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A Review of the Prediction of Squat in Shallow Water

Published online by Cambridge University Press:  21 October 2009

A. Millward
A. Millward
Affiliation:
(University of Liverpool)
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Abstract

Recent evidence has shown that the effect of a ship moving in shallow water and the resultant squat are not well understood. This paper reviews the general problem of a ship in shallow water and illustrates the corresponding resistance, trim and sinkage at both sub-critical and also at super-critical speeds.

The paper then reviews the various methods of predicting the squat of a ship in shallow water in the sub-critical range, which is applicable to most ships. It is suggested that the simple rule-of-thumb methods are, at best, unreliable and the paper gives examples of empirical methods which have been tested against various sets of data and seem to give more representative answers. A summary of the notation used is given at the end of the paper.

Keywords

1. Hydrodynamics.2. Squat.3. Shallow water.4. Ship handling.
Type
Research Article
Information
The Journal of Navigation , Volume 49 , Issue 1 , January 1996 , pp. 77 - 88
Copyright
Copyright © The Royal Institute of Navigation 1996

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References

REFERENCES

1Department of Trade (1980). Interaction between ships. Merchant Shipping Notice No. M930.Google Scholar
2Dand, I. W. (1989). Hydrodynamic aspects of the sinking of the ferry Herald of Free Enterprise. Transactions Royal Institution of Naval Architects, vol. 131, pp. 145–165.Google Scholar
3Millward, A. and Bevan, M. G. (1990). Data on the effect of shallow water on high speed round bilge ship forms. University of Liverpool, Department of Mechanical Engineering. Report TF/002/90.Google Scholar
4Comstock, J. P. (1967). Principles of Naval Architecture. Society of Naval Architects and Marine Engineers.Google Scholar
5Willis, C. J.Crapper, G. D. and Millward, A. (1994). A numerical study of the hydrodynamic forces developed by a marine rudder. Journal of Ship Research, vol. 38, no. 3, pp. 182–192.CrossRefGoogle Scholar
6Willis, C. J. (1988). Steady sideforce on a ship due to a marine propeller. University of Liverpool, Ph.D. Thesis.Google Scholar
7 Ortlepp (1989). Natural squat. Canadian Maritimes Sailing Aids, vol. IV, Peltro Ltd, Canada.Google Scholar
8Dennis, B. C. (1993). Squat in depths of less than twice the draft. Seaways, pp. 27, October.Google Scholar
9Admiralty Manual of Navigation (1987). HMSO, vol. 1, pp. 308.Google Scholar
10Blaauw, H. G. and van der Knaap, F. M. C. (1983). The prediction of squat of ships sailing in restricted water. Proceedings 8th International Harbour Congress, Antwerp, Belgium. Ardon International Ltd, Publication No. 302, pp. 1–13.Google Scholar
11Millward, A. (1990). A preliminary design method for the prediction of squat in shallow water. Marine Technology, vol. 27, no. 1, pp. 10–19.Google Scholar
12Dand, I. W. and Ferguson, A. M. (1973). The squat of full ships in shallow water. Transactions Royal Institution of Naval Architects, vol. 115, pp. 237–255.Google Scholar
13Dand, I. W. (1972). Full form ships in shallow water: some methods for the prediction of squat in sub-critical flows. NPL Ship Division Report 160.Google Scholar
14Tuck, E. O. (1978). Hydrodynamic problems of ships in restricted waters. Annual Review of Fluid Mechanics, vol. 10, pp. 33–46.CrossRefGoogle Scholar
15Tuck, E. O. and Taylor, P. J. (1970). Shallow water problems in ship hydrodynamics. Proc. 8th Symposium on Naval Hydrodynamics, Pasadena, pp. 627–659, August.Google Scholar
16Collinson, R. G. (1994).A review of methods of predicting the squat of a ship in shallow water. University of Liverpool, Department of Mechanical Engineering, M.Sc (Eng) Thesis.Google Scholar
17Barrass, C. B. (1979). The phenomenon of ship squat. International Shipbuilding Progress, vol. 26, pp. 44–47..CrossRefGoogle Scholar
18Fuhrer, M. and Romisch, K. (1977). Effects of modern ship traffic on inland and ocean waterways and their structures. Proc. PIANC XXIV, Leningrad, pp. 79–93.Google Scholar
19Soukhomel, G. I. and Zass, V. M. (1978). Abaissement du navire en marche. Navires, Ports et Chantiers, pp. 18–23.Google Scholar
20Eryuzlu, N. E. and Hausser, R. (1978). Experimental investigation into some aspects of large vessel navigation in restricted waterways. Proceedings Symposium on Aspects of Navigability, Delft, Netherlands, vol. 2, pp. 1–15.Google Scholar