Ship motion test

[2] There are various types of test: the model may be towed along a straight line or circular path, and may be subjected to oscillations.

[2] The velocity-dependent derivatives Yv and Nv of the ship at any draft and trim can be determined from the model test carried in the towing tank.

The Planar motion mechanism (PMM)[4] can be used instead of Rotating Arm Test where towing tank facilities are longer and narrower.

The DTMB Planar-Motion-Mechanism System was conceived and developed jointly by the Author and Mr. Alex Goodman, both members of the staff of the Hydromechanics Laboratory of the David Taylor Model Basin.

The originators wish to express their gratitude to the many members of the Industrial Department of the Model Basin whose contributions and efforts in the design and construction of components made the ultimate system possible.

40 Some of the formulations given by the ITTC 1978 for the performance prediction method are as follows:[5] VRM2 = VAM2 + (0.75π nM DM) 2 RncM = VRM cM / υM