Design and optimization of an efficient overboarding mechanism for the drop/lift automation of an active/passive sonar system in a surface ship

An active/passive sonar system consists of 1) a transmitter towing cable for adjusting the depth of the transmitter towed body, 2) a receiving array for measuring sound waves, 3) a transmitter towed body for transforming sound waves and 4) an array cable for connecting a receiving array to a transmitter towed body. There is a need to develop an automated equipment to drop the active/passive sonar system into the deep sea from the surface ship and then lift it, since this consists of a cable with a length of over 1000m, a transmitter towed body, etc. With the research on the active/passive sonar system, a variety of mechanisms of the overboarding unit suitable for the limited environments have been developed. This paper suggests a new overboarding mechanism which is efficient in operation and maintenance of the sonar system. First, we analyzes the strengths and weaknesses of the existing overboarding mechanisms, and then suggest a new mechanism to improve these problems. For the proposed mechanism, we will treat with a technique to optimize the link length and the actuator length for the mechanism not to interfere in the hull´s internal environment, to satisfy work ROM (Range of Motion) and to have good torque-angle properties. Our approach will be helpful for calculating the maximized output torque of the actuator for the actual application of a similar type of the proposed mechanism in practice.