficult turn in a river or avoid an accident; again these episodes tend to be relatively 

short and were not included in this analysis. For the purpose of this study, the likely load factors 

noted in Table 3-2 were used in the calculation of the horsepower hours while vessels are 

cruising under way, and the minimum load factors were used while vessels were idling at sea. 

36.2%

63.8%

19.2%

37.2%

51.9%

62.5%

60.0%

60.0%

24.1%

18.0%

4.9%

22.3%

39.7%

18.2%

75.9%

62.8%

25.8%

37.5%

40.0%

40.0%

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Research

Offshore 

Coast Guard 

Great Lake

Commercial 

Fishing

Ferries

Tow Boats 

Deep Water

Cargo

% Underway % Underway Idling % In Port
0203.02.002.001\Category 2 Vessel Census-Activity Report 3-7 

The load factor was not considered a variable in the Monte Carlo analysis, though it was varied 

by vessel type. 

3.3 Horsepower Hours 

The equation used to calculate horsepower hours is provided in Section 4.0. To use this equation 

all operating days were converted to hours by assuming that an operating day is equivalent to 

24 hours. As mentioned earlier, this equation was applied to a Monte Carlo analysis. The Monte 

Carlo methodology is a system that incorporates variable data that have a uniform distribution in 

order to measure the level of uncertainty associated with a calculated value. This is done by 

running the model repeatedly using values from the identified distribution for each variable. In 

this project we used a triangle distribution for our variables based on the minimum, maximum 

and most likely values for horsepower and operation days. These minimum, maximum, and most 

likely values for horsepower and operating days are presented in Tables 3-1 and 3-2, 

respectively. Graphic representations of these distributions are also presented in Appendix B. 

Crystal Ball® software was used in this analysis. The model was set to run 10,000 trials for each 

vessel type. The distribution of the calculated horsepower hours are presented in Figures 3-2 

through 3-9 and summarized in Table 3-3. Summary output statistics are also provided in 

Appendix B. 

As Table 3-3 suggests, given the variance within the input data, the distribution of total 

horsepower hours is fairly large ranging from ± 26 percent for Deep Water Ships to ± 43 percent 

for offshore vessels. The sensitivity analysis included in Appendix B, notes that most of the 

variance is due to the wide range of horsepower ratings that vessels equipped with Category 2 

engines represent. The exception to this observation concerns Coast Guard vessels, where the 

operating days accounted for a similar amount of variance as horsepower rating. 

Quantifying the underlying level of uncertainty is important because it helps define the likely 

range of activity associated with Category 2 vessels. In the future, uncertainty may be able to be 

reduced by using disaggregated horsepower categories for each vessel type and compiling better 

days of operation for each of the horsepower categories. 

Table 3-3. Category 2 Propulsion Horsepower Hours by Vessel Type 

Vessel Type 

Mean Values 

(million hp-hrs) 

Standard Deviation 

(million hp-hrs) 

Deep Water 2,666 698 

Towboat 7,920 3,020 

Ferry 1,464 443 

Fishing 3,413 1,143 

Great Lakes 1,393 405 

Coast Guard 1,441 496 

Offshore 27,810 11,933 

Research 654 217 
0203.02.002.001\Category 2 Vessel Census-Activity Report 3-8 

As a quality check for this vessel activity assessment, data from the California Air Resource 

Board’s (CARB) Commercial Harbor Craft Survey were compared to data in this study. The 

comparison showed differences in operating hours and load factors. Some of the differences 

could be explained due to the different vessels included in each inventory. The CARB study 

includes all vessel types and sizes, while this report only considered vessels equipped with 

Category 2 propulsion engines. The CARB study also only considered vessels that operate within 

surrounding waters and should be considered California-specific data, while this report attempted 

to capture vessels used throughout the country. An example of this difference is offshore support 

vessels; California has relatively few of these vessels, while states like Texas and Louisiana have 

a large number of these vessels because the vast majority of offshore oil platforms operate in the 

Gulf of Mexico. Considering these observations, it appears that the estimates included in this 

study, particularly with regard to the load factors, are higher than the CARB data. CARB 

developed their load factors from fuel usage reported in their survey, as such the estimate of total 

horsepower hours are higher than similar estimates developed by CARB. 

Frequency Chart

 HP-HR

.000

.005

.010

.015

.020

0

50.75

101.5

152.2

203

1,191,707,853 2,003,905,237 2,816,102,622 3,628,300,007 4,440,497,391

10,000 Trials 9,994 Displayed

Forecast: Deep Water HP-HR Figure 3-2 - Deep Water Vessel 

HP-HR Calculation Frequency Chart 
0203.02.002.001\Category 2 Vessel Census-Activity Report 3-9 

Frequency Chart

 HP-HR

.000

.005

.011

.016

.022

0

53.75

107.5

161.2

215

3,243,495,839 6,368,463,929 9,493,432,019 12,618,400,110 15,743,368,200

10,000 Trials 9,807 Displayed

Forecast: Towboats HP-HR

Frequency Chart

 HP-HR

.000

.005

.010

.015

.020

0

50.25

100.5

150.7

201

537,632,473 1,067,786,214 1,597,939,956 2,128,093,697 2,658,247,438

10,000 Trials 9,914 Displayed

Forecast: Ferries HP-HR

Figure 3-3 - Tow Vessel 

HP-HR Calculation Frequency Chart 

Figure 3-4 - Ferry Vessel 

HP-HR Calculation Frequency Chart 
0203.02.002.001\Category 2 Vessel Census-Activity Report 3-10 

Frequency Chart

 HP-HR

.000

.005

.010

.015

.021

0

51.25

102.5

153.7

205

376,459,662 841,982,144 1,307,504,627 1,773,027,109 2,238,549,592

10,000 Trials 9,975 Displayed

Forecast: Great Lakes HP-HR

Frequency Chart

 HP-HR

.000

.006

.011

.017

.022

0

55

110

165

220

1,733,197,125 2,894,035,450 4,054,873,775 5,215,712,099 6,376,550,424

10,000 Trials 9,792 Displayed

Forecast: Commerical Fishing HP-HR Figure 3-5 - Commercial Fishing Vessel 

HP-HR Calculation Frequency Chart 

Figure 3-6 - Great Lakes Vessel HP-HR 

Calculation Frequency Chart 
0203.02.002.001\Category 2 Vessel Census-Activity Report 3-11 

Frequency Chart

 HP-HR

.000

.005

.010

.016

.021

0

51.75

103.5

155.2

207

7,660,583,858 20,890,281,606 34,119,979,354 47,349,677,102 60,579,374,850

10,000 Trials 9,951 Displayed

Forecast: Offshore HP-HR

Frequency Chart

 Hp-HR

.000

.005

.010

.015

.020

0

50.25

100.5

150.7

201

403,019,387 984,966,086 1,566,912,786 2,148,859,485 2,730,806,185

10,000 Trials 9,876 Displayed

Forecast: Coast Guard HP-HR Figure 3-7 - Coast Guard Vessel 

HP-HR Calculation Frequency Chart 

Figure 3-8 - Offshore Vessel 

HP-HR Calculation Frequency Chart 
0203.02.002.001\Category 2 Vessel Census-Activity Report 3-12 

3.4 Vessel Activity References 

American Waterways Operators, call with Roger Chang and Mr. Doug Scheffler, April 2006. 

Corbett, J.J., J.J. Winebrake, and P. Woods, An Evaluation of Public-Private Incentives to 

Reduce Emissions from Regional Ferries: Synthesis Report, pp. 15, Rutgers, State University of 

New Jersey and University of Delaware, New Brunswick, NJ, 2005. 

Corbett, Jim and Horst Koehler, Considering Alternative Input Parameters in an Activity-based 

Ship Fuel Consumption and Emissions Model: Reply to Comments by Øyvind Endresen et al.on 

“Updated Emissions from Ocean Shipping”, Journal of Geophysical Research, Vol 109, D23303 

(2004). 

Ocean Physics Laboratory (OPL), University of California - Santa Barbara, call with Roger 

Chang and Dr. Tommy Dickey, Dr. Grace Chang, and Frank Spada, April 2006. 

American Public Transportation Association, Public Transportation Fact Book – Ferry Boats, 

http:www.apta.com/rearch/stats/factbook/index.cfm. May 8, 2006. 

U.S. Coast Guard /National Offshore Safety Advisory Committee, call with Richard Billings and 

James Mcgill, April 2006. 

Winebrake, J.J., J.J. Corbett, C. Wang, A.E. Farrell, and P. Woods, Optimal Fleetwide Emissions 

Reductions for Passenger Ferries: An Application of a Mixed-Integer Nonlinear Programming 

Model for the New York-New Jersey Harbor, Journal of Air and Waste Management, 55 (4), 

458–466, 2005. 

Frequency Chart

 HP-HR

.000

.005

.010

.015

.020

0

49.25

98.5

147.7

197

222,501,388 470,656,327 718,811,265 966,966,204 1,215,121,143

10,000 Trials 9,973 Displayed

Forecast: Research HP-HR Figure 3-9 - Research Vessel 

HP-HR Calculation Frequency Chart 
0203.02.002.001\Category 2 Vessel Census-Activity Report 4-1 

4.0 IN-PORT / AT-SEA SPLITS 

4.1 Introduction 

Vessel activities can be divided between in-port and at-sea activities. The in-port activities 

include approaching or departing the port, maneuvering within the port area and between 

terminals, and hoteling operations while cargo is being removed or added to the vessel. At-sea 

activities are dominated by underway operations. For the purposes of this study the port area 

includes the area within a 25 mile radius from the outer edge of the harbor where vessels dock at 

terminals and shift cargo. This definition of a port area works reasonably well for coastal ports, 

but can be problematic for inland ports where adjacent ports are less than 25 miles away, such 

that the port areas conflict. For Category 2 vessels, that tend to shut off their propulsion engines 

while at dock, in port propulsion engine activity is limited to time spent maneuvering up to and 

within the port area. The data obtained to estimate propulsion engines operating within the port 

area were all in terms of time spent manueuvering. It should be noted that actual maneuvering 

times vary significantly between individual ports. 

The Category 2 vessel list primarily includes medium to large commercial vessels and as such 

this listing excludes certain Category 1 vessel types such as smaller excursion vessels and private 

recreational boats. 

4.2 In-Port / At-Sea Methodology 

In developing the in-port / at-sea splits for Category 1 and Category 2 vessels, each vessel type 

was evaluated separately as the operations for each vessel type can be significantly different. The 

data sources used to estimate the splits also varied by vessel type and are discussed in greater 

detail in Section 3 of this report. For most vessels, in-port propulsion engine operations are 

limited to the amount of time vessels spending maneuvering. While at dockside auxiliary engines 

are used to maintain power or assist in the loading and unloading. Operation of these auxiliary 

engines was not included in this evaluation. 

The period of time that propulsion engines were involved in in-port maneuvering was estimated 

for each vessel type and converted to a percentage based on a typical vessel’s total propulsion 

operating hours. This value was used to estimate the at-sea percentage can using the following 

equation: 

ASi = (1-(IPi / THi)) ×100 

Where: 

ASi = At-sea hours of operation for vessel type i 

IPi = In-port hours of operation for vessel type i 

THi = Total vessel hours of operation for vessel type i 

i = Vessel type i (e.g, tug/towboat, commercial fishing vessel, 

offshore support vessel) 
0203.02.002.001\Category 2 Vessel Census-Activity Report 4-2 

For many of the vessel types included in this study, there are sub-types that have significantly 

different operations. For example, assist tugs help bring larger vessels into port, so their in-port 

activities are significantly more than line haul and ocean going tugs that shift barges from portto-port and operate their propulsion engines within a port for relatively short periods of time. 

Where possible, this evaluation was preformed at the sub-vessel type level. To calculate a 

weighted average for the vessel type that takes into consideration differences at the sub-type 

level the fractions were weighted relative to the vessel populations using the following 

equations: 

WASi = ∑ASij × STij 

Where: 

WASi = Weighted at-sea split for vessel type i; 

ASij = At-sea percentage for vessel type i and subtype j; 

STij = The percentage of the vessel population for type i and subtype j; 

i = Vessel type (e.g, tug/towboat, commercial fishing vessel, 

offshore support vessel); 

j = Vessel subtype (e.g., ocean going tug, line haul tug, assist tug, 

dredge support tugs). 

These procedures were repeated for in-port weighted splits. The in-port and at-sea splits were 

checked to ensure that they summed to 100 percent. 

Activity data at the subtype level would have been preferred for weighting purposes, but were 

not available at the vessel sub-type level. The calculations by vessel subtype are noted in 

Appendix C for Category 1 vessels and Appendix D for Category 2 Vessels. 

It should be noted that innocent passage of vessel through a port area without stopping was not 

considered in this assessment. Vessels at-sea are to be allocated relative to shipping lane segment 

and therefore will be included in the overall calculation, but were not handled as an in-port 

activity. 

4.3 Vessel Type Overview 

The following sections discuss the vessel population data used in this analysis and the basis for 

the in-port / at-sea split for each vessel type. 

4.3.1 Tugs/Towboats 

The Category 2 Vessel Census and Activity Report quantified that there are approximately 3,164 

Category 1 tugs and towboats and 1,057 Category 2 tugs and tow boats. 

For in-port maneuvering, the European Commission report estimate 300 annual hours was used. 

This value combined with the assumption that propulsion engines for these vessels operate 2,000 

hours per year, as noted in the CARB harbor study to provide and in-port fraction of 15%. Assist 
0203.02.002.001\Category 2 Vessel Census-Activity Report 4-3 

tugs and support vessels for dredging activities mostly occur within or near ports, so their in-port 

fractions were adjusted to reflect the increase in the import activity. 

4.3.2 Commercial Fishing 

As noted in the Category 2 Vessel Census and Activity report, commercial fishing is dominated 

by 29,346 smaller crafts equipped with Category 1 propulsion engines; many of these are smaller 

fishing boats and charter fishing operations. The Category 2 commercial fishing vessel 

population noted in the Category 2 Vessel Census and Activity report was 333 vessels. 

The commercial fishing in-port activity was obtained from the CARB harbor study; 62 % of 

smaller fishing vessels (Category 1) and 5% of larger fishing vessels (Category 2) propulsion 

engine operations occur within the port area. The nature of the Category 1 fishing vessels 

represent a mixture of input maneuvering and active fishing operations within the 25 mile area 

considered to be the port. 

4.3.3 Offshore Support Vessels 

The Category 2 vessel population was obtained from the Category 2 Vessel Census and Activity 

report. The report also noted that the Category 1 fleet was approximately 87% of the Category 2 

value; therefore the Category 1 vessel population was estimated for each offshore category based 

on this assumption. 

To estimate time spent maneuvering in-port the assumption in European Commission report that 

support vessels require two hours per trip and other offshore vessels require 0.5 hours was used. 

The estimate for typical number of trips for offshore vessels was derived from information 

provided from the Coast Guard’s offshore vessel consultant. Typically an offshore support vessel 

cycle to and from the ports is between one and two days. 

4.3.4 Ferries 

The Category 2 Vessel Census and Activity report identified 508 Category 1 and 99 Category 2 

ferries. The in-port value of 65% was obtained from the ARB Harbor study. It was assumed that 

smaller Category 1 ferries probably spend more time operating in-port than the Category 2 

vessels, so the in-port fraction was increased to 80%. 

4.3.5 Deep Water Vessels 

The vast majority of deep water vessels are larger Category 3 vessels, but in developing the 

Category 2 Vessel Census and Activity report, 23 Category 1 and 45 Category 2 vessels were 

identified. These deep water vessels are primarily oceangoing tugs and general cargo vessels that 

go through U. S. Customs entrance and clearance procedures. Given their relative size these 

vessels are probably visiting adjacent countries such as Canada, Mexico, other Central and South 

American countries and the Caribbean islands. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 4-4 

It was assumed that the majority of these vessels probably operate on a seven day cycle with five 

days at-sea followed by two days in-port loading and unloading, providing a rough estimate of 

52 trips per year. Many of these vessels shut off their main propulsion engines while hoteling at 

dockside. The European Commission report estimates that such vessels maneuver in-port an 

average of 1.1 hours per trip. Assuming these vessels’ propulsion engines operate approximately 

6,240 hours per year than the in-port /at-sea fraction for the propulsion engines is approximately 

1% / 99%, respectively. 

4.3.6 Research 

For research vessels, 107 Category 1 vessels and 31 Category 2 vessels were identified in the 

Category 2 Vessel Census and Activity report.

Data from the European Commission report were used that suggested that research vessels 

maneuver in-port between 0.5 (likely to be Category 1 vessels) and 1.3 (Category 2 

vessels) hours per port trip. Activity data from the research vessel database were evaluated and it 

was estimated that Category 1 vessels make 27.5 trips per year and Category 2 vessels make 16. 

Assuming an annual hours of operation of 5,280 as provided in the Category 2 Vessel Census 

and Activity report, this provides an in-port fraction of 0.3 % for Category 1 vessels and 0.4% 

for Category 2 vessels. These values were rounded to 1% to reflect the relative accuracy of 

assumptions used in this calculation. 

4.3.7 Great Lakes and Other Vessels 

The Category 1 and 2 vessel population estimates were taken directly from the Category 2 

Vessel Census and Activity report. It was assumed that the Great Lakes vessels would be similar 

to deepwater vessels so their in-port/at-sea split was 1% / 99%. 

4.3.8 Government Vessels 

The Coast Guards web site provided an estimate of 291 smaller diesel powered patrol boats 

which are likely to be Category 1 vessels. Unfortunately the list did not include navigational aid 

vessels or harbor tugs and as such, this estimate for Category 1 Coast Guard boats should be 

considered an underestimation of the vessel population; the actual Category 1 vessel count is 

probably significantly higher than the value reported here. 

There are also a number of pilot boats, police vessels, and firefighting boats that probably are 

equipped with Category 1 engines, but were not evaluated in this effort. 

For the purpose of the assessment, it is assumed that patrol boats and buoy tenders operate in and 

around the harbor area. The bigger cruisers and smaller icebreakers probably maneuver to and 

from the dock, but once at the dock, their main propulsion engines are shut off so their in-port 

fraction is much less than patrol boats and buoy tenders. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 4-5 

4.4 Summary 

Appendix C compiles the calculations developed for the Category 2 vessel types in-port/at-sea 

splits, while Appendix D compiles the calculations for the Category 1 vessel in-port/at-sea splits. 

Table 4-1 below summarizes the in-port and at-sea activity splits by vessel type for vessels 

equipped with Category 1 and 2 propulsion engines. Averages were provided by vessel type and 

aggregated averages for each vessel category for state and local agencies to use to estimate 

vessel activity where detailed data are not readily available. 

