July 2, 1998

Intelligent Systems Division • National Institute of Standards and Technology • Gaithersburg MD 20899

Submitted By:

Intelligent Systems Division

National Institute of Standards and Technology

Gaithersburg, Maryland 20899

To:

Gene M. Remmers, Code 334

Office of Naval Research (ONR)

800 N. Quincy St.

Arlington, VA 22217-5666

Survey of Cargo 

Handling Research

Relative to the Mobile Offshore Base (MOB) Needs
Project Title

ADMINISTRATIVE INFORMATION 1

ADMINISTRATIVE INFORMATION

Project Title

Survey of Cargo Handling Research Relative to the Mobile Offshore 

Base Needs

ONR Order No.

N00014-97-F-0196

Responsible Person / Organization

Gene M. Remmers, Code 334

Office of Naval Research (ONR)

800 N. Quincy St.

Arlington, VA 22217-5666

Performing Organization

National Institute of Standards and Technology

Intelligent Systems Division

Building 220/ Office B-127

Gaithersburg, MD 20899

Principal Investigators

Mr. Roger Bostelman Phone: 301-975-3426

Email: rbostelman@nist.gov

Mr. Ken Goodwin Retired

The authors would like to acknowledge critical contributors to this report 

including: Information providers, Debbie Russell for scanning many 

included images, NSWC Reviewers, MURI Reviewers, and ONR 

Reviewers.
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2 Intelligent Systems Division • National Institute of Standards and Technology

TABLE OF CONTENTS

EXECUTIVE SUMMARY ...........................................5

Purpose...........................................................................5

Scope..............................................................................5

Background ....................................................................5

Requirements..................................................................7

Crane Technology ..........................................................7

Conclusions....................................................................8

Recommendations..........................................................9

PURPOSE ....................................................................10

SCOPE .........................................................................11

BACKGROUND .........................................................12

T-ACS Ships.................................................................12

Rider Block Tagline System.........................................12

Joint Logistics Over the Shore .....................................12

JLOTS Master Plan......................................................13

Advanced Technology Demonstration Proposal ..........13

REQUIREMENTS ......................................................15

Reach............................................................................15

Height...........................................................................16

Crane Lift Capacity......................................................18

MOB Container Storage/Stacking/Selective Retrieval 18

Longitudinal Crane Motion Along MOB.....................19

Docking and Mooring to the MOB..............................19
Principal Investigators

Table of Contents 3

Airspace Restrictions ...................................................19

MOB Structural Side Loading .....................................20

Crane Stowage..............................................................21

Operations in High Sea States......................................22

MOB Cargo Handling Requirements In Sea State 3....23

Lighter Loading............................................................23

Crane Throughput ........................................................24

NIST ACTIVITIES .....................................................26

Literature and Patent Searches.....................................26

Site Visits......................................................................26

MOB Contractor Reviews............................................27

Other.............................................................................27

CRANE TECHNOLOGY DEVELOPMENT ..........28

Port Crane Anti-Sway Reeving ....................................29

Port Crane Anti-Sway Control.....................................34

Sensors .........................................................................40

Motion Prediction.........................................................43

Horizontal Motion Control...........................................45

Offshore Platform Resupply.........................................52

Vertical Motion Compensation ....................................54

Crane Designs-Structures and Reeving........................58

Wave Motion Damping ................................................59

Integrated Motion Control............................................61

Dynamical Systems......................................................65

Winches and Drives......................................................66

Container Terminal Automation...................................67
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Material Handling Alternatives....................................69

Simulation ....................................................................70

CONCLUSIONS ..........................................................72

RECOMMENDATIONS ............................................73

REFERENCES ............................................................75

Executive Summary......................................................75

Purpose.........................................................................75

Background ..................................................................75

Requirements................................................................75

Crane Technology Development ..................................76

Port Crane Anti-Sway ...........................................................76

Sensors ..................................................................................77

Motion Prediction .................................................................77

Horizontal Motion Compensation .........................................77

Offshore Platform Resupply .................................................78

Vertical Motion Compensation .............................................78

Crane Designs .......................................................................78

Wave Motion Damping .........................................................79

Integrated Motion Control .....................................................79

Dynamical Systems ...............................................................79

Winches, Drives ....................................................................79

Container Terminal Automation ............................................79

Material Handling .................................................................80

Simulation .............................................................................80

BIBLIOGRAPHY .......................................................81

Control..........................................................................81

Heave Compensation....................................................82

Container Terminal Automation...................................82

POINTS OF CONTACT ............................................83
Purpose

EXECUTIVE SUMMARY 5

EXECUTIVE SUMMARY

Purpose

The Mission Need Statement for the Mobile Offshore Base (MOB) calls 

for a capability to perform full logistics support through Sea State 3, 

including waves of approximately 1.6 m (5 ft). However, a technical 

crane capability to do loading and unloading of cargo containers in Sea 

State 3 has not yet been demonstrated.

The Office of Naval Research (ONR) MOB program management team 

has recognized crane development as a critical technology that will be 

necessary for any feasible MOB. ONR has requested the National 

Institute of Standards and Technology (NIST) to assess the current state 

of practice in crane automation and motion compensation. This report is 

intended to establish a baseline and identify research needed to satisfy 

any gaps in the requisite technology.

Scope

The scope of this report will include cranes and other automation 

technology to achieve the lift on/lift off (LO/LO) transfer of cargo. This 

will include containers and break bulk cargo, such as tanks and causeway 

sections. Emphasis will be primarily upon the transfer of containers 

between the MOB and cargo container ships, landing craft, and lighters. 

This report will not deal with loading and unloading cargo brought by 

aircraft to the flight deck. Such cargo will be handled by specialized forklifts, rolling equipment, ramps, and elevators. 

Also, it will not address Roll On/Roll Off (RO/RO) cargo (such as 

trucks), nor bulk liquids transfer.

Background

The current need for off-loading ships where port facilities are not 

available or inadequate was recognized during the Vietnam war when 

cargo ships waited up to six months or more to unload. 

Following the Vietnam war, the Navy undertook a search for at sea cargo 

handling alternatives. This led to the design, construction and deployment in the 1980s and 90s of a fleet of 10 Keystone State Class Auxiliary 

Crane Ships (T-ACS). These are container ships which have up to three 
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6 Intelligent Systems Division • National Institute of Standards and Technology

twin-boom pedestal cranes to lift containers or other cargo from itself or 

adjacent vessels and deposit it on a pier or into lighterage. 

To restrain horizontal pendulation (swinging) of the load, T-ACS cranes 

were equipped with a Rider Block Tagline system (RBTS) consisting of a 

rider block, which can be moved up and down the lift line, and two 

winch-controlled taglines. Crane operators control the height of the rider 

block and the pull of the taglines by foot controls. They control the slew 

and luff of the boom and the height of the hook with hand controls. 

In Joint Logistics Over The Sea (JLOTS) exercises, it has been 

determined that the operators do not fully utilize the RBTS. As summarized in [1] [Bird], “a general consensus for sea state (SS) 3 is: maximum 

relative vertical displacements are approximately ±3 m (±10 ft) over the 

lighterage with maximum relative vertical velocities at approximately 

±2m/s (±7 ft/sec) over the lighterage.” Crane ship roll is “the largest contributor to relative vertical displacement.” This concensus is based on 

motion studies conducted by the Naval Coastal Systems Center (NCSC), 

the Naval Civil Engineering Laboratory (NCEL), the Massachusetts 

Institute of Technology (MIT), the Stevens Institute of Technology, and 

others. [1] [Bird] Operators do not get an opportunity to practice under 

such conditions and consequently are not trained adequately for the task. 

Current lighters can not operate in SS 3. The Navy does not have a current capability to off-load cargo containers in Sea State 3 or higher. A sea 

state 3 capable system (Joint Modular Lighterage System (JMLS)) is in 

development and is slated for procurement.

In the early 1980s the Navy undertook research to develop a Platform 

Motion Compensator (PMC) to deal with relative vertical motion. The 

original PMC design and concept was developed by EG&G. A prototype 

PMC was installed on the KEYSTONE STATE (T-ACS 1) and was used 

for a short time under SS 2 or less during the J-LOTS II exercise at Ft. 

Story, Virginia during the fall of 1984. While the PMC prototype was a 

technical success, the PMC was not implemented in the fleet because of 

its perceived cost and complexity.

Under the JLOTS Master Plan, three critical technologies are under 

development:

Rapidly Installed Breakwater (RIBS)

Joint Modular Lighter System (JMLS)

Sea State 3 Crane 

The Sea State 3 Crane has been accepted as an Advanced Technology 

Demonstration (ATD) to start in FY00. Its objective would be to demon-
Requirements

EXECUTIVE SUMMARY 7

strate shipboard crane pendulation control, for throughput of 300 containers per day per ship in sea state 3. It will employ non-linear, dynamic, 

control algorithms, some of which are now under development under 

ONR 6.2 supported research. The ATD is budgeted at approximately $9.9 

million over 3 years. 

Requirements

MOB crane requirements have evolved from NIST laboratory research 

and development of MOB cargo crane concepts. Additional input has 

been provided by several MOB concept developers also under contract to 

DARPA and the ONR.

The MOB cranes must be similar in size and capacity to the port cranes 

that load container ships. They must have similar reach, height, hook 

height, and lift capacity. They must be able to lift 23 t containers @ 36 m 

(from MOB), 72 t tanks @ 22 m, and 100 t causeway sections @ 11 m. 

In addition, the MOB cranes must meet several special (currently 

assumed) requirements because of the operating conditions of the MOB. 

Cranes must traverse the length of container ships in order to reach all 

cargo cells. They cannot project above the plane of the flight deck during 

air operations. Because of this constraint, the cranes must be mounted on 

the side of the MOB, which may require a stronger structure to support 

the cranes. During transit and storms, it will be necessary to secure or 

stow the cranes, preferably where they can be easily maintained. In order 

to operate a majority of the time in many operating areas of interest 

around the world, the MOB must have the capability to load ships and 

lighters in Sea State 3. Sea State 4 capabilities for loading container ships 

would be highly desirable. Finally, the cranes must be capable of loading 

many containers in a single day to support various deployment missions.

Crane Technology

Crane technology relevant to the MOB needs has been developed in several streams of research, development, and demonstration. 

A primary source of technology development has been the Joint Logistics 

Over the Shore (JLOTS) program to develop a capability to off-load 
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8 Intelligent Systems Division • National Institute of Standards and Technology

cargo in Sea State 3, 1.6 m (5 ft) significant wave height, weather conditions. 

Other major developments have come from the evolution of port cranes, 

resupply of off-shore platforms, and industrial, university, and government laboratory crane research.

Conclusions

Horizontal pendulation control has been demonstrated by the Rider 

Block Tagline System (RBTS), Integrated RBTS (IRBTS), feed forward 

control, and other methods.

Vertical motion compensation was demonstrated by NAVSEA/Coastal 

Systems Services (CSS) and EG&G on T-ACS 1, but not implemented in 

the T-ACS fleet.

MOB cargo container operations will require rapid, 6-D compensation of 

ship motions that are not as severe as lighter loading, but still on the order 

of ±1 meter for 5 second wave periods in sea state 3.

Enabling technologies for 6-D motion compensation have been developed and demonstrated in the laboratory and wave tank, but not yet demonstrated in full scale operations. 

The Rider Block Tagline System could be significantly improved by the 

Craft Engineering Inc. IRBTS project, which will insert computer coordinated control of the rider block to constrain horizontal motions. A prototype system has been installed and demonstrated at dockside but has not 

yet been demonstrated at sea. However, vertical motion compensation 

will not be achieved by the Integrated RBTS.

The JLOTS Advanced crane control ATD, if developed successfully, 

could provide much of the technology needed for a MOB crane.

We believe that a compound control system, including wave sensing with 

feed forward control, combined with fast, closed loop control of relative 
Recommendations

EXECUTIVE SUMMARY 9

motion between the load and lighter or container ship will be required. 

Sensors of incoming waves are critical to feed forward control. 

Recommendations

Simulate and model the cranes required for cargo handling.

Develop the advanced computer control system necessary to achieve 

wave motion compensation.

Develop and demonstrate full scale integrated 6-D cargo container control for MOB operations.
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10 Intelligent Systems Division • National Institute of Standards and Technology

PURPOSE

The Mission Need Statement for the Mobile Offshore Base (MOB) calls 

for a capability to perform full logistics support through Sea State 3, with 

significant wave height of approximately 1.6 m (5 ft). [2][JPD]

However, a technical capability to load and unload cargo containers in 

sea state 3 has not yet been demonstrated.

The Office of Naval Research (ONR) MOB program management team 

has recognized crane development as a critical technology that will be 

necessary for any feasible MOB. ONR has requested the National 

Institute of Standards and Technology (NIST) to assess the current state 

of practice in crane automation and motion compensation. This report is 

intended to establish a baseline and identify research needed to satisfy 

any gaps in the requisite technology.
Recommendations

SCope 11

SCOPE

The scope of this report will include cranes and other automation 

technology to achieve the lift on/lift off (LO/LO) transfer of cargo. 

This will include containers and break bulk cargo, such as tanks and 

causeway sections. Emphasis will be primarily upon the transfer of 

containers between the MOB and cargo container ships, landing craft or 

lighters. 

This report will not deal with loading and unloading cargo brought by 

aircraft to the flight deck. Such cargo will be handled by specialized forklifts, rolling equipment, ramps, and elevators. 

Also, it will not address Roll On/Roll Off (RO/RO) cargo (such as 

trucks), nor bulk liquids transfer.
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12 Intelligent Systems Division • National Institute of Standards and Technology

BACKGROUND

History does not tell us whether cranes were used to build the Egyptian 

pyramids around 2500 B.C. [3][Wislicki] If we are to believe recent Hollywood movie makers, cranes were used to load stone blocks on barges to 

go up the Nile River.

The current need for off-loading ships where port facilities are not available or inadequate was recognized during the Vietnam war when cargo 

ships were kept waiting up to six months to unload. 

T-ACS Ships

Following the Vietnam war, the Navy undertook a search for alternatives, 

which led to the design, modification and deployment in the 1980s and 

90s of a fleet of 10 Keystone State Class Auxiliary Crane Ships (T-ACS) 

which are container ships which have up to three twin boom pedestal 

cranes to lift containers or other cargo from itself or adjacent vessels and 

deposit it on a pier or into lighterage. 

Rider Block Tagline System

To restrain horizontal pendulation (swinging) of the load, T-ACS cranes 

were equipped with a Rider Block Tagline system (RBTS) consisting of a 

rider block with two pulleys, which can be moved up and down the lift 

line, and two winch-controlled taglines. Crane operators control the 

height of the rider block and the pull of the taglines by foot controls. 

They control the slew and luff of the boom and the height of the hook 

with hand controls. [4] [Cecce]

Joint Logistics Over the Shore

Joint Logistics Over-The-Shore is defined as “... the loading and unloading of ships without the benefit of fixed port facilities in either friendly or 

undefined territory and, in the time of war, during phases of theater development. LOTS operations are conducted over unimproved shorelines, 

through fixed ports not accessible to deep draft shipping, and through 

fixed ports that are not adequate without the use of LOTS capabilities.” 

