Net Drag Estimation of 18.0 m Semi Pelagic Trawl through Calculated Twine Area in Comparison to Projected Prototype Values by Model Studies

Abstract

Designing a trawl gear can effectively be accomplished by matching its size to the available horsepower. A simple method of trawl gear estimation at the design stage, utilizing the information available from a net drawing, will immensely ease the designing process without having to wait for the experimental values of net drag. Drag estimation through calculated twine area is attempted with 18.0m semi pelagic trawl and is compared with the total drag of the projected prototype values by I/IS"1 model studies conducted at the ship model testing tank at IIT, Chennai. Method of calculation of twine area in m2 of the different webbings that go into the making of the gear is required to calculate the total twine resistance to enable to optimise the designed net and to optimally utilize the available horse power. Net drag estimation using calculated twine area and the total drag of the prototype arrived at by model studies are calculated and compared.