Research On The Towing System Performance Of Large Floating Body Based On AQWA

With the uninterrupted growth of global economy, the business of ocean shipping is becoming more and more prosperous, ships and platforms'towing operations are relatively increased. Lots of new problems have come up when the position of towing manipulation is becoming much more important. There are many risks which would affect the security of towing system during operations, such as the rapture of the towing rope, unreasonable layout of the towing rope and towed ship's yawing. In the past, sailors operated with their experience without systematic theory when encounter these situations. Thus, research on the towing performance is certainly important for keeping the towing operation going on smoothly.This paper uses the hydrodynamic analysis program AQWA which is based on the theories of potential flow and diffraction/radiation to establish a single-tug towing system which includes one towing ship and one towed ship. In addition, the single-tug towing system is simulated in time-domain. The wave loads, wind loads and current loads are considered to analyze the motion performance of the towing system under different sea conditions. After that, the multi-tug towing system is built up to do some studies on the alternative schemes for the multi-tug towing system, and then discusses the parameters of the disposition and optimization for the system.Through the using of AQWA program, this paper studies the factors that affect the towing system which consist of the length of the towing rope, velocity of towing, draft of the towed ship, trim of the towed ship, environment conditions and so on. The results show that AQWA program can rightly reflect the motion state of the towing system; wind, wave and current would have a comparatively effect and exist an range; the length change of the rope, the velocity of towing, the draft of the towed ship and water depth will partly affect the stability of the course; three-tugs towing is more stable than two-tugs'.This paper describes the towing motion objectively which is helpful to explore the rules of towing performance and also can give guidance to the towing operation.