Table 4-1. Average In-Port and At-Sea Fraction by Vessel Type for 

Vessels Equipped with Category 1 and 2 Propulsion Engines 

Vessel Type In-Port At-Sea 

Category 1 

Towboats 15% 85% 

Fishing 62% 38% 

Offshore 4% 96% 

Ferries 80% 20% 

Deepwater 1% 99% 

Research 1% 99% 

Great Lakes 1% 99% 

Government 95% 5% 

Average 32% 68% 

Category 2 

Towboats 17% 83% 

Fishing 5% 95% 

Offshore 4% 96% 

Ferries 65% 35% 

Deepwater 1% 99% 

Research 1% 99% 

Great Lakes 1% 99% 

Government 59% 41% 

Weighted Average 10% 90% 

The averages developed for Category 1 vessels was a straight average based on vessel type data. 

The straight average was considered a more useful value for state and local agencies as weighted 

average had a significant bias toward fishing vessels as they represent a very large portion of the 

Category I fleet. It is recognized that fishing vessel activity is not uniformly distributed through 

out the United States, furthermore activity levels can vary significantly from year-to-year for a 

specific port. It is recommended that port specific estimates be developed for ports with 

significant Category 1 commercial fishing vessel traffic. 

For Category 2 vessels, weighted averages were calculated based on activity level of each vessel 

type as estimated in the Category 2 Vessel Census and Activity report using the following 

equation: 
0203.02.002.001\Category 2 Vessel Census-Activity Report 4-6 

AASi = ∑WASi × STi 

Where: 

AASi = Activity weighted at-sea split for vessel type i; 

WASi = Weighted at-sea percentage for vessel type i; 

STi = The percentage of activity associated with vessel type i; 

i = Vessel type (e.g, tug/towboat, commercial fishing vessel, offshore 

 support vessel); 

The data used for these calculations are provided in Appendix C. These steps were repeated to 

estimate the in-port fractions. In-port and at-sea values were checked to insure that they sum to 

100 percent. 

The uncertainly associated with the Category 1 data is much greater than the uncertainty 

associated with the Category 2 data and as such the Category 1 in-port and at-sea values should 

be viewed as rough approximation of the actual in-port / at-sea activity. 

It should be noted that these values are intended for use in developing national activity data sets 

and as such do not necessarily reflect in-port and at-sea splits for a specific port. Where a port 

has non-typical traffic patterns such as a large amount of fishing boat traffic or offshore support 

vessel traffic, in-port and at-sea splits should be developed for these ports using local data. 

4.5 References 

California Air Resource Board, 2002 Statewide Commercial Harbor Craft Survey – Draft 

Report. December 2003. 

European Commission, Quantification of Emissions From Ships Associated with Ship 

Movements between Ports in the European Community. Brussels, Belgium. 2002. 

Fairplay, Ltd Lloyd’s Register of Ships. 8410 N.W. 53rd Terrace, Suite 207, Miami, FL. 2004. 

U.S. Army Corps of Engineers / Waterborne Statistics Division, Vessel Clearance and Entrance 

Data. New Orleans, LA. 2006. 

U.S. Coast Guard official website - www.uscg.mil/datasheet/dataindx.htm

U.S. Coast Guard /National Offshore Safety Advisory Committee, call with Richard Billings and 

James Mcgill, April 2006. 

U.S. Department of Transportation, Bureau of Transportation Statistics, National Ferry 

Database. 2000. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 4-7 

University National Oceanographic Laboratory System website - 

www.unols.org/info/vessels.htm

U.S. Environmental Protection Agency, May 15, 2006, Category 2 Vessel Census and Activity– 

Draft Report, Ann Arbor, MI. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-1 

5.0 CATEGORY SPATIAL ALLOCATIONS 

This section discusses how the in-port and at-sea components were spatially allocated to county 

and federal waters. County waters include all navigable waterways within and surrounding all 

50 states, including Hawaii and Alaska. In some of the figures Hawaii and Alaska are not shown 

due to space limitations or the source category is not associated with these states (e.g., Great 

Lakes Vessels, Tugs and Towboats). Federal Waterways extend from the boundary of the state 

waters 200 miles out to sea, including the area around Hawaii. 

In general, the port activities were spatially allocated to individual ports based on surrogate data 

such as the amount of cargo handled for tow boats, deepwater cargo vessels and Great Lakes 

vessels; fish catch processed for commercial fishing boats; and the vessel’s home port for 

offshore, research and government vessels, and ferries. At-sea activities were spatially allocated 

to shipping lanes for tow boats, deepwater vessels, and Great Lakes vessels; fishing zones for 

commercial fishing; Coast Guard districts for Coast Guard vessels; active offshore oil platforms 

for offshore support vessels; and research areas for research vessels. The allocation approaches 

for each vessel type are summarized in Table 5-1 and discussed in greater detail in Section 5.1. 

Table 5-1. Summary of Spatial Allocation Approaches Used 

Memo 

Section Vessel Type In-Port Approach At-Sea Approach 

2.1 Tugs/Towboats Cargo handled at 

individual ports 

Ship traffic on 

commercial shipping 

lanes 

2.2 Commercial Fishing 

Annual commercial 

landings at individual 

fishing ports 

State and federal waters 

by fishing zone 

2.3 Offshore Support Vessels 

Equally to ports that 

provide services to 

offshore support vessels 

Active lease blocks based 

on number of offshore oil 

platforms 

2.4 Ferries Home port associated with 

individual vessels Same county as home port

2.5 Deepwater Ports calls for individual 

vessels at individual ports 

Individual commercial 

shipping lanes 

2.6 Research Ports that individual 

vessels visit 

Distributed to research 

districts 

2.7 Great Lakes & Others 

Cargo handled at 

individual ports in the 

Great Lakes area 

Ship traffic on Great 

Lakes commercial 

shipping lanes 

2.8 Government Home port of individual 

vessels 

Distributed to Coast 

Guard districts 

The in-port and at-sea activities were mapped using Geographic Information Systems (GIS) 

tools. County and federal boundaries were developed and mapped on top of the port and 

underway activities to allow for aggregation of activity estimates to the county level. The GIS 

map projection used for this project was the North America Albers Equal Area Conic projection. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-2 

Figure 5-1 summarizes the approach used to disaggregate national activity data to individual 

county and federal waters. 

Figure 5-1. Overview of Approach Used to Develop and Spatially Allocate Annual 

Activity of Vessels Equipped with Category 2 Engines 

The county waterway boundary file was developed based on Census Department’s county maps. 

To disaggregate federal waters into smaller grids, the Department of Interior’s Mineral 

Management Services’ (MMS) “lease blocks” were used. This lease block system of geographic 

blocks is used to identify offshore locations for the installation of offshore oil platforms. These 

blocks extend from the state waters boundary to 200 miles out and include all U.S. coastal 

waters, except surrounding the Hawaiian Islands. As these are no lease blocks associated with 

the Hawaiian Islands, a single area extends 200 miles from the shore was used. Each block has a 

unique identifier, which vessel activity data can be linked to in the GIS metafile. The MMS lease 

block shape file is readily available from MMS’s Web site. 

Activity by 

Vessel Type

In-Port At-Sea

Allocated to 

Individual Ports 

Based on: 

• Cargo Handled 

• Fish Landings 

• Vessel Home 

 Port/Visited

 Ports

Allocated to:

• Shipping 

Lane 

• Fishing Zone 

• Coast Guard 

 District 

• Offshore Oil 

 Platforms 

• Research

 Districts

• Home Ports

Applied to GIS 

Map Overlaid 

with 

County/Federal 

County Level 

Activity by 

Vessel Type
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-3 

Each vessel type was handled separately in order to apply the most appropriate spatial surrogate 

to the vessel’s activity. Section 5.1 discusses the surrogates used for each vessel type. The 

surrogate data are the latest publicly available data. This section also presents the derived in-port 

and at-sea activity maps. Section 5.2 summarizes the results and provides national maps that 

include all vessel activities. 

5.1 Vessel Type Overview 

The following sections discuss the approach used to spatially disaggregate the national or 

regional activity to individual ports, shipping lanes, counties, or federal blocks. In general, 

activity is disaggregated by using an appropriate surrogate. Use of surrogate data intrinsically has 

limitations and bias because the actual activity level may be greater than or less than that 

estimated using the surrogate. These limitations are noted in each section. 

5.1.1 Tugs/Towboats 

In-Port – Tugs/Towboat 

Tug and towboat activity in the port area was estimated by apportioning the national tug/towboat 

in-port hours of operation to individual ports based on the amount of cargo handled at the 

designated port. The port cargo handling data were obtained from the U.S Army Corps of 

Engineers and included cargo data for the top 150 ports. 

The following equation was used for this allocation approach: 

TTipa = HOttip × CHa / CHn

Where: 

TTipa = Estimate of 2004 activity for tugs and towboats for port a (hp-hrs/year) 

HOttip = National estimate of 2004 in-port hours of operation for tugs and 

 towboats (hp-hrs/year) 

CHa = Amount of cargo handled at port a in 2004 (tons per year) 

CHn = Amount of cargo handled at all ports in 2004 (tons per year) 

a = Port a 

The county in which each cargo port is located was identified for each cargo port included in this 

study. County FIPS codes were matched to each county and retained in the project database. 

Three ports, Matagorda Ship Channel, Duluth, and Camden/Gloucester, crossed county or state 

lines, so their activity was split equally between the adjacent counties. Results of this approach 

are presented in Figure 5-2 and the associated data are included in the project database. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-4 

Figure 5-2. Tug/Towboat In-Port Activity 

At-Sea – Tugs/Towboats

Tug and towboat activity while at sea was estimated by apportioning the national tug/towboat atsea hours of operation to individual shipping lanes based on the amount of cargo traffic 

associated with the shipping lane segment. The shipping lane GIS data were obtained from the 

Department of Transportation and the cargo traffic data were obtained from the U.S. Army Corps 

of Engineers. 

The following equation was used to allocate tug and towboat at-sea activity: 

TTasi = HOttas × CTi / CTn

Where: 

TTasi = Estimate of 2004 activity for tugs and towboats for sea shipping lane 

segment i (hp-hrs/year) 

HOttas = National estimate of 2004 at-sea hours of operation for tugs and 

 towboats (hp-hrs/year) 

CTi = Amount of cargo traffic for at-sea shipping lane segment I for 2004 

(tons) 

CTn = Amount of cargo traffic for all at-sea shipping lanes for 2004 (tons) 

i = At-sea shipping lane segment i 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-5 

Some of the tugs and towboats included in this study are assist tugs or fleeting tugs that remain 

in port longer than other tugs such that actual activity may be slightly overestimated along 

shipping lanes and underestimated near major ports. Results of this approach are presented in 

Figure 5-3 and the associated data are included in the project database. 

Figure 5-3. Tug/Towboat At-Sea Activity 

5.1.2 Commercial Fishing 

In-Port – Commercial Fishing

Commercial fishing activity in the port area was estimated by apportioning the national 

commercial fishing in-port hours of operation to individual ports based on the annual 

commercial fishing landing statistics at a designated port. The fish landing data include 715 fish 

species handled at 97 ports. The annual commercial fish landings data were obtained from the 

National Marine Fisheries Service. 

The following equation was used for this allocation approach: 

CFipa = HOcfip × FHa / FHn

Where: 

CFipa = Estimate of 2004 activity for commercial fishing for port a (hp- 

 hrs/year) 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-6 

HOcfip = National estimate of 2004 in-port hours of operation for commercial 

 fishing (hp-hrs/year) 

FHa = Annual commercial fish landing at port a in 2004 (tons per year) 

FHn = Amount of fish handled at all ports in 2004 (tons per year) 

a = Port a 

The county was identified for each fishing port included in this study. County FIPS codes were 

matched to each county and retained in the project database. 

Category 2 vessels tend to be large commercial fishing ships and may not be visiting all 97 ports 

included in the National Marine Fisheries Service data. Thus, actual activity at major ports may 

be underestimated, while activity at smaller ports may be overestimated. Results of this approach 

are presented in Figure 5-4 and the associated data are included in the project database. 

Figure 5-4. Commercial Fishing In-Port Activity 

At-Sea – Commercial Fishing

Commercial fishing activity while at sea was estimated by apportioning the national commercial 

fishing at-sea hours of operation to state or federal fishing waters based on the amount of fish 

catches associated with each area. The at-sea fish catch data were obtained from National Marine 

Fisheries Service. 

The following equation was used for this allocation approach: 

CFasj = HOcfas × FCj / FCn
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-7 

Where: 

CFasj = Estimate of 2004 activity for commercial fishing at sea for fishing area j 

 (hp-hrs/year) 

HOcfas= National estimate of 2004 at-sea activity for commercial fishing (hp- 

 hrs/year) 

FCj = Amount of fish caught for fishing area j in 2004 (tons) 

FCn = Amount of fish caught for all fishing areas for 2004 (tons) 

j = At-sea fishing area j 

Some fishing areas restrict or ban fishing and these areas were not identified by the National 

Marine Fisheries Service and could not be considered in this analysis. Thus; at-sea activities in 

these areas may be overestimated and activity levels in other areas may be slightly 

underestimated. Results of this approach are presented in Figure 5-5 and the associated data are 

included in the project database. This map clearly notes a reduction in commercial fishing 

activities around the areas in the Gulf where oil platforms are operating. 

 Figure 5-5. Commercial Fishing At-Sea Activity 

5.1.3 Offshore Support Vessels 

In-Port – Support Vessels

Twenty ports were identified that provide services to offshore support vessels. Support vessel 

activity in the port area was estimated by apportioning the regional offshore in-port hours of 

operation equally to individual ports. For the Gulf of Mexico, listing of offshore support vessel 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-8 

ports was provided by Tidewater, one of the larger offshore support vessel companies. As most 

of the offshore platforms in Alaska are in the Prudhoe Bay area, all Alaskan offshore vessel 

activity was assigned to the port of Barrow. For California, most of the oil platforms are located 

off the coast of Ventura and Santa Barbara counties, therefore, port activities were split equally 

between the ports of Ventura and Santa Barbara. 

The following equation was used for this allocation approach: 

OSipa = HOosip / OSpr

Where: 

OSipr = Average activity for an offshore support vessel for port in region r (hp- 

 hrs/year-port) 

HOosipr = Estimate of 2005 in-port hours of operation for offshore support 

 vessels in region r (hp-hrs/year) 

OSpr = Number of ports in region r 

r = Region r (Gulf of Mexico, Alaska, and California) 

These port averages were assigned to each port in the region. The county was identified for each 

offshore support vessel port included in this study. County Federal Information Processing 

Standards (FIPS) codes were matched to each county and retained in the project database. Some 

ports such as Houston probably have considerably more offshore vessel traffic than smaller 

ports, suggesting that activity is underestimated at large ports and overestimated at smaller ports. 

Results of this approach are presented in Figure 5-6 and the associated data are included in the 

project database. 

Figure 5-6. Offshore Support Vessel In-Port Activity 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-9 

At-Sea – Offshore Support Vessels

Offshore support vessel activity while at sea was estimated by apportioning the regional offshore 

support vessel at-sea hours of operation to lease blocks based on the number of active offshore 

oil platforms operating in a given lease block. The offshore oil platform data were obtained from 

the MMS. 

The following equation was used for this allocation approach: 

OSaskr = HOosas × OPk / OPr

Where: 

OSask = Estimate of 2005 activity for offshore support vessels at sea for lease 

 block k in region r(hp-hrs/year) 

HOosas = National 2005 estimate of at-sea hours of operation for offshore 

 support vessels (hp-hrs/year) 

OPk = Number of active offshore oil platforms operating in 

 lease block k in 2005 for region r 

OPr = Total number of active offshore oil platforms operating in region r for 

 2005 

k = At-sea lease block or county area k 

r = Region (Gulf of Mexico, California, Alaska) 

Results of this approach are presented in Figure 5-7 and the associated data are included in the 

project database. 

Figure 5-7. Offshore Support Vessel At-Sea Activity 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-10 

5.1.4 Ferries 

Ferry activity for both in-port and at-sea were assigned to the county in which the ferry provides 

services which was defined by the vessel’s home port. The ferry boat population was obtained 

from Bureau of Transportations National Ferry Database and the American Public 

Transportation Association. Thirty-four (34) ports were identified that provide services using 

Category 2 propelled vessels and are listed in Table 5-2. County FIPS codes were matched to 

each county and retained in the project database. Ferry activity was apportioned to individual 

counties by developing an average hours of operation and applying those hours to each vessel 

using the following equation: 

AF = HOf / FP 

Where: 

AF = Average activity per ferry for 2004 (hp-hrs/year-vessel) 

HOf = National 2004 estimate of in-port and at-sea hours of operation for 

 ferries (hp-hrs/year) 

FP = National ferry population for 2004 

Table 5-2. List of Ferry Ports 

Alameda, CA Orient Point, NY 

Balboa, CA Port Clinton, OH 

Bellevue, WA Port Jefferson, NY 

Charlottetown, ME Portland, ME 

Chatham, Ontario, Canada Port Townsend, WA 

Columbus, OH Provincetown, MA 

Freeland, WA Riviera, FL 

Galveston, TX Salt Lake City, UT 

Highlands, NJ San Francisco, CA 

Hyannis, MA San Juan, PR 

Juneau, AK San Pedro, CA 

Larkspur, CA Seattle, WA 

Little Falls, NJ Staten Island, NY 

Ludington, MI Surry, VA 

Mackinac Island, MI Vallejo, CA 

New London, CT Wilmington, DE 

Newburyport, MA Woods Hole, MA 

The average annual activity was applied to each vessel. The estimated activity levels of multiple 

ferries that service a port were summed to get a port total. Similarly, multiple ports within the 

same county were summed to get a county total of Category 2 ferry activity. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-11 

Some larger ferries travel outside of the home port area or to adjacent counties, thus the activity 

estimates for a given county may be overestimated. Results of this approach are presented in 

Figure 5-8 and the associated data are included in the project database. 

Figure 5-8. Ferry In-Port and At-Sea Activity 

5.1.5 Deep Water Vessels 

In-Port – Deep Water Vessels

Deep water vessel activity in the port area was estimated by developing average vessel in-port 

hours of operation for a port call. The U.S. Maritime Administration (MARAD) 2005 entrance 

and clearance data were used to quantify the number of calls to each port for each vessel 

identified as being equipped with Category 2 engines. The average in-port hours of operation 

were applied to the number of Category 2 vessel calls to estimate deep water vessel in-port 

activity for each of the 80 deep water ports. The 80 deep water ports are located in 78 counties 

that were identified as having Category 2 traffic. 

The following equation was used for this deep water allocation approach: 

DWipa = ∑(HOdwipn / VCn) ×VCaq

Where: 

DWipa = Estimate of 2005 activity for deep water vessels for port a (hp- 

 hrs/year) 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-12 

HOdwipn = National estimate of 2005 in-port hours of operation for deep water 

 vessels (hp-hrs/year) 

VCn = National number of vessel calls to all ports in 2005 

VCaq = Number of vessel calls for vessel q at port a in 2005 

q = Specific vessel equipped with category 2 engines 

a = Port a 

The county was identified for each port where deep water vessels comply with U.S. entrance and 

clearance requirements. County FIPS codes were matched to each county and retained in the 

project database. In-port maneuvering times vary significantly between ports and type of cargo 

being handled, thus actual hours of operation for a specific port may be higher or lower than the 

average value used in this assessment. Results of this approach are presented in Figure 5-9 and 

the associated data are included in the project database. 

