Design of Safe Mooring Arrangement for Large Oil Tankers

In order to keep pace with the modern oil transport trends, the Indian ports are also developing terminal facilities for Very Large Crude Carrier (VLCC). A conceptual design methodology for marine oil terminal (MOT) including mooring system for large oil tankers has been evolved. The orientation of the MOT and mooring arrangements for 200000 DWT oil tanker were determined considering the environmental conditions prevailed at the site. Water flow velocity played an important role in the orientation of the MOT. Quick Fender Selection Method (QFSM) has been considered for the selection of fender system and it was found that supercone fenders of 2 m height or equivalent type of fenders were suitable for the oil tanker. The mooring arrangements comprising of steel ropes with nylon tails, sustained the effect of high winds of 60 knots associated with currents and waves. Finally, simulation of moored ship motions for moderate environmental conditions i.e., wind speed of 30 knots, current speed of 4 knots and 1 m wave height was carried out using quasi-static approach. The ship motions in six degrees of freedom were found within the permissible limit for safe cargo handling operation. The maximum rope tensions, fender compressions and bollard pull were found to be 195 ton, 0.51 m and 199 ton respectively.