[5] [Vaughters]

In Joint Logistics Over The Shore (JLOTS) exercises, it has been found 

that the operators do not fully utilize the RBTS. Operators do not get an 
JLOTS Master Plan

Background 13

opportunity to practice under high sea state (SS) conditions (e.g. SS 3) 

and consequently are not adequately trained for the task.

“The T-ACS demonstrated the capability to move containers in SS 3 as 

long as the sea conditions consisted of small period waves, i.e. wave/chop 

rather than long period ground swells. Navy lighterage did not demonstrate a SS3 capability. Whenever the T-ACS became exposed to ground 

swells on her beam she would begin to roll slightly, about 1 degree, 

which induced spreader bar pendulation. The controls for the RBTS were 

difficult to use and have an unacceptable time lag of 6 seconds in transitioning from raising the rider block to tensioning the taglines... As such, 

the crane and RBTS are not integrated and lack the control characteristics 

and functions needed for the operator to control the hook at all times so 

that load pendulation cannot start.” [6][Department of Defense]

Current lighters can not operate in SS 3. The Navy does not have a current capability to off-load cargo containers in SS 3 or higher.

JLOTS Master Plan

The JLOTS Master Plan, jointly prepared by the Army and Navy, is the 

synthesis of critical, interdependent, enabling technologies, training, and 

command and control functions designed to meet Service and unified 

command Logistics Over-the-Shore (LOTS) and Joint LOTS (JLOTS) 

requirements. The CINC’s require a safe, sustained, service-interoperable 

LOTS/JLOTS operational capability through sea state 3 to support expeditionary, force reception, and theater sustainment logistics. Utilizing the 

“system of systems” philosophy, the JLOTS Master Plan defines the intricacies of heavy weather JLOTS operations and provides both a near-term 

solution to the sea state 3 problem to meet the CINC requirements and a 

link to the future. [7] [JLOTS Master Plan]

Under the JLOTS Master Plan, three critical technologies are under 

development:

Rapidly Installed Breakwater (RIBs)

Joint Modular Lighter System (JMLS) [8] [Webb]

Sea State 3 Crane 

Advanced Technology Demonstration Proposal

The Sea State 3 Crane has been accepted as an Advanced Technology 

Demonstration (ATD). Its objective would be to demonstrate shipboard 
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14 Intelligent Systems Division • National Institute of Standards and Technology

crane pendulation control, for throughput of 300 containers per day per 

ship in SS 3. It will employ non-linear, dynamic, control algorithms, 

some of which are now under development under ONR 6.2 supported 

research.

The current JLOTS 6.2 program includes the Applied Research Logistics 

Technology Program (PE62233N) Replenishment Project. The project 

includes: Advanced Shipboard Crane Technology, VLS At-Sea Rearming, Magnetostrictive Actuators for Weapons Elevator Applications, 

which are the topics relevant to this report. Objectives for the project are 

to improve performance, reduce total cost of ownership, and facilitate 

reduced manning initiatives of replenishment systems by application of 

science and technology. [6]

The Joint Logistics Over-the-Shore (JLOTS) executive plan through 

1998 is to develop non-linear algorithms, evaluate control system concepts, perform concept trade-offs and model tests, and enhance the 

RBTS. This project links the container ship, shipboard cranes, lighterage, 

shore cranes, and beach clearance. 

Future plans advance toward an At-Sea demonstration of the systems 

developed. The ATD is budgeted at $9.9 million over 3 years and is 

scheduled to start in FY00. [9] Rausch
Reach

Requirements 15

REQUIREMENTS

The following requirements have been identified by NIST for MOB crane 

capabilities. These requirements are discussed in greater detail in a separate NIST report. [10][Goodwin]

Two sets of requirements are discussed below. The first set are typical of 

a port crane for loading container ships. They include reach, height, and 

lift capacity at various distances.

The second set of requirements are specific to the MOB because of its 

special characteristics. These include requirements to operate without 

intruding into airspace, to move along the length of a MOB section to 

reach the cells of container ships, structural support on the side of a 

MOB, operating in high sea states, and lighter loading.

Reach

Cranes must be able to reach the far side of the largest container 

ships currently in use (Panamax class ships). 

This requires almost a 50 m reach when fenders are considered. The distance from the outer edge of the MOB to the ship wall berthed against the 

MOB will be 3 m (e.g. compressed fender) to 4.5 m (e.g. non-compressed fender). Figure 1 shows a Panamax ship berthed against the 

MOB with a compressed fender.
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16 Intelligent Systems Division • National Institute of Standards and Technology

FIGURE 1. Cut-away view of a Panamax ship berthed against the MOB with a compressed fender

Height

Cranes must clear the superstructure of the ship and all shipboard 

obstacles.

This means that the crane booms must be luffed or hinged so that they 

can be raised while container ships are docking.

The crane must have sufficient hook height to handle shipboard 

stacking of containers.

For the design shown in Figure 1, the MOB flight deck and top of the rail 

crane, will only be 36.5 m above the waterline during typical operations. 

The top container on a large, fully-loaded container ship may sit 23.2 m 

or more above the waterline (not considering vertical wave motion). This 

leaves only 13.3 m (= 36.5 m - 23.2 m) from the MOB flight deck to the 

waterline

MOB flight deck

MPS AMSEA Class Ship

(cross section)

containers

crane boom
Height

Requirements 17

top of the highest container. This means that the crane boom must be thin 

vertically to allow the highest possible hook height. 

Figure 2 shows the crane (28.2 m above the waterline) and container 

stack height for 3 containers (23.2 m above the waterline). The minimum 

crane hook height is approximated at 25.8 m above the waterline. This 

allows retrieval of cargo containers stacked at most 2 high on the top 

deck of an MPS AMSEA Class Ship. 

FIGURE 2. Height Restrictions of the rail crane for large ships (MPS AMSEA Class ship) 

To unload containers stacked 3 high on this ship, the crane must retrieve 

the top containers in sequence from closest to farthest from the MOB. An 

MOB

36.5

23.2 28.2

waterline

crane height

top ship deck container stack

flight deck height above waterline

m

m

m
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18 Intelligent Systems Division • National Institute of Standards and Technology

additional 2.5 m hook height would be required to lift a container over 

the top stacked container. 

To load or unload containers stacked higher than three levels on the MOB 

design shown, the MOB would have to ballast up to a higher level, or an 

alternative crane design, such as a luffing boom crane, would be required.

Crane Lift Capacity

Cranes must lift 23 t containers from the far beam of Panamax class 

ships (about 50 m from the MOB frame).

Cargo is containerized mainly in 6 m to 16 m long x 2.5 m wide x 2.5 m 

high (20 ft to 52 ft long x 8 ft wide x 8.5 ft high) standard ISO containers. 

LO/LO operations may also include break bulk and palletized cargo. 

Estimated, maximum, cargo weight positioned at a distance of 36 m 

(118ft) from the MOB edge is 23 t (25 tons).

Cranes should be capable of lifting break bulk cargo, vehicles, and 

barge sections.

This will provide lift of a 72 t tank at the center of a Panamax class ship 

(22 m) and lift of a 102 t causeway section at the near side of a ship 

(11m).

Cranes may be required to lift disabled RO/RO vehicles from ramps.

In the event that RO/RO vehicles or other equipment becomes immobilized, cranes may be required to remove such items (up to the maximum 

crane lift capacity) from ramps to continue cargo retrieval/loading operations.

MOB Container Storage/Stacking/Selective 

Retrieval

The MOB should have the capability to store and retrieve individual 

containers, remove pallets, and repackage containers on demand.

Although containerized cargo is simple and efficient for moving high 

volumes of cargo, Special Forces operations, OMFTS operations, and 

“marrying up” of MPF equipment with troops aboard the MOB will typically need cargo moved in smaller quantities, usually pallet sized loads. 

Therefore, an area for break-out, marshalling, and staging will be 
Longitudinal Crane Motion Along MOB

Requirements 19

required. A capability to access multiple containers and load pallets and/

or containers is needed.

Longitudinal Crane Motion Along MOB

Cranes must access container cells at various positions along the 

length of container ships. 

Fixed cranes would not be able to reach many cells of container ships 

moored alongside the MOB without warping the ship along the MOB. 

While moving the ship is technically possible, it is difficult and time consuming. Port cranes typically move on rails along the length of container 

ships. Similarly, it will be necessary for MOB cranes to move along the 

length of container ships. 

However, if a container ship is longer than a MOB section, it may be necessary to warp the ship so that cranes can reach more cells. Some preliminary studies have shown that mooring lines can withstand the dynamic 

loads of container ships moored to the MOB in sea state 4. [11] [Seaworthy Systems] 

Docking and Mooring to the MOB

The MOB must have a capability of docking and mooring container 

ships. Container ships typically do not have sufficient dynamic positioning capability to dock with a MOB. In harbors, container ships are 

assisted by tugs. It will be necessary for the MOB to have its own tugs, or 

some automated docking system to achieve docking and mooring.

Airspace Restrictions

Cranes should not interfere with airspace above the flight deck.

Cranes must not protrude into the airspace directly above the flight deck 

during air operations (see Figure 3). The vertical crane support tower 

commonly used to support and luff typical port rail or luffing cranes may 

not be feasible for the MOB, at least not on both sides of the flight deck. 

It might be feasible on one side where there are air control towers. 

However, there are examples of low-profile, rolling boom cranes currently being used in ports. These low profile booms suggest a similar rail 

crane design. They have larger rail cross sections than the high profile 
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20 Intelligent Systems Division • National Institute of Standards and Technology

cranes because they must support the weight of the boom and cargo as a 

cantilevered load.

Cranes should only rarely protrude above the plane of the flight 

deck.

Air operations may require parking of aircraft with wings or tails overhanging the edge of the flight deck. Figure 3 shows “potential aircraft 

parking” extending 12 meters beyond the MOB edge. This would interfere with luffing crane booms or their longitudinal movement along the 

length of container ships during crane operations. For larger aircraft, such 

as the C-17 transport, takeoffs and landings may be made with one wing 

tip beyond one edge of the flight deck. The degree of interference 

between aircraft operations and crane operations depends upon the air 

traffic to and from the MOB.

FIGURE 3. MOB Potential Airspace Restrictions

MOB Structural Side Loading

The MOB structure should support cranes mounted on the side of 

the MOB. 

To avoid interference with aircraft operations above the flight deck, 

cranes must mount on the side of the MOB (see example in Figure 3). 

Therefore, the MOB structure must provide hard points that can support 

the load of the crane boom, the crane trolley, and a variety of cargos that 

are lifted at specified reaches. We have serious concerns about the forces 

waterline

MOB flight deck

crane boom

crane at 70° raised

position to allow 

ship docking

Assumed Restricted Airspace

12.0

Potential Aircraft

Parking

MOB end view

m
Crane Stowage

Requirements 21

that a fully loaded rail crane would exert on the MOB. A fully loaded 

luffing boom crane would generate much lower forces on the MOB than a 

rail crane, but would require the lowest deck to extend out beyond the 

flight deck. This is not provided in some current MOB designs.

Crane Stowage

The cargo cranes should be stowed for travel and excessive sea states.

When not in operation, the cranes should be stowed, preferably in locations that provide for convenient servicing. The preferred method of 

stowing a crane is to move it to a home position where it can be retracted 

into a compartment that is internal to the MOB (see Figure 4). This 

option places the crane inside where it can be easily serviced. An alternative stowage concept is to rotate the crane into a position beside the 

MOB, as shown in Figure 5. This method can be used for either rail or 

luffing cranes.

FIGURE 4. Crane Stow by Retracting the Minimum Length (shown in meters) of Crane Boom on rails 

and into the MOB

waterline

MOB flight deck crane boom

1.0

3.1

crane rails

fender

38.3 m trolley

m

m
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22 Intelligent Systems Division • National Institute of Standards and Technology

FIGURE 5. Alternative Stowage concept. The top view of a luffing crane is shown.

Operations in High Sea States

The MOB must be able to perform lift-on and lift-off (LO/LO) operations under weather conditions up to sea state 3, and preferably in 

sea state 4.

The Mission Needs Statement For the Mobile Offshore Base (MOB) 

calls for an operational capability in sea state 3. [2] It would be highly 

desirable to conduct cargo handling operations in sea state 4 allowing 

potentially increased operation time above lower sea states. The maximum operational sea state in which cargo loading or unloading operations are to be performed is estimated at sea state 4. Operations would be 

done only with large cargo container ships, since lighters would not be 

able to operate in sea state 4. Therefore, the design goal for cranes is to be 

top view groove including crane

traversing rails

crane support structure rotary joint

Crane in LO/LO Operational State

Crane Stow Position

MOB Flight Deck
MOB Cargo Handling Requirements In Sea State 3

Requirements 23

able to perform lift-on and lift-off (LO/LO) operations under conditions 

up to sea state 4.

MOB Cargo Handling Requirements In Sea State 3

The MOB crane must compensate for longitudinal, lateral, and vertical ship motions relative to the MOB in high seas 

Maximum motions for a T-ACS 4 Auxiliary Crane Ship relative to the 

MOB in sea state 4 are estimated to be: [12][Cooper]

Displacement Acceleration

Longitudinal: 0.51 m (1.67 ft) 0.94 g x 100

Lateral: 1.12 m (3.69 ft) 2.16 g x 100

Vertical: 1.12 m (3.66 ft) 3.21 g x 100

Shipboard cargo motion compensation could be achieved by using automated rigging control as with the NIST RoboCrane technology. [13] 

[Albus] 

This advanced technology would allow crane operators to retrieve cargo 

rapidly, even while at high sea states, by using an Intelligent Spreader 

Bar, with sensors and computer-assisted control that follows the cargo 

motion.[14] [Dougherty]

Lighter Loading

Loading containers from the MOB to lighters will be necessary.

The U. S. Marine Corps vision of Operational Maneuver from the Sea 

(OMFTS), if implemented, would eliminate the need for displacement 

hull lighterage by bypassing the beach and moving cargo by aircraft from 

the seabase. [15][Krulak]

However, the Army will continue to require lighterage. The larger Army 

lighterage (LSV, LCU2000) and the proposed Joint Modular Lighter System (JMLS) are most likely to be used for lighterage operations from the 

MOB. [8][Webb] Smaller lighters could potentially be used, depending 

upon shore to MOB distance and weather conditions.

Motions of lighters and other small ships in sea state 4 (assuming they are 

operable at this sea state) are expected to be considerably larger than 

motions of container ships. Wave motion compensation will require more 
Survey of Cargo Handling Research

24 Intelligent Systems Division • National Institute of Standards and Technology

horsepower since the smaller ships have greater relative motion, due to 

their size, than larger vessels. 

It may be feasible for the MOB to replenish the Vertical Launch System 

(VLS) of DDG 51 ships, a capability that does not exist in the fleet now. 

[16][Bouchoux]

Crane Throughput 

Operational cargo container throughput requirements are mission 

dependent, but could be set as high as 30 containers per hour per 

crane.

Desired crane throughput rates have been estimated differently by different organizations. The following cargo retrieval rate estimates represent 

different views of what may be required of a MOB.

• The current JLOTS throughput target, using the NSWC Advanced 

Shipboard Crane Motion Control System, is to unload 300 containers 

in one day per T-ACS Ship (e.g. approximately 4 booms working 

simultaneously). Current capabilities are to make one lift about every 

7 minutes.