At-Sea – Deep Water Vessels

Deep water vessel activity while at sea was estimated by apportioning the national deep water 

vessel at-sea hours of operation to individual shipping lanes based on the amount of cargo traffic 

associated with the shipping lane segment. The shipping lane GIS data were obtained from the 

Department of Transportation and the cargo traffic data were obtained from the U. S. Army 

Corps of Engineers. 

Figure 5-9. Deep Water Vessel In-Port Activity 

The following equation was used to allocate deep water at-sea activity to individual shipping 

lanes: 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-13 

DWasi = HOdwas × CTi / CTn

Where: 

DWasi = 2005 estimate of activity for deep water vessels for at-sea shipping lane 

segment i (hp-hrs/year) 

HOdwas = National 2005 estimate of at-sea hours of operation for deep water 

 vessels (hp-hrs/year) 

CTi = Amount of 2005 cargo traffic for at-sea shipping lane segment i (tons) 

CTn = Amount of cargo traffic for all at-sea shipping lanes for 2005 (tons) 

i = At-sea shipping lane segment i 

Results of this approach are presented in Figure 5-10 and the associated data are included 

in the project database. It should be noted that some counties, specifically in the Great Lakes, 

have relatively large areas of water that include a larger number of shipping lanes compared with 

coastal areas where state waters only extend from 3-7 miles. 

Figure 5-10. Deep Water Vessel At-Sea Activity 

5.1.6 Research Vessels 

In-port – Research

Research vessel activity in the port area was estimated by apportioning the national research 

vessel in-port hours of operation to individual ports based on the ports that research vessels visit. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-14 

The research vessel port data was obtained from the University National Oceanographic 

Laboratory System (UNOLS). This system identified 12 ports that research vessels frequent. 

Note that the available port data were project specific and the number of port calls was not 

directly quantified; thus, if a vessel had a project that extended over a long period of time, the 

port was identified, but not the number of visits. If a vessel had a different project every time it 

left the port, each port call would be identified. Also note that the UNOLS research vessel port 

data did not seem to be complete. Because alternative data were not readily available and 

because research vessels represent a small portion of the fleet of vessels equipped with 

Category 2 engines, the UNOLS data was used to estimate in-port hours of operation, despite its 

limitations. 

The following equation was used for this allocation approach: 

RVipa = (HOrvipn / RVn) *VCa

Where: 

RVipa = Estimate of 2004 in-port activity for research vessels for port a (hp- 

 hrs/year) 

HOrvipn = National estimate of 2004 in-port hours of operation for research 

 vessels (hp-hrs/year) 

RVn = Total number of research vessels operating in 2004 

VCa = Number of vessel that visit port a in 2004 

a = Port a 

The county was identified for each port from which research vessels operate. County FIPS codes 

were matched to each county and retained in the project database. Results of this approach are 

presented in Figure 5-11 and the associated data are included in the project database. 

Figure 5-11. Research Vessel In-Port Activity 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-15 

At-Sea – Research

Research vessel activity while at sea was estimated by apportioning the national research vessel 

at-sea hours of operation to broad study areas based on the surface area of the study district. The 

research vessel study area data were obtained from UNOLS. 

The following equation was used for this allocation approach: 

RVasl = HOrvas × CTp / CTn

Where: 

RVasl = Estimate of 2004 research vessel activity at sea for research area l 

 (hp-hrs/year) 

HOrvas = National estimate of 2004 at-sea hours of operation for research 

 vessels (hp-hrs/year) 

CTp = Surface area of study districts p (square kilometers) 

CTn = Total area of all study districts (square kilometers) 

p = At-sea research study area l. 

Results of this approach are presented in Figure 5-12 and the associated data are included in the 

project database. 

Figure 5-12. Research Vessel At-Sea Activity 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-16 

5.1.7 Great Lakes and Other Vessels 

In-port – Great Lakes and Other Vessels

Great Lake and other vessel activity in the port area was estimated by apportioning the national 

Great Lake in-port hours of operation to individual ports based on the amount of cargo handled 

at the designated Great Lake ports. The U.S. Army Corps of Engineers provided cargo handling 

data for 35 ports on the Great Lakes. 

The following equation was used for this allocation approach: 

GLipa = HOglip × CHa / CHn

Where: 

GLipa = Estimate of 2004 activity for Great Lake vessels for port a (hp- 

 hrs/year) 

HOglip = National estimate of 2004 n-port hours of operation for Great Lake 

 vessels (hp-hrs/year) 

CHa = Amount of cargo handled at port a in 2004 (tons) 

CHn = Amount of cargo handled at all Great Lake ports in 2004 (tons) 

a = Port a 

The county was identified for each Great Lake port included in this study. County FIPS codes 

were matched to each county and retained in the project database. Note that even though the tugs 

and towboat in-port activity data overlap with the Great Lake vessel data, there is no double 

counting of activity as duplicate tug/towboats and Great Lake vessels were identified and 

removed. Results of this approach are presented in Figure 5-13 and the associated data are 

included in the project database. 

At-Sea – Great Lakes and Other Vessels 

Great Lake vessel activity while at sea was estimated by apportioning the national Great Lake atsea hours of operation to individual shipping lanes in the Great Lakes based on the amount of 

cargo traffic associated with the shipping lane segment. The shipping lane GIS data were 

obtained from the Department of Transportation and the cargo traffic data were obtained from 

the U. S. Army Corps of Engineers. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-17 

Figure 5-13. Great Lake and Other Vessel In-Port Activity 

The following equation was used for this allocation approach: 

GLasi = HOglas × CTi / CTn

Where: 

GLasi = Estimate of 2004 activity for Great Lakes vessels for at sea shipping 

 lane segment i (hp-hrs/year) 

HOglas = National estimate of 2004 at-sea hours of operation for Great Lake 

 Vessels (hp-hrs/year) 

CTi = Amount of cargo traffic for at-sea shipping lane segment i in the 

 Great Lakes for 2005 (tons) 

CTn = Amount of cargo traffic for all at-sea shipping lanes for 2005 in the 

 Great Lakes (tons) 

i = At-sea shipping lane segment i in the Great Lakes. 

Results of this approach are presented in Figure 5-14 and the associated data are included in the 

project database. Note that some counties that have relatively large areas of water include a 

larger number of shipping lanes than counties with smaller areas of water. Also note in the U.S. 

Army Corps of Engineer’s shipping lane data, vessel activity is not quantified for shipping lanes 

in Canadian waters, specifically vessels travel through the Saint Lawrence Seaway; such that, 

there are counties in New York that are adjacent to Lake Eire, Lake Ontario, and the Saint 

Lawrence River that do not have marine vessel activities as ship traffic is shifted to Canadian 

waters. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-18 

5.1.8 Government Vessels 

In-Port – Government Vessels

Coast Guard activity in the port area was estimated by apportioning the national Coast Guard inport hours of operation to individual ports based on each vessel’s home port of call. The home 

port for each Category 2 Coast Guard vessel was obtained from the Coast Guard Web site. 

Eighty-three (83) ports were identified as having Category 2 Coast Guard vessels. Note that a 

home port was not identified for 10 percent of the Category 2 Coast Guard vessels. Activity from 

these ports was allocated equally to the other home ports where Coast Guard vessels operate. 

Figure 5-14. Great Lakes and Other Vessel At-Sea Activity 

The following equation was used for this allocation approach: 

CGipa = (HOcgipn / CGn) ×CGa 

Where: 

CGipa = Estimate of 2005 activity for Coast Guard vessels for port a (hp- 

 hrs/year) 

HOcgipn = National estimate of 2005 in-port hours of operation for Coast Guard 

 vessels (hp-hrs/year) 

CGn = Total national Category 2 Coast Guard Vessels operating in 2005 

CGa = Number of Coast Guard vessels associated in port a 

a = Port a 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-19 

This average in-port estimate of activity was applied to each Category 2 Coast Guard vessel’s 

home port. The county was identified for each Coast Guard home port included in this study. 

County FIPS codes were matched to each county and retained in the project database. Coast 

Guard vessels sometimes visit multiple ports in a district; thus in-port activity may be 

overestimated for the home port and underestimated for other ports that these vessels visit. More 

detailed data on Coast Guard vessel activities were not readily available due to security concerns. 

Results of this approach are presented in Figure 5-15 and the associated data are included in the 

project database. 

Figure 5-15. Coast Guard In-Port Activity 

At-Sea – Government Vessels

Category 2 U.S. Coast Guard vessel activity while at sea was estimated by apportioning the 

national Coast Guard at-sea hours of operation to individual districts based on the water surface 

area of each district. Currently, there are nine U.S. Coast Guard districts, District 1 includes 

waters from Maine to New Jersey, the 5th District includes the mid-Atlantic states, the 7th District 

includes the southeastern states, the 8th District includes the Gulf of Mexico and the Mississippi 

River Basin, the 9th District includes the Great Lakes, the 11th District includes California, while 

the 13th District contains the Pacific Northwest, the 14th District is Hawaii, and the 17th District is 

Alaska. Information about vessels assignments to each district and the geographic area of each 

district was obtained from Coast Guard Web sites. 

The following equation was used for this allocation approach: 

CGasd = HOcgas × SAd / SAn
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-20 

Where: 

CGasd = Estimate of 2005 activity for Coast Guard Vessels while at sea for 

 District D (hp-hrs/year) 

HOcgas = National estimate of 2005 at-sea hours of operation for Coast Guard 

 Vessels (hp-hrs/year) 

SAd = Surface area of Coast Guard district d (square kilometers) 

SAn = Total surface area of all Coast Guard Districts (square kilometers) 

d = District d 

Some of the districts are very large and it is likely that vessels do not transit the whole district. 

Vessels may actually spend slightly more time closer to shore, thus deep water activity may be 

overestimated and coastal activity may be underestimated using this approach. More detailed 

data on Coast Guard vessel activities were not readily available due to security concerns. Results 

of this approach are presented in Figure 5-16 and the associated data are included in the project 

database. 

Figure 5-16. Coast Guard At-Sea Activity 

5.2 Summary 

The county waterway boundary file was developed based on Census Department county and 

state maps. County boundaries were extended perpendicular to the coast out to the state water 

boundary. Where adjacent counties shared an inland waterway, the boundary was considered to 

be at mid-stream running parallel to the shore. If the shared boundary was in a larger body of 

water such as a bay, the area was split between the two counties based on the amount of shore 

associated with each county. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-21 

To disaggregate federal waters into smaller grids, the Department of Interior’s Mineral 

Management Services’ lease blocks were used. The MMS lease block shape file is readily 

available from MMS’s Web site. Lease blocks are located in all U.S. coastal waters, regardless 

of whether or not there are active oil and gas activities occurring in the area. Lease blocks extend 

from the state waters boundary to 200 miles out to sea. The areas around Hawaii and U.S. 

protectorates such as Puerto Rico and the U.S. Virgin Islands do not have lease blocks. 

This approach using MMS lease blocks in conjunction with state county boundary data matched 

up well for all states except Alaska, where a slight gap between federal and state boundaries. The 

gap was noticeable, but not considered significant. 

The spatial allocations discussed in Section 2 were developed as GIS shape files and the 

state/county and lease block boundary files were applied to them. Activity within a county or 

lease block boundary was summed by vessel type and activity. Each county/lease block has a 

unique identifier; for counties, the county identifier is the associated county FIPS code. 

Vessel activity data were linked by the unique county/lease block code in the GIS metafile. Such 

that some county blocks include port and underway activities for each of the vessel types 

included in this study. Lease blocks are in Federal waters and tend to include only at-sea 

activities. 

Summary results from combining all of the Category 2 vessel type data are presented in the 

following maps. Figure 5-17 shows combined port activities for all vessel types. 

Figure 5-17. Combine Category 2 In-Port Activities 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-22 

Figure 5-18 shows combined at-sea activities for all vessel types. Again, the Great Lakes appear 

elevated due to the size of the county waters in comparison to coastal state and federal lease 

blocks which represent significantly smaller ones. 

Figure 5-18. Combined Category 2 At-Sea Activities 

Figure 5-19 shows what the Category 2 vessel activity looks like when in-port and at-sea 

activities are combined. 

Figure 5-19. Combined In-Port and At-Sea Activities for Category 2 Vessels 
0203.02.002.001\Category 2 Vessel Census-Activity Report 5-23 

5.3 References 

U.S. Maritime Administration (MARAD), Office of Data and Economic Analysis, Vessel 

Movement 2005 Database. July 2006. 

National Oceanic and Atmospheric Administration, National Marine Fisheries Service, National 

Annual Commercial Landings by Group. Downloaded June 2006 

http://www.st.nmfs.gov/st1/commercial/landings/gc_runc.html

National Oceanic and Atmospheric Administration, National Marine Fisheries Service, 2004 

United States Commercial Landings. 2006. 

U.S. Army Corps of Engineers / Waterborne Statistics Division, Vessel Clearance and Entrance 

Data. New Orleans, LA. 2004. 

U.S. Army Corps of Engineers, Navigation Data Center, Waterway Network Link Commodity 

Data. Downloaded September 2006. 

U.S. Coast Guard official Web site. Downloaded August 2006; 

www.uscg.mil/datasheet/dataindx.htm

U.S. Department of Census, GIS maps Downloaded June 2006; 

http://www.census.gov/geo/www/cob/cs2000.html

U.S. Department of Interior, Mineral Management Services, Digital Geographic Mapping Data.

downloaded September 2006.

http://www.gomr.mms.gov/homepg/pubinfo/repcat/arcinfo/index.html

U.S. Department of Transportation, Bureau of Transportation Statistics, National Ferry 

Database. 2000. 

University National Oceanographic Laboratory System Web site. Downloaded May 2006. 

www.unols.org/info/vessels.htm
0203.02.002.001\Category 2 Vessel Census-Activity Report 6-1 

6.0 CATEGORY 2 VESSEL DATABASE 

To organize the compiled data it was necessary to merge the data into a single database. This 

data merge was challenging because the different vessel types had different data sources that 

included different data fields in different formats. The data were reviewed to see how all the 

fields could be aggregated into common field names. In the end the data were compiled into a 

database containing 28 fields. It was important to retain any data fields dealing with 

identification of the vessels, the vessel characteristics, the engine identification, and the engine 

characteristics. 

6.1 Data Matching

Table 6-1 shows how the different data sources were matched into the aggregated database. It 

should also be noted that not all the data fields were populated, this generally indicates that the 

data source used to quantify the Category 2 vessels population did not compile all of the same 

data elements. Those fields that were not filled are denoted with NA’s in Table 6-1. 

The group type field was populated to mirror the vessel types discussed in Section 2 of this 

report. This field included the following vessel types codes: “fishing,” “ferry,” “deepwater,” 

“offshore,” “research,” “tug,” “US CG,” or “Great Lakes and others.” 

Data elements from the individual vessel type databases were occasionally in different units. 

These units had to be converted so that they were reported consistently in the aggregated 

database. This occurred for length, draft, and breadth. Most sources were in feet. However, ocean 

going vessels were in meters. Therefore, ocean going vessels were converted to be consistent 

with the other data sources. 

It should be noted that data gaps for individual vessels that existed in the individual database 

were carried over into the aggregated database. One example is Great Lakes Vessels did not have 

the displacement filled in for all of its entries. And in another case, U.S. Coast Guard vessels had 

gross tons as one of their data fields, but it was blank for all of its entries. As in the Coast Guard 

example, the data fields or entries that were blank were retained in the aggregated database to 

maintain consistency in the database structure. 
6-2

Table 6-1. Mapping of Database Field Names by Vessel Type 

Aggregated Towboats Offshore 

Comm ercial 

Fishing US CG Ferry Deepwater R

Eng Cat Category Category Eng Cat Eng Cat Eng Cat Revised Category Group Type "Tug" Offshore "Fishing" "US CG" "Ferry" "Ocean Going" "RVessel ID NA NA Vessel ID Vessel ID Vessel ID NA CG Number USACE_CG_No CG Number CG Number CG_Number USCGNumber NA IMO Number NA IMO Number IMO Number IMO_Number NA IMO Call Sign NA Call Sign NA NA CallsignCG Call Sign CVessel Name VS Name Name Vessel Name Vessel Name Vessel Name Ship Name SVessel Type Job Type 2 Vessel Type Vessel Type NA ShipType HP HP NA HP HP HorsePowerCG NA EnTotal Kw NA Total Kw NA NA NA Total Power Length (ft) NA NA Length Length RegisteredLengthCG Length Fuel Type NA Fuel NA NA NA Revised Fuel Propulsion Type NA NA Propulsion Propulsion NA Propulsion Type Gross Ton NT NA Gross Ton Gross Tons RegisteredGrossTonsCG Deadweight GBuild MY NA NA NA NA Date of Build YEngine Number Engine NA NA Notes NA Mains EngEngine Make NA Engine Builder NA NA NA Engine Builder EnEngine Model Model Engine Designation NA NA NA 

Engine 

Designation Eng

State NA NA Port State Port State State NM NA Port NA NA Port Name Port Name City NA Area Area NA Region NA NA Flag Speed (kph) NA NA NA NA Speed Typical Speed SpNotes Hull NA Comment Notes NA NA Source Data NA NA NA NA NA Displacement NA Displace NA NA Displace Draft (ft) NA NA RegisteredDepthCG Draft Draft NA Breadth (ft) NA NA RegisteredBreadthCG NA Beam NA 
0203.02.002.001\Category 2 Vessel Census-Activity Report 6-3 

6.2 Data Augmentation and Assurance 

Once all of the data sources were compiled into one database, the data were checked for quality 

assurance. In checking the database, certain data were also augmented to fill in blanks, when 

possible. It should also be noted that at this point, the data had already been checked by the 

people who obtained and formatted the data and reviewed by the project manager. 

The quality assurance at this stage dealt mostly with checking for duplicates in the database. 

Vessels from one vessel type may overlap with vessels from another, but this might not be 

apparent until all of the data are merged. For example, tugs or fishing vessels may be ocean 

going tugs or ocean going fishing vessels and be included in both the tug or fishing vessel 

database and ocean going vessel database. Duplicates were matched based on the identification 

data, which included Vessel ID, CG Number, IMO Number, Call Sign, and Vessel Name. 

Identified duplicates were double checked to make sure they were in fact duplicates. Duplicates 

were confirmed by checking other data fields to see if the vessels were actually the same. The 

other fields usually included the engine characteristics and/or the engine make and model. 

