Active control for installation of underwater structures

摘要

The trend towards deepwater development re- quires a new approach to underwater installation of offshore structures. The present method using crane vessels has some drawbacks in operations at more than 2000 m depth. The natu- ral period of the coupled system of the rigged structure and the crane vessel becomes longer, so that it is no longer pos- sible to manipulate the cranes to achieve the desired position- ing accuracy. This paper examines the application of an active control technique for underwater installations as one of the solutions to the present problems.