• Brown and Root estimated that it would take 120 hours to load 1720 

containers, at a rate of 8 minutes per container, to support an Army 

Division.

• McDermott estimated that, with more cranes, it would take only 24 

hours to load 720 containers, at a rate of 6 minutes per container to 

support a Marine Expeditionary Force.

• The Center for Naval Analyses has estimated that support of a Maritime Prepositioning Force for 2010 (MPF 2010) will require off loading of 4,166 containers with no currently specified rate. [17, 18] 

[Nance] Containers are estimated to hold 16 pallets each. Without containers, typically 4 to 6 pallets can be crane-lifted using a net per lift.

• Approximate maximum port crane throughput is about 30 containers 

per hour (i.e. 2 min/container). While some port cranes are capable of 

unloading a maximum of 60 containers per hour, crane operation typically does not achieve this rate due to delays associated with ground 

transportation of cargo.

We believe that it is technically possible for MOB LO/LO operations to 

match port crane LO/LO rates (2 minutes per container) under conditions 

of SS 4, provided that an advanced crane control system is developed and 
Crane Throughput

Requirements 25

used for the MOB. With advanced crane control on a minimum of seven 

cranes, each operating 20 hours per day, the MOB could meet the most 

stringent containerized, load-out requirement for the MPF 2010 in one 

day.
Survey of Cargo Handling Research

26 Intelligent Systems Division • National Institute of Standards and Technology

NIST ACTIVITIES

• Survey Crane Automation and Motion Compensation Relative to the MOB

• Develop Functional Criteria for MOB Cargo Container Handling

• Participate in MOB Mission Requirements and Performance Measures Working 

Group and Contractor Reviews

Literature and Patent Searches

Completed a literature search, interviews, site visits, and MOB contractor 

reviews as listed below:

Literature Search

• Literature search through NIST library, targeted at the following key words: Crane, 

Anti-sway, Control cable systems

• Government Reports Search through NIST library targeted at the following key 

words: Crane, Anti-sway, Control cable systems

Patent Search

• United States and International Patent Searches through NIST library targeted at the 

following key words: Crane, Anti-sway, Control, Cable Systems

Site Visits

• Ted Vaughters, Art Rausch, and Frank Leban, NSWC Carderock, Advanced Crane 

Research Program and to view current NRL experiments in crane load pendulation 

measurements using a scale T-ACS model in a wave tank.

• Rob Overton, Wagner Associates, and Anthony Simkus, Virginia International Terminal to discuss recent developments in anti-sway control as applied to port cranes.

• Dexter Bird, Craft Engineering, Hampton Virginia to discuss recent Rider Block 

Tagline System (RBTS) Developments

• Yvan Beliveau, Virginia Polytechnic Institute to discuss recent developments in antisway computer algorithms and mechanical enhancements. Also visited ONR MultiUniversity Research Initiative, Non-Linear Active Control of Dynamical Systems.

• Sandeep Vohra and Micheal Todd, Naval Research Laboratory for a demonstration 

of the 1/24 scale model T-ACS crane on a 6-axis motion simulator.

• Vito Milano, Center for Naval Analysis to discuss the Maritime Prepositioning Force 

2010 study.

• Theodore Mordfin, Advanced Marine Enterprises to view and test the T-ACS crane 

simulator.

• Cdr. Lehr and Lt. Cdr. Dettbarn, N422-Navy Captain W. Lee Harris
MOB Contractor Reviews

NIST ACTIVITIES 27

• Max D. Weber, David Whalen, Steven Naud, Coastal Systems Station at Panama 

City, Florida, Dahlgren Division Naval Surface Warfare Center, Code A42, to discuss history of crane automation and current plans.

• Marty Fink, NAVSEA to discuss NAVSEA programs and other background information regarding crane/cargo handling research.

MOB Contractor Reviews

• Attended ONR MOB Contract Review meetings for the following companies:

1.Kvaerner

2.August Design Inc.

3.Syntek Technologies, Inc.

4.Atlantic Research Corp.

Other 

• Presented Cargo Container Handling Requirements at MOB Contractor Conference, 

October 21-24,1997

• JLOTS Board Meeting, December 2, 1997

• Presented Cargo Container Handling Requirements at Requirements Working 

Group, January 29, 1998.
Survey of Cargo Handling Research

28 Intelligent Systems Division • National Institute of Standards and Technology

CRANE TECHNOLOGY DEVELOPMENT

Crane technology, which is relevant to meeting the MOB requirements, 

has been developed in several streams of research, development, and 

demonstration. 

The primary source of technology development has been the Joint Logistics Over the Sea (JLOTS) program to develop a capability to off-load 

cargo in Sea State 3, 1.6 m (5 ft) waves, weather conditions. 

Other major developments have come from the evolution of port cranes, 

off-shore drilling industry resupply of off-shore platforms, and industrial, 

university, and government laboratory crane research.

Following the war in Vietnam, the Navy undertook a series of studies for 

alternatives, which led to the design, construction and deployment in the 

1980s and 90s of a fleet of 10 Keystone State Class Tactical Auxiliary 

Crane Ships (T-ACS). They are container ships to which have been added 

up to three twin boom pedestal cranes which will lift containers or other 

cargo from itself or adjacent vessels and deposit the cargo onto a pier or 

into lighterage. [19] [Jane’s Ships] 

The T-ACS cranes were equipped with a Rider Block Tagline system 

with two winch-controlled taglines to restrain horizontal pendulation 

(swinging) of the load. Their crane operators control the height of the 

rider block and the pull of the taglines by foot controls; while they control the slew and luff of the boom and the height of the hook with hand 

controls. [4] [Cecce]

In the 1980’s the Navy undertook research to develop a Platform Motion 

Compensator (PMC) that was to stabilize suspended crane loads using 

the RBTS. The original PMC design and concept was developed by 

EG&G. A prototype PMC was installed on the KEYSTONE STATE (TACS 1) and was used during the J-LOTS II exercise at Ft. Story, Virginia 

during the fall of 1984. [1] [Bird] The Platform Motion Compensator was 
Port Crane Anti-Sway Reeving

Crane Technology development 29

a technical success but, was not implemented because of its perceived 

cost and complexity. [20] [CNO] 

Port Crane Anti-Sway Reeving

A variety of reeving and structural supplements have greatly 

reduced sway in port cranes. 

Soest

Cornelius Soest, et.al. filed a patent for an anti-sway, anti-rotation mechanism for crane reeving which comprises four spaced-apart overhead 

sheaves on an overhead support. A lifting beam assembly has four pairs 

of lifting beam sheaves also spaced apart. A tool is attached to the lifting 

beam. Cables connect between the sheave quads with a V-shaped 

arrangement to prevent sway and rotation while operating the crane. [21]

[Soest]

Kleinschnittger

Andreas Kleinschnittger, University of Dortmund, Germany, proposed an 

eight-cable crane reeving system (see Figure 6) as part of his dissertation. 
Survey of Cargo Handling Research

30 Intelligent Systems Division • National Institute of Standards and Technology

The system is composed of eight independently controlled cables attaching the trolley to a suspended, square platform. [22] [Kleinschnittger]

FIGURE 6. Eight Cable Crane Reeving configuration proposed by Kleinschnittger

National Fisheries University of Pusan, Korea

Kim, et. al. of the National Fisheries University of Pusan, Korea 

describes in their paper, “Development of a Crane System for High Speed 

Transportation in Container Terminal,” control of a container crane system with the use of two trolleys (see Figure 7). They state that with a single trolley, requirements for the typical accelerating, constant, and 

decelerating intervals of trolley motion cannot easily be satisfied. Therefore, they propose an independently controlled, dual trolley system. 

Based on experimental results, the proposed system addresses key issues 
Port Crane Anti-Sway Reeving

Crane Technology development 31

of anti-sway, traversing time reduction and “swing of the grab” that is 

stopped at the end-point. [22] [Kim]

FIGURE 7. Dual trolley crane system configuration proposed by Kim

Shaper

Donald Shaper obtained a U.S. patent for an apparatus to stabilize against 

sway of a body suspended by cables from an overhead support. The apparatus includes first and second opposed rigid stabilizing members pivotally connected at the lower ends to the body. Also, guides carried by the 

overhead support are used for guiding the upper ends of the stabilizing 

members. Stabilizing members are used for pivotal and longitudinal 

movement relative to the overhead support and force transmission means 

interconnecting the stabilizing members. And also, for transmitting 

forces there between to generate substantially equal sway, without interfering with the raising and lowering of the body by the suspension cables. 

[24] [Shaper]

Bernaerts

Henry Bernaerts obtained a U.S. patent for an anti-sway device that uses 

roller chains (see Figure 8) to greatly restrict the lateral movement of the 

lifting lines suspended from hoists or cranes. The roller chain is suspended parallel to the lifting lines or lifting chains. The end is attached to 

the free end of the lifting lines. The other end of the roller chain is wound 

around a take-up reel that prevents the roller chain from going slack. 

Since the roller chains tend to be very stiff in a direction parallel to the 

pivotal axes of the roller links, the roller chain will tend to prevent the 
Survey of Cargo Handling Research

32 Intelligent Systems Division • National Institute of Standards and Technology

lifting lines from moving in the plane of the pivotal axes of the roller 

links. [25] [Bernaerts]

FIGURE 8. Graphics disclosed in Bernaerts patent (numbers are referenced in the patent).

Hasegawa

Shuji Hasegawa et.al. obtained a U.S. patent for a variable level platform 

suspended from the gantry of a cargo container handling gantry crane by 

a pair of scissors jacks (see Figure 9) with fleet through wire rope reeving 

for suspending a lifting spreader, whereby the platform effectively short-
Port Crane Anti-Sway Reeving

Crane Technology development 33

ens the spreader lift lines for reducing container sway and container handling cycle times. [26] [Hasegawa]

FIGURE 9. Graphics disclosed in Hasegawa patent (numbers are referenced in the patent)

Foit

Vilem Foit obtained a series of patents for anti-sway crane reeving, in 

which a winch drum is used to take up/payout cable through four separated snatch blocks, attached to an overhead frame, and suspend cables 

through four snatch blocks, attached to a spreader bar, to support and stabilize the load (see Figure 10). Two pairs of cables wrap around the same 

alternate snatch blocks to generate friction forces in response to swaying 
Survey of Cargo Handling Research

34 Intelligent Systems Division • National Institute of Standards and Technology

motions thereby dissipating swaying energy. The same anti-sway technique is applied for the other pairs of cables, also. [27, 28, 29] [Foit]

FIGURE 10. Graphics disclosed in Foit patent showing Anti-Sway Reeving

Port Crane Anti-Sway Control

Numerous advances have been made in port cranes and their control 

systems. This technology is available to be incorporated into any 

MOB crane design.

Anthony Simkus, at Virginia International Terminals, Inc. (VIT), 

together with Rob Overton, of Wagner Associates, have installed 

open loop, feed forward control on a port crane to reduce sway. This 

control provides smooth motions and increased throughput. It also 
Port Crane Anti-Sway Control

Crane Technology development 35

records motions taught by the operator and then allows playback for performing repetitive motions. 

Simkus

Tony Simkus and his associates at Virginia International Terminals have 

made a number of inventions to reduce sway and to optimize paths to 

provide smooth operations of port cranes. The crane has an elongated 

girder extending horizontally over the dock and the vessel. The crane can 

raise and lower the girder to change its elevation to minimize distance 

and time travel for the cargo. A trolley moves horizontally on the girder, 

and has a cargo engaging device that can be raised to become adjacent to 

the trolley. The cargo engaging device may be held rigidly against the 

trolley to permit large horizontal accelerations and velocities with virtually no attendant sway of the trolley or cargo. Paddles extending beneath 

the center of gravity can supplement the apparatus to further restrict 

sway. An operator cab moves independently of the trolley, allowing the 

operator several vantage points for viewing cargo movement.[30] [Davis]

Overton

Using a computer control system patented by Rob Overton, [31] [Overton] (see Figure 11), installed sensors on the winches are used to measure 

hook height and trolley position. The system then calculates velocity and 

acceleration of both. With a simulated model of the crane, it is able to 

predict load swing and use computer control to cancel sway of the load. 

The movements, load position as a function of time, and the weight are 

stored. Thereafter, in the Auto mode, the operator may entrust movement 

of the load to the control system, which causes the load to efficiently and 

safely traverse an optimum path (with minimum sway) in a minimum 

period of time. The operator is able to concentrate on movement of the 

load and the computer control virtually eliminates sway. Open loop, feed 

forward control in this situation provides fast and smooth operation. 
Survey of Cargo Handling Research

36 Intelligent Systems Division • National Institute of Standards and Technology

Manual control can be attained at any point during load movement. The 

operator takes manual control at the end of every move.

FIGURE 11. Learning Control System Block Diagram disclosed in Simkus patent (numbers are 

referenced in the patent) 

Overton

Through an ONR SBIR (Small Business Innovative Research), Robert 

Overton (Daniel H. Wagner Associates, Inc.) addressed crane control in 

sea state 3, efficiency and safety, seamless position demand/manual operations, improving the Rider Block Tagline System (RBTS) effectiveness, 

and development of commercial applications. The Computerized Antisway Crane Control System (CACCS) approach was outlined (see Figure 

12), including sensing the T-ACS motion, tracking a target on a lighter, 

calculating the path to the target, using modified 3-D double pulsed control and position demand to move the load, maintaining the load over the 
Port Crane Anti-Sway Control

Crane Technology development 37

target, and maintaining the RBTS within its work volume. 3D pendulum 

simulation snapshots were displayed showing experimental evaluation. 

Phase 2 plans are proposed as part of a Phase 2 SBIR, including model 

crane building, specifications addressed, algorithms tested, coding software modules, integration of the system on a T-ACS, and test at sea.[32] 

[Overton]

FIGURE 12. Overton patented Anti-sway Control System

Sandia National Laboratories

Gordon Parker, Michigan Technological University and Rush Robinett, 

Sandia National Laboratories have developed a control algorithm for a 

bridge trolley crane that suppresses the load pendulation. The control system outlined uses a configuration-dependent blend algorithm, combined 

with two inputs (operator induced sway and base excitation (sea condition) induced sway) to form the crane actuator inputs. [33] [Parker] 

Rushmer

Michael Rushmer obtained a patent on the use of the natural frequency 

n

 of a simple pendulum to estimate the velocity and displacement of the 

suspended load. A signal representative of measured load displacement is 

used to drive the estimated load displacement to the measured load dis-
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38 Intelligent Systems Division • National Institute of Standards and Technology

placement and modify the estimated velocity (see Figure 13). [34] [Rushmer]

FIGURE 13. Control System proposed in the Rushmer patent (numbers are referenced in the patent)

Lacarbonara

Lacarbonara, et. al. are studying new actuators for ship-mounted crane 

pendulation suppression under the ONR Multi-University Research Initiative Program at Virginia Polytechnic Institute. In the presentation, they 

offer four points including: Crane Actuation, Variable Geometry Trusses 

(VGT’s) (see Figure 14), Application to the Crane, and Preliminary 

Investigation of the Pendulation Suppression Truss (PST).

