Stopping Abilities of Ships Equipped with Controllable Pitch Propeller : 2nd Report

Abstract

In the previous report 1), 2), the authors discussed the stopping abilities of ships equipped with controllable pitch propeller (CPP), from a viewpoint of both sea trial results and theoretical computation about transient phenomena, by using a one-dimensional equation of ship motion. They described the CPP ship's superiorities in both its easy manoeuvring of astern-going and overa11 stopping abilities. As for the results of theoretical calculation it was found that CPP stopping characteristics can be estimated enough quantitative1y. In this report, the authors describe the fluctuating characteristics of shaft revolution number at CPP crash astern test, by solving simultaneous equations in respect to ship motion and prope11er-shaft revolutional motion. Furthermore, using the about computer program, the authors investigated influence of blade changing time on fluctuation of shaft revolution, CPP blade root strain, etc. It is also very important to investigate on stopping abilities of FPP ships in order to grasp stopping abilities of CPP ships. The authors devide transient phenomena of FPP ships into five ranges and fully examine each of them from actual astern test results. Based on these results, they calculated some transient phenomena of FPP ships with computer program and compare them with actual trial data and make some simulation to find important factors of stopping abilities of FPP ships. Finally they make comparisons of stopping abilities under the same initial condition, between CPP-installed and FPP-installed ships by astern programs for them.