Vessels sometimes had Coast Guard identification numbers, IMO numbers, or Call Signs. These 

identification numbers are unique and useful in flagging duplicates. But, there were also other 

vessel identification numbers provided by the reference which were not necessarily unique and 

sometimes conflicted with other data sources, therefore these vessels IDs could not be used to 

identify duplicates. Where the same name is attributed to a vessel also did not necessarily 

indicate a duplicate. When it was unclear if the matches were actually the same vessel, the 

entries were kept. Whereas, matches between the IMO number, the CG Number, and the Call 

Signs were actually duplicates. 

When duplicates were found the data fields were merged to ensure that the retained data 

contained was as complete as possible. At this point the duplicate entry was deleted. For 

example, in most cases the ocean going vessels had more vessel and engine characteristics than 

the other datasets so those entries were retained, but some of the duplicate data included 

geographic information, so these data elements were first appended to the ocean going data 

before being deleted. 

Once all of the duplicates were removed, the rest of the data were cleaned up so the data could be 

easily grouped and summarized. For example port names like Boston and Boston, MA were 

changed to Boston. The state names were changed into their abbreviations for consistency. When 

the area field was empty, it was filled in with appropriate data for the state and port where the 

vessel operated. States on the East coast were identified as Atlantic, the West coast states were 

identified as Pacific, Gulf states were identified as Gulf, Great Lake states were identified as 

Great Lakes, and depending on which side of Florida vessels were identified as being based, they 

were either flagged as Atlantic (east coast of Florida) or Gulf (west coast of Florida). 

Finally the data were checked to make sure that only commercial Category two domestic vessels 

were included in the compiled database. Other vessels, like yachts, foreign vessels, or Category 1 

vessels, were deleted. 
0203.02.002.001\Category 2 Vessel Census-Activity Report 6-4 

As noted above, not all of the data fields were filled in. The quality of the database could be 

improved significantly if more time and resources were made available to implement a formal 

survey of the vessel owners for the missing information. 

6.3 Compiled Database Structure 

The Category2Activiy_FINAL database is comprised of 17 separate tables. 

There are two tables, one for port activity and one for sea (underway) activity for the each of the 

8 different vessel types, in the final project database. The 8 vessel types are: deepwater vessels, 

ferries, fishing vessels, government vessels, Great Lake vessels, offshore vessels, research 

vessels, and tugs. All 16 of these tables have the same format and have the same naming 

convention, Vessel Type_Operating Area. There are only two fields for these tables: BLOCKID 

and Activity. The BLOCKID links to the BLOCKID used in the GIS files. The activity field is 

the total hp-hr for that BLOCKID and vessel type. 

The final table is a summary table called ALL Activity Summary Table, which has 7 fields: 

Type, In Port %, At Sea %, Port Activity, Sea Activity, and Total Activity. Type is the vessel 

type. In Port % and At Sea % are the percent time the vessel type operates in port or at sea. The 

percent adds up to 100% in all cases and the port activity and sea activity are derived on the 

percentages. The activity data are all in hp-hrs. 
Appendix A. Identified Category 2 Marine Diesel Engines 
A-1 

Appendix A. Identified Category 2 Marine Diesel Engines 

(U.S. and Foreign Manufacturers) 

