AUV launch & recovery handling simulation on a rough sea

Abstract

Launch & recovery operations performed on a rough sea are challenging from many perspectives. Not only the risk of equipment damage is high, but also waiting for an acceptable weather window can be costly and may affect the installation or investment plans. This work concentrates on a LARS and AUV handling system operated from a vessel subjected to motions due to waves. A mathematical model developed uses joint coordinates and homogeneous transformations to derive the equations of motion. Then a numerical model is developed and implemented, forming an own, dedicated code. The model and computer programme allows to simulate a launch and recovery operation. Hydrodynamic loading is proposed with an own modelling approach, which should suit an early project design stage. The aim of developed tool is to support with decisions such as vessel pre-selection, LARS location on deck, possible operational weather limits, system loads and performance and to assist with many other related problems. Simulations presented in this work are examples of practical analyses performed when a design of handling equipment enters an early engineering stage and fast variant calculations are required to advance the project. The tool developed may be applied in early discussions and design iterations as the time needed for analyses do not influence any other technical or commercial processes.