CONSIDERATIONS OF SHIPHANDLING IN HULL DESIGN
In this consideration of the strong relationship between hull size and shape and ship-handling, and of electronic aids to steering and manoeuvring, the Author (of B.S.R.A.) first discusses turning performance. The turning-circle test is considered in relation to full-scale ships (for which there is a shortage of systematic data covering hull-form variations) and to ship-models. In particular, the results of Shiba's model tests (published in 1960) are discussed. Dynamic stability (the term is preferred to "course stability") is next considered. Some results of Dieudonne and Bech spiral tests are discussed; there is a lack of data from these full-scale trials, making it difficult (as in the case of turning performance) to compare the behaviour of ships with different geometries. Recourse may be had to captive-model experiments with a planar motion mechanism; the results of the systematic study by Wagner Smitt are discussed. Stopping ability is also dependent on ship size and geometry. A useful way of displaying stopping data in the wheelhouse is that suggested by R.I. Price in 1970; this is briefly discussed, together with a 1971 study by the present Author which included the development of a "universal stopping curve" and a consideration of braking devices. Model-following techniques, used in aircraft control-systems, could greatly reduce the strain on ship-handlers and ships' pilots, but a drawback is that these techniques demand a mathematical description of the ship's actual behaviour as well as its required behaviour. This mathematical model might be obtained by another control technique, system identification, on which B.S.R.A. have carried out some preliminary investigations. Once it is accepted that complicated control tasks can be undertaken by pre-programmed dedicated micro-computer, a range of possibilities will open up for better ship-handling, ship control and guidance, and navigation; such devices can be expected on the market very soon. Some basic work by B.S.R.A. (a study of a ship being steered by a conventional autopilot in rough seas) is briefly discussed. Possible further developments incorporating radiometric position-fixing aids are mentioned. Order from: BSRA as No. 47,694.
- Conference on Shiphandling held in Plymouth, November 1977.
Nautical InstituteAlderman's House, Alderman's Walk
London EC2M 3UU, England
- Clarke, D
- Publication Date: 1977
- Features: References;
- Pagination: 18 p.
- TRT Terms: Automatic steering control; Braking; Dynamic stability (Ships); Hulls; Maneuvering; Mathematical models; Ship motion; Ship pilotage; Stopping; Turning radius; Vehicle design
- Uncontrolled Terms: Ship design; Ship models
- Old TRIS Terms: Course stability; Turning circle calculations
- Subject Areas: Design; Education and Training; Marine Transportation; Safety and Human Factors; Vehicles and Equipment;
- Accession Number: 00173656
- Record Type: Publication
- Source Agency: British Ship Research Association
- Report/Paper Numbers: Proceeding
- Files: TRIS
- Created Date: Apr 26 1978 12:00AM