THE EFFECT OF CHANNEL WIDTH AND DEPTH ON THE RESISTANCE OF A HIGH SPEED HULL

Abstract

An investigation has been made into the effect of channel width and depth on the resistance of a high speed hull in the Froude number range F _n from 0.3 to 1.0 using experimental results from tests on two different sized models of the NPL 100A hull and also theoretical work using Wigley hulls as representative of a suitable high speed hull.

The results of the investigation showed that for there to be no significant effect from the boundaries of a channel or towing tank the model size should be approximately not more than half the width of the channel nor more than the depth of water in the channel. This result is in broad agreement with the guidance resulting from larger towing tanks given in the published literature which is generally for lower speed ships. The results also showed that using linear wave theory on a simpler hull shape, modified for the effect of a transom on the real hull, gave reasonable guidance of the magnitude of the correction for data from tests on larger hulls to allow for channel effects.