Depressor

An attachment to a sonar tow cable that assists in increasing the depths of the towed body; commonly of two types: deadweight and hydrodynamic. The depressor allows the user to bring a sonar towbody within an optimum altitude above the seabed. Although lower tow speeds also assist in lowering a towfish, speeds below 1-1.5 knots may produce towbody instability such as kiting and yaw resulting in data distortions.