A Study on the Turning Ability of Twin‑engine Twin‑propeller and Twin‑rudder ship "KAKUYO MARU"-II

We made a turning trial of a twin‑engine twin‑propeller and twin‑rudder ship “KAKUYO MARU” that has equipped the two sets of main engines and rudders and a comparison was made between two engines and one engine as well as between two rudders and one rudder about the factors of turning. The trial results are stated below. 1 Comparing to the operation of two engines the ratio of steady turning diameter (D/L the speed reduction rate (RATE and the time for turning (TIME were large when the position of engine and the turning direction was the same. And these decreased when rudder angle was large. Also the drift angle (ANGLE was small and increased when rudder angle was large. 2 In comparison with using two engines D/L and TIME when using one engine and turning to the opposite direction of engine position were small and increased when rudder angle was large. Also the RATE and ANGLE were large and decreased when rudder angle was large. 3 When using one engine D/L and TIME of turning by one rudder were 1.1 to 1.6 times larger than these of turning by two rudders at both turning directions and decreased when rudder angle was large. Also RATE and ANGLE were as small as 0.7 to 1.0 times and increased when rudder angle was large.