Design and Analysis of a Towed Submersible System

Abstract

Hydrodynamic design of a towed submersible system is presented in this paper. The towed system consists of the towed body and the cable towed behind a surface ship. The towed body design described here has the unique feature of having positive buoyancy, which enable the body to stay afloat on the water surface when at rest. This unique feature facilitate retrieval of the towed body in case of an emergency such as cable snapping, since the towed body being positively buoyant will surface on its own thus ensuring the retrieval of the valuable payload.
The geometry of the towed body is determined based on the requirements of payload to be housed. Weight buoyancy budgeting is carried out such that the body is slightly positively buoyant. The optimum value of cable scope and cable tension are determined using Pode's tables. The design of wings is carried out of meet the requirements of negative lift and cable tension to be generated in order to attain the required depth at the specified speed of the towing ship. Stabilizer fins are designed to provide stability in the pitch and yaw planes. Plan form area and aspect ratio of the stabiliser fins are systematically varied until stable configuration is arrived at.