Engine Model Bore Stroke Displace Cylinders RPM kW 

1026MTBF-40 260 400 21.2 10 600.0 1820.5 

1038D8-1/8 207 254 8.5 10 814.0 1293.7 

1038TD-1/8 207 254 8.5 10 1854.0 

10ASL25D s 250 300 14.7 10 883.3 1632.8 

10DNL120/500 190 350 9.9 10 500.0 772.0 

10DNL150 s 190 350 9.9 10 898.3 

10DNL170/600 190 350 9.9 10 1103.0 

10DNL190/600 190 350 9.9 10 1398.0 

10RUB215 215 260 9.4 10 735.5 

10RVB215 215 260 9.4 10 1033.5 

10T23 s 225 300 11.9 10 804.5 971.2 

10V28 s 280 360 22.2 10 625.7 3497.0 

10V29 s 225 300 11.9 10 919.0 

10VDNL150/600 190 350 9.9 10 1103.0 

10VDNL190/600 190 350 9.9 10 1398.0 

1226MTB s 260 400 21.2 12 600.0 1506.4 

12278 s 220 267 10.2 12 893.0 

1238D8-1/8 207 254 8.5 12 800.0 1487.6 

1238TD-1/8 207 254 8.5 12 750.0 2158.0 

12567-BC 216 254 9.3 12 825.0 846.2 

12645 s 230 254 10.6 12 883.3 1258.1 

12ASV25/30 250 300 14.7 12 958.3 1988.7 

12ATCM 318 368 29.2 12 2276.3 

12CHSP18/20 180 200 5.1 12 772.5 

12CSVM 254 305 15.5 12 1398.0 

12DRN23/30 230 300 12.5 12 750.0 1573.3 

12DRPN23/30 230 300 12.5 12 2115.5 

12DVDA 200 260 8.2 12 441.0 

12GV s 220 380 14.4 12 381.3 905.6 

12M282AK 240 280 12.7 12 1000.0 2163.3 

12MB275 275 305 18.1 12 2869.5 

12MGV28BX 280 320 19.7 12 2207.0 

12NVD18/21A3 180 210 5.3 12 1500.0 1176.0 

12PA4V185VG 185 210 5.6 12 1340.0 1075.5 

12PA4V200 s 200 210 6.6 12 1466.7 1919.5 

12PA6V280 280 290 17.9 12 1033.3 2794.9 

12PBVCS12F 241 305 13.9 12 1519.0 

12PSN s 260 280 14.9 12 825.0 1645.4 

12PVBCS12 s 242 305 14.0 12 750.0 1280.5 

12RK s 254 305 15.5 12 900.0 1664.0 

12RVB215 215 260 9.4 12 950.0 1097.4 

12SW280 280 300 18.5 12 1000.0 3089.3 

12TD200 220 380 14.4 12 1553.8 

12U28L s 280 320 19.7 12 775.0 2192.7 
A-2 

Engine Model Bore Stroke Displace Cylinders RPM kW 

12UEV30/40C 300 400 28.3 12 2648.0 

12V1163TB62 230 280 11.6 12 2207.0 

12V190ZC 190 210 6.0 12 900.0 

12V20/27 200 270 8.5 12 975.0 1133.0 

12V200 200 240 7.5 12 1400.0 2126.7 

12V22 s 220 240 9.1 12 923.3 1615.4 

12V23 s 225 300 11.9 12 757.7 1339.9 

12V25 s 234 275.426 11.9 12 906.8 1729.6 

12V27 275 320 19.0 12 1688.3 

12V28 s 280 326.452 20.1 12 713.4 2685.7 

12V32 s 320 350.159 28.2 12 739.1 4346.3 

12V538TB82 185 200 5.4 12 670.0 1284.5 

12V645 s 230 254 10.6 12 900.0 1103.0 

12V652TB s 190 230 6.5 12 1410.0 1142.6 

12VDL75/475 190 350 9.9 12 662.0 

12VDNL s 190 350 9.9 12 600.0 1457.0 

12VP185 185 196 5.3 12 1892.5 2209.3 

12VSHTB26D 260 320 17.0 12 956.0 

12YJCM 197 216 6.6 12 716.5 

12YLCM 248 267 12.9 12 75.0 1083.7 

12ZLST 280 340 20.9 12 2354.0 

1426MTBF-40V 260 400 21.2 14 600.0 1863.7 

14T23LVO 225 300 11.9 14 1390.0 

14U28LVO 280 320 19.7 14 775.0 2728.5 

14V s 200 270 8.5 14 610.0 1400.5 

14V23 s 225 300 11.9 14 811.7 1498.1 

14V28/32 280 320 19.7 14 2729.0 

14VDNL150/600 190 350 9.9 14 1996.3 

1626MTBF-40V 260 400 21.2 16 2118.0 

16278 s 222 267 10.3 16 1187.1 

16567 s 216 254 9.3 16 803.3 1261.6 

16645 s 230 254 10.6 16 855.1 1681.1 

16710-G7 230 279 11.6 16 900.0 3089.3 

16ASV25/30 250 300 14.7 16 745.7 2904.3 

16ATV25D 250 300 14.7 16 750.0 1589.0 

16CSVM 254 305 15.5 16 2501.0 

16DPN23/30 230 300 12.5 16 3310.0 

16GV s 220 380 14.4 16 362.5 1157.3 

16MB275 275 305 18.1 16 900.0 4104.0 

16MGV28BXE 280 320 19.7 16 2942.0 

16PA4 s 192 210 6.1 16 1432.1 2180.3 

16PA5V 255 270 13.8 16 900.0 2574.0 

16PA6V280 280 290 17.9 16 1016.7 4162.6 

16PSN3 260 280 14.9 16 2207.0 

16PVBCS12F 242 305 14.0 16 750.0 2057.1 

16RK s 260 305 16.2 16 853.5 3063.4 

16RP200 197 216 6.6 16 2176.0 
A-3 

Engine Model Bore Stroke Displace Cylinders RPM kW 

16SW280 280 300 18.5 16 4644.3 

16T23LVO 225 300 11.9 16 825.0 1824.0 

16TD200 220 380 14.4 16 2354.0 

16U28LVO 280 320 19.7 16 775.0 2973.2 

16V1163 s 230 280 11.6 16 3823.5 

16V190ATC 190 230 6.5 16 1450.0 1931.0 

16V22 s 220 240 9.1 16 948.3 2290.4 

16V23 s 225 300 11.9 16 741.0 1646.4 

16V25 s 234 274.8 11.8 16 932.1 2244.3 

16V27 s 275 320 19.0 16 2930.0 

16V28 s 280 320 19.7 16 747.5 3359.0 

16V32 s 320 350 28.1 16 730.0 5368.2 

16V358TB82 185 200 5.4 16 1710.0 1415.5 

16V538TB91 185 200 5.4 16 1790.0 1986.0 

16V595TE70 190 210 6.0 16 1800.0 3565.0 

16V652TB s 190 230 6.5 16 1425.0 1589.4 

16VBCS12F 242 305 14.0 16 2060.0 

16VDNL150/600 190 350 9.9 16 1765.0 

16Y s 231 250 10.8 16 1627.7 

18PA6V280 280 290 17.9 18 4413.0 

18RP2002 197 216 6.6 18 1550.0 3020.0 

18V20/27 200 270 8.5 18 1800.0 

18V200 200 240 7.5 18 3600.0 

18V23 s 225 300 12.0 18 795.8 1975.1 

18V251F 229 267 11.0 18 1066.7 2879.6 

18V32 320 350 28.1 18 720.0 6695.8 

18VDNL150/600 190 350 9.9 18 2096.5 

194MARS 190 240 6.8 4 1000.0 199.0 

195V12 s 195 180 5.4 12 1397.5 1314.8 

195V16RVR 195 180 5.4 16 1600.0 2689.0 

196/RS 190 240 6.8 6 375.0 

20645 s 230 254 10.6 20 900.0 2587.3 

20RK270 270 305 17.5 20 1018.8 6818.6 

20V1163TB s 230 280 11.6 20 1238.9 6541.5 

240G12VS 240 220 10.0 12 1442.0 

240G16VS 240 220 10.0 16 1673.3 

240G20VS 240 220 10.0 20 2901.5 

240G8LS 240 220 10.0 8 1029.7 

240V16ESHR 240 220 10.0 16 2501.5 

240V20ESHR 240 220 10.0 20 3531.0 

27DH42 270 420 24.0 6 662.0 

2M32 210 320 11.1 2 450.0 44.0 

3427 s 270 400 22.9 3 425.0 202.7 

342FO 200 340 10.7 2 450.0 146.0 

343 s 200 340 10.7 3 450.0 102.3 

344 s 200 340 10.7 4 410.8 154.8 

3606 s 280 300 18.5 6 922.2 1700.5 
A-4 

Engine Model Bore Stroke Displace Cylinders RPM kW 

3608 s 280 300 18.5 8 940.0 2119.8 

3612 s 280 300 18.5 12 966.3 6176.0 

3616 s 280 300 18.5 16 905.2 4683.1 

3ACA s 280 420 25.9 3 300.0 285.4 

3DCT 200 300 9.4 3 147.0 

3M421 280 420 25.9 3 121.0 

3TC(TL) 240 360 16.3 3 110.0 

3VCBM 203 273 8.8 3 75.0 

40224VO 240 400 18.1 2 375.0 93.5 

403VO 230 400 16.6 3 375.0 143.0 

404 s 230 400 16.6 4 376.3 197.8 

40424VO 240 400 18.1 4 375.0 203.9 

40426VO 260 400 21.2 4 268.5 

405 s 230 400 16.6 5 375.0 236.0 

40524VO 240 400 18.1 5 375.0 256.8 

40526VO 260 400 21.2 5 400.0 353.4 

40624VO 240 400 18.1 6 380.0 307.0 

40626VO 260 400 21.2 6 403.3 443.8 

406VO 230 400 16.6 6 383.3 257.7 

40724VO 240 400 18.1 7 375.0 406.0 

40726VO 260 400 21.2 7 413.0 532.0 

40824VO 240 400 18.1 8 370.0 434.0 

40826VO 260 400 21.2 8 406.5 536.0 

40926VO 260 400 21.2 9 400.0 735.8 

40MX-8 232 267 11.3 8 736.0 

40S2X-8 232 267 11.3 8 655.0 

414T 240 310 14.0 4 301.0 

422VF-37 220 370 14.1 4 221.0 

424TS 240 310 14.0 4 441.0 

438D8-1/8 207 254 8.5 4 477.3 

4427-DO s 270 400 22.9 4 425.0 264.7 

4ACA 280 420 25.9 4 337.5 330.9 

4CK 270 340 19.5 4 118.0 

4DCT 200 300 9.4 4 230.0 

4DNL190/600 190 350 9.9 4 600.0 149.0 

4ED 290 450 29.7 4 164.0 

4GB 220 380 14.4 4 350.0 165.0 

4L20 200 280 8.8 4 1300.0 

4L28A 280 360 22.2 4 600.0 1200.0 

4L50/430 190 350 9.9 4 147.0 

4M351A 240 350 15.8 4 

4M36 215 360 13.1 4 88.0 

4MS 200 280 8.8 4 88.0 

4NVD262 180 260 6.6 4 750.0 99.0 

4PSN3L 260 320 17.0 4 850.0 699.0 

4R22 s 220 250 9.5 4 720.0 576.5 

4R32 s 320 350 28.1 4 735.0 1609.3 
A-5 

Engine Model Bore Stroke Displace Cylinders RPM kW 

4R538 185 200 5.4 4 346.5 

4S275 275 360 21.4 4 500.0 191.0 

4SAC1 200 240 7.5 4 289.3 

4SGAC1 220 240 9.1 4 441.0 

4SN3 260 280 14.9 4 954.0 

4TAD24 240 400 18.1 4 309.0 

4TD24 240 400 18.1 4 221.0 

4VCBM 203 273 8.8 4 100.0 

4VD6A 280 400 24.6 4 330.0 145.0 

4ZU421 290 420 27.7 4 368.0 

524TS 240 310 14.0 5 720.0 605.0 

525MTBF-40 250 400 19.6 5 327.5 

526MTBF-40 260 400 21.2 5 607.0 

538D8-1/8 207 254 8.5 5 635.5 

5427 s 270 400 22.9 5 425.0 401.1 

5ACA 280 420 25.9 5 529.2 

5AR25 250 300 14.7 5 441.0 

5ASL25/30 250 300 14.7 5 342.0 

5D6 250 350 17.2 5 202.0 

5DL75/475 190 350 9.9 5 237.0 257.0 

5DNL s 190 350 9.9 5 533.3 533.2 

5DR210 210 300 10.4 5 302.0 

5ED 290 450 29.7 5 221.0 

5EN 260 380 20.2 5 191.0 

5GVH 220 380 14.4 5 239.0 

5L20/27 200 270 8.5 5 966.7 438.0 

5L23/30 225 300 11.9 5 825.0 612.0 

5M 200 240 7.5 5 132.0 

5S28LU 280 320 19.7 5 975.0 

5T23LKVO 225 300 11.9 5 816.7 557.7 

5VCBM 203 273 8.8 5 122.5 

5VEBCZ 260 368 19.5 5 482.0 

614TK 240 310 14.0 6 596.0 

6190ZLC 190 210 6.0 6 1000.0 275.5 

61MS28 280 400 24.6 6 400.0 552.0 

6200Z 200 225 7.1 6 950.0 343.3 

621MTBH-30 205 300 9.9 6 300.0 449.0 

6230ZC 230 300 12.5 6 736.0 

624 s 240 334 15.1 6 534.8 

6250 s 250 303.6 14.9 6 714.3 591.2 

6267 267 330 18.5 6 350.0 184.0 

626MTBF-40 260 400 21.2 6 728.0 

6275 s 275 330 19.6 6 700.0 

6278 s 221 267 10.3 6 1.0 380.5 

6300 300 380 26.9 6 453.3 473.8 

638D8-1/8 207 254 8.5 6 720.0 735.6 

6427 s 270 400 22.9 6 431.4 530.3 
A-6 

Engine Model Bore Stroke Displace Cylinders RPM kW 

6ACA s 280 420 25.9 6 375.0 517.0 

6AL s 203 243.2 7.9 6 830.0 512.6 

6AP2 s 219 273 10.3 6 623.4 

6AP3 s 203 273 8.8 6 642.3 

6AR s 260 368 19.5 6 750.0 917.1 

6ASL s 250 300 14.7 6 905.0 916.4 

6AT s 313 362.8 28.1 6 760.0 1075.1 

6BA22 220 320 12.2 6 177.0 

6BCAH22 220 320 12.2 6 600.0 327.5 

6CH25 s 250 340 16.7 6 500.0 286.5 

6CHN1A30/38 300 380 26.9 6 1100.0 

6CHN25/34 250 340 16.7 6 500.0 225.3 

6CHN30/38 300 380 26.9 6 1076.8 

6CHN31.8/33 318 330 26.2 6 740.0 736.0 

6CHNSP18 s 180 220 5.6 6 221.0 211.5 

6CHNSP2A18/22 180 220 5.6 6 750.0 232.0 

6CHRP25/34 250 340 16.7 6 500.0 230.2 

6CHSP18/22 180 220 5.6 6 141.7 

6CHSP23/30 230 300 12.5 6 349.5 

6CHSPN18/22 180 220 5.6 6 165.5 

6CHSPN2A s 180 220 5.6 6 202.8 

6CSVM 254 305 15.5 6 713.5 

6D6 250 350 17.2 6 221.0 

6D6DH 250 350 17.2 6 300.0 993.0 

6DA 200 260 8.2 6 221.0 

6DCT 200 300 9.4 6 349.5 

6DH27SS 270 420 24.0 6 390.0 533.5 

6DK20 200 300 9.4 6 950.0 846.0 

6DKM26 260 380 20.2 6 715.5 1372.7 

6DKM28 280 390 24.0 6 660.0 1504.8 

6DKM32 320 360 28.9 6 720.0 1986.0 

6DL20 200 260 8.2 6 515.0 

6DL75/475 190 350 9.9 6 309.0 

6DLM19 190 230 6.5 6 900.0 560.8 

6DLM20 s 200 260 8.2 6 900.0 558.8 

6DLM22 s 220 300 11.4 6 784.2 732.9 

6DLM24 s 240 320 14.5 6 1208.8 818.4 

6DLM26 s 260 340 18.0 6 691.2 1027.8 

6DLM28 s 280 362.3 22.3 6 654.1 1194.7 

6DM28FS 280 360 22.2 6 1250.0 

6DNL s 190 350 9.9 6 500.0 497.0 

6DRO210K 210 300 10.4 6 420.3 

6DS18 180 230 5.9 6 441.0 

6DS22 220 280 10.6 6 613.2 

6DS26 s 260 320 17.0 6 836.8 

6DS28 280 340 20.9 6 720.0 882.5 

6DSM18 s 180 230 5.9 6 374.0 
A-7 

Engine Model Bore Stroke Displace Cylinders RPM kW 

6DSM19A 190 230 6.5 6 900.0 533.5 

6DSM22 s 220 280 10.6 6 900.0 756.2 

6DSM26 s 260 318 16.9 6 736.9 876.1 

6DSM28 s 280 340 20.9 6 668.3 1178.1 

6DV26A 260 300 15.9 12 1820.0 

6DVM26 s 260 313.333 16.6 12 2010.3 

6DZC 256 310 16.0 6 851.1 1125.3 

6EF 290 450 29.7 6 284.0 

6F/SW240 240 260 11.8 6 647.3 

6F24 s 240 288.571 13.1 6 500.0 440.4 

6FAHD240 240 260 11.8 6 929.0 

6FCHD240 240 260 11.8 6 750.0 635.3 

6FDHD240 240 260 11.8 6 793.0 772.8 

6FEHD240 240 260 11.8 6 950.0 758.8 

6FFHD240 240 260 11.8 6 943.4 

6FGHD240 240 260 11.8 6 915.0 898.8 

6FHD240 s 240 260 11.8 6 898.8 858.3 

6FR24TK 240 300 13.6 6 750.0 719.3 

6GAET / 6GALET 240 290 13.1 6 820.0 919.7 

6GB 220 380 14.4 6 525.0 267.6 

6GDT 240 290 13.1 6 553.0 583.0 

6GLDT 240 290 13.1 6 740.0 625.0 

6GLET 240 290 13.1 6 858.3 

6GLHT 240 290 13.1 6 570.0 

6GLST 240 290 13.1 6 735.7 

6GLUT 240 290 13.1 6 674.3 

6GST 240 290 13.1 6 639.3 

6GUT 240 290 13.1 6 625.0 

6GV 220 380 14.4 6 320.0 290.7 

6GVH 220 380 14.4 6 375.0 523.8 

6HM1558 290 380 25.1 6 439.5 

6K28FD 280 480 29.6 6 379.0 875.0 

6L18CX 180 240 6.1 6 925.0 537.3 

6L19HX 190 260 7.4 6 736.0 

6L20 s 200 268.837 8.4 6 924.6 740.4 

6L22 s 220 272.5 10.4 6 900.8 800.0 

6L23 s 225 300 11.9 6 740.9 801.6 

6L24 s 240 400 18.1 6 400.0 398.6 

6L25 s 250 320.25 15.7 6 765.4 945.3 

6L26 260 320 17.0 6 956.7 1902.2 

6L26A s 260 391.579 20.8 6 593.3 550.0 

6L26B s 260 400 21.2 6 396.1 498.0 

6L26H s 260 312.5 16.6 6 1250.0 

6L27 s 274 347.5 20.5 6 640.4 868.8 

6L28 280 360 22.2 6 600.0 1200.0 

6L28/32 s 280 320 19.7 6 746.0 1350.9 

6L28ASH 280 430 26.5 6 390.0 566.3 
A-8 

Engine Model Bore Stroke Displace Cylinders RPM kW 

6L28B s 280 332.5 20.5 6 689.5 1309.9 

6L28HX 280 370 22.8 6 636.7 1519.5 

6L28X 280 440 27.1 6 385.0 854.1 

6L31 s 310 380 28.7 6 600.0 1209.1 

6L32 s 320 355 28.5 6 2871.0 

6L50/430 190 350 9.9 6 221.0 

6LB26 s 260 440 23.4 6 387.1 523.8 

6LDSR28K 280 360 22.2 6 750.0 883.0 

6LH26 s 260 440 23.4 6 397.0 690.6 

6LH28 s 280 460 28.2 6 353.0 811.4 

6LN28G 280 480 29.6 6 1030.0 

6LU24 s 240 410 18.5 6 395.0 514.7 

6LU26 s 260 439.42 23.3 6 382.5 653.7 

6LU28 s 280 440 27.1 6 388.8 820.2 

6LUD24 s 240 410 18.5 6 400.0 514.9 

6LUD26 s 260 440 23.4 6 393.8 728.4 

6LUK27 270 420 24.0 6 390.0 736.0 

6LUN28 s 280 480 29.6 6 361.2 916.0 

6LUS24 s 240 405 18.3 6 400.0 610.2 

6LUS28 s 280 440 27.1 6 392.5 874.7 

6M20 200 300 9.4 6 992.5 1042.7 

6M200LET 200 260 8.2 6 625.0 

6M22EGT 220 380 14.4 6 392.0 

6M23C s 230 260 10.8 6 613.2 

6M23L 230 260 10.8 6 809.5 

6M24 s 240 410 18.5 6 514.7 

6M25 255 400 20.4 6 764.1 1726.6 

6M26A s 260 460 24.4 6 364.0 642.7 

6M26B s 260 460 24.4 6 400.0 547.1 

6M26CHS 260 400 21.2 6 331.0 

6M26EGT 260 460 24.4 6 625.0 

6M26GX 260 440 23.4 6 380.0 956.0 

6M26HET 260 460 24.4 6 405.0 680.0 

6M26HS 260 400 21.2 6 385.0 417.0 

6M26K s 260 400 21.2 6 373.8 491.9 

6M26X 260 440 23.4 6 588.0 

6M26Z s 260 400 21.2 6 377.5 529.5 

6M27.5 s 275 320 19.0 6 827.3 

6M281AK 240 280 12.7 6 850.0 662.0 

6M282AK 240 280 12.7 6 840.0 701.8 

6M28A s 280 479.149 29.5 6 376.5 816.4 

6M28B s 280 479.512 29.4 6 362.6 758.7 

6M28DHS 280 440 27.1 6 625.0 

6M28GX 280 440 27.1 6 380.0 833.3 

6M28H s 280 480 29.6 6 414.5 1072.1 

6M28K s 280 440 27.1 6 380.0 685.3 

6M28X 280 440 27.1 6 380.0 846.0 
A-9 

Engine Model Bore Stroke Displace Cylinders RPM kW 

6M30 s 300 350 24.7 6 750.0 1743.0 

6M322AK 240 330 14.9 6 900.0 1200.0 

6M331AK 240 330 14.9 6 635.0 638.3 

6M332 s 240 330 14.9 6 701.8 817.7 

6MA s 200 240 7.5 6 900.0 257.3 

6MADT 200 240 7.5 6 825.0 381.0 

6MAHT 200 240 7.5 6 232.5 

6MAL s 200 240 7.5 6 905.0 384.2 

6MAUT 200 240 7.5 6 441.0 

6MB275 275 305 18.1 6 1000.0 1637.4 

6MBHTS 200 240 7.5 6 280.0 

6MD27.5 s 275 320 19.0 6 506.2 

6MD28 280 400 24.6 6 257.0 

6MDX s 242 320 14.7 6 700.0 502.7 

6MDZC 256 310 16.0 6 789.0 1040.8 

6MG18 s 180 233.333 5.9 6 925.0 525.8 

6MG19HX 190 260 7.4 6 1000.0 711.0 

6MG20 s 200 260 8.2 6 775.3 507.2 

6MG22 s 220 285.714 10.9 6 887.3 718.9 

6MG25 s 250 321.176 15.8 6 707.0 803.7 

6MG26 s 275 354.524 21.2 6 713.3 1329.2 

6MG31 s 310 380 28.7 6 601.5 1332.9 

6MG32CX 320 360 28.9 6 1214.0 

