Trawler-trawling gear interaction

The paper presents a method for the simulation of the dynamic interaction between a trawler and its trawling gear. The main parameters affecting the interaction are the resistance forces acting on the gear and the trawler´s hull, and the thrust made available by the propulsion system of the trawler. Inputs to the simulation method are trawling gear geometry, hull geometry, engine and propeller characteristics, and trawling speed. The output is a set of interaction curves showing the variation of hull and gear resistance with trawling speed, and available thrust as a function of speed and propeller rpm. The resistance of the trawl is obtained from theoretical and experimental studies conducted previously by the authors. Trawler hull resistance is obtained by means of a regression technique. In addition to simulating the actual trawler-trawling gear interaction the method can be used to predict the effects of changes made to the system on overall efficiency.