Under crane actuation, concepts considered are VGT’s, passive vibration 

isolation (base-mounted), nutation damping, tuned vibration absorbers 

(passive, semi-active, “virtual”), smart material (SM) cables, and a dou-
Port Crane Anti-Sway Control

Crane Technology development 39

bled pendulum (passive, semi-active, and sliding mass). [35] [Lacarbonara]

FIGURE 14. Variable Geometry Truss considered by Lacarbonara, Soper, and Pratt

Through the ONR MURI (Multi-University Research Initiative) Program, the Pendulation Suppression Truss (PST) has been investigated in a 

simplified model that shows the effect of a force applied to the crane load 

suspension cable to consider it as a means for dampening load oscillations. Equations of motions have been derived showing the constraints, 

analytical dynamics, and resulting motions. Open-loop resonance cancellation is currently being studied along with fixed-gain, nonlinear, state 

feedback, fuzzy, and neural strategies.

Rudnick

Siegfried Rudnick provides the details of cargo handling cranes self-optimizing digital control systems to move cargo quickly, precisely, and economically. Rudnick’s paper describes standard high performance 

systems, automatic controller tuning, rotary digitizers that measure hoist-
Survey of Cargo Handling Research

40 Intelligent Systems Division • National Institute of Standards and Technology

ing height, the stop and speed governed by crane load, and fast diagnostics. [36] [Rudnick]

Sensors

Several sensor systems have been developed for real-time motion 

measurement of ships, loads, and cranes.

Overton

Rob Overton, at Wagner Associates developed a sensor system (see Figure 15) for accurately measuring the position of a moored container ship 

relative to a fixed pier. Measurement occures after loading or unloading 

each container on the ship and including a processor mechanism that 

combines the measured relative position with previously acquired data. 

This indicates the ship position prior to the loading and unloading of the 

previous container. Also, it utilizes the combined data to facilitate automatic control of placing or removing a subsequent container on the ship 

by a crane structure. The system is applicable for measuring movement 

of any large object in six degrees-of-freedom (6 DOF). [37] [Nachman]

FIGURE 15. Moored Ship Motion Determination System disclosed in Nachman patent (numbers are 

referenced in the patent)
Sensors

Crane Technology development 41

August Design, Inc.

Ed Dougherty and his staff at August Design, Inc. have developed an 

Intelligent Spreader Bar (ISB) which includes a laser structured light sensor system to locate the corners of containers. With support from early 

DARPA funding in the MOB program, August Design and Bromma Inc., 

a major producer of spreader bars, are building a full size ISB and will 

demonstrate its performance this fall.

Under separate funding from Frank Leban, at Carderock, August Design 

has also been experimenting with stereo vision as an aid to crane operators in situations where the load is hidden from them. This is the case 

when reaching a container behind another one or when unloading a container over the side of a ship to a lighter. [7] In recent tests with 20 crane 

operators, there was enthusiastic agreement that stereo vision greatly 

facilitates such tasks.

Bonsor

Nigel Bonsor, et.al. of the UK, claimed a patent for a machine vision system (see Figure 16) that could be used to co-ordinate the interaction 

between a floating object (ship) at sea and a reference object (platform). 

The floating body is measured in real-time directly relative to the reference object using three visible non-aligned points on the floating object 
Survey of Cargo Handling Research

42 Intelligent Systems Division • National Institute of Standards and Technology

and using imaging to capture the points for feedback information to control the crane or other device. [38] [Bonsor]

FIGURE 16. a) Machine Vision System and b) Cargo Measurement points shown in Bonsor patent 

(numbers are referenced in the patent) 

Akos

Crane sensing developments have also taken place in other industries, 

such as nuclear power. For example, Gy Akos has developed and 

installed telemetric position sensing equipment in the nuclear power station of Paks, for accurate monitoring of the crane position during reactor 

a

b
Motion Prediction

Crane Technology development 43

maintenance. The equipment utilizes high-resolution line scan cameras 

and special bar-codes. [39] [Akos]

Similar encoding has been installed on a bridge crane at NIST as part of 

the National Advanced Manufacturing Testbed Construction Automation 

project for determining precise crane positioning.

Motion Prediction

Various groups have studied, modeled, and measured crane and load 

motions.

Several universities have done research on crane motion prediction 

within the Office of Naval Research MURI (Multi-University Research 

Initiative) Program under the topic of Ship-Mounted Cranes. These studies are described below:

Todd

The Naval Research Laboratory (NRL) and Carderock Naval Surface 

Warface Center (NSWC), under the Office of Naval Research (ONR) 

Multi-University Research Initiative (MURI), combined theoretical and 

experimental study of a spherical pendulum placed upon a Stewart Platform - a dry test bed for simulating six-axis motions. When the platform 

was programmed to provide relatively simple roll motions, itindicates a 

likely presence of complex, amplitude-modulated oscillations (including 

chaotic modulations) at a very slow time scale relative to the primary roll 

frequency. These complex, slow-time oscillations can be isolated in an 

experimental or real system by means of a phase-sensitive detectiondemodulation scheme. The fast-time “carrier” driving frequency dynamics are stripped off by tuning to a reference signal at the driving frequency and low-pass filtering similar to AM radio operation. Theoretical 

and experimental analyses of the slow-time dynamics have revealed a 

rich Hopfand flip bifurcation sequence as load swing resonance is 

approached, leading to large-scale out-of-plane load oscillations.

In addition to the spherical pendulum studies, a 1:24 scale model crane 

was fabricated and placed upon the Stewart Platform. The crane retained 

most functionality of real T-ACS ship cranes, including motorized slew, 

luff, and hoist motions, as well as a rider block tag line (RBTS) control 

system. Roll-forced studies of the model crane revealed dynamical features very similar to the spherical pendulum, including slow-time chaos 

near resonance. A wave tank test consisting of the model crane, along 

with a 1:24 scale T-ACS crane ship, container ship, and lighter barge, was 

conducted at the NSWC-Carderock facility. The test parameters inluded 
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44 Intelligent Systems Division • National Institute of Standards and Technology

sea state, ship heading, crane geometry and configuration, ship configuration, and load type. All together, almost 250 different experiments were 

completed with each run approximately 8 min long, over 30 measurands, 

such as ship motions, load motions, and sea spectrum, were obtained in 

each run. Preliminary analysis of some data sets again indicates behavior 

similar to what was observed in both the spherical pendulum and the 

crane on the Stewart platform. [40] [Todd]

Kimiaghalam - NASA and North Carolina A&T State University

Kimiaghalam, et. al. use the relatively new method of Genetic Algorithm 

(GA) to provide control and motion planning in the test case of the nonlinear dynamics of a crane. There are several approaches to solving a 

dock-mounted, container crane control problem using optical control 

methods. Usually the necessary conditions for solving this problem 

require finding the initial co-states vector. In the research, real value GA 

is used to optimize the initial values of the sea states of the system. Each 

individual gene has its own fitness value based on its ability to move the 

system to desired final states after a given time. In order to evaluate the 

fitness, a system simulator is used to simulate systems trajectories continuously. The dynamics of the crane and GA approach is reported to have 

solved two-point boundry value problems. Application of the steady-state 

GA and different crossover operators to speed up the process are tested to 

maintain the diversity of the individuals in a population and to improve 

the convergence. [41] [Kimiaghalam]

Baptista - University of Maryland

Baptista studied the quantitative results for the cargo pendulation amplitude in a large number of simulations of rolling crane ships. Results for 

ships equipped with the existing rider block tag line system (RBTS) to 

those of the Maryland rigging are compared. A variety of roll-motion 

data sets measured in the field are used. In the Maryland rigging, the pendulation is damped by applying a combination of dry and viscous friction 

to a moving pulley. Optimal coefficients for the frictional terms are determined and, without any active control, a reduction of pendulation amplitude is possible by more than a factor of ten compared to the RBTS.[42] 

[Baptista]

Chin and Nayfeh - Virginia Polytechnic Institute

A simplified model of a cargo container motion while at sea was studied 

by Chin and Nayfeh in [43]. The study illustrates how the instabilities 

could arise due to the combination of a one-to-one internal resonance and 

a primary (additive) resonance or a parametric (multiplicative) resonance. 

The method of multiple scales is use to drive four ordinary-differential 
Horizontal Motion Control

Crane Technology development 45

equations describing the amplitudes and phases of the two modes. The 

resulting two sets of modulation equations are used to study the equilibrium and dynamic solutions and their stability. The response could be a 

single-mode solution or a two-mode solution. A combination of a shooting technique and Floquet theory is used to calculate limit cycles and 

ascertain their stability. The numerical results indicate the existence of a 

sequence of period-doubling bifurcations that culminates in chaos, multiple attractors, intermittency of type I, and cyclic-fold bifurcations. The 

excitation parameters that lead to complex motions, including chaos, are 

identified in the study. In [44] [Chin], an elastic spherical pendulum subjected to parametric excitations is used to model the load pendulations. 

Derived equations are used to investigate the instabilities of the load 

motion and to provide information for controlling load pendulations. The 

analytical results are verified by numerical simulations of the original, 

full, nonlinear equations.

Horizontal Motion Control

Simkus

As discussed in the previous section on port-crane anti-sway control, 

Tony Simkus and Rob Overton have studied the instinctive concerns 

about open-loop control, the operators perspective, and the anti-sway, 

closed-loop control system including sway sensor requirements and the 

control system based on trolley response and cycle. An integrated crane 

model is stated as the only way to optimize trolley cycle. Conclusions 

suggest that closed-loop control has the best control of the sway and handles wind. Also, open-loop is the fastest and smoothest and operators take 

manual control at the end of every move.[45] [Simkus]

Control of containerized cargo suspended by a port crane is improved 

substantially with integrated, feed-forward control. Load sway is 

decreased when moving it from, for example, the ship to a transport vehicle on the ground. The typical operator controls are augmented with 

transparent computer controls so that minimal control complexity is 

added. Rapid cargo retrieval and placement does not affect the operator 

since the control cab is driven independently from the crane trolley. Endpoint locations can be taught so that the spreader bar can move at maximum speeds to the taught locations where an operator interjects addi-
Survey of Cargo Handling Research

46 Intelligent Systems Division • National Institute of Standards and Technology

tional commands, such as move slowly to acquire the target container and 

grip/ungrip the spreader.

Clarke Chapman Marine Crane Testbed 

A 13.6 t (15 ton) Clarke Chapman Marine Pedestal crane was mounted 

on a 16.4 m x 48.7 m (54 ft x 160 ft) barge to act as a testbed for the TACS 1 crane-system, motion-compensation studies. The testbed RBTS 

served the dual purpose of providing a scale model to evaluate the performance and effectiveness of the T-ACS 1 RBTS and permitted safe at-sea 

operations of the testbed crane. The RBTS on the Clarke Chapman crane 

was approximately a 5/8-scale model of the full scale T-ACS 1 RBTS, 

which was installed later on the six cranes aboard the KEYSTONE 

STATE. The testbed crane and its RBTS functioned well and demonstrated that the RBTS concept could be applied successfully to level luffing and marine pedestal cranes. [1] [Bird]

EG&G -Rider Block Tagline System

The first, full-scale Rider Block Tagline System (RBTS) (see Figure 17) 

was installed on a T-ACS 1 crane built by Lakeshore. 

The T-ACS 1 crane with the RBTS has the following characteristics: 

Rated Load: 36 t (40 tons =33 tons and spreader bar)

Boom Length: 39 m (129 ft)

Tagline Beam Length: 7.6 m (25 ft)

Hoist Reeving: 2x2 part 34 mm (1 3/8 in) wire rope

Rider Lift Line: 1 part 34 mm (1 3/8 in) wire rope

Taglines: 1 part 34 mm (1 3/8 in) wire rope

Tagline and Rider Lift Winch: SCR electric driven, single controller

The T-ACS 1 RBTS was a primary test item during the JLOTS II exercises off Ft. Story, Virginia during September 1984. Evaluation of the 

RBTS on the T-ACS 1 disclosed design problems that greatly reduced its 

effectiveness during these exercises. The problems were primarily in 

three areas: structural (several tagline beams showed signs of structural 

inadequacy), controls (delays in prioritizing control to the RB lift and 

tagline winches), and human factors (operator training on the new, 

unique RBTS is necessary for effective, efficient operation at sea).

The RBTS has been installed on 10 different cranes over a 6 year development period, including both Lakeshore and Haglund manufactured 

cranes. It has demonstrated repeatedly that it can be a simple and effec-
Horizontal Motion Control

Crane Technology development 47

tive deterrent to dangerous, uncontrollable pendulation during container 

handling operations at sea [1] [Bird] 

FIGURE 17. Rider Block Tagline System used on T-ACS Cranes

Craft Engineering (Dexter Bird III) - Integrated Rider Block 

Tagline System

The Rider Block Tagline System (RBTS) was developed by the Navy for 

use in mitigating the effects of pendulation when handling cargo at sea. 

Primarily, the RBTS permits control of the pendulum length by allowing 

the operator to select the position of the rider block in the vertical boom 

plane. This, however, increases the complexity of the crane control prob-
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48 Intelligent Systems Division • National Institute of Standards and Technology

lem by the addition of two or more degrees-of-freedom (tagline and rider 

liftline) to the existing three degrees-of-freedom problem (hoist, boom 

and slew). This increased complexity places additional decision-making 

and physical-dexterity requirements upon the crane operator. The rider 

block must be maintained within a feasible region (see Figure 18) for it to 

be effective. Control functions and algorithms have been designed to 

facilitate the Integrated RBTS (IRBTS) control that reduces operator 

control complexity. [46] [Craft Engineering Assoc.]

FIGURE 18. T-ACS Crane Feasible Region (Dexter Bird, Craft Engineering)

Rosenfeld - Virginia Polytechnic Institute

Yehiel Rosenfeld, converted a full-scale 4.5 t (5 ton) payload crane into a 

semi-automatic “Handling Robot” that scale-models typical construction 

cranes. The control system allows operation of the crane in either a manual or a semi-automatic mode, and it can be taught to memorize up to 50 

different benchmarks. Tests of performance, accuracy, repeatability, and 

safety aspects were completed and demonstrated a 15% to 50% reduction 

in typical work cycles, high accuracy and repeatability, and a generally 
Horizontal Motion Control

Crane Technology development 49

safer operation resulting from anti-sway of suspended loads. [47]

[Rosenfeld]

MURI

Several universities have performed crane motion control research within 

the ONR MURI Program under the topic of Ship-Mounted Cranes. These 

studies are described below:

Li and Balachandran - University of Maryland

Li and Balachandran studied a mechanical filter concept to control pendulation. A filter was incorporated at the pivot point about which the 

crane load oscillates. In the considered filter, the pivot point is constrained to move in a circular track in a two-dimensional space. It was 

demonstred that large crane-load responses excited by ship-roll motions 

and other disturbances can be suppressed effectively by using a passive 

filter as well as an active filter. In the active filter, a static feedback control law was used. In the current work, the active filter has been explored 

further and this filter has been extended to a three-dimensional case. The 

authors show that this filter is effective in suppressing responses of a 

crane load that is allowed to oscillate in a three-dimensional space. Relevance of the filter concept to crane systems on fixed platforms has also 

been considered. [48] [Li]

Dadone and Vanlandingham - Virginia Polytechnic Institute

Dadone and Vanlandingham studied control of pendulation of shipmounted crane loads by separating control effort into several levels. First, 

effort must be expended to minimize the rolling motion of the ship itself. 

