スケグによる高速船の針路安定性改善

抄録

This paper describes the improvement of course-keeping ability of a ship by attaching the skegs. The ship was designed as a high speed monohull with 40 knots by water jet propulsion system, however, the remarkable course-keeping instability appeared unfortunately. To improve the course-keeping ability, the skegs with A_s/(LT)=1/50, where A_s is the total skeg area, L the ship length and T the draft were designed. The captive model tests such as the resistance test and circular motion test were carried out to capture the hydrodynamic force characteristics for the ship with and without skegs. Based on the experimental data, maneuvering simulations such as 15/15 zig-zag maneuver and 30deg turning were made to investigate the effectiveness of the skegs. Through the simulations, we found that skegs with A_s/(LT)=1/33 are needed for improving the course-keeping ability of the ship. It was confirmed that the skegs are effective in the wide speed range from slow to high near 40 knots by oblique towing test for various ship speed.