OPTIMUM CONFIGURATION OF MOORING LINES FOR SEMI-SUBMERSIBLE PLATFORMSUBJECTED TO REGULAR AND IRREGULAR WAVES

Floating offshore structure is widely used in deepwater and ultradeepwater fields all around the world. The configuration of mooring line for semi submersible platform subjected to regular and irregular waves has been studied experimentally. Initially, semi- submersible models were designed. The model was design base upon Froude Law to scale down the platfrom prototype and environmental surroundings. The model tests were performed in the wave tank located in the Offshore Laboratory of Universiti Teknologi PETRONAS. In the experiment the models were subjected to regular waves and irregular waves and limited to long crested waves. Comprehensive experimental studies were conducted to the semi submersible model. The model tests including quasi- static and free decay test were conducted to measure the stiffness of the system and natural frequencies. In addition, to measure the platform motions subjected to regular and random waves, a series of station keeping test were performed.

All three series of the experiment were conducted for the model with different parameter.The effect of pretension, and mooring line configuration among the parametric studies performed towards the experiment. Towards the end, the results of the experiment were analyzed to examine the effect of each parameter on the dynamic motion of the semi submersible platform model.