New hull from Macduff Ship Design

01 Apr 2008

Macduff Ship Design, in conjunction with CTO [a renowned tank testing facility in Gdansk, Poland] has completed an exhaustive study into the performance of trawler hull forms and has developed a new one.

With a significantly modified bow section the new hull has increased the free running speed, decreased the power required, increased the bollard pull and improved on the general sea keeping properties.

The driving force behind the study was the continuing increase in the cost of fuel and the desire to examine all aspects of hull design from basic principals including the close relationship between ballast and the vessels beam.

An existing 20m trawler design was used as the benchmark, as this class of vessel has known properties and it was compared with a new 24m design. The same propulsive power has been used for the longer new design but with a larger diameter propeller, the idea not to create a larger vessel requiring more power but in fact the reverse.

The longer vessel will have increased space and safety for catch handling, processing and crew amenities and will be more comfortable especially in bad weather. The new hull form will be able to maintain speed in worsening weather conditions either while towing or free running.

CFD [computational fluid dynamic] calculations predict an increase in free running speed of about two knots for the same installed power or a reduction of about 40% of power for the same speed – this is a combination of the additional length and the new bow form. Clean and straight buttock lines optimise the flow into the nozzle and a generous rise of floor amidships further improves the flow.

By increasing the vessel's beam, the amount of internal ballast is reduced and accordingly there is no major increase in overall displacement for the larger design. In addition to this there is a considerable gain in deck space to allow improved catch handling, processing and freezing equipment to be fitted. The increased beam allows for a finer hull form below the waterline which is also a contributing factor to the improved performance figures.

Macduff Ship Design will be using the results of this study to produce the next generation of fishing vessel designs building on the already successful range of designs produced by the Company over the last 15 years.