Second, an effective design for the crane must include an adequate control authority. And finally, full use must be made of this control capability 

through the use of intelligent control methods (since conventional techniques are incapable generally of dealing with complex, nonlinear models). In the study, the use of neural-fuzzy control techniques are applied 

to the crane control problem in the separate levels mentioned. Using a 

simple model of the ship rolling dynamics (provided by Professor Saad 

Ragab and his students) the effect of active (pumping) control of liquid 

ballast is studied for both single-frequency and multi-frequency wave 

motion. Using an augmented “Maryland rigging” crane design, some 

simulations are studied that offer evidence of a feasible design, in that 

load transfers can be made in relatively high sea states. The “golden 

thread” for all the control action is Fuzzy Logic Control (FLC), which is 

an approach that permits the use of both “human” knowledge about the 

system and data-training methods in which control can be improved online. Future work will utilize more complex dynamic models, including 6 
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50 Intelligent Systems Division • National Institute of Standards and Technology

DOF coupled motion, and elaborate on the necessarily more complex 

control algorithms required. [49] [Dadone]

Wen, et. al. - NASA and NCA&T State University

Wen, et. al. consider the Maryland Rigging mechanism for pendulation 

control where the load is connected at two different points on the crane 

boom. Equations of motion are derived that consider an active suppression method. Based on angle measurement and angular velocity of the 

roll motion of the boom attained by the rate gyro, the control action used 

to suppress the swinging consists of changing the length of the rope on 

which the pulley slides. The complete system has been simulated with the 

ability to change the boom angle, the amount of friction and/or length of 

the rope with no simplification. Moreover, the simulater requires control 

inputs and their derivitives as well as, rolling angle and its derivitives. 

The full, nonlinear model is used to test control design based on a linearized system. Also, dynamic friction is applied to improve performance. 

[50] [Wen]

Lacarbonara, et. al. - Virginia Polytechnic Institute

Lacarbonara, et. al. studied a modified, variable-truss-geometry architecture (refer to Figure 14) for pendulation control in ship-mounted cranes. 

A progressive approach to developing a hybrid control strategy is followed by the design methodology applied to a mechanical filter. The two 

limiting cases, a fully-active and fully-passive control, are considered 

using a planar control architecture. The 3D version is envisioned for 

future research. The fully-active control law is designed using Linear 

Quadratic Regulator theory. The system is linearized around the operating equilibrium, and a cost function penalizing pendulation and actuator 

stroke is employed. The fully-passive system makes use of a linear 

spring, a viscous damper, and an intermediate mass. The number of 

parameters associated with the passive design is reduced to two by 

assuming that the optimal combination of mass and stiffness is that of 

Den Hartog vibration absorber. Using the results of the fully-active and 

fully-passive analyses, a starting point for hybrid or semi-active design is 

obtained. Further, results provide a base line for comparing the performance of these more sophisticated control architectures. [51] [Lacarbonara]

Soper, et. al. - Virginia Polytechnic Institute

Soper, et. al. developed a new, open-loop control strategy applied to a 

planar pendulum subjected to the most severe combination of base excitations - horizontal motion at the primary-resonance frequency and vertical motion at the principal-parametric resonance frequency. The actuator 
Horizontal Motion Control

Crane Technology development 51

architecture is that of the planar pendulation suppression truss developed 

at Virginia Polytechnic Institute. The control action is typical of many 

single-input control systems - the control authority in one direction is 

high and the control authority in the orthogonal direction is zero in a linear sense. Although the action of the controller is linearly decoupled from 

part of the system dynamics, effects are transferred to the orthogonal 

direction through nonlinear coupling. Proper detuning of the control 

input allows the nonlinear coupling to provide control action in the direction that is uncontrollable in a linear sense. The maximum pendulation 

angle of the steady-state motion system is one of the appropriate system 

response metrics. It is used as the cost function for evaluation of the optimal detuning gains. Transfering energy to uncontrollable modes via nonlinear coupling through either plant or actuator action is recognized and 

explored for control objectives. The control strategy is refered to as “open 

loop” because neither the system state nor a measured output are 

employed in direct feedback. However, the approach tactily assumes 

direct availablity of the disturbance levels and relative phases. [52] 

[Soper]
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52 Intelligent Systems Division • National Institute of Standards and Technology

Offshore Platform Resupply

In the 1970s and early 1980s, several systems were developed to compensate for heave of boats engaged in offshore oil platform replenishment.

Cojean

In 1978, Maurice Cojean obtained a patent for removal and deposition of 

loads between two supports in repeated, relative, vertical movement (see 

Figure 19). The device consists essentially of a crane close to the high 

point of the support on which the load rests in its rising movement for 

lifting the load. To do this, the lifting device, which is suspended from the 

hook of a crane, includes a structure supporting a winch, a detection 

device for the winding in or out of cable wound by the winch, and brakes 

adapted to block the cable pay-out when its crane lift speed is equal to the 

decreasing support heaving speed. The device is applicable to the unloading of ships supplying off-shore platforms.[53] [Cojean]

FIGURE 19. Graphics from the Cojean patent (numbers are referenced in the patent)

Wudtke

Donald Wudtke obtained a patent in 1979 for a motion compensator for a 

crane to assist the operator in safely lifting loads from the deck of a heaving work boat (see Figure 20). The crane hook follows the motion of the 

load because a level of pre-tension is maintained on the line by use of a 
Offshore Platform Resupply

Crane Technology development 53

counterweight connected to the reeving system. A hydraulic cylinder is 

connected to the counterweight and also provides a cushion at both ends 

of its travel. [54] [Wudtke]

FIGURE 20. Graphics from the Wudtke patent (numbers are referenced in the patent)
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54 Intelligent Systems Division • National Institute of Standards and Technology

Archibald

Archibald, et.al. of the U.K., patented a concept in 1982 for a hoist or 

crane incorporating a hydraulic compensator to provide heave compensation when installed at either end of two stations or at a single station. 

Pressured by gas-loaded accumulators and including a sector for achieving either bi-directional hydraulic fluid flow between accumulators and 

the compensator (to compensate for load position movements) or a unidirectional flow (permitting heaving in but preventing subsequent paying 

out) whereby the load is removed from the sea at the wave crest level. 

[55] [Archibald]

Vertical Motion Compensation 

Rucker Transloader

In 1968, Rucker Control Systems delivered the Rucker Transloader to the 

Navy. It consisted of a hydraulic ram tensioner that could be placed in the 

load line of a crane cable system to provide for adjustment in cargo position. This system was operated hydraulically and was designed to heave a 

2.7 t (3 ton) capacity and linear displacement capability of ±2.4 m (±8 ft) 

while responding to a maximum velocity of 1.2 m/sec (4 ft/sec). Testing 

was conducted by the David Taylor Naval Ship Research and Development Center during 1970 on a land based mock-up of a crane boom.The 

Transloader functioned satisfactorily with a load of 172 kg (380 Lb) 

attached, but when the 1542 kg (3400 lb) load was lifted, oscillations 

began that soon reached violent proportions. Extensive analysis was performed and hydraulic valves were replaced with hydraulic servo valves to 

permit easy adjustment of the system feedback gain. Enhanced performance resulted, but with overdamped control of heavier loads and with 

too slow response times for practical use. [1] [Bird]

EG&G Platform Motion Compensator

In the 1980’s the Navy undertook research to develop a Platform Motion 

Compensator (PMC) to deal with relative vertical motion. The original 

PMC design and concept was developed by EG&G. A prototype PMC 

was installed on the KEYSTONE STATE (T-ACS 1) and was used during 

the J-LOTS II exercise at Ft. Story, Virginia during the fall of 1984. 

While the PMC prototype was a technical success, the PMC was not 

implemented in the fleet because of its perceived cost and complexity.

The PMC was designed specifically to remove the vertical component of 

the load motion induced by the crane platform’s motion. The PMC is an 

electro-hydraulic mechanical device that, without the aid or attention of 
Vertical Motion Compensation

Crane Technology development 55

the crane operator, moves the hook load in a velocity and direction equal 

and opposite to the vertical motion imparted to the load by the crane platform as it rolls, pitches, and heaves during offshore cargo off-loading 

operations. 

The PMC includes primary power supplied by four 74.6 kW (100 Hp) 

electric motors, a pair of accumulators and pressure sensors (for tension 

control), main winch modification with increased torque and double 

grooving (two part line reeving), modified controls (built-in microcomputer, sensor displays, diagnostic lights). Components were installed 

above the operators cab. A PMC block diagram is shown in Figure 21. 

FIGURE 21. Platform Motion Control Basic Schematic Diagram

An inertial ship motion sensor, a crane load radius, and slew angle sensors are all that is needed to provide inputs for the calculation of the 

instantaneous vertical velocity of the load. Basic design goals were limited to: 36 t (40 tons). maximum crane load, ±1 m/s (3.5 ft/s) maximum 

compensated hook speed, and ±3.7 m (±12 ft) maximum compensated 

amplitude.

Prototype testing was performed at dockside and at-sea. At dockside, 

containers were landed repeatedly on the dock successfully. The close-
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56 Intelligent Systems Division • National Institute of Standards and Technology

ness of the operators cab and the hydraulic pumps resulted in excessive 

noise in the cab. The at-sea testing was conducted during JLOTS-II exercises. Crane operators commented that the difference with and without 

the PMC was significant. Consensus on the exercise was that the operation could not have been accomplished without the PMC. [1] [Bird]

Draper Laboratory Automatic Touchdown Algorithm

Instead of following the motion of the entire wave period, C.S. Draper 

Laboratory was commissioned by the Naval Coastal Systems Center to 

investigate adaptive loading strategies by attempting to land the cargo at 

the wave peak. The result was an adaptive automatic touchdown algorithm developed in 1980. The function of the algorithm is a velocity control with higher gain as the load approaches the deck, i.e. if the load and 

the lighter deck are not in danger of high velocity collision, do not 

attempt to get out of the way. The automatic touchdown algorithm was 

developed and tested on the Manitowac 4100W Ringer Crane at Port 

Hueneme, California in 1980. The basic system components were an 

ultrasonic range measuring device mounted on the spreader bar, a crane 

winch controller including a tachometer on the winch and potentiometers 

on the torque converters as feedback, and a desk-top computer to 

implement the touchdown algorithm. An on-deck control unit, to be 

replaced by automatic controls, allows an operator, stationed at the rail of 

the ship, to switch the unit from automatic landing to constant tension 

when the load touches the lighter deck.

With less than one-foot amplitudes, the demonstration of the system was 

sufficiently successful to indicate that the concept was viable and had the 

potential to enhance greatly the container handling operation at the 

lighter interface. [1] [Bird]

Dummer

Robert Dummer obtained a patent for a heave compensating system (see 

Figure 22) in 1980. A marine crane, including a high-speed winch having 

a hydraulic heave compensating system, automatically controls the crane 

winch to compensate for the vertical movement of the load during offloading operations. The heave compensating system includes a reversing 

valve for overriding manual control and for directing control pressure to 

stroke the pump of a hydrostatic winch drive into its raise mode of operation. Also included is a compensating valve that regulates the displacement of the pump, permitting it to develop and maintain only a 

predetermined pressure in the high pressure main fluid line. The heave 

compensating system preferably includes a lift control system for auto-
Vertical Motion Compensation

Crane Technology development 57

matically hoisting a heaving load only at or near the crest or trough of a 

wave.[56] [Dummer]

FIGURE 22. Hydraulic Schematics showing the drive system for a boom crane disclosed in the 

Dummer patent (numbers are referenced in the patent)
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58 Intelligent Systems Division • National Institute of Standards and Technology

Crane Designs-Structures and Reeving

Lee - AACTS

Don Lee, at the Franklin Institute, conceived [57] [Lee] and together with 

August Design [58] [Dougherty], built a working scale model of an 

advanced, automated, vessel cargo transfer system for loading and 

unloading of ships and lighters (see Figure 23). It includes an articulated 

manipulator arm mounted on a frame. The arm is provided with a 

spreader bar at the distal end. The spreader bar is provided with facilities 

for grasping cargo. Sensors track the movement of the vessel, and automatically responsive controllers adjust the motion and position of the 

spreader bar to follow the motion of the vessel. Berthing modules are 

provided to aid in controlling the motion of the vessel. In a major embodiment (of the patent), the manipulator arm is mounted on a transverse 

frame that bridges spaced apart floating barges, and provisions are made 

for serving vessels both on the outboard and inboard sides of the barges. 

In another embodiment, the manipulator is shore-based. The figure shows 

applications for flexible truss bumpers, also. 

FIGURE 23. AACTS graphic from Lee Patent

SCARA Arm

(1 of 4)

Ship

Barges

Crane

Actuated Legs

Gantry 
Wave Motion Damping

Crane Technology development 59

Liebherr

Liebherr’s new (CBS) crane designs include a series of new cranes 

intended specifically for multi-purpose vessels, with higher capacities

(25 t to 100 t) and outreach (22 m to 45m). [59] [Liebherr]

Wave Motion Damping

JLOTS - Rapidly Installed Breakwater

The RIB (Rapidly Installed Breakwater) System is a SS3 enabler. It will 

allow JLOTS cargo transfer operations to continue through sea state 3. 

The RIB system is a V-shaped floating structure consisting of two legs 

joined at the front and anchored at each end such that the legs form a 45° 

angle. Each leg of the RIBs acts as a diffraction element for obliquelyincident waves, leaving relatively calm water inside and behind the structure. A stiff curtain with triangular elements at each end extends through 

the water column to a depth sufficient to deflect most of the wave energy. 

Most applications would include a depth of 6 m (20 ft), have 2.4 m (8 ft) 

of structure above the waterline, with each leg on the order of about 305 

m (1000 ft) in length. Scientists believe that the RIB has the potential to 

dramatically increase throughput, for a relatively small cost, in some 

locations by a factor of more than 1000 percent. Obstacles to completion 

include its deployment and employment, mooring, repositioning, recovery, and survivability. Initial conclusions suggest that there are no insurmountable problems. [7] 

Kuo

Chengi Kuo filed a UK patent that proposes that marine vessels be 

equipped with moonpools (see Figure 24) in a way to isolate the motion 

of a crane from a ship’s motions. A moonpool is a vertical passage within 

a vessel, in this case closed at the upper end and open at the lower end to 

the sea, to provide a column of sea water within the vessel. Moonpools as 

proposed, allow small motions in heave, roll, and pitch and, when 

equipped with controlled air pressure at the upper end and a pontoon 

work area, provide a controlled means of supporting, for example, a 
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60 Intelligent Systems Division • National Institute of Standards and Technology

crane that is vertically steady with the sea bed and independent of the 

vessel motion. [60] [Kuo]

FIGURE 24. Top and Side views of the Moonpool concept proposed in the Kuo patent (numbers are 

referenced in the patent)

Blood - Float, Inc.