6MH20SS 200 360 11.3 6 265.0 

6MH25SSR 250 400 19.6 6 382.5 499.0 

6MHL / 6MHLUT 200 240 7.5 6 611.0 539.7 

6MHT s 200 240 7.5 6 742.5 273.1 

6ML s 200 240 7.5 6 750.0 257.5 

6MMG20HS 200 260 8.2 6 294.0 

6MMG25 s 250 320 15.7 6 938.0 

6MMG31EZ 310 380 28.7 6 1471.0 

6MT s 200 240 7.5 6 750.0 198.7 

6MU281AK 240 280 12.7 6 221.0 

6MU351A s 240 350 15.8 6 350.0 279.4 

6MUH28 280 340 20.9 6 630.0 1042.0 

6MUT 200 240 7.5 6 368.0 

6MX28 280 380 23.4 6 680.0 1498.0 

6MZ28 280 420 25.9 6 405.0 

6N18A s 180 280 7.1 6 900.0 698.5 

6N21AEN 210 290 10.0 6 800.0 

6N260 s 260 360 19.1 6 730.5 1261.9 

6N280 s 280 380 23.4 6 735.0 1511.3 

6NHLUT 200 240 7.5 6 552.0 

6NL190 190 350 9.9 6 475.0 441.0 

6NSCM 190 260 7.4 6 906.8 541.1 

6NSFZ 190 260 7.4 6 268.5 

6NVD 361U 240 360 16.3 6 
A-10 

Engine Model Bore Stroke Displace Cylinders RPM kW 

6NVD24 175 240 5.8 6 95.5 

6NVD26 s 180 260 6.6 6 778.8 255.2 

6NVD36 s 240 360 16.3 6 428.9 219.9 

6PA4L185VG 185 210 5.6 6 495.5 

6PA4V185VG 185 210 5.6 6 625.0 

6PA5 s 254 270 13.7 6 913.9 1154.3 

6PA6L s 280 290 17.9 6 925.0 1523.7 

6PBC512DX 241 305 13.9 6 633.0 

6PBCS12C 241 305 13.9 6 390.0 

6PS12F 241 305 13.9 6 397.0 

6PSHT26D 260 320 17.0 6 479.1 

6PSHT6M26DF 260 320 17.0 6 515.0 

6PSHTB s 250 310 15.6 6 313.0 528.9 

6PSHTC s 255 314.651 16.2 6 665.0 569.8 

6PSN3 s 260 297.143 15.8 6 805.0 1131.3 

6PST6M26D 260 320 17.0 6 340.0 

6PSTB s 264 324 17.8 6 720.0 555.4 

6PSTC s 235 296.364 13.3 6 800.0 435.4 

6PSTLM26DLS 260 320 17.0 6 386.5 

6R20 200 280 8.8 6 937.3 928.0 

6R22 s 220 240 9.1 6 978.3 883.4 

6R25 250 300 14.7 6 975.0 1199.2 

6R26L 260 320 17.0 6 780.0 1167.0 

6R32 s 320 350 28.1 6 724.5 2180.6 

6RK215 215 275 10.0 6 927.0 

6RK270M 270 305 17.5 6 866.7 1388.3 

6RK3CM 254 305 15.5 6 976.0 

6RKC s 254 305 15.5 6 900.0 814.5 

6RKX 254 305 15.5 6 456.0 

6S23 s 230 370 15.4 6 240.0 

6S26N s 260 410 21.8 6 400.0 493.0 

6S27.5 s 275 410 24.3 6 380.0 620.5 

6S275 s 275 372.5 22.1 6 390.3 

6S27F 270 510 29.2 6 300.0 618.0 

6S28 s 277 320 19.3 6 1013.9 

6SAC 200 240 7.5 6 900.0 552.0 

6SD26 s 260 407.5 21.6 6 400.0 448.8 

6SD27.5 s 275 410 24.3 6 669.4 

6SD27BH 270 400 22.9 6 346.0 

6SH20/26AC 200 260 8.2 6 306.7 

6SH24AC 240 280 12.7 6 221.0 

6SL28LVO 280 320 19.7 6 746.0 1079.7 

6SN s 260 280 14.9 6 850.0 930.6 

6SW240 240 260 11.8 6 580.0 

6SW28 s 280 300 18.5 6 885.6 1561.7 

6T23L s 225 300 11.9 6 800.0 603.6 

6T240 s 240 310 14.0 6 750.0 662.3 
A-11 

Engine Model Bore Stroke Displace Cylinders RPM kW 

6T260LET 260 330 17.5 6 750.0 1103.3 

6T260LST 260 330 17.5 6 720.0 956.3 

6T329 290 430 28.4 6 463.0 

6TD200 220 380 14.4 6 816.5 

6TD24 240 400 18.1 6 331.0 

6TM270 270 500 28.6 6 294.0 

6TM290 290 400 26.4 6 1103.0 

6TR240CO 241 305 13.9 6 1000.0 1103.0 

6U28 280 340 20.9 6 720.0 1839.0 

6U28AK 280 380 23.4 6 1471.0 

6UAL s 200 240 7.5 6 900.0 726.3 

6UAUT 200 240 7.5 6 900.0 498.4 

6UHLUT 200 240 7.5 6 640.0 

6UL s 200 240 7.5 6 496.5 

6UST 200 240 7.5 6 750.0 437.5 

6UUT 200 240 7.5 6 750.0 416.7 

6VCBM / 6VCRM 203 273 8.8 6 150.0 

6VD26/20A s 200 260 8.2 6 980.0 581.0 

6VD29/24A s 240 290 13.1 6 850.0 946.0 

6VD36/241 / 

6VD36/24A1 240 360 16.3 6 500.0 423.8 

6VDS24/24AL1 240 240 10.9 6 800.0 

6VDS26/20AL1 200 260 8.2 6 1000.0 441.0 

6VDS29/24AL2 240 290 13.1 6 1000.0 1050.0 

6VEBCZM 260 368 19.5 6 600.0 633.3 

6VEBXM 260 368 19.5 6 386.5 

6VJMS 255 300 15.3 6 750.0 513.0 

6VJS 255 300 15.3 6 485.5 

6Z280A s 280 360 22.2 6 720.0 1422.3 

6Z280E s 280 360 22.2 6 676.3 1268.0 

6Z280L s 280 360 22.2 6 679.4 1183.9 

6Z280ST 280 360 22.2 6 650.0 1317.8 

6Z36 s 220 360 13.7 6 176.5 

6ZDT 280 340 20.9 6 680.0 1030.0 

6ZET 280 340 20.9 6 680.0 1275.0 

6ZL s 280 340 20.9 6 680.0 1091.4 

6ZL20/24 200 240 7.5 6 419.0 

6ZST 280 340 20.9 6 1177.0 

721MTBF-30 205 300 9.9 7 350.0 548.5 

726MTBF s 260 400 21.2 7 600.0 886.4 

7AC s 280 420 25.9 7 676.8 

7ATCM 318 368 29.2 7 927.0 

7DNL120/500 190 350 9.9 7 618.0 

7DNL150/600 190 350 9.9 7 600.0 772.0 

7DNL190/600 190 350 9.9 7 600.0 908.0 

7FDM12 s 229 267 11.0 12 1839.0 

7FDM16 229 267 11.0 16 1765.3 
A-12 

Engine Model Bore Stroke Displace Cylinders RPM kW 

7FDS12A2 229 267 11.0 12 1000.0 1618.0 

7FDS16A2 229 267 11.0 16 1200.0 2832.0 

7L20/27 200 270 8.5 7 705.7 548.3 

7L28/32 s 280 320 19.7 7 769.9 1707.3 

7L32/36 320 360 28.9 7 750.0 2589.0 

7SM 250 300 14.7 7 600.0 276.0 

7T23LKVO / 

7T23LVO 225 300 11.9 7 803.3 763.3 

7V233LH 225 300 11.9 7 800.0 

7V23LVO 225 300 11.9 7 750.0 

7VEBC s 260 368 19.5 7 699.3 

7VEBXM 260 368 19.5 7 

7VHK 230 330 13.7 7 243.0 

814TK 240 310 14.0 8 750.0 794.0 

8185CU 185 260 7.0 8 1000.0 588.0 

823MTBF 225 300 11.9 8 721.0 

824TS 240 310 14.0 8 757.5 910.9 

8250 250 320 15.7 8 750.0 1030.0 

826MTBF-40 260 400 21.2 8 971.0 

8278 s 221 267 10.3 8 675.0 574.4 

8300 300 380 26.9 8 527.2 662.2 

838D8-1/8 207 254 8.5 8 1020.2 

8427-HT s 270 400 22.9 8 594.3 691.4 

8567 216 254 9.3 8 750.0 633.4 

8645 s 230 254 10.6 8 900.0 892.3 

8ACA 280 420 25.9 8 350.0 735.7 

8AL20/24 200 240 7.5 8 750.0 591.5 

8ASL25 s 250 300 14.7 8 930.0 1350.9 

8ATC s 318 368 29.2 8 600.0 1505.8 

8ATL25 s 250 300 14.7 8 1000.0 1679.5 

8BAH22 220 320 12.2 8 500.0 294.5 

8CHNP25/34 250 340 16.7 8 310.0 638.5 

8CHNRP30/38 300 380 26.9 8 515.0 

8CHNSP18/22 s 180 220 5.6 8 750.0 230.2 

8CHNSP25/34 250 340 16.7 8 885.0 

8CHNSP2A18/22 180 220 5.6 8 232.0 

8DKM28 280 390 24.0 8 660.0 1569.3 

8DKM32L 320 360 28.9 8 2427.0 

8DL75/475 190 350 9.9 8 441.0 

8DNL150/600 190 350 9.9 8 883.0 

8DNL170/600 190 350 9.9 8 1000.0 

8DNL190/600 190 350 9.9 8 

8DRO21 s 210 300 10.4 8 494.1 

8DS26 260 320 17.0 8 720.0 956.5 

8DSM26 s 260 320 17.0 8 726.0 1149.2 

8DSM28 280 340 20.9 8 720.0 1765.0 

8DV26 260 320 17.0 8 720.0 1177.0 

8DVM26 260 320 17.0 16 720.0 2391.0 
A-13 

Engine Model Bore Stroke Displace Cylinders RPM kW 

8DZC 256 310 16.0 8 1768.0 

8EF 290 450 29.7 8 320.0 419.3 

8F/SW240 240 260 11.8 8 794.5 

8FAHD240 240 260 11.8 8 908.0 

8FBHD240 240 260 11.8 8 900.0 821.0 

8FCHD240 240 260 11.8 8 805.0 

8FDHD240 240 260 11.8 8 1214.0 

8FDM240G 240 260 11.8 8 965.0 1445.0 

8FEHD240 240 260 11.8 8 1250.0 

8FGHD240 240 260 11.8 8 825.0 1247.5 

8FHD240 240 260 11.8 8 873.7 1025.2 

8GV s 220 380 14.4 8 356.7 584.1 

8H27.5 275 300 17.8 8 2104.0 

8L20 s 200 275.8 8.7 8 987.8 1016.0 

8L23/30 s 225 300 11.9 8 815.3 960.9 

8L25 s 250 314.7 15.4 8 809.0 1267.4 

8L26 260 320 17.0 8 950.0 2540.0 

8L27.5 s 275 320 19.0 8 1614.7 

8L27/38 270 380 21.8 8 800.0 2482.8 

8L28 s 280 320 19.7 8 766.5 1759.0 

8L31 s 310 380 28.7 8 600.0 1809.2 

8L32 s 320 356.7 28.7 8 3090.5 

8L50/430 190 350 9.9 8 

8M20 200 300 9.4 8 933.8 1288.1 

8M23C 230 260 10.8 8 1118.0 

8M25 255 400 20.4 8 750.0 2264.0 

8M27.5 275 320 19.0 8 680.0 

8M281AK 240 280 12.7 8 750.0 721.8 

8M282AK 240 280 12.7 8 750.0 919.5 

8M331AK 240 330 14.9 8 901.0 

8M332AK 240 330 14.9 8 835.7 1246.4 

8M332C 240 330 14.9 8 825.0 1506.7 

8MB275 275 305 18.1 8 916.7 2032.7 

8MD s 251 313.8 15.5 8 850.0 1183.0 

8MD27.5H 275 320 19.0 8 827.5 

8MG25 s 250 320 15.7 8 705.7 1083.6 

8MG28HX 280 370 22.8 8 750.0 1839.0 

8MG31 s 310 380 28.7 8 600.0 1520.8 

8N21A s 210 290 10.0 8 850.0 1152.3 

8N280EN 280 380 23.4 8 720.0 2354.0 

8NVD26 s 180 260 6.6 8 750.0 496.5 

8NVD36 s 240 360 16.3 8 459.7 305.3 

8NVDS36/24A1 240 360 16.3 8 500.0 494.3 

8PA4V185 s 185 210 5.6 8 1475.0 798.7 

8PA4V200VG 200 210 6.6 8 1337.5 1219.0 

8PA5 255 270 13.8 8 986.0 1581.1 

8PA6L280 280 290 17.9 8 940.0 1995.5 
A-14 

Engine Model Bore Stroke Displace Cylinders RPM kW 

8PBCS12 s 242 305 14.0 8 750.0 903.3 

8PS12F 242 305 14.0 8 734.0 

8PSHSM26D 260 320 17.0 8 736.0 

8PSHT26D 260 320 17.0 8 680.0 680.5 

8PSHT6M26D 260 320 17.0 8 587.3 

8PSHTB26D 260 320 17.0 8 700.8 

8PSHTBM26D 260 320 17.0 8 721.5 

8PSHTC s 263 323.9 17.6 8 703.6 723.0 

8PSHTM26D 260 320 17.0 8 736.0 

8PSN3 s 260 300 15.9 8 772.5 1259.5 

8PSTBM s 268 332 19.0 8 806.0 

8PSTCM30 s 300 380 26.9 8 600.0 917.3 

8PSTM26D 260 320 17.0 8 620.3 

8PSTM30 300 380 26.9 8 978.0 

8R20 200 280 8.8 8 1000.0 1160.0 

8R22 s 220 242 9.2 8 966.7 1177.7 

8R32 s 320 350 28.1 8 738.5 3054.9 

8R530TZ 175 220 5.3 8 349.0 

8RDV136 240 360 16.3 8 221.0 

8RK s 255 304 15.6 8 875.0 1258.3 

8S12D 241 305 13.9 8 1269.0 

8S28LU 280 320 19.7 8 750.0 1496.5 

8SL28LVO 280 320 19.7 8 766.7 1502.4 

8SN s 258 280 14.7 8 750.0 909.9 

8SW28 s 280 300 18.5 8 866.7 2177.7 

8T23HU 225 300 11.9 8 782.5 

8T23LVO 225 300 11.9 8 800.0 957.8 

8TAD24 240 400 18.1 8 400.0 621.5 

8TM270 270 500 28.6 8 380.0 660.4 

8TR240CO 241 305 13.9 8 1214.0 

8U28HU 280 320 19.7 8 775.0 1681.0 

8V190C 190 210 6.0 8 1200.0 471.0 

8V22 s 220 240 9.1 8 1000.0 1299.3 

8V23 s 225 300 11.9 8 812.5 823.0 

8V25 s 247 295.1 14.2 8 841.7 1636.7 

8V28 s 280 360 22.2 8 597.0 2261.0 

8VD26/20AL s 200 260 8.2 8 1000.0 788.0 

8VD29/24AL2 240 290 13.1 8 900.0 1600.0 

8VD36/24 s 240 360 16.3 8 500.0 364.9 

8VDS29/24AL2 240 290 13.1 8 950.0 1736.2 

8VDS36/24A1 240 360 16.3 8 442.3 

8VEBCM 260 368 19.5 8 600.0 724.5 

8VJMS 255 300 15.3 8 

8VJS 255 300 15.3 8 485.0 

8VKL60/475 190 350 9.9 8 353.0 

8VSHTBM26D 260 320 17.0 16 1368.0 

8YJCM 197 216 6.6 8 993.0 
A-15 

Engine Model Bore Stroke Displace Cylinders RPM kW 

8YLC s 248 267 12.9 8 630.0 762.6 

8Z280 s 280 360 22.2 8 566.5 1637.5 

8ZST 280 340 20.9 8 680.0 1496.0 

8ZU421AK 290 420 27.7 8 1030.0 

938D8-1/8 207 254 8.5 9 1265.0 

9ACA s 280 420 25.9 9 350.0 901.3 

9ASL25/30 250 300 14.7 9 1927.0 

9ATCM 318 368 29.2 9 587.5 1659.2 

9DNL120/500 190 350 9.9 9 794.0 

9DNL150/600 190 350 9.9 9 993.0 

9DNL170/600 190 350 9.9 9 600.0 978.0 

9DNL190/600 190 350 9.9 9 1260.0 

9F/SW240 240 260 11.8 9 900.0 1041.9 

9FBHD240 240 260 11.8 9 898.7 

9FCHD240 240 260 11.8 9 983.5 

9FDHD240 240 260 11.8 9 1136.8 

9FHD240 s 240 260 11.8 9 918.0 1421.5 

9L20 s 200 276.9 8.7 9 983.3 1322.6 

9L25/30 250 300 14.7 9 1760.7 

9L26 260 320 17.0 9 825.0 2811.0 

9L27/38 270 380 21.8 9 3061.0 

9L28/32 s 280 320 19.7 9 780.0 2209.1 

9L32/36 320 360 28.9 9 750.0 3330.0 

9M20 200 300 9.4 9 961.7 1402.0 

9M25 255 400 20.4 9 732.0 2568.0 

9R20 200 280 8.8 9 1000.0 1478.0 

9R26 260 320 17.0 9 950.0 2761.7 

9R32 s 320 350 28.1 9 738.0 3305.1 

9SW280 280 300 18.5 9 2477.3 

9VD29/24AL2 / 

9VDS29/24AL2 240 290 13.1 9 1000.0 2100.0 

9VDS29/24AL2 240 290 13.1 9 1000.0 2225.0 

A2216VIS 220 340 12.9 16 1103.0 

A230.12 s 230 270 11.2 12 1000.0 1518.5 

A230.8 s 230 270 11.2 8 1000.0 963.7 

A238S s 230 270 11.2 8 993.0 

A24 s 240 450 20.4 6 521.0 

A245 s 245 450 21.2 6 399.0 662.0 

A320.12V 320 360 28.9 12 750.0 4413.0 

AH25 s 250 410 20.1 6 390.0 662.0 

AH27 s 270 420 24.0 6 345.0 809.0 

AH28 s 280 442.5 27.2 6 379.2 966.3 

B230 s 230 270 11.2 11 1100.0 1937.7 

BL230 s 230 310 12.9 11 944.4 1972.3 

BR218 210 300 10.4 8 276.0 

BRG8 320 360 28.9 8 720.0 3370.0 

BRM6 320 360 28.9 6 734.1 2427.4 
A-16 

Engine Model Bore Stroke Displace Cylinders RPM kW 

BRM8 320 360 28.9 8 744.0 3187.8 

BRM9 320 360 28.9 9 748.2 3198.5 

BV6M536 270 360 20.6 8 662.0 

BVM12 320 360 28.9 12 750.0 5298.0 

C25:33L s 250 330 16.2 8 900.0 2610.0 

D440 s 230 270 11.2 8 600.8 

D441V12 230 270 11.2 12 596.0 

DB6 290 410 27.1 6 386.5 

DM26K s 260 440 23.4 6 410.0 639.1 

DM26R 260 440 23.4 6 405.0 551.8 

DM28A s 280 460 28.3 6 400.0 862.9 

DM28AR 280 460 28.3 6 390.0 927.6 

DM28R 280 460 28.3 6 390.0 956.0 

DM330 300 410 29.0 3 168.3 

DMG36 304 381 27.6 6 936.0 

DMG38 305 381 27.8 8 550.0 661.7 

DMG6 305 381 27.8 6 400.0 319.0 

DMG8 305 381 27.8 8 448.1 

DMT330 300 410 29.0 3 254.0 

DMT530 300 410 29.0 5 405.0 

DMT630 300 410 29.0 6 518.5 

DN6 290 410 27.1 6 331.0 

DR218 210 300 10.4 8 485.0 

DR329 290 410 27.1 3 154.0 

DRO216K 210 300 10.4 6 383.0 

DRO218 s 210 300 10.4 8 736.7 487.6 

DVX12 s 185 200 5.4 12 1250.0 524.0 

DY25 s 250 440 21.6 6 420.0 680.5 

DY26 s 260 440 23.4 6 735.5 

E6 222 292 11.3 6 900.0 368.7 

E8 222 292 11.3 8 

ECSL8 222 292 11.3 8 735.0 

EGL6 178 229 5.7 6 177.0 

EK6 270 400 22.9 6 368.0 

ELS16MK2 222 292 11.3 16 1471.0 

EM6 260 400 21.2 6 291.7 

EMB5 216 343 12.6 5 

ER4M 222 292 11.3 4 166.0 

ER6 s 222 292 11.3 6 750.0 256.4 

ER8 s 222 292 11.3 8 453.7 

ERL4 178 229 5.7 4 

ERL5 178 229 5.7 5 

ERL6 178 229 5.7 6 184.0 

ERMGR6 222 292 11.3 6 750.0 372.3 

ERN6 178 229 5.7 6 147.0 

ERS4 s 222 292 11.3 4 750.0 233.8 

ERS4MGR 222 292 11.3 4 243.0 
A-17 

Engine Model Bore Stroke Displace Cylinders RPM kW 

ERS6 222 292 11.3 6 725.0 354.6 

ERS8 s 222 292 11.3 8 696.2 474.7 

ES4 s 222 292 11.3 4 243.0 

ES6 222 292 11.3 6 308.8 

ES8 222 292 11.3 8 660.7 632.6 

ESHC629 290 440 29.1 6 370.0 662.0 

ESL12M s 222 292 11.3 12 796.7 1216.7 

ESL16 s 222 292 11.3 16 1153.7 1774.3 

ESL4MK2 222 292 11.3 4 235.0 

ESL5M s 222 292 11.3 5 900.0 515.8 

ESL6 s 222 292 11.3 6 815.0 572.4 

ESL8 s 222 292 11.3 8 887.0 757.4 

ESL9M s 222 292 11.3 9 1333.3 1398.2 

ESS4M 222 292 11.3 4 294.0 

ESS6 222 292 11.3 6 415.5 

ESS8 222 292 11.3 8 670.0 588.0 

ESSL12 222 292 11.3 12 883.0 

ETS8 222 292 11.3 8 300.0 579.3 

ETSL16 222 292 11.3 16 1250.0 

ETSL8 222 292 11.3 8 601.0 

EV6M 222 292 11.3 6 210.0 

EV8M 222 292 11.3 8 250.0 

EVS4M 222 292 11.3 4 194.0 

EVS6M 222 292 11.3 6 291.0 

EVS8M 222 292 11.3 8 370.7 

EWSL12M 222 292 11.3 12 883.0 

EWSL16 s 222 292 11.3 16 1472.4 

EWSL6 222 292 11.3 6 640.0 

EWSL8 s 222 292 11.3 8 900.0 703.0 

EWZL8 222 292 11.3 8 897.0 

EZSL8 222 292 11.3 8 1000.0 758.7 

F212V 250 300 14.7 12 844.4 1694.9 

F216V 250 300 14.7 16 862.5 2438.7 

F26R s 250 300 14.7 6 787.5 894.9 

F2896D s 216 216 7.9 6 330.0 

F28V 250 300 14.7 8 775.0 1190.3 

F312V 250 300 14.7 12 735.0 2077.9 

F316V 250 300 14.7 16 825.0 3111.7 

F38V 250 300 14.7 8 825.0 1459.0 

F4AUDM s 305 380.3 27.8 7 646.3 

F6S27.5FH4C 275 450 26.7 6 783.5 

FMD98 228 292 11.9 8 390.0 

FNS626 280 400 24.6 6 405.0 

FSCMGR6 305 381 27.8 6 772.0 

FSHC6275 275 400 23.8 6 400.0 588.0 

FSM5 305 381 27.8 5 493.0 

FSM6 305 381 27.8 6 637.3 
A-18 

Engine Model Bore Stroke Displace Cylinders RPM kW 

FSM8 305 381 27.8 8 868.0 

FSSAM6 305 381 27.8 6 853.0 

FSSM6 305 381 27.8 6 772.0 

G16VS240 240 220 10.0 16 2501.0 

G20VS240 240 220 10.0 20 2942.0 

G250E s 250 290 14.2 6 719.8 966.7 

G5V235/330 s 235 330 14.3 5 392.3 

