TLP sea test

Abstract

Japan Marine Science and Technology Center carried out successfully the TLP sea test in 1986. The installation site is 41 m deep and 2. 6 km NNW offshore of Yura harbor. In the test the performance of the tension mooring system was evaluated in the real ocean environments. This paper discusses the experiences on the TLP sea test.The TLP consists of a platform, tension legs, a sinker and a monitoring system. The platform is a semisubmersible with 12 column-footings and the principal dimensions of the platform are length overall 34 m, breadth overall 24 m, height 13. 5 m, draft 5. 5 m and displacement 527 ton.The platform is tautly moored by the 4 tension legs which are at sea bottom connected to the sinker weighing 536 ton in water. Each tension leg is a chain filled and covered with rubber applied to absorb the shock loads and prevent the mooring line from local abrasion. The anchor connector is made robust and monitored by using underwater TV camera at any time. The total initial tension is 125 ton which is equal to 24% of the platform displacement. The maximum wave height experienced during the test period is 7. 3 m which is just under the critical condition not to hit the bottom face of the upper structure.This research and development was performed through the Special Coordination Fund for Promoting R & D of the Science and Technology Agency of the Japanese Government, as a part of the Research on the Utilization of Marine Space by Coastal and Offshore Structure.