The use of variable body forces to control the depth of towed submersibles

The relationship between the depth and trail attained by a towed submerged vehicle and the magnitude and direction of the forces on it has been examined theoretically, for cases involving faired cables.It is shown that when the body force is varied the body in equilibrium moves on an almost circular path as if the cable were straight, and that depth changes depend primarily upon the change in the component of the body force that acts at right angles to the line joining the top and bottom of the cable.Examples are given which demonstrate that for bodies towed at large depression angles the use of water brakes is more effective in changing depth than the use of lifting wings.The data is presented so that a rapid preliminary assessment can be made of any proposed system to obtain the best combination of speed and scope for achieving a given depth with a body having known lift and drag coefficients.