Maneuvering simulations of a POD-driven ship

Abstract In this study, we conducted captive model tests using a scale model of a 324 m-long cruise ship equipped with two POD propulsors. The aim was to capture the maneuvering hydrodynamic force characteristics acting on the ship model with the POD propulsors. Based on the test results, we developed a maneuvering simulation method for a POD-driven ship. This simulation method includes motion coupling effect with roll. To validate the developed simulation method, we conducted maneuvering simulations of the ship model and compared their results with those of free-running model tests. The simulation results of turning and zig-zag maneuvers agree with the results of free-running model tests within practical accuracy. This verifies the validity of the simulation method. Furthermore, we conducted maneuvering simulations for the cruise ship in full scale to investigate the effect of the metacenter height $$\overline{GM}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mrow> <mml:mi>GM</mml:mi> </mml:mrow> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> on the ship maneuverability and rolling characteristics during turning. As $$\overline{GM}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mrow> <mml:mi>GM</mml:mi> </mml:mrow> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> decreases, the ship’s course stability deteriorates, and although the turning performance is improved, the overshoot angles for zig-zag maneuver increase. Meanwhile, we observed that the roll generated immediately after steering became large as $$\overline{GM}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mrow> <mml:mi>GM</mml:mi> </mml:mrow> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> decreased. Furthermore, an unreasonably large roll tended to occur depending on the magnitude of $$\overline{GM}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mrow> <mml:mi>GM</mml:mi> </mml:mrow> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> .