On the towfish motion characteristics of single-body vs. two-body sidescan systems

The basic mechanisms by which towing vessel motions in a seaway result in towfish angular motions are presented for both single-body and for two-body sidescan systems. It is shown that a neutrally buoyant towfish displays superior motion characteristics compared to a negatively buoyant towfish, either when depressed by a separate depressor or by a weighted towline. The influences of such design parameters as speed of tow and towfish geometry on the resultant towfish motions are discussed both qualitatively and quantitatively for a representative system. It is shown that a towfish designed for near-neutral stability, with both dynamic and hydrodynamic balance about its towpoint, displays superior motion characteristics as compared to one designed for high static stability