SNAME Chesapeake Section Discusses Steering, Maneuvering And Controllability Of Surface Ships

The Chesapeake Section of The Society of Naval Architects and Marine Engineers met at the Officers' Club at the Washington Navy Yard on January 18, 1978, to hear C.C. Glansdorp and Dr.

Gerald van Oortmerssen discuss "Research on Steering, Maneuvering, and Controllability of Surface Ships." Mr. Glansdorp is the senior scientific officer of the Netherlands Maritime Institute and Delft University of Technology in the Department of Naval Architective and Maritime Studies. The paper was divided into two sections, with Mr. Glansdorp's portion being concerned with "Ship Maneuvering Trials and Some New Concepts in Ship Controllability." His presentation included a general treatment of the execution of maneuvering trials for practical nautical purposes, and for compliance with recent resolutions on maneuvering adopted by the General Assembly of the International Maritime Consultative Organization. Mr. Glansdorp also discussed the function and application of a ship maneuvering simulation to the training of navigators and helmsmen, noting the encouraging experience that the institute had encountered in the modeling of a navigator's behavior.

The second part of the presentation covered the "Hydrodynamic Research by means of Model Tests," which developed the technology base upon which the motions simulator was constructed.

Dr. van Oortmerssen, who is senior scientific officer at the Netherlands Ship Model Basin in Wageningen, presented a general description of the mathematical models required for describing the horizontal plane motions of a maneuvering ship. The model testing techniques which are used to determine the coefficients in the mathematical model were discussed in detail by Dr. van Oortmerssen. He gave special attention in his presentation to the interesting and often anomalous effects of shallow water, proximate canal banks and soft mud bottoms. Dr. van Oortmerssen's presentation of the interesting modeling and scaling problems generated in soft bottom model testing was particularly entertaining as well as instructive.

This was followed by an analysis of the maneuvering disturbances produced by wind, waves, currents and passing ships. Dr. van Oortmerssen concluded with a presentation of correlations of predictions of standard maneuvers with the results of freerunning model tests and full-scale trials.

The session was chaired by Gerald Cann, who is presently serving as Deputy Assistant Secretary of the Navy for Systems.

Mr. Cann is a geophysicist who held the position of Assistant Director for Ocean Control in the OSD D.D.R. & E office in years prior to his present appointment.

Following technical presentations, Mr. Cann called for a presentation of the written discussions prepared by seven members of the Society, (R. Falls, DTNSRDC; A.

Landsburg, MarAd; G. Miller, Hydronautics ; Lt. Comdr. W. Snider, Coast Guard; A. Taplin, NSEC; V. Keith, ECO, and L. Crane, Exxon).

Mr. Cann also presented a brief summary of the Navy's ship design program. Mr. Cann encouraged the community of naval architects to remember three key areas when considering naval ship design: vulnerability, modularity, and maintenance.

The fact that the currently planned ships will have to serve the needs of the Navy into the next century requires that weapon suites be modular. It further requires that the special maintenance problems created by both modularity and an all-volunteer service be carefully addressed in the near future.

Other stories from March 1978 issue


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