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Experimental investigation of fishing vessel stability in a transverse seaway

University of British Columbia

The continuing loss of life at sea due to the capsizing of fishing vessels in inclement weather requires the research and design communities to continue their search to find methods for the prevention of further occurances. As part of this investigative process this thesis was prepared. To gain an initial foothold on the dynamics of capsizing the area of transverse seaways was considered for its contribution to capsizing through the impact of breaking waves on the side of the ship. Two model fishing vessels, built without bulwarks or superstructure, were prepared for testing in a 220 foot test basin where, through the use of computer control, a repeatable sea environment could be created. The models were equipped with adjustable displacements and centers of gravity to allow testing of IMO stability guidelines and the simulation of wind induced decreases in general stability. Tests were conducted in still water, regular waves and breaking waves of the plunging jet type. Motions, including roll, pitch, heave, sway and yaw, were measured and stored on media for analysis by computer. Along with the electronic monitoring of the vessel's motions a video tape was made of the tests to allow visual verification of motions at a later date. From the results of the tests it was found that the single chine seiner exhibited greater intact stability in all transverse sea conditions tested than did the west coast trawler. Under no circumstance did the single chine seiner capsize while, in breaking waves, the trawler exhibited repeated capsizing behaviour when at its heaviest displacement and lowest metacentric height. This capsizing illustrates the need for greater stability characterisitics and improved safety criterion for breaking waves survival over that required in regular seas.

Text

2010-07-11

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http://hdl.handle.net/2429/26323

Mechanical Engineering

University of British Columbia

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