In the case of a ship equipped with controllable pitch propeller, when the pitch of propeller is changed, by maneuver of pitch-changing device, the speed of ship will also change. But, due to inertia of ship-body, the speed-change does not take place immediately, The author has made a theoretical study about this phenomenon, by solving an equation of motion corresponding to it.
In constructing the equation of motion, the towing resistance is firstly assumed to be proportional to the square of ship-speed. Also, a simple relation between the propeller-thrust, ship-speed and pitch is assumed. Thus, it was possible to show the timely change of propeller-slip, during the pitch-changing operatipn. The theoretical formula obtained in this way is illustrated by numerical examples. Also a supplementary consideration about the case wherein the towing resistance is proportional to V³, instead of V², is made.
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