G6V23/33 235 330 14.3 6 321.5 

G6V235/330 s 235 330 14.3 6 365.8 

G6V285/42 285 420 26.8 6 257.0 

G6V42 280 420 25.9 6 375.0 

G7235/330ATL 235 330 14.3 7 618.0 

G7V235/330ATL 235 330 14.3 7 600.0 602.7 

G7V235/33AT 235 330 14.3 7 515.0 

G8V23/33 235 330 14.3 8 441.0 

G8V235/33 s 235 330 14.3 8 536.8 

GN24 240 410 18.5 6 410.0 478.0 

GNLH623 230 410 17.0 6 552.0 

GNLH624 240 410 18.5 6 410.0 527.0 

GNLH625 250 420 20.6 6 400.0 736.0 

GNLH6275 275 450 26.7 6 390.0 805.6 

GSHC6275 275 450 26.7 6 736.0 

GSLH6275 275 450 26.7 6 723.7 

HGN4 267 343 19.2 4 400.0 286.0 

HGN5 267 343 19.2 5 316.0 

HGN6 267 343 19.2 6 345.0 412.8 

HGN8 267 343 19.2 8 435.0 750.6 

HGP6 267 343 19.2 6 827.5 

HGP8 267 343 19.2 8 1177.0 

HRL5 265 290 16.0 5 300.0 243.0 

HRN4 267 343 19.2 4 300.0 235.5 

HRN5 267 343 19.2 5 255.4 

HRN6 267 343 19.2 6 374.3 

HRN8 267 343 19.2 8 563.4 

HRN9 267 343 19.2 9 651.0 

HRP8 267 343 19.2 8 750.0 

HS6MZ28 280 420 25.9 6 450.0 478.0 

HS6NV229 290 430 28.4 6 481.8 

HS6X19 240 330 14.9 6 257.0 

HSC6MZ28 280 420 25.9 6 552.0 

HSN8 267 343 19.2 8 450.0 613.0 

JLSSGMR6 248 318 15.4 6 521.5 

JLSSGMR8 248 318 15.4 8 771.0 

JSSMR8 248 267 12.9 8 636.0 

JVSSM12 248 267 12.9 12 919.0 

K26S s 260 480 25.5 6 376.6 731.9 

K28B s 280 480 29.6 6 358.3 797.6 
A-19 

Engine Model Bore Stroke Displace Cylinders RPM kW 

KA6 s 230 360 15.0 6 410.0 270.0 

KGRMR265 250 380 18.6 6 235.0 

KL21B 185 260 7.0 6 235.0 

KMBV12 250 300 14.7 12 750.0 3703.0 

KMVB12 250 300 14.7 12 2207.0 

KNLH625 258 430 22.6 6 395.0 814.0 

KNLH6275 275 450 26.7 6 390.0 956.0 

KR2285U / 

KR228SU 295 420 28.7 6 250.5 

KRGB6 250 300 14.7 6 787.5 1011.5 

KRGB9 250 300 14.7 9 850.0 2435.6 

KRM6 250 300 14.7 6 750.0 990.0 

KRM8 250 300 14.7 8 775.0 1494.0 

KRM9 250 300 14.7 9 841.7 1817.3 

KRMB6 250 300 14.7 6 841.4 1026.6 

KRMB8 250 307.5 15.1 8 840.0 1617.4 

KRMB9 250 300 14.7 9 818.8 2007.2 

KSHC6275 275 400 23.8 6 588.0 

KV6M536 270 360 20.6 6 265.0 

KVGB12 250 300 14.7 12 850.0 2221.3 

KVGB16 250 300 14.7 16 825.0 2977.7 

KVGB18 250 300 14.7 18 3358.0 

KVM12 250 300 14.7 12 765.0 1646.4 

KVM16 250 300 14.7 16 750.0 1840.0 

KVMB12 250 300 14.7 12 778.4 1992.2 

KVMB16 250 300 14.7 16 800.0 2469.7 

KVMB18 250 300 14.7 18 3010.3 

KVMB8 250 300 14.7 8 825.0 1460.0 

L20710-G7B 230 279 11.6 20 900.0 1839.0 

L230 s 230 350 14.5 6.5 600.0 382.5 

L5792DS s 216 216 7.9 12 1057.5 998.2 

L6670DS s 232 216 9.1 12 839.0 

LA230.8SS 230 350 14.5 8 577.0 

LDM5 250 300 14.7 5 515.0 

LDM6 250 300 14.7 6 750.0 670.8 

LDM8 250 300 14.7 8 992.4 

LDM9 250 300 14.7 9 780.0 1054.8 

LDMB6 250 300 14.7 6 825.0 766.3 

LDMB8 250 300 14.7 8 213.0 1088.4 

LDMB9 250 300 14.7 9 780.0 1170.8 

LDMC6 250 300 14.7 6 787.5 627.0 

LDMC8 250 300 14.7 8 750.0 809.0 

LDMCB6 250 300 14.7 6 825.0 625.0 

LH26G 260 440 23.4 6 

LH28G s 280 460 28.3 6 1177.0 

LSMC5 250 300 14.7 5 478.0 

LSMC6 250 300 14.7 6 574.0 

LSMC8 250 300 14.7 8 750.0 769.8 
A-20 

Engine Model Bore Stroke Displace Cylinders RPM kW 

LSMC9 250 300 14.7 9 1986.0 

LSMCB9 250 300 14.7 9 825.0 993.0 

LZ6 260 400 21.2 6 331.0 

M200 s 200 260 8.2 6 861.8 524.7 

M220 s 220 300 11.4 6 789.4 752.9 

M24UT 240 420 19.0 6 588.0 

M400 180 200 5.1 12 1625.0 686.4 

M401 s 180 200 5.1 12 1561.1 709.5 

M412 180 200 5.1 12 1500.0 627.0 

M416 180 200 5.1 12 810.0 

M419AM3 180 200 5.1 12 1600.0 791.3 

M421 180 200 5.1 12 990.0 

M423 290 420 27.7 8 375.0 552.0 

M44I 250 420 20.6 4 228.4 

M45I 250 420 20.6 5 334.5 

M46 s 253 422.2 21.3 7 320.0 372.5 

M47 s 241 405 19.0 7 325.0 392.8 

M470 180 200 5.1 12 990.0 

M50 180 200 5.1 12 735.5 

M6D20B s 200 240 7.5 6 750.0 368.7 

M6D26B s 260 320 17.0 6 720.0 551.8 

MA301FA 230 300 12.5 8 750.0 605.3 

MA423 290 420 27.7 8 555.5 

MA424AK 290 420 27.7 8 425.0 736.0 

MA6SS 270 400 22.9 6 390.0 456.0 

MAS278 270 500 28.6 8 427.0 

MAU423 s 290 420 27.7 8 370.0 444.4 

MB518C 185 250 6.7 20 1720.0 2207.0 

MB839 190 230 6.5 16 1398.0 

MD1081 185 200 5.4 20 2530.0 

MD330 185 200 5.4 6 1500.0 436.7 

MD36 215 360 13.1 3 74.0 

MD655 s 185 200 5.4 9 1450.0 662.5 

MDS623S 230 380 15.8 6 221.0 

MF24 s 234 390.8 17.2 6 411.4 445.3 

MF26 s 260 500 26.5 6 349.1 613.5 

MF28 s 280 450 27.7 6 364.3 687.6 

MH22 s 220 390 14.8 6 416.7 

MH23 s 230 390 16.2 6 433.3 479.4 

MK6 s 300 420 29.7 6 370.0 400.0 

ML624GA s 240 400 18.1 6 257.0 

ML624GHS s 240 400 18.1 6 405.0 370.8 

ML624GS s 240 400 18.1 6 398.8 386.7 

ML626GS s 260 480 25.5 6 340.0 551.7 

ML627GS s 270 480 27.5 6 340.0 652.0 

MNL28M 280 480 29.6 6 328.0 676.8 

MS24 180 240 6.1 6 162.0 
A-21 

Engine Model Bore Stroke Displace Cylinders RPM kW 

MS245G s 245 470 22.2 6 791.0 

MS25GSC s 250 470 23.1 6 320.0 563.1 

MS25GTSC s 250 470 23.1 6 420.0 698.7 

MS26GSC s 260 470 24.9 6 346.7 565.5 

MS26GTSC2 260 470 24.9 6 956.0 

MS27SC 270 420 24.0 6 625.0 

MS28FSC 280 420 25.9 6 400.0 956.0 

MS28GFSC 280 420 25.9 6 790.5 

MS28SC 280 420 25.9 6 400.0 736.0 

MS423 290 420 27.7 6 412.0 

MS726 260 400 21.2 6 184.0 

MSU36 s 215 360 13.1 6 174.0 

MSU423 s 290 420 27.7 6 341.7 304.9 

MSU424 s 290 420 27.7 6 345.0 

MU323CG s 230 380 15.8 5 294.5 

MU323CGS1 230 380 15.8 3 147.0 

MU323DGSC 230 380 15.8 3 420.0 267.3 

MU36 215 360 13.1 6 147.0 

MU623 s 230 380 15.8 6 420.0 353.0 

MU625HS 260 420 22.3 6 368.0 

MU626HS 270 420 24.0 6 496.5 

MU627 s 270 420 24.0 6 496.5 

MV36 215 360 13.1 4 103.0 

MV421 280 420 25.9 4 110.0 

MV423 290 420 27.7 4 226.7 

Q265/3 265 410 22.6 3 110.0 

R321 210 330 11.4 3 

R4A7 229 305 12.6 7 390.0 

R4AUUN5 229 305 12.6 5 750.0 355.0 

R6DV136 240 360 16.3 6 205.3 

R6Z133U 225 330 13.1 6 600.0 308.0 

R8DV136 240 360 16.3 8 350.0 238.3 

R8V22/30ATL 220 300 11.4 8 791.0 

R8Z133 225 330 13.1 8 500.0 368.0 

RA6M428 220 280 10.6 6 176.3 

RA6M528 220 280 10.6 6 186.3 

RA8M428 220 280 10.6 8 228.0 

RA8M528 220 280 10.6 8 287.0 

RBA12M528 220 280 10.6 12 1066.5 

RBA6M428 220 280 10.6 6 268.5 

RBA6M528 220 280 10.6 6 807.0 362.2 

RBA8M528 220 280 10.6 8 810.0 507.2 

RBV6M536 270 360 20.6 6 353.2 

RBV6M628 240 280 12.7 6 1235.0 

RDV136 240 360 16.3 6 221.0 

RH230 s 215 300 10.9 5 475.0 126.0 

RH235 250 350 17.2 4 110.0 
A-22 

Engine Model Bore Stroke Displace Cylinders RPM kW 

RH330 s 215 300 10.9 6 600.0 182.4 

RH335SU 250 350 17.2 6 500.0 216.0 

RH435SU 250 350 17.2 6 239.0 

RH526A 180 260 6.6 8 173.0 

RHO215 210 300 10.4 5 280.0 

RHO216K 210 300 10.4 6 204.5 

RHO218K 210 300 10.4 8 485.0 

RHS435 s 250 350 17.2 7 294.5 

RHS526 s 180 260 6.6 7 900.0 196.5 

RSBA12M528 220 280 10.6 12 829.7 1058.3 

RSBA16M528 220 280 10.6 16 1588.5 

RSBA6M528 220 280 10.6 6 900.0 551.0 

RSBA8M528 220 280 10.6 8 784.3 701.9 

RSP5 250 360 17.7 5 331.0 

RSP6 250 360 17.7 6 425.0 397.0 

RTG 8 250 360 17.7 8 445.0 373.7 

RTG7 250 360 17.7 7 386.0 

RTG8 250 500 24.5 8 364.0 

RV6M 270 360 20.6 6 147.0 

RV6M436 240 360 16.3 6 177.0 

RV6M536 270 360 20.6 6 506.3 233.7 

RV8M536 270 360 20.6 8 500.0 625.0 

RZI6 210 330 11.4 6 430.0 221.0 

S12UMTK 240 260 11.8 12 2354.0 

S185 s 185 230 6.2 6 848.8 402.4 

S23G 230 400 16.6 6 404.3 385.9 

S25G 250 450 22.1 6 426.8 

S26G 260 470 24.9 6 379.5 603.1 

S27G 270 480 27.5 6 380.0 855.3 

S623 s 230 400 16.6 6 410.0 277.5 

S6EDSS 240 400 18.1 6 441.0 

S6MBHS 220 400 15.2 6 331.0 

S6MBTHS 220 400 15.2 6 380.0 343.3 

S6MUH28 280 340 20.9 6 1177.0 

S6NDTE 270 400 22.9 6 294.0 

S6UCT s 260 400 21.2 6 324.0 

S6UDT s 260 400 21.2 6 397.5 544.0 

S6UFGSS 260 400 21.2 6 427.0 

S6UFTSS 260 400 21.2 6 410.0 625.0 

S6UMPTK 240 260 11.8 6 900.0 978.5 

S6UMTK 240 260 11.8 6 2000.0 978.1 

S6YDTSS 280 420 25.9 6 644.0 

S6YFSS 280 440 27.1 6 956.0 

S8UMTK 240 260 11.8 8 1839.0 

SA4M428 220 280 10.6 4 

SA6M428 220 280 10.6 6 158.0 

SBA12M528 220 280 10.6 12 867.0 1050.8 
A-23 

Engine Model Bore Stroke Displace Cylinders RPM kW 

SBA4M428 220 280 10.6 4 

SBA6M528 220 280 10.6 6 830.5 381.0 

SBA6M628 240 280 12.7 6 763.7 670.3 

SBA8M528 220 280 10.6 8.21621622 812.8 640.7 

SBV12M628 240 280 12.7 12 800.0 1976.8 

SBV16M628 240 280 12.7 16 950.0 3097.1 

SBV6M536 270 360 20.6 6 600.0 542.5 

SBV6M628 240 280 12.7 6 864.7 935.2 

SBV8M536 270 360 20.6 8 500.0 736.8 

SBV8M628 240 280 12.7 8 841.3 1230.4 

SBV9M628 240 280 12.7 9 867.2 1376.0 

SF112V s 250 300 14.7 12 750.0 1584.1 

SF116V s 250 300 14.7 16 800.0 2259.5 

SF13RSF 250 300 14.7 3 357.0 

SF14RS 250 300 14.7 4 331.0 

SF15RSC 250 300 14.7 5 508.0 

SF16RS s 250 300 14.7 6 750.0 725.9 

SF18VS s 250 300 14.7 8 766.7 943.0 

SIIB 280 420 25.9 6 239.0 

SOD629 s 290 420 27.7 6 420.0 736.0 

SODCHS6S25 250 410 20.1 6 420.0 552.0 

SODHS6S24 240 390 17.6 6 379.7 

SODHS6S25 250 410 20.1 6 552.0 

SODHS6S26 260 410 21.8 6 420.0 588.0 

SODHS6X26 260 410 21.8 6 600.3 

SODHS6X29 290 440 29.1 6 717.5 

SR4Z127 160 270 5.4 4 110.0 

SR8 260 330 17.5 8 552.0 

SV3M345 280 450 27.7 3 110.0 

SV6M536 270 360 20.6 6 500.0 279.0 

T12RS18/22 180 220 5.6 12 1200.0 496.5 

T220 s 222 289.2 11.2 6 801.0 698.0 

T220AL s 220 280 10.6 6 686.7 

T240 s 240 310 14.0 6 766.7 701.6 

T260 s 260 330 17.5 6 703.3 978.9 

T26S s 260 440 23.4 6 447.0 602.3 

T5B26YC 260 400 21.2 5 199.0 

T6EKA 270 400 22.9 6 257.0 

TARHS335AU 250 350 17.2 8 530.0 

TB12RS18/22 180 220 5.6 12 1250.0 699.0 

TB16RS18/22 180 220 5.6 16 1300.0 949.0 

TBD4406 s 230 270 11.2 6 831.6 625.8 

TBD4408 s 230 270 11.2 8 798.7 799.7 

TBD441V12 s 230 270 11.2 12 810.0 1121.5 

TBD441V16 s 230 270 11.2 16 1465.2 

TBD4446 230 320 13.3 6 750.0 809.3 

TBD4448 230 320 13.3 8 750.0 1157.5 
A-24 

Engine Model Bore Stroke Displace Cylinders RPM kW 

TBRH526SU 180 260 6.6 6 220.0 

TBRS18/22V12 180 220 5.6 12 721.0 

TD4406 230 270 11.2 6 463.3 

TD4408 230 270 11.2 8 603.5 

TD441V12 230 270 11.2 12 1067.0 

TD441V16 230 270 11.2 16 1103.0 

TEB296 290 400 26.4 6 1132.5 

TEBF296 290 400 26.4 6 1103.0 

TLADM4 216 349 12.8 4 150.0 

TLSDMR6 216 330 12.1 6 269.0 

TMAB276 270 500 28.6 6 607.0 

TMAB278 270 500 28.6 8 691.0 

TMABS278 270 500 28.6 8 380.0 752.0 

TMAS276 270 500 28.6 6 375.0 307.0 

TMBAS276 270 500 28.6 6 291.0 

TRH435 s 250 350 17.2 7 437.5 395.9 

TRHS435 s 250 350 17.2 7 504.4 

TRHS518V16 180 220 5.6 16 1500.0 471.0 

TRHS526A 180 260 6.6 8 206.0 

UHS27 270 420 24.0 6 390.0 736.0 

V12A/12 185 210 5.6 12 993.0 

V12TR240CO 241 305 13.9 12 225.0 1888.3 

V16A/12 185 210 5.6 16 1353.0 

V16A/9 185 210 5.6 16 1236.0 

V16TR240CO 241 305 13.9 16 1000.0 3118.0 

V18A/10 185 210 5.6 18 1566.5 

V18B/12 210 210 7.3 18 1200.0 2111.0 

V6A/12 185 210 5.6 6 662.0 

V6A/9 185 210 5.6 6 423.0 

V6B 210 210 7.3 12 1663.0 1957.0 

V6V22/30 s 220 300 11.4 12 780.0 868.2 

V8A s 185 210 5.6 8 588.0 

V8V22/30ATL 220 300 11.4 16 850.0 1350.7 

V8V30/42AL 300 420 29.7 16 2700.0 

VC8M 203 273 8.8 8 150.0 

W4VSLM 175 220 5.3 4 666.5 156.0 

W6LSR 180 220 5.6 6 221.0 

W6V175/22A 175 220 5.3 6 122.5 

W6V22/30A 220 300 11.4 6 515.0 

W6VBSLM 175 220 5.3 6 670.0 284.7 

W8V175/22 s 175 220 5.3 8 950.0 188.9 

W8V30/38 300 380 26.9 8 1102.5 

W8VBSLM 175 220 5.3 8 1182.9 382.6 

W8VCSLM 175 220 5.3 8 386.0 386.0 

WX28 s 280 390 24.0 7 548.8 1593.7 

YYYY 240 400 18.1 8 1.0 618.0 

Z27 s 270 420 24.0 6 390.0 588.0 
A-25 

Engine Model Bore Stroke Displace Cylinders RPM kW 

Z280EN 260 280 14.9 6 720.0 1209.0 

Z3 300 360 25.4 3 375.0 154.0 

Z35 235 300 13.0 6 405.0 

Z4 300 360 25.4 4 206.0 

Z4EM 260 400 21.2 4 

Z6235SH 235 300 13.0 6 429.0 

Z626SH 260 330 17.5 6 496.5 

Z627ASH 270 400 22.9 6 441.4 

Z66 260 330 17.5 6 496.5 

Z68 260 330 17.5 8 736.0 

Z6L28ASH 280 430 26.5 6 588.0 

Z6UK27 270 420 24.0 6 74.0 

Z6VSH 280 450 27.7 6 637.3 

Z76 270 400 22.9 6 441.3 
Appendix B. Summary of Monte Carlo Input and Output data 
Deep Water Vessel

Forecast: Deep Water HP-HR

Summary:

Display Range is from 1,191,707,853 to 4,440,497,391 HP-HR

Entire Range is from 1,169,729,099 to 4,465,240,444 HP-HR

After 10,000 Trials, the Std. Error of the Mean is 6,989,695

Statistics: Value

Trials 10000

Mean 2,666,159,213

Median 2,596,210,614

Mode ---

Standard Deviation 698,969,510

Variance 5E+17

Skewness 0.30

Kurtosis 2.36

Coeff. of Variability 0.26

Range Minimum 1,169,729,099

Range Maximum 4,465,240,444

Range Width 3,295,511,345

Mean Std. Error 6,989,695.10

Target Forecast: Deep Water HP-HR

Deep Water HP 1.00

Deep Water LF -.01

Deep Water Transit Days -.01

-1 -0.5 0 0.5 1

Measured byRankCorrelation

Sensitivity Chart

Deep Water HP

Deep Water LF

Deep Water Transit Days

B-1
Deep Water Vessel Assumptions

Assumption: Deep Water HP

Triangular distribution with parameters:

Minimum 1,860

Likeliest 3,603

Maximum 7,200

Selected range is from 1,860 to 7,200

Assumption: Deep Water Underway Days

 Custom distribution with parameters: Relative Prob.

Single point 219 1.000000

Total Relative Probability 1.000000

Assumption: Deep Water LF

 Custom distribution with parameters: Relative Prob.

Single point 80% 1.000000

Total Relative Probability 1.000000

Mean = 4,221

1,860 3,195 4,530 5,865 7,200

Deep Water HP

Mean = 219

.000

.250

.500

.750

1.000

217 218 219 220 221

Deep Water Transit Days

Mean = 80%

.000

.250

.500

.750

1.000

-120% -20% 80% 180% 280%

Deep Water LF

Deep Water Underway Days

B-2
Towboats

Forecast: Towboat HP-HR

Summary:

Display Range is from 3,243,495,839 to 15,743,368,200 HP-HR

Entire Range is from 3,213,901,615 to 25,888,889,076 HP-HR

After 10,000 Trials, the Std. Error of the Mean is 30,200,146

Statistics: Value

Trials 10000

Mean 7,920,359,723

Median 7,390,600,445

Mode ---

Standard Deviation 3,020,014,562

Variance 9E+18

Skewness 0.95

Kurtosis 3.99

Coeff. of Variability 0.38

Range Minimum 3,213,901,615

Range Maximum 25,888,889,076

Range Width 22,674,987,462

Mean Std. Error 30,200,145.62

Target Forecast: Towboats HP-HR

Towboats HP 1.00

Towboats LF .01

Towboats Transit Days .01

-1 -0.5 0 0.5 1

Measured byRankCorrelation

Sensitivity Chart

Towboats HP

Towboats LF

Towboats Transit Days

B-3
Towboat Assumptions

Assumption: Towboat HP

Weibull distribution with parameters:

Location 900

Scale 1,477

Shape 1.596695

Selected range is from 900 to +Infinity

Assumption: Towboat Underway Days

 Custom distribution with parameters: Relative Prob.

Single point 219 1.000000

Total Relative Probability 1.000000

Assumption: Towboat LF

 Custom distribution with parameters: Relative Prob.

