A Study of Ice Class Rules for Propellers

Abstract

A study has been carried out of existing classification society and government regulatory body rules for propeller 'strength of ice class ships. The problem of propeller/ice interaction has been studied from an analytical standpoint, and full scale ice load data obtained from the propulsion shafts of Arctic icebreakers have been reviewed. Using these data and the framework of existing regulations and design methods for ice-worthy propellers, a number of conclusions on the static and dynamic strength requirements for such systems have been reached. The main conclusions of the study are that present regulations, while they may be sufficient for non-Arctic ice going ships, are not adequate for ships sailing in Arctic waters where propeller ice encounters are much more frequent and severe, and that using an 11ice torque factor" is not the most rational approach. Recommendations on design procedures are made.