Friction coefficient between sea ice and different test surfaces

Among the projects of the scientific program of the F. S. Polarstern expedition of May 1984 along the coast of Labrador, Canada, was the measurement of the kinetic friction factor between various surfaces and sea ice samples collected at the site of the ship trials. The surfaces included a steel sheet coated with Inerta 160 to represent the ship hull, and base steel sheets of two roughnesses. The latter had previously been tested at CRREL with urea-doped ice, which is used as model ice in tests of icebreakers and other structures (Forland and Tatinclaux 1984). A friction test table was specially constructed by the Hamburgische Schiffbau- Versuchsanstalt (HSVA), the organization leading the expedition, and was instrumented on board the Polarstern. The ice samples used in the friction tests were cut from two large ice blocks gathered at the trials site, primarily Hebron Fjord; samples from the same blocks were used in two other projects, which were studies of ice structures (Gow 1984) and ice strength properties (Timco and Frederking, in prep.).NRC publication: Ye

Comparative model tests in ice of a Canadian coast