on – or multiplying – gears between an engine and propulsion device:\\ <m>eta_G = P_S/P_B</m>\\
where //P//<s... ship and the work done by the propeller or other propulsion devices in a given time that is effective power P... E and the power delivered to the propeller or the propulsion device P<sub>D</sub>.\\
<m>eta_D = P_E/P_D=eta_... one</note>
===== Friction deduction force in self propulsion test =====
> and the power delivered to the propeller or the propulsion device //p//<sub>D</sub>.\\
<m>eta_D=P_E/P_D=eta... Geometry section]].
===== Rudder, active =====
A propulsion device installed in the rudder for ship manoeuvri... f merit for comparing the relative performance of propulsion devices at zero speed given by the equation:\\
<... oefficient]] respectively.
===== Thruster =====
A propulsion device for zero or low speed manoeuvring of vesse
caused by some action other than that of the main propulsion devices of a ship, such as wind, waves, current a... wind and waves at a constant setting of the main propulsion plant. Usually speed loss is determined at consta... caused mainly by reducing the setting of the main propulsion plant in order to minimise the adverse effects io