Single point 44% 1.000000

Total Relative Probability 1.000000

Mean = 44%

.000

.250

.500

.750

1.000

-156% -56% 44% 144% 244%

Towboats LF

Mean = 219

.000

.250

.500

.750

1.000

217 218 219 220 221

Towboats Transit Days

Mean = 2,225

900 2,033 3,167 4,300 5,433

Towboats HP

Towboat Underway Days

Towboat LF

Towboat HP

B-4
Ferry Vessels

Forecast: Ferry HP-HR

Summary:

Display Range is from 537,632,473 to 2,658,247,438 HP-HR

Entire Range is from 462,593,200 to 3,055,815,023 HP-HR

After 10,000 Trials, the Std. Error of the Mean is 4,432,935

Statistics: Value

Trials 10000

Mean 1,464,293,131

Median 1,438,633,302

Mode ---

Standard Deviation 443,293,456

Variance 2E+17

Skewness 0.31

Kurtosis 2.71

Coeff. of Variability 0.30

Range Minimum 462,593,200

Range Maximum 3,055,815,023

Range Width 2,593,221,823

Mean Std. Error 4,432,934.56

Target Forecast: Ferries HP-HR

Ferries HP .94

Ferries Transit Days .30

Ferries LF .00

-1 -0.5 0 0.5 1

Measured byRankCorrelation

Sensitivity Chart

Ferry HP

Ferry Transit Days

Ferry LF

B-5
Ferry Vessel Assumptions

Assumption: Ferry HP

Triangular distribution with parameters:

Minimum 865

Likeliest 2,412

Maximum 4,400

Selected range is from 865 to 4,400

Assumption: Ferry Underway Days

Triangular distribution with parameters:

Minimum 152

Likeliest 174

Maximum 243

Selected range is from 152 to 243

Assumption: Ferry LF

 Custom distribution with parameters: Relative Prob.

Single point 68% 1.000000

Total Relative Probability 1.000000

Mean = 68%

.000

.250

.500

.750

1.000

-132% -32% 68% 168% 268%

Ferries LF

Mean = 190

152 175 198 220 243

Ferries Transit Days

Mean = 2,559

865 1,749 2,633 3,516 4,400

Ferries HP

Ferry Underway Days

Ferry LF

Ferry HP

B-6
Commerical Fishing Vessels

Forecast: Commerical Fishing HP-HR

Summary:

Display Range is from 1,733,197,125 to 6,376,550,424 HP-HR

Entire Range is from 1,658,213,722 to 10,825,122,187 HP-HR

After 10,000 Trials, the Std. Error of the Mean is 11,426,276

Statistics: Value

Trials 10000

Mean 3,412,840,776

Median 3,183,342,782

Mode ---

Standard Deviation 1,142,627,610

Variance 1E+18

Skewness 1.05

Kurtosis 4.29

Coeff. of Variability 0.33

Range Minimum 1,658,213,722

Range Maximum 10,825,122,187

Range Width 9,166,908,466

Mean Std. Error 11,426,276.10

Target Forecast: Commerical Fishing HP-HR

Commercial Fishing HP 1.00

Commercial Fishing Transit Days .08

Commercial Fishing LF .01

-1 -0.5 0 0.5 1

Measured byRankCorrelation

Sensitivity Chart

Commercial Fishing HP

Commercial Fishing Transit Days

Commerical Fishing LF

B-7
Commercial Fishing Assumptions

Assumption: Commercial Fishing HP

Weibull distribution with parameters:

Location 1,000

Scale 1,054

Shape 1.478789

Selected range is from 1,000 to +Infinity

Assumption: Commercial Fishing Underway Days

Triangular distribution with parameters:

Minimum 250

Likeliest 271

Maximum 292

Selected range is from 250 to 292

Assumption: Commercial Fishing LF

 Custom distribution with parameters: Relative Prob.

Single point 70% 1.000000

Total Relative Probability 1.000000

Mean = 271

250 261 271 282 292

Commercial Fishing Transit Days

Mean = 70%

.000

.250

.500

.750

1.000

-130% -30% 70% 170% 270%

Commercial Fishing LF

Commercial Fishing Underway Days

Mean = 1,953

1,000 1,884 2,768 3,651 4,535

Commercial Fishing HP

B-8
Great Lakes Vessels

Forecast: Great Lakes HP-HR

Summary:

Display Range is from 376,459,662 to 2,238,549,592 HP-HR

Entire Range is from 332,637,421 to 2,273,199,755 HP-HR

After 10,000 Trials, the Std. Error of the Mean is 4,051,230

Statistics: Value

Trials 10000

Mean 1,393,243,855

Median 1,433,115,004

Mode ---

Standard Deviation 405,123,010

Variance 2E+17

Skewness -0.27

Kurtosis 2.38

Coeff. of Variability 0.29

Range Minimum 332,637,421

Range Maximum 2,273,199,755

Range Width 1,940,562,333

Mean Std. Error 4,051,230.10

Target Forecast: Great Lakes HP-HR

Great Lake HP 1.00

Great Lake LF -.02

Great Lake Transit days -.02

-1 -0.5 0 0.5 1

Measured byRankCorrelation

Sensitivity Chart

Great Lakes HP

Great Lakes LF

Great Lakes Transit Days

B-9
Great Lakes Vessel Assumptions

Assumption: Great Lakes HP

Triangular distribution with parameters:

Minimum 518

Likeliest 2,505

Maximum 3,600

Selected range is from 518 to 3,600

Assumption: Great Lakes Underway days

 Custom distribution with parameters: Relative Prob.

Single point 136 1.000000

Total Relative Probability 1.000000

Assumption: Great Lakes LF

 Custom distribution with parameters: Relative Prob.

Single point 84% 1.000000

Total Relative Probability 1.000000

Mean = 2,208

518 1,289 2,059 2,830 3,600

Great Lake HP

Mean = 136

.000

.250

.500

.750

1.000

134 135 136 137 138

Great Lake Transit days

Mean = 84%

.000

.250

.500

.750

1.000

-116% -16% 84% 184% 284%

Great Lake LF

Great Lakes Underway Days

Great Lakes LF

Great Lakes HP

B-10
Coast Guard Vessels

Forecast: Coast Guard HP-HR

Summary:

Display Range is from 403,019,387 to 2,730,806,185 Hp-HR

Entire Range is from 357,200,211 to 3,319,883,788 Hp-HR

After 10,000 Trials, the Std. Error of the Mean is 4,955,407

Statistics: Value

Trials 10000

Mean 1,441,432,575

Median 1,387,144,416

Mode ---

Standard Deviation 495,540,718

Variance 2E+17

Skewness 0.53

Kurtosis 3.01

Coeff. of Variability 0.34

Range Minimum 357,200,211

Range Maximum 3,319,883,788

Range Width 2,962,683,577

Mean Std. Error 4,955,407.18

Target Forecast: Coast Guard HP-HR

Coast Guard Transit Days .79

Coast Gurad HP .59

Coast Guard LF .00

-1 -0.5 0 0.5 1

Measured byRankCorrelation

Sensitivity Chart

Coast Guard Transit Days

Coast Guard HP

Coast Guard LF

B-11
Coast Guard Vessel Assumptions

Assumption: Coast Guard HP

Triangular distribution with parameters:

Minimum 1,250

Likeliest 2,289

Maximum 3,650

Selected range is from 1,250 to 3,650

Assumption: Coast Guard Underway Days

Triangular distribution with parameters:

Minimum 29

Likeliest 88

Maximum 157

Selected range is from 29 to 157

Assumption: Coast Guard LF

 Custom distribution with parameters: Relative Prob.

Single point 80% 1.000000

Total Relative Probability 1.000000

Mean = 2,396

1,250 1,850 2,450 3,050 3,650

Coast Gurad HP

Mean = 91

29 61 93 125 157

Coast Guard Transit Days

Mean = 80%

.000

.250

.500

.750

1.000

-120% -20% 80% 180% 280%

Coast Guard LF

Coast Guard Underway Days

B-12
Offshore Vessels

Forecast: Offshore HP-HR

Summary:

Display Range is from 7,660,583,858 to 60,579,374,850 HP-HR

Entire Range is from 6,009,238,235 to 61,335,988,555 HP-HR

After 10,000 Trials, the Std. Error of the Mean is 119,330,949

Statistics: Value

Trials 10000

Mean 27,810,331,286

Median 26,052,108,450

Mode ---

Standard Deviation 11,933,094,915

Variance 1E+20

Skewness 0.49

Kurtosis 2.43

Coeff. of Variability 0.43

Range Minimum 6,009,238,235

Range Maximum 61,335,988,555

Range Width 55,326,750,320

Mean Std. Error 119,330,949.15

Target Forecast: Offshore HP-HR

Offshore HP 1.00

Offshorse Transit Days .04

Offshore LF .00

-1 -0.5 0 0.5 1

Measured byRankCorrelation

Sensitivity Chart

Offshore HP

Offshore Transit Days

Offshore LF

B-13
Offshore Vessel Assumptions

Assumption: Offshore HP

Triangular distribution with parameters:

Minimum 740

Likeliest 2,016

Maximum 7,502

Selected range is from 740 to 7,502

Assumption: Offshorse Underway Days

Triangular distribution with parameters:

Minimum 280

Likeliest 299

Maximum 317

Selected range is from 280 to 317

Assumption: Offshore LF

 Custom distribution with parameters: Relative Prob.

Single point 85% 1.000000

Total Relative Probability 1.000000

Mean = 299

280 289 299 308 317

Offshorse Transit Days

Mean = 85%

.000

.250

.500

.750

1.000

-115% -15% 85% 185% 285%

Offshore LF

Offshore Underway Days

Mean = 3,419

740 2,431 4,121 5,812 7,502

Offshore HP

B-14
Research Vessels

Forecast: Research HP-HR

Summary:

Display Range is from 222,501,388 to 1,215,121,143 HP-HR

Entire Range is from 204,627,058 to 1,231,848,504 HP-HR

After 10,000 Trials, the Std. Error of the Mean is 2,170,568

Statistics: Value

Trials 10000

Mean 654,876,718

Median 632,414,746

Mode ---

Standard Deviation 217,056,751

Variance 5E+16

Skewness 0.31

Kurtosis 2.38

Coeff. of Variability 0.33

Range Minimum 204,627,058

Range Maximum 1,231,848,504

Range Width 1,027,221,446

Mean Std. Error 2,170,567.51

Target Forecast: Research HP-HR

Research HP 1.00

Research LF .01

Research Transit Days .01

-1 -0.5 0 0.5 1

Measured byRankCorrelation

Sensitivity Chart

Research HP

Research LF

Research Transit Days

B-15
Research Vessel Assumptions

Assumption: Research HP

Triangular distribution with parameters:

Minimum 600

Likeliest 1,622

Maximum 3,750

Selected range is from 600 to 3,750

Assumption: Research Underway Days

 Custom distribution with parameters: Relative Prob.

Single point 220 1.000000

Total Relative Probability 1.000000

Assumption: Research LF

 Custom distribution with parameters: Relative Prob.

Single point 85% 1.000000

Total Relative Probability 1.000000

Mean = 1,991

600 1,388 2,175 2,963 3,750

Research HP

Mean = 220

.000

.250

.500

.750

1.000

218 219 220 221 222

Research Transit Days

Mean = 85%

.000

.250

.500

.750

1.000

-115% -15% 85% 185% 285%

Research LF

Research Underway Days

B-16
Appendix C. Category 2 In-Port / At-Sea Splits 
C-1 

In-Port and At Sea Summary 

 (weighted by Activity, HP-HR) 

Straight Straight Weighted Weighted 

Average Average Activity Category 2 Fraction Fraction 

In-Port At-Sea (HP-HR) In-Port At-Sea 

Towboats 17% 83% 1,387,249,658 0.87% 4.22%

Fishing 5% 95% 3,341,826,590 0.61% 11.65%

Offshore 4% 96% 16,406,300,754 2.59% 57.63%

Ferries 65% 35% 1,267,998,585 3.02% 1.63%

Deepwater 1% 99% 1,387,249,658 0.05% 5.04%

Research 1% 99% 534,376,948 0.02% 1.94%

Great Lakes 1% 99% 1,588,928,635 0.06% 5.77%

Government 59% 41% 1,332,989,402 2.86% 2.03%

Total -- -- 27,246,920,230 10.09% 89.91%

Average 19% 81% -- -- -- 
C-2 

1. Towboats, Tugs, and Tractors 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Assist Vessel 19 1.8% 95.0% 5.0% 

Line Haul Tug – Inland 713 67.5% 15.0% 85.0% 

Line Haul Tug – Oceanic 314 29.7% 15.0% 85.0% 

Dredge Support 11 1.0% 85.0% 15.0% 

Total 1057 100.0% 

 

Subgroup In-Port At-Sea 

Assist Vessel 1.7% 0.1% 

Line Haul Tug - Inland 10.1% 57.3% 

Line Haul Tug - Oceanic 4.5% 25.3% 

Dredge Support 0.9% 0.2% 

Total 17.2% 82.8% 

 

2. Commercial Fishing 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Commercial Fishing 333 100.0% 5.0% 95.0% 

Total 333 100.0% 

 

Subgroup In-Port At-Sea 

Commercial Fishing 5.0% 95.0% 

Total 5.0% 95.0% 

 

3. Offshore 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Crewboat/supply/crane 462 76.6% 5.0% 95.0% 

Survey 24 4.0% 2.0% 98.0% 

Pipelayer 14 2.3% 2.0% 98.0% 

Anchor 21 3.5% 2.0% 98.0% 

Liftboat 82 13.6% 2.0% 98.0% 

Total 603 100.0% 

 

Subgroup In-Port At-Sea 

Crewboat/supply/crane 3.8% 72.8% 

Survey 0.1% 3.9% 

Pipelayer 0.0% 2.3% 

Anchor 0.1% 3.4% 

Liftboat 0.3% 13.3% 

Total 4.3% 95.7% 

 
C-3 

4. Ferries 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Passenger Ferry 99 100.0% 65.0% 35.0% 

Total 99 100.0% 

 

Subgroup In-Port At-Sea 

Passenger Ferry 65.0% 35.0% 

Total 65.0% 35.0% 

 

5. Deepwater 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

US Flagged 45 100.0% 1.0% 99.0% 

Total 45 100.0% 

 

Subgroup In-Port At-Sea 

US Flagged 1.0% 99.0% 

Total 1.0% 99.0% 

 

6. Research 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Univesity 31 100.0% 1.0% 99.0% 

Total 31 100.0% 

 

Subgroup In-Port At-Sea 

Univesity 1.0% 99.0% 

Total 1.0% 99.0% 

 
C-4 

7. Great Lakes and others 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Auto 0 0.0% 1.0% 99.0% 

Bulk 18 16.1% 1.0% 99.0% 

Container 2 1.8% 1.0% 99.0% 

Cruise 5 4.5% 1.0% 99.0% 

General Cargo 35 31.3% 1.0% 99.0% 

RORO 2 1.8% 1.0% 99.0% 

Special Carrier 43 38.4% 1.0% 99.0% 

Tanker 7 6.3% 1.0% 99.0% 

Total 112 1.0 

 

Subgroup In-Port At-Sea 

Auto 0.0% 0.0% 

Bulk 0.2% 15.9% 

Container 0.0% 1.8% 

Cruise 0.0% 4.4% 

General Cargo 0.3% 30.9% 

RORO 0.0% 1.8% 

Special Carrier 0.4% 38.0% 

Tanker 0.1% 6.2% 

Total 1.00% 99.00% 

 

8. Government 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

USCG - Cruiser/Ice Breaker 37 23.6% 4.0% 96.0% 

USCG - Patrol 106 67.5% 80.0% 20.0% 

USCG - Buoy Tender 14 8.9% 40.0% 60.0% 

Total 157 100.0% 

 

Subgroup In-Port At-Sea 

USCG - Cruiser/Ice Breaker 0.9% 22.6% 

USCG - Patrol 54.0% 13.5% 

USCG - Buoy Tender 3.6% 5.4% 

Total 58.5% 41.5% 
Appendix D. Category 1 In-Port / At-Sea Splits 
D-1 

1. Towboats, Tugs, and Tractors 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Line Haul Tug - Inland 2504 79.1% 15.0% 85.0% 

Line Haul Tug - Oceanic 660 20.9% 15.0% 85.0% 

Total 3164 100.0% 

 

Subgroup In-Port At-Sea 

Line Haul Tug - Inland 11.9% 67.3% 

Line Haul Tug - Oceanic 3.1% 17.7% 

Total 15.0% 85.0% 

 

2. Commercial Fishing 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Commercial Fishing 29346 100.0% 3.0% 97.0% 

Total 29346 100.0% 

 

Subgroup In-Port At-Sea 

Commercial Fishing 3.0% 97.0% 

Total 3.0% 97.0% 

 

3. Offshore 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Crewboat/supply/crane 405 76.6% 5.0% 95.0% 

Survey 21 4.0% 2.0% 98.0% 

Pipelayer 12 2.3% 2.0% 98.0% 

Anchor 18 3.5% 2.0% 98.0% 

Liftboat 72 13.6% 2.0% 98.0% 

Total 529 100.0% 

 

Subgroup In-Port At-Sea 

Crewboat/supply/crane 3.8% 72.8% 

Survey 0.1% 3.9% 

Pipelayer 0.0% 2.3% 

Anchor 0.1% 3.4% 

Liftboat 0.3% 13.3% 

Total 4.3% 95.7% 

 

4. Ferries 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Ferries 508 100.0% 80.0% 20.0% 

Total 508 100.0% 

 

Subgroup In-Port At-Sea 

Ferries 80.0% 20.0% 

Total 80.0% 20.0% 
D-2 

5. Deepwater 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

US Flagged 23 100.0% 15.0% 85.0% 

Total 23 100.0% 

 

Subgroup In-Port At-Sea 

US Flagged 15.0% 85.0% 

Total 15.0% 85.0% 

 

6. Research 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Univesity 107 100.0% 1.0% 99.0% 

Total 107 100.0% 

 

Subgroup In-Port At-Sea 

Univesity 1.0% 99.0% 

Total 1.0% 99.0% 

 

7. Great Lakes and others 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Auto 0 0.0% 15.0% 85.0% 

Bulk 6 4.3% 15.0% 85.0% 

Container 1 0.7% 15.0% 85.0% 

Cruise 14 10.0% 15.0% 85.0% 

General Cargo 36 25.7% 15.0% 85.0% 

RORO 6 4.3% 15.0% 85.0% 

Special Carrier 68 48.6% 15.0% 85.0% 

Tanker 9 6.4% 15.0% 85.0% 

Total 140 1.0 

 

Subgroup In-Port At-Sea 

Auto 0.0% 0.0% 

Bulk 0.6% 3.6% 

Container 0.1% 0.6% 

Cruise 1.5% 8.5% 

General Cargo 3.9% 21.9% 

RORO 0.6% 3.6% 

Special Carrier 7.3% 41.3% 

Tanker 1.0% 5.5% 

Total 15.00% 85.00% 

 
D-3 

8. Government 

Subgroup Population 

Population 

Fraction In-Port At-Sea 

Pilot Boat 0.0% 

USCG - Patrol 291 100.0% 95.0% 5.0% 

USCG - Buoy Tender 0.0% 

USCG - Harbor Tugs 0.0% 

Total 291 100.0% 

 

Subgroup In-Port At-Sea 

Pilot Boat 

USCG - Patrol 95.0% 5.0% 

USCG - Buoy Tender 

USCG - Harbor Tugs 

Total 95.0% 5.0%