Howard Blood developed a concept called PSP (pneumatically supported 

platform) that is a modular floating platform composed of a number of 

top view

side view
Integrated Motion Control

Crane Technology development 61

cylindrical shaped components. Each cylinder is sealed at the top with an 

end cap and open to the ocean at its base. Each cylinder contains air at a 

pressure greater than atmospheric pressure. This compressed column of 

air supports the platform in a manner that reduces the wave induced 

forces acting on the PSP structure as compared to a platform with a 

closed bottom. This cushioning effect of the air column is expressed by 

the air pocket factor. Another aspect of the PSP design is that air is 

allowed to flow from each cylinder to its neighbors through connecting 

orifices. The air flow provides a mechanism to help level out highs and 

lows in the pressure distribution beneath the structure and provides an 

additional mechanism for dissipating wave energy. [61] [Blood]

World City

World City conceptualized a floating city called the Phoenix World City. 

It would be the first in a generation of cruising resorts and floating cities 

of the future. It would be nearly a quarter-mile long, accommodate 6,200 

guests in 2,800 staterooms and suites, offer a variety of facilities, restaurants, and shops. The floating city would include massive portals in the 

stern of the vessel that open to reveal a large marina within the hull and a 

lively seaport. Four 400-passenger day cruisers, ships themselves, would 

dock inside the marina and be deployed at high speeds to and from ports 

and a variety of destinations within a fifty mile radius of the city. [62]

[World City Corp.]

McDermott

The McDermott MOB concept conceptualized an artificial beach to land 

LCAC (Landing Craft Air Cushion) vehicles and, potentially, other lighterage with this “beach” capability. This would essentially eliminate the 

wave effects on the lighterage.

Integrated Motion Control

August Design

As part of the Carderock NSWC JLOTS Advanced Crane Technology 

Program (initiated by the DARPA MOB Program), a 6 DOF spreader bar, 

called the Intelligent Spreader Bar (see Figure 25), is being developed by 

August Design, Inc. The technology includes a two-part container 

spreader bar with an automated, 6 DOF positioning system that manipulates the spreader bar relative to the container and maintains the container’s motion and orientation relative to a selected frame of reference 
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62 Intelligent Systems Division • National Institute of Standards and Technology

(such as the deck of a lighter). It also manipulates the connection part of 

the spreader relative to a container during latching. [7] [63] [Dougherty]

The system includes six, computer-controlled rotary actuators mounted 

in a headblock. Cables connect the rotary actuators to a lower spreader 

bar and provide six-axis motion compensation between the crane, suspending the ISB, and the cargo. The six cables then provide 20.4 t 

(22.5tons) maximum lift for container loads using electrical or hydraulic 

power. Sensors for measuring container position relative to the reference 

are proposed to be ultrasonic or optical range finders. Processing of sensor and position data occurs onboard the ISB in a microprocessing unit.

Benefits from the ISB are that container pitch, roll, and heave motions 

will be compensated for during latching and set-down. The ISB could 

eliminate the need for tagline handlers aboard lighters while increasing 

the speed of engaging and placing containers.

FIGURE 25. I/16th scale model of the August Design Intelligent Spreader Bar

JLOTS - Spreader Bar Tagline System

Also within the JLOTS Core SS3 Project, a Spreader Bar Tagline System 

(see Figure 26) is being studied. This technology provides automated, 

powered taglines to control cargo pendulation and cargo spotting during 

cargo handling operations. The current procedures for using taglines are 

hazardous since they rely on personnel to maintain continuous tagline 

control. The hardware for this technology relates to a set of powered 
Integrated Motion Control

Crane Technology development 63

taglines located on the spreader frame and belayed to hard-points on the 

lighters. [7] 

FIGURE 26. Spreader bar Tagline System

JLOTS - Remote Crane Control Station

Within the JLOTS Operational Enhancement Program, a remote crane 

control station has been proposed. This mature technology includes a 

second crane operator who would be located at the ship bulwark and have 

a close and direct view of the lighter deck. The operator based in the 

crane cab would transfer crane control to the mobile crane operator at a 

non-critical point in the lift. The mobile crane operator would use the 

remote control to spot and land the cargo. Upon completion of the move, 

and with the spreader bar or hook safely hoisted, the control would be 

reverted to the cab-based operator for another cycle. [7]

Albus - NIST RoboCrane 

During the late 1980’s, DARPA contracted NIST to study robot cranes. In 

this study, a revolutionary crane design evolved by James Albus, et. al., 

based on the Stewart-platform, parallel-link manipulator. NIST turned 

this configuration upside-down, used cables as the parallel links, winches 

as actuators, and gravity as the vertical force component. This allows a 

lower platform to be suspended from an upper (reference) frame and 

maneuvered with full 6 DOF capability. Multiple adaptations to the original design, now trademarked as the RoboCrane, have been studied. [64, 

65, 66] [Albus]

In 1996, NIST was contracted by DARPA, followed by ONR, to study 

the RoboCrane applied to LO/LO operations for the MOB. Several con-
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64 Intelligent Systems Division • National Institute of Standards and Technology

cepts were developed, including a rail crane that is similar to a port crane 

and a luffing crane as shown in Figure 27. A final project report includes 

these and other concepts that NIST developed. [67] [MOB RoboCrane] 

In the final report, detailed descriptions of the RoboCrane reeving and 

control are explained. 

FIGURE 27. Photograph of a 1/16th scale model luffing crane configured with RoboCrane cabling.

The concept includes the use of upper and lower Stewart Platform-reeved 

spreader bars, that augment the typical heavy lift lines, and provide sufficient constraint in 6 DOF to compensate for relative ship motions. The 

two spreader bars can be joined to minimize power and maximize control 

speed. Also, the spreader bars can be separated with the lower spreader 

joining the upper spreader with an additional Stewart Platform reeving. 

This allows the lower spreader to enter ship cells, reach between stacks of 
Dynamical Systems

Crane Technology development 65

ship deck containers, and reach over container stacks blocking the upper 

spreader bar access to the targeted container.

Dissanayake and Durrant-Whyte - University of Sydney Australia

Dissanayake and Durrant-Whyte of the University of Sydney Australia 

have described the design and implementation of a semi-autonomous 

and, ultimately, fully-autonomous, container quay-crane. The new crane 

is based on a novel, reeving arrangement (see Figure 28), similar to the 

NIST RoboCrane, which allows both fast and accurate gross motion as 

well as fine micropositioning. Their paper, “Towards Automatic Container Handling Cranes,” describes the essential theory behind this design 

and presents experimental results from a 1/15th scale model. The proposed instrumentation of this crane is also briefly described as are key 

elements of the operator interface. [68] [Dissanayake]

FIGURE 28. a) Kinematic structure of the trapezoidal reeving arrangements b) Arrangement of 

sheaves on the trolley and the head-block.

Dynamical Systems

Dadone

Paolo Dadone, through the MURI Program at Virginia Polytechnic Institute, is studying a three dimensional crane model pendulum that uses 

a b
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66 Intelligent Systems Division • National Institute of Standards and Technology

fuzzy logic to reduce pendulation while incorporating the “Maryland 

Rigging” scheme with variable friction. Simulation of this model shows 

fuzzy control of trolley motion and enhanced anti-sway load positioning 

control.

Also, using a neural (fuzzy) model reference, adaptive-control technique, 

Dadone does not model the crane first. Instead, using the adaptive control 

technique, the neural model is to learn (identify) what the crane actually 

does to reduce errors between output from the crane and a reference 

model (goal point).[69] [Dadone]

Winches and Drives

Electric drives with direct frequency converters (DFC) have been developed to “modernize” crane and ship controllable ac drives.

Feldman

I. Yu Feldman has pointed out recently that electric drives of crane and 

ship winch mechanisms utilize not only relay-contact control systems but 

also systems with TTS direct frequency converters (DFC). Frequency 

converters may be used to modernize crane and ship-controllable ac 

drives, as well as new developments (i.e. removing deficiencies of the 

DFC by increasing grid frequency). [70] [Feldman] 

Podobedov

E. G. Podobedov, et.al, have described automatic electric drives with frequency converters for hoist and deck mechanisms. They provide the technical characteristics, circuitry, and basic data and for electric drives with 

direct frequency converters. [71] [Podobedov]

Allen

Richard Allen, at Ship’s Equipment Centre, a firm specializing in turnkey 

contract, electro-hydraulic, SEC Ten Horn winches, provides a compact, 

self-contained unit that is filled with lubricant and mounted on an 

enclosed foundation framework. Rapid installation and simple connect 

enable turnkey operation. [72] [Allen]
Container Terminal Automation

Crane Technology development 67

Container Terminal Automation

Many new ports have been expanded and modernized in the last 

decade. Several of these utilize advances in anti-sway control to 

achieve semi-automatic control and consequent improvements in 

operating efficiency.

Barker - Deltaport

Ann Barker has described the development of Deltaport and the key operating features such as berth design, on-dock intermodal yard, container 

storage yard, infrastructure improvements and cranes (see Figure 29). 

Cranes will be equipped with an electronic anti-sway system. The system 

will detect spreader sway in relation to the trolley. There will be a corresponding trolley movement to dampen the spreader sway. This semiautomatic operation and other features, such as enhanced crane monitoring and maintenance system (advanced diagnostics, crane production 

monitor, data logging, and preventive maintenance data logging).[73] 

[Barker]

FIGURE 29. Graphic showing Deltaport Terminal Crane
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68 Intelligent Systems Division • National Institute of Standards and Technology

Reiss - Advanced Research Projects Agency

Daniel Reiss describes recent advances that can be used to design a fullyintegrated, automated container terminal (IACT) capable of providing 

order of magnitude improvements in operating efficiencies, life cycle 

costs, and land utilization. Specifically, high capacity Rail Mounted Gantry designs including spans greater than 100 m and direct drives and controls (high-precision, static, stepless drives and controls allowing precise 

positioning and computer control of large devices over long distances. 

[74] [Reiss]

GRAIL - August Design

August Design designed and constructed a working 1:100 scale model of 

the GRAIL robotic container handling facility (see Block Diagram in 

Figure 30) for Sea Land Service. The system manages and controls the 

movement of cargo containers throughout a shipping facility - from the 

time a container arrives at the container yard to the time it is placed 

onboard ship. The system features traffic management, redundant collision avoidance systems, fail safe design, an expert system for placement 

of containers in the yard (fully automated shore cranes and container 

accumulators (for queuing below the cranes)), a unique data management 

system that uses color graphics to display the entire yard, an efficient network control system and a number of autonomous mobile robots. The 

robots include a highly reliable end effector, infrared communications, 
Material Handling Alternatives

Crane Technology development 69

accurate positioning, extensive mobility, speed control, and onboard collision avoidance. [75] [Dougherty]

FIGURE 30. GRAIL System Block Diagram

Material Handling Alternatives

Naval Architect

Sources, such as Naval Architect, describe new developments in shipboard cargo handling equipment, particularly so where future reefer ships 

are concerned, including: automatic pallet lifting in reefer ships, the SLoader System (Mark IV), knuckle-boom deck crane for container handling, KSW system automatic pallet handling, and MacGregor-Hagglunds LC Cylinder-Luffing Cranes. [76] [Naval Architect]

Material handling alternatives to cranes include: conveyors, mono-rails, 

footed bridge boom, AGV, forklifts, elevators, air bearing pallets, and 
Survey of Cargo Handling Research

70 Intelligent Systems Division • National Institute of Standards and Technology

stackers. All alternatives to cranes would require ramps or connections 

with motion compensation.

Simulation

Simulators have been developed to facilitate design, testing, development of operator interfaces, and operator training. 

Virginia International Terminals

Implementation of an advanced operator interface has been integrated on 

cranes at VIT. Three cranes have been equipped with an electronic antisway system, which involves two modes: a “Learn” mode and an “Auto” 

mode. In the Learn mode, an experienced operator operates the crane 

manually while his specific control movements are observed by the 

invented system. The movements, load position as a function of time, and 

the weight are stored. Thereafter, in the Auto mode, the operator may 

entrust movement of the load to the present system, which causes the 

load to traverse an optimum path efficiently and safely (with minimum 

sway) in a minimum period of time. Manual control can be attained at 

any point during load movement.[77] [VIT]

Advanced Marine Engineering and Jason Associates Corp.

Advanced Marine Engineering and Jason Associates Corp. have both 

built crane simulators that respond to joystick and foot pedal commands 

while updating crane and cargo motion representing actual crane operations. The load pendulation on the crane simulator is typical of cranes 

and, therefore, provides an education tool for crane operators. [78]

[Mordfin] The RBTS has also been programmed into the simulator and 

the operator can view the effect of the rider block in controlling the load 

without using the actual crane. Various lighting and wave motions can be 

set to simulate varying conditions at sea. Jason Associates has developed 

similar trainers called Crane Operators Training Systems, which also 

include a “universal crane cab” mounted on a motion base. [79] [Jason 
Simulation

Crane Technology development 71

Associates] Figure 31 shows a snapshot of the LMSR operator cab simulator by Jason Associates.

FIGURE 31. Snapshot of LMSR Crane Operator Cab Simulator by Jason Associates

Craft Engineering

The RBTS permits control of the pendulum length by allowing the operator to select the position of the rider block in the vertical boom plane. 

This, however, increases the complexity of the crane control problem by 

the addition of two more degrees-of-freedom (tagline and rider liftline) to 

the existing three degree-of-freedom problem(hoist, boom, and slew). 

The Integrated RBTS (IRBTS) allows simultaneous control of the tagline 

and rider liftline without the additional complexity of their independant 

functional controls. Dexter Bird developed a PC-based simulation of the 

IRBTS to facilitate development of the actual control algorithms and 

operator command set. 
Survey of Cargo Handling Research

72 Intelligent Systems Division • National Institute of Standards and Technology

CONCLUSIONS

Horizontal pendulation control has been demonstrated by the Rider 

Block Tagline System, IRBTS, feed forward control and other methods.

Vertical motion compensation was demonstrated by EG&G on T-ACS 1, 

but not implemented in the T-ACS fleet.

MOB cargo container operations will require rapid, 6-D compensation of 

ship motions. These motions are not as severe as lighter loading but are 

still on the order of ±1 meter for 5 second wave periods in sea state 3.

The Rider Block Tagline System could be significantly improved by the 

Carderock NSWCCSS/Craft Engineering Inc. project to insert computer 

coordinated control of horizontal motions.

Vertical motion compensation will not be achieved by the improved 

RBTS.

Enabling technologies for 6-D motion compensation have been developed and demonstrated in the laboratory and wave tank, but not yet demonstrated in full scale operations ( e.g. Intelligent Spreader Bar, 

RoboCrane, U-Sydney trapezoidal reeving).

The JLOTS ATD, if developed successfully, could provide much of the 

development needed for a MOB crane.

Sensors of incoming waves are critical to feed forward control. Large 

waves actually occur rather infrequently. If they can be sensed and anticipated, then operations can be conducted during the lulls between major 

waves or motions.

A compound control system, including wave sensing with feed forward 

control, combined with fast, closed-loop control of relative motion 

between the load and lighter or container ship may be required.
Simulation

Recommendations 73

RECOMMENDATIONS

• Simulate and model the cranes required for cargo handling.

