ANALYSIS OF TOWED VESSEL COURSE STABILITY IN SHALLOW WATER

Towed vessels are engaged in many commercial and naval operations where the navigation conditions correspond to shallow water conditions. The present study considers the influence of shallow water on towed vessel course stability for four representative towed vessels. Towing stability in shallow water is studied using the classic linear time-invariant towing theory. This allows the calculation of the critical tow line tension necessary for stable towing. The results of a systematic investigation indicate that shallow water improves the towed vessel course stability and that in the case of the course-unstable towed tanker, extreme shallow water conditions make it course-stable. The influence of towrope length and towing speed are also discussed, and a towing course stability index, K, is introduced.