The study of propellers efficiency in bollard-pull mode
The speed of icebreakers operating in ice of ultimate thickness is 2-3 knots. In this case the mode of icebreaker propellers operation is close to bollard-pull mode. In bollard-pull mode the coefficient of efficiency and propulsion coefficient are equal to zero. In order to estimate the efficiency of main engines’ power conversion, one can use the value of achieved effective thrust per unit of delivered power. The results of study to determine the influence of propellers hydro- dynamic characteristics and propeller-hull interaction coefficients on the value of effective thrust per unit of delivered power make it possible to take correct decisions and select the parameters of propellers and their position behind vessel’s hull.