Scale models of a rail crane, luffing crane, triangular crane, and box crane 

have been constructed at NIST. These have provided some insight into 

the crane requirements for the MOB concepts developed by Brown and 

Root and McDermott. For other concept developers, it would be very 

useful to simulate and build a scale model of proposed container cranes 

and their interface to the MOB. The models could be used to verify the 

concept design, such as the pulley and winch locations, the stability of 

the cargo as a two or three stage compensation system attached to this 

model, actuated boom raise, crane traversal along the MOB, and computer controlled cargo acquisition. Cargo motion simulation and/or 

hydrodynamic response with crane model control should follow.

• Develop the advanced computer control system necessary to 

achieve wave motion compensation.

Upon construction of a representative rail crane as described in [67], the 

model will demonstrate static control of the spreader bar and verify stability requirements. Additionally, the crane model must also demonstrate, 

under computer control, the synchronized winch control that will be 

required of a full-scale version of the crane to achieve relative motion 

compensation. Algorithms must be designed and demonstrated to achieve 

continuous servo control of the trolley and the taglines for full operator 

assisted/monitored six degree-of-freedom spreader bar and cargo control 

during high sea state conditions.

• Develop and demonstrate full scale integrated 6-D cargo container 

control for both MOB and JLOTS operations.

In order to minimize crane power during operations, especially including 

high sea states, smart control of the crane operations is necessary. We 

believe that a compound control system, including wave sensing with 

feed forward control, combined with fast, closed-loop, 6 DOF control of 

relative motion between the load and lighter or container ship will be 

required. Sensoring of incoming waves is critical to feed-forward control. 

To investigate this control concept, we recommend a joint proposal be 

submitted to the Navy, including industry and government experts in 
Survey of Cargo Handling Research

74 Intelligent Systems Division • National Institute of Standards and Technology

these areas, targetting both the MOB and JLOTS LO/LO operations challenge. 

Also, we recommend that the joint ARMY/NAVY lighter project include 

research complementing MOB LO/LO operations whereby lighter usage 

at high sea states be considered.

And, we recommend that the Army crane operator simulator at Fort Eustice be studied and modified to include operator training on six degree-offreedom motion compensation systems, such as the dual or triple stage 

systems modeled in [67]. This will provide direct information from 

potential crane operators regarding the use of six-degree-of-freedom 

motion compensation systems through high states (i.e. SS3 or above).
Executive Summary

References 75

REFERENCES

References are listed in order of their occurence. If a reference is previously cited, it will not appear again in another section.

Executive Summary

1. Bird, J. Dexter, III, Motion Compensation for Offshore Container Handling, EG&G 

Washington Analytical Services Center, Inc. February, 1986.

Purpose

2. JPD, Mission Need Statement For The Mobile Offshore Base (MOB), ACAT Level, 

September 15,1995.

Background

3. Wislicki, Alfred; Cohrs, Heinz-Herbert; Bachmann, Oliver; and Whiteman;Tim; The 

History of Cranes, International Cranes, UK, October 1997.

4. Cecce, Robert, Antipendulation Crane, U.S. patent 4,171,053.

5. Vaughters, T.G., Mardiros, M.F., Joint Logistics Over the Shore Operations in Rough 

Seas, Naval Engineer Journal, May 1997, pp. 385-396.

6. Department of Defense, Analysis and Evaluation Report - JLOTS II Throughput 

Test, August 1985, section 3.2.1.1.4 Sea State 3, Ground Swells, and Load Pendulation, pp. 3.69-3.76.

7. JLOTS Master Plan, December 1997.

8. Webb, Bob, Naval Facilities Engineering Command, draft RFP for the Joint Modular 

Lighter System (JMLS) Mission Need Statement, Civil Engineering Support Office 

(CESO), http://199.123.61.61.

9. Rausch, Art, Advanced Technology Demonstration Proposal, Naval Surface Weapons Center-Carderock, CDNSWC 293, November 1997.

Requirements

10.Goodwin, Ken; Bostelman, Roger; Cargo Container Transfer Requirements for the 

Mobile Offshore Base, NIST Internal Report (draft), March 1998.

11.Wood, William, Seaworthy Systems, Inc., Preliminary Design Mobile Offshore Base 

Ship Interface, (draft), April 1, 1997.

12.Cooper, Kelly, “Motion Responses for Selected Cargo Location Points on a T-ACS 

Auxiliary Crane Ship in an Open Seaway,” Carderock Naval Systems Warfare Center, Sept. 1996: Tables 3 and 4: Ochi-Hubble Spectra Corresponding to Natural Roll.

13.Albus, James; Bostelman, Roger; Jacoff, Adam; MOB RoboCrane Final Report, 

Mobile Offshore Base Project, Vol. 1, 2, NIST Internal Report (draft), 1997.
Survey of Cargo Handling Research

76 Intelligent Systems Division • National Institute of Standards and Technology

14.Dougherty, E.J.; Lee, D.E.; Shively, P.D., Automated All-weather Cargo Transfer 

System (AACTS), Society of Naval Architects and Marine Engineers, STAR Symposium, pp S2-3-1, S2-3-6, April, 1989.

15.Krulak, General Charles, MPF 2010 and Beyond, December 30, 1998, reprinted in 

Inside the Navy, January 12, 1998.

16.Bouchoux, Donald; The MOB as a Supplement to the CVX, Whitney, Bradley & 

Brown, Inc.BB, January 29, 1998.

17.Nance, John, Jr.; Milano, Vito R.; Souders, Robert M.; and Bowditch, Thomas A., 

Mission Area Analysis (MAA) for Maritime Prepositioning Force (MPF) Future 

Seabasing Concepts Phase 1 Summary Report, Center for Naval Analyses, CRM 97-

102.09, 26 Sep 1997.

18.Nance, John, Dry Cargo and Vehicle Lift Requirements, MPF MAA Study Notice 

#23, Center for Naval Analyses, 29 Sep, 1997.

Crane Technology Development

19.Janes’s Ships, USA/Amphibious Warfare Forces, page 846.

20.CNO Strategic Sealift Division (N-42), Cargo Off-load and Discharge System 

(COLDS), October 1992.

Port Crane Anti-Sway

21.Soest, Cornelius; et. al., Anti-sway, Anti-rotation mechanism for crane reeving, U.S. 

Patent 4,376,487, filed Jan. 22, 1981.

22.Kleinschnittger, Andreas, University of Dortmund, Germany. 

23.Kim, Sang-Bong, et. al, Development of a Crane System for High Speed Transportation in Container Terminal, Sixth (1996)-International Offshore Polar Engineering 

Conference Proc., Los Angeles, CA, May 26-31, 1996, pp. 542-547.

24.Shaper, Donald, Stabilizing Device, U.S. Patent 4,273,242, filed May 18, 1979.

25.Bernaerts, Henry, Anti-sway device for hoists and cranes, U.S. Patent 4,227,677, 

filed Mar. 26, 1979.

26.Hasegawa, Shuji; et. al., Variable level lifting platform for a cargo container handling 

crane, U.S. Patent 5,538,382, filed June 3. 1994.

27.Foit, Vilem, Anti-sway crane reeving apparatus, U.S. Patent 4,949,854, filed Dec. 9, 

1988. 

28.Foit, Vilem, Anti-sway crane reeving apparatus, U.S. Patent 4,949,855, filed Dec. 9, 

1988. 

29.Foit, Vilem, Anti-sway crane reeving apparatus, U.S. Patent 4,953,721, filed Dec. 9, 

1988. 

30.Davis, Rudolf, C. III; Simkus, Anthony P. Jr., Method and apparatus for moving containers between a ship and a dock, U.S. Patent 5,478,181, filed Jan. 26, 1994.

31.Overton, Robert; Anti-sway control system for cantilevering cranes, U.S. Patent 

5,526,946, filed Dec. 5, 1994.

32.Overton, Robert, Shipboard Crane Control, presentation at NSWC Carderock on 

July 24, 1996.
Crane Technology Development

References 77

33.Parker, Gordon; Robinett, Rush; Ship-based Crane Payload Sway Control, Sandia 

National Laboratories.

34.Rushmer, Michael; et. al, Electronic Anti-sway Control, U.S. Patent 5,443, 566, filed 

May 23, 1994.

35.Lacarbonara, Walter; Soper, R. Randall; Pratt, Jon; Nayfreh, Ali; and Mook, D.T.; 

MURI Seminar, July 24, 1997.

36.Rudnick, Siegfried, Container Cranes: Top Performance with Standard Systems, 

Energy and Automation XII, No. 2, 1990, pp. 4-7.

Sensors

37.Nachman, Marcus; Overton, Robert, Moored ship motion determination system, 

U.S. Patent 5,089,972, filed Dec. 13, 1990. 

38.Bonsor, Nigel; et. al., Method and system for interacting with floating objects, UK 

patent GB-2,267,360B, filed May 22, 1992.

39.Akos, Gy, et. al., Development of an Optical Telemetric Position Sensing Equipment 

for Nuclear Power Station Reactors, 16th Congress of the International Commission 

for Optics, Budapest, Hungary SPIE Volume 1983, part 2 of 2, Aug. 9-13, 1993, pp. 

971-972.

Motion Prediction

40.Todd, Micheal; Vohra, Sandeep; Leban, Frank, Studies of Crane Load Pendulation: 

Stewart Platform Testing and Wave Tank Model Testing, Third Semi-Annual MURI 

Meeting Nonlinear Active Control of Dynamical systems, Virginia Polytechnic Institute , Blacksburg, VA, April 13-14, 1998.

41.Kimiaghalam, Bahram; Homaifar, Abdollah; Bikdash, Marwan, Optimal Control for 

Gantry Crane Two Point Boundary Value Problem by Genetic Algorithm, Third 

Semi-Annual MURI Meeting Nonlinear Active Control of Dynamical systems, Virginia Polytechnic Institute , Blacksburg, VA, April 13-14, 1998.

42.Baptista, Murilo da Silva; Hunt, Brian R., A Comparitive Study of Cargo Pendulation on Rolling Crane Ships, Third Semi-Annual MURI Meeting Nonlinear Active 

Control of Dynamical systems, Virginia Polytechnic Institute , Blacksburg, VA, April 

13-14, 1998.

43.Chin, C; Nayfeh, A. H., Nonlinear Dynamics of Crane Operation at Sea, American 

Institute of Aeronautics and Astronautics, AIAA-96-1485, 1996.

44.Chin, C; Nayfeh, A. H.; Mook, D. T., Dynamics and Control of Ship-Mounted 

Cranes, American Institute of Aeronautics and Astronautics, AIAA-98-1731, 1998.

Horizontal Motion Compensation

45.Simkus, Anthony, Jr.; Rudolf, Chester, System for learning control commands to 

roboticly move a load, especially suitable for use in cranes to reduce load sway, U.S. 

Patent 5,117,992, filed Jan. 28, 1991. 

46.Craft Engineering Associates, Inc., Integrated RBTS Control System for T-ACS 

Crane, A preliminary Design Study for the Coastal Systems Station NSWC, Dahlgren Division, May 1997.
Survey of Cargo Handling Research

78 Intelligent Systems Division • National Institute of Standards and Technology

47.Rosenfeld, Yehiel, Automation of existing cranes: from Concept to Prototype, Automation in Construction 4, Elvesier Science, 1995, pp. 125-138.

48.Li, Y.-Y.; Balachandran, B., Dynamics, Stability, and Control of Cranes, Third SemiAnnual MURI Meeting Nonlinear Active Control of Dynamical systems, Virginia 

Polytechnic Institute , Blacksburg, VA, April 13-14, 1998.

49.Dadone, Paolo; VanLandingham, Hugh, Intelligent Control Methods for ShipMounted Cranes, Third Semi-Annual MURI Meeting Nonlinear Active Control of 

Dynamical systems, Virginia Polytechnic Institute , Blacksburg, VA, April 13-14, 

1998.

Offshore Platform Resupply

50.Wen, Bing; Kimiaghalam, Bahram; Momaifar, Abdollah; Bikdash, Marwan, Control 

and Simulation of Ship Crane with Maryland Rigging, Third Semi-Annual MURI 

Meeting Nonlinear Active Control of Dynamical systems, Virginia Polytechnic Institute , Blacksburg, VA, April 13-14, 1998.

51.Lacarbonara, Walter; Soper, R. Randall; Pratt, Jon; Nayfeh, Ali H.; Mook, D.T., New 

Actuators for Ship-Mounted Crane Pendulation Suppression, Second Semi-Annual 

MURI Meeting Nonlinear Active Control of Dynamical systems, Virginia Polytechnic Institute , Blacksburg, VA, July 29, 1997.

52.Soper, R. Randall; Lacarbonara, Walter; Chin, Char-Ming; Nayfeh, Ali H.; Mook, 

Dean T., Nonlinear Resonance-Cancellation of a Base-Excited Planar Pendulum, 

Third Semi-Annual MURI Meeting Nonlinear Active Control of Dynamical systems, Virginia Polytechnic Institute , Blacksburg, VA, April 13-14, 1998.

53.Cojean, Maurice; Colin, Jean-Paul, Device for removing and depositing loads 

between two supports in repeated relative vertical movement, U.S. Patent 4,324,385, 

filed Aug. 30, 1978. 

54.Wudtke, Donald, Motion compensator and control system for crane, U.S. Patent 

4,354,608, filed June 8, 1979. 

55.Archibald, et. al., Sea Swell and Shock Load Compensator, UK Patent Application, 

GB-2,096,563A, filed Mar. 31, 1982.

Vertical Motion Compensation 

56.Dummer, Robert, Marine Crane Lifting Control, U.S. Patent 4,304,337, filed May 

29, 1980. 

Crane Designs

57.Lee, Donald, Automated all-weather cargo transfer system, U.S. Patent 5,154,561, 

filed April, 11, 1990. 

58.Dougherty, E.J., Lee, D.E., Shively, P.D., Automated All-weather Cargo Transfer 

System (AACTS), Society of Naval Architects and Marine Engineers, STAR Symposium, pp S2-3-1, S2-3-6, April, 1989.

59.Naval Architect Journal, New Designs at Liebherr, May 1996 Issue, pp. 36-40.
Crane Technology Development

References 79

Wave Motion Damping

60.Kuo, Chengi; Marine vessels and moonpool structures therein, UK patent GB2,150,516B, filed Nov. 30, 1984.

61.Blood, Howard, Conceptual Design Report of the Pneumatically Stabilized Platform, Report Number FI-TR-09-96, Float Incorporated, December 1996.

62.World City Corporation, Phoenix World City Update, Fall 1993.

Integrated Motion Control

63.Dougherty, Edmond, Intelligent Spreader Bar Quarterly Presentation to NSWC: 

Contract #N00167-95-C-0088, August Design, Inc. Merion, PA, November 20, 

1996.

64.Albus, James; Bostelman, Roger; Dagalakis, Nicholas, The NIST RoboCrane, Journal of Research of the National Insitute of Standards and Technology, Vol. 97, Number 3, May-June 1992.

65.Bostelman, Roger; Albus, James; Dagalakis, Nicholas; Jacoff, Adam; Gross, John, 

Applications of the NIST RoboCrane, 5th International Symposium on Robotics and 

Manufacturing Proc., Maui, HI, August 14-18, 1994.

66.Bostelman, Roger; Albus, James; Dagalakis, Nicholas; Jacoff, Adam, RoboCrane 

Project: An Advanced Concept for Large Scale Manufacturing, Association for 

Unmanned Vehicle Systeems International (AUVSI) Proc., Orlando, FL, July 15-19, 

1996.

