Moonpool과 Azimuth Thruster를 장치한 Drillship의 저항추진성능

Abstract

The performance of a deep water drillship, is investigated with the view of the characteristics of the thrusters and the resistance increasement due to moonpool. The model tests have been performed to obtain the resistance of two drillships with the moonpool open and closed including shape changes of moonpool step. To design the DP system, thrust forces of azimuth thrusters have been measured during azimuthing at zero speed condition. Thrusters, azimuthing under the bottom of ship, have the interactions of the other thrusters due to flow changes made by other thrusters, and the existence of ship hull makes the thrust deduction higher than when the thrust operates by itself. The resistance increasement due to the moonpool is highly dependent on the step height of the moonpool and the draft. It is found that the height of moonpool step can reduce the resistance increasement by moonpool.