Similar ships followed nearly the same trackline with different rudder controls. They tended to have similar patterns of distance off the channel centerline and heading differentials from the channel heading even with different patterns of rudder and RPM positions; indicating similar paths in a restricted channel can be achieved with different control forces.

　

 Initial comparisons of the measured ship responses to simulated model ship responses with the measured ship rudder positions and RPM controls being input demonstrated different ship motions. Some effects of additional detail in developing the channel model could be observed,indicating that modeling the bank and depth conditions along the channel is affecting the ship response.

　

 Autopiloted simulations can produce similar heading differentials from the channel heading and similar positions in the channel with smoother and smaller rudder controls. The rudder control required is affected by the magnitude of the simulated bank moments.

　

 Reinitializing a ship within a measured transit should be able to recover with the same control input and follow a similar path if the initial conditions are similar and the forces acting on the ship are similar.

　

 The real-time simulation model seemed to be more difficult to control than the measured ship. Local pilots should validate and perform simulator runs after necessary model adjustments are made.

　

 Consideration should be given to making modifications to the bank and shallow water models, especially based on recent research. The models reported on here are based on Norbbin's 1970's model results.

　

 Additional approaches of validation analysis should be developed; e.g., a more stastically based method.

　

 Additional simulation modeling methods should be applied to this data to evaluate how different modeling approaches perform.

　

 Additional methods for evaluating the accuracy of model replication of measured ship responses are required.

　

 Consideration should be given to collecting unconfined, deeper-water ship maneuvering data for these ships with the measured load conditions to better develop the basic deep-water unconfined ship model. This is possible since many of the ships modeled are used in lightering operations and generally have similar load conditions.

　

 The rudder and thrust forces and moments and the resultant forces and moments based on the measured ship mass and accelerations should be computed throughout the transit. These can then be compared to the modeled bank forces and moments at each channel location.

　

 Use of computational fluid dynamic models could shed some light on the bank and shallow water effects with the low h/T rations involved.

　

 The authors welcome any suggestions and recommendations.

　

[1] William C. Webster, Editor, "Shiphandling Simulation - Application to Waterway Design,National Research Council, Marine Board Committee on Assessment of Shiphandling Simulation, National Academy Press,Washington, D.C., 1992, pp 76-78.

[2] "Capability of Ship Manoeuvring Simulation Models for Approach Channels and Fairways in Harbours", Permanent International Association of Navigation Congresses, Report of Working Group No.20 of Permanent Technical Committee II, Supplement to Bulletin No. 77, 1992.

[3] "Simulated Voyages -Using Simulation Technology to Train and License Mariner", National Research Council, Committee on Ship-Bridge Simulation Training, National Academy Press, Washington, D.C., 1996, pp 160-l62, p 171, p 184.

[4] B.B. Parker and L.C. Huff, "Modern Under-Keel Clearance Management", International Hydrographic Review, Monaco, September 1998.

[5] L.L. Daggett, J.C. Hewlett, "Prototype Ship Measurements in the Houston Ship Channel", Report to the Society of Naval Architects and Marine Engineers, 2000.

[6] L.L. Daggett, J.C. Hewlett, "Ship Performance Measurements, Houston Ship Channel, Galveston Bay, Texas, WST/D&P report to U .S. Army Engineer and Development Centers, Contract No. DACW39-97-000l, D012, Vicksburg, MS, July l0, 2001

[7] V. Ankudinov, 'Development of Four Hi-Fidelity Ship Models", BMT Designers & Planners Technical Report 2212-01 to U.S. Army Engineering Research and Development Centers Contract No. DACA42-02-D-003 Delivery Order No. 000l, Arlington, VA, August 1, 2002.

　

 Dr. Daggett retired from the Corps of Engineers in April 1997 and joined in forming an engineering consulting firm, Waterway Simulation Technology, Inc (WST). WST is a private engineering consulting company specializing in navigation studies involving port, harbor, and channel design, systems behavior, ship and/or tow maneuvering simulations, prototype measurements of ship and/or tow behavior, and hydrodynamic modeling.

　

 As Chief of the Navigation Division at the Waterways Experiment Station, Dr. Daggett was responsible for management of special studies of hydraulic engineering problems concerning navigation channel design and environmental impacts of navigation. This included the development of a numerical ship/tow simulator, application of ship/tow simulators and scale physical models using remote controlled vessels to navigation channel project designs and/or operational problems of specific projects, application of two-dimensional hydrodynamic models, prototype measurements of vessel behavior in waterways, development and application of electronic navigation charts and vessel positioning to inland waterways, application of physical modeling and field measurements to deter-mine the physical effects of navigation traffic on the waterways environment,briefings,lectures,and training on simulation/ physical model applications and channel design, development of channel design criteria, and consulting and point of contact for Corps navigation modeling applications.