67.Albus, James; Bostelman, Roger; Jacoff, Adam; MOB RoboCrane Final Report, 

Mobile Offshore Base Project, Vol. 1, 2, NIST Internal Report (draft), 1997.

68.Dissanayake, Durrant-Whyte, Towards Automatic Container Handling Cranes, University of Sydney, Australia.

Dynamical Systems

69.Dadone, Paolo, Interview at Virginia Polytechnic Institute, July 29, 1997.

Winches, Drives

70.Feldman, Yu. I., et. al., Automated Electric Drives with Frequency Converters for 

Crane and Ship Winch Mechanisms, Russian Electrical Engineering, Vol. 66, No. 10, 

pp. 1-5, 1995 (Allerton Press, Inc. 1996).

71.Podobedov, E. G., et. al., Automatic Electric Drives with Frequency Converters for 

Hoist and Deck Mechanisms, Elektroteknika, Vol. 64, No.8, Aug. 8, 1993, pp. 24-28.

72.Allen, Richard, Winches and mooring equipment from Ship’s Equipment Centre, 

The Naval Architect, Sept. 1995 Issue, p. E474.

Container Terminal Automation

73.Barker, Ann, Deltaport: A new Container Terminal for Vancouver Port Corporation, 

Ports ‘95 Proc., Tampa, FL, Mar. 13-15, 1995, pp. 37-48.

74.Reiss, Daniel, Advanced Container Terminal Design, Ports ‘95 Proc., Tampa, FL, 

Mar. 13-15, 1995, pp. 652-664.
Survey of Cargo Handling Research

80 Intelligent Systems Division • National Institute of Standards and Technology

75.Dougherty, Edmond, J; Lee, Donald E.; Shively, Paul D., Automated All-Weather 

Cargo Transfer System, Society of Naval Architects and Marine Engineers, Sprint 

Meeting/STAR Symposium, New Orleans, LA, April 12-15, 1989.

Material Handling

76.Unknown Author, New Developments in Reefer Cargo Handling, Naval Architect, 

Feb. 1995, E99-E102.

Simulation

77.Simkus, Anthony, Interview and Site Visit to Virginia International Terminals, July 

1997.

78.Mordfin, Theodore; Interview and Site Visit to Advanced Marine Enterprises, 1997.

79.Jason Associates Corp., Crane Operator Training System White Paper, San Diego, 

CA.
Control

Bibliography 81

BIBLIOGRAPHY

The following literature citations have not been specifically referenced in 

this report but provide information that may be of interest to workers in 

crane technology. Abstracts or patent claims are included.

Control

• Jorge Angeles, Evtim Zakhariev, Computational Methods in Mechanisms, NATO, 

Advanced Study Institute, Volume 2, Varna, Bulgaria, June 16-28, 1997 [c/o Prof. 

Dr.-Ing.habil.Christoph Woernie, Universitat Rostock]

Deals with the direct and inverse kinematic problem of cable suspension 

robots that belong to the class of under constrained structural systems 

(Kuznetsov, 1991). [This work is contributed by Prof. Dr.-Ing. habil. 

Christopher Woernie, Universitat Rostock]

• Shu-Zi Yang, et. al. (Editors), Weiping Li, et. al. (Paper Author), Precise Positioning 

Control of Overhead Traveling Cranes, International Conference on Intelligent Manufacturing Proc., Vol. 2620, pp. 792-797, June 14-17, 1995, Wuhan, China.

A new control design is presented for precisely controlling overhead traveling cranes using microprocessors using state feedback control algorithms to guarantee stability of the crane, a trajectory planner to avoid 

saturation, and an additional integral term to eliminate steady-state error. 

Theoretical analysis and experimental implementation on a laboratory 

crane verifies the effectiveness of the approach.

• Yang, Li-Farn, Mikulas Jr., Martin M., Mechanism Synthesis and Two-Dimensional 

Control Designs of an Active Three-Cable Crane, Spacecraft and Rockets Journal, 

Vol. 31, No. 1, Jan.-Feb. 1994, pp. 135-144.

The vibrational characteristics of a three-cable suspension mechanism is 

investigated by comparing a simple two-dimensional suspension model 

and a swinging pendulum in terms of their analytical natural frequency 

equations. Also, a study of active control is made of the crane dynamics 

using two different actuator concepts. Two regulator-type control laws 

based on Lyapunov control are determined to provide vibration suppression for both dynamic systems. Simulations including initial-valued 

dynamic responses as well as active control performances are also presented.

• Armstrong, N.A., Moore, P. R., A distributed control Architecture for Intelligent 

Crane Automation, Automation in Construction 3, Elvesier Science, 1994, pp. 44-

53.

Design and implementation of a modular distributed control system for 

crane and hoist automation in manufacturing and construction. Technology was evaluated on a gantry crane which embodies control structures 
Survey of Cargo Handling Research

82 Intelligent Systems Division • National Institute of Standards and Technology

such as anti-sway, condition monitoring, tele-operation, automatic load 

coupling/decoupling, and automatic cycling.

• Itoh, Osamu, et. al., Application of fuzzy control to Automatic Crane Operation, 

International Conference on Industrial Electronics and Instrumentation Proc., Vol. 1: 

Plenary Session, Emerging Technologies, and Factory Automation, pp. 161-164.

Crane outline showing overhead-trolley drive and the factors that cause 

swing such as delay and friction of the crane even if controlled along a 

pattern. Conformation using computer simulation and practical machine 

show the effect of the fuzzy control method which combines the means 

of the control of positioning and swing pendulation.

• Murata, Istuo; Nakajima, Masamichi; Automatic Control System of Container 

Crane, Transactions of the Japan Society of Mechanical Engineers, Aug. 1993, pp. 

137-143.

Explains the automated container crane system within the total management system of a container yard. The system includes: anti-sway control, 

position control, optimum route control, container stacking profile recognition, and management of operation. (in Japanese).

Heave Compensation

• Kerr, Andrew; McGill, William; Crane cable tensioning arrangement, UK Patent 

Application, GB-2,045,196, filed Mar. 31, 1979.

A cable-tensioning, piston-actuated pulley and another similar arrangement but with full-load capacity, maintains relative heave compensation 

between floating vessels.

Container Terminal Automation

• Unknown author, Watching over the Weight: Automation for a Taipei Cargo Terminal, Airport Forum, Weisbaden, West Germany, June, 1993.

Modern cargo terminals need comprehensive container handling with a 

sophisticated control system that can guide and monitor the mechanical 

handling equipment, track every single shipment, and command handling 

and inventory functions. This automated system was being built by ICM 

of Germany for Everterminal in Taipei.
Container Terminal Automation

POINTS OF CONTACT 83

POINTS OF CONTACT

Phillip Abraham

Office of Naval Research

ONR 331

800 N. Quincy St.

Arlington, VA 22217-5660

703-696-4307

703-696-6887 FAX

LTC Christopher Barbour

Logistics Directorate, J-4

4000 Joint Staff, Pentagon

Washington, DC 20318-4000

703-697-6155

703-614-1076 FAX

barbourcr@js.pentagon.mil

Roderick Barr

Hydronautics Research, Inc.

7210 Pindell School Road

Fulton, MD 20759

301-369-4201

301-470-3427 FAX
Survey of Cargo Handling Research

84 Intelligent Systems Division • National Institute of Standards and Technology

Yvan J. Beliveau

Dept. of Building Construction

122H Burruss Hall

Virginia Polytechnic Institute

Blacksburg, VA 24061-0156

540-231-5948

540-231-7339 FAX

yvan@vt.edu

Dexter Bird, III

Craft Engineering Associates, Inc.

2102 48th Street

Hampton, VA 23661

757-825-1516

757-827-5097 FAX

crafteng@erols.com

Howard Blood

Float Incorporated

1660 Hotel Circle North, Suite 725

San Diego, CA 92108

619-299-9231

619-299-8878 FAX
Container Terminal Automation

POINTS OF CONTACT 85

Donald R. Bouchoux

Whitney, Bradley & Brown, Inc.

1600 Spring Hill Road

Suite 400

Vienna, VA 22182

703 448 6081 ext. 154

703-821-6955 FAX

dbouchoux@wbbinc.com

Kelly Cooper

Naval Surface Warfare Center

Carderock Division

David Taylor Model Basin, Code 29

9500 Mac Arthur Blvd.

West Bethesda, MD 20817-5700

301-227-5429

301-227-1041 FAX

cooperkb@nswccd.navy.mil

Richard Currie

McDermott International, Inc.

P.O. Box 11165

Lynchburg, VA 24506-1165

804-522-5656

804-522-6933FAX

richard.l.currie@mcdermott.com
Survey of Cargo Handling Research

86 Intelligent Systems Division • National Institute of Standards and Technology

M.W.M.G. Dissanayake

Dept. of Mechanical and Mechatronic Engineering

The University of Sydney, 2006, NSW. Australia

Edmond J. Dougherty

August Design, Inc.

120 West Lancaster Ave., 3rd Floor

Ardmore, PA 19003-1305

610-642-4000

610-642-5137 FAX

www.august-design.com

Martin D. Fink

Naval Sea Systems Command

Strategic Sealift Program Office

PMS 385, PEO CLA

2531 Jefferson Davis highway

Arlington, VA 22242-5160

703-602-0920 ext 109

703-602-5385 FAX

Len Haynes

Intelligent Automation Inc.

2 Research Place, Suite 202

Rockville, MD 20850

301 590-3155

301-590-9414 FAX
Container Terminal Automation

POINTS OF CONTACT 87

J.L. Korenek

Brown & Root Energy Services

PO Box 4574 

10200 Bellaire Blvd.

Houston TX 77072-5299

281-575-4371

713-575-3227 FAX

Frank Leban

Naval Surface Warfare Center

Carderock Division

David Taylor Model Basin, Code 2930

9500 Mac Arthur Blvd.

West Bethesda, MD 20817-5700

301-227-4698

301-227-1041 FAX

leban@oasys.dt.navy.mil

CDR Steve Lehr

N42

OPNAV

Crystal City Square 2, Room 1002

1725 Jefferson Davis Highway

Washington DC 20350

703-602-7305
Survey of Cargo Handling Research

88 Intelligent Systems Division • National Institute of Standards and Technology

Vito Milano

Center for Naval Analyses

4401 Ford Avenue

P.O.Box 16268

Alexandria, VA 22302-1498

703-824-2684 

703-824-2949 FAX

Ted Mordfin

Advanced Marine Enterprises, Inc.

1725 Jefferson Davis Highway

Suite 1300

Arlington, VA 22202

703-413-9200

703-413-9221 FAX

mordfin_ted@advmar.com

Jack Nance

Center for Naval Analyses

4401 Ford Avenue

P.O.Box 16268

Alexandria, VA 22302-1498

703-824-2204

703-824-2949 FAX

nancej@cna.org
Container Terminal Automation

POINTS OF CONTACT 89

Prof. Ali Nayfeh

Dept. of Engineering Science and Mechanics

Virginia Polytechnic Institute

Blacksburg, VA 24061-0219

John Nicholson

Float Incorporated

1660 Hotel Circle North, Suite 725

San Diego, CA 92108

619-299-9231

619-299-8878 FAX

Clyde Nolan

Brown & Root Energy Services

PO Box 4574 

10200 Bellaire Blvd.

Houston TX 77072-5300

281-575-4370

713-575-3227 FAX

cnolan@b-r.com

Rob Overton

Wagner Associates

Suite 500

2 Eaton Street

Hampton, VA 23669

757-727-7700

757-722-0249 FAX

rob@va.wagner.com
Survey of Cargo Handling Research

90 Intelligent Systems Division • National Institute of Standards and Technology

Gordon Parker

Sandia National Laboratories

P.O. Box 5800, MS 0949

Albuquerque, NM 87185

Art Rausch

Naval Surface Warfare Center

Carderock Division

David Taylor Model Basin, Code 293

9500 Mac Arthur Blvd.

West Bethesda, MD 20817-5700

301-227-4590

301-227-1041 FAX

rausch@oasys.dt.navy.mil

Gene Remmers

Office of Naval Research

ONR 334

800 N. Quincy St.

Arlington, VA 22217-5660

703-696-0814

703-696-0308 FAX

remmerg@onr.navy.mil

Don Resio

EDRC

3909 Hallsferry Road

Vicksburg, MS 39180

601-634-2018

d.resio@cerc.wes.army.mil
Container Terminal Automation

POINTS OF CONTACT 91

L.CDR Thomas Satterly

N422

OPNAV

Crystal City Square 2, Room 1002

1725 Jefferson Davis Highway

Washington, DC 20350

Curtis E. Schelle

MAR, Incorporated

6110 Executive Blvd., Suite 410

Rockville, MD 20852

301 230-4595

301-770-2680 FAX

William E. Schulz

John J. McMullen Associates, Inc.

Century Building, Suite 715

2341 Jefferson Davis Highway

Arlington, VA 22202

703-418-0100

703-418-4269 FAX

Anthony P. Simkus, Jr.

Virginia International Terminals, Inc.

P.O. Box 1387,

Norfolk, VA 23501

757-440-2878

757-440-2879 FAX

simkus-t@vit.org
Survey of Cargo Handling Research

92 Intelligent Systems Division • National Institute of Standards and Technology

Randy Tagg

University of Colorado

1250 14th St. 

Denver, CO 80202-1712

303-556-2293

Robert Weibel

McDermott Shipbuilding, Inc.

160 James Drive East

St. Rose LA 70087

504-471-4067

504-471-4103 FAX

bob.weibel@mcdermott.com

Mike Todd

Naval Research Laboratory

Room 127, Bldg. 215

4555 Overlook Ave., S.W.

Washington D.C. 20375-5338

202-767-1480

202-404-8645 FAX

Jack Turner

Syntek Technologies, Inc.

4301 North Fairfax Drive 

Suite 850

Arlington, VA 22203 

703-525-3403

703-525-0833 FAX

jturner@snap.org
Container Terminal Automation

POINTS OF CONTACT 93

Ted Vaughters 

Naval Surface Warfare Center

Carderock Division

David Taylor Model Basin, Code 29

9500 Mac Arthur Blvd.

West Bethesda, MD 20817-5700

301-227-4591

301-227-1041 FAX

vaughter@oasys.dt.navy.mil

Sandeep T. Vohra

Naval Research Laboratory

4555 Overlook Ave., S.W.

Washington D.C. 20375-5338

202-767-9349

202-404-8645 FAX

vohra@ccfsun.nrl.navy.mil

Jim York

University of Maryland

4201 Computer Science Bldg.

IPST

College Park, MD 20742

301-405-4875

301-314-9363 FAX

york@ipst.umd.edu
Survey of Cargo Handling Research

94 Intelligent Systems Division • National Institute of Standards and Technology

Max Weber

Steven Naud

Coastal Systems Station

6703 West Highway 98

Panama City, FL 32407-7001

904-235-5445

904-235-5443 FAX

weber_max@ccmail.ncsc.navy.mil

William Wood

Seaworthy Systems, Inc.

P.O. Box 975

Barnegat, NJ 08006

609-361-0479

609-361-0802 FAX