Model test of active jacking system for float-over operation at swell area

Abstract

As offshore topside continues to become larger and heavier, the float-over method was developed and employed these days as the popular and efficient means for topside installations. Within the float-over method for the topside installation at offshore, passive jacking (rapid load transfer) systems are commonly used in areas with swell wave such as West Africa, India and Myanmar due to high vessel motions. There is an increasing trend in the use of active jacking system in place of passive system which employs sensor suites to compensate for the vessel motions to ensure minimum clearances during all stages of the float-over operation and improve operational confidence. This paper outlines the feasibility of active jacking system for float-over operation at the swell wave area based on the model test result in order to compensate the vertical vessel motions during docking operation stages. The model test has been performed using VMG (Virtual Motion Generator) to simulate vessel motion behavior artificially with 4ea of 50M-ton Jacks for 6 M-ton Topside weight and the 3.5-degree angle with 10~13 second was considered. The results give some confidence that vessel motions could be compensated vertically by the active jacking system and it is a beneficial test that helps to establish additional test plans better results in the future. ？ 2020 by the International Society of Offshore and Polar Engineers (ISOPE).