Ship Squat

  • Jelenko Švetak
Keywords: ship squat, ship trim, ship design, depth of influence, width of influence, squat prediction, prevention

Abstract

Although a recognised phenomenon affecting a vessel, particularlyin shallow and confined wate1ways, squat is difficult tocalculate, quantify and apply.Many different factors affect its impact. It is always a predictedfigure, depending on factors that may at any given timebe unknown or difficult to asce11ain with any degree of accuracy.It involves, but is not limited to the input of informationfrom the vessel's particulars, as well as those of the limitationsof the wale/Way to be transited, traffic interaction, factor oftides and tidal streams, currents and prevailing weather etc.The knowledge of squat, its calculation and application ofsafe margins, and timely preventive action (reduction of speed)may save a vessel from grounding and its aftermath. Lack ofappreciation of squat can prove to be ve1y costly.

References

Barrass, C. B.: 'Ship squat manual', Polytechnic

International Luton (1978).

BARRASS, C. B. 'A Unified Approach to SQUAT

calculations for ships'. Conference on 'Shiphandling'

organised by The Nautical Institute (November 1977).

Yamaguchi et al. 'Full scale tests on Sinkage of a

Supertanker through Shallow water'. Nautical Society

of Japan. (January 1968).

Bayer, G. S. 'Ship Design, Resistance and Screw

Propulsion', Vol. 1, page 221. Birchall (1951).

Todd, F. H. 'Ship Hull Vibration', Arnold (1961).

LACKENBY, H. 'The effect of Shallow water on ship

speed'. Shipbuilder and Marine Engine-Builder.

(September 1963).

RAWSON, K. J. and Basic Ship Theory, page 323.

Longman (1968). TUPPER, E.C.

BARRASS, C. B. 'Calculating Squat - a practical

approach'. 'Safety at Sea' Journal (February 1978).

How to Cite
1.
Švetak J. Ship Squat. PROMET [Internet]. 1 [cited 2020Sep.25];13(4):247-51. Available from: http://traffic.fpz.hr/index.php/PROMTT/article/view/1082
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