The Development of a "Green Trawler"

As quota and fishing effort restrictions become tighter, and fuel costs spiral, it is likely that fishing time will further reduce and therefore the design pressure on fishing vessels of the future will be to improve efficiency when steaming and to retain optimum thrust when trawling. Rules and regulations have shaped our modern trawlers. The necessary fullness for carrying fish is accentuated by the imposition of restrictions in length. While it is generally accepted that there is a penalty in fuel consumption relating to this evolution this study sets out to quantify it. This paper describes the development of a “green trawler” designed to incorporate the highest level of efficiency available in a practical form for use in the demersal fishing fleet. Results from field tests on existing trawlers and towing tank tests on the green trawler design are presented. Comparison is made between a typical demersal trawler, at sea and in the test tank, and the green trawler. The model tests were designed to confirm that the design concept was fuel efficient; and to determine the potential for increased fuel efficiency if certain regulatory restrictions on fishing vessel design parameters were lifted. Savings of 30% on fuel consumption could be achieved with relatively modest length increases. Additional savings of 10 to 20% can be achieved by reducing the drag of hull appendages, for example, better alignment of bilge keels. The study concludes by introducing the concept of “Green Tonnage” as an option that should be considered by the EU and Member States, whereby vessel owners would be allowed additional GT’s for new builds over and above existing limits without being penalized. This should be strictly on the basis that no increase in effective fishing effort results