Prawn trawl drag due to material properties - an investigation of the potential for drag reduction

Rising fuel costs, impending oil deficit and global concern for greenhouse gas emission necessitate improvements of energy efficiency in commercial fisheries. Innovative high strength netting materials provide the potential for a positive outcome in relation to the energy efficiency of prawn trawling. Usage of high strength netting in Australian prawn trawling applications has returned mixed results over the last 10 years. The presented work investigated the drag of prawn trawl models constructed from innovative and traditional materials. The major finding was that drag reductions achieved with innovative materials were not directly related to the associated reductions in twine area: knot area and orientation produce amplified effects on drag. It was also shown that netting stiffness affects trawl shape and hence the corresponding drag.