Minimal-resistance hullforms for high-speed craft

There is a continuing interest in the improvement of the design of vessels in order to minimise the power required to propel them. When operating in rivers, an additional concern is the environmental impact of the wave generation, in which case there is a desire to reduce the erosion of the river banks as much as possible.

In a previous study of the problem, the hullform yielding the minimal wavemaking resistance at a given speed and water depth was calculated, subject to constraints on the displacement, the maximal local beam, and the interior space required, and the requirement that the profile of the hull was to be rectangular.

The work presented here extends this effort in a number of practically-relevant directions. The total resistance of the vessel is minimised either for a single speed and water depth, or over a range of speed/depth conditions. The length of any waterline, and the draft oat any station are allowed to vary within a prescribed range, thus allowing non-rectangular profiles and, hence, further generalising the approach. A constraint on the maximal waterline slope is introduced in order to restrict flow separation. Minimisation is carried out using a hybrid of classical 'hill-climbing' techniques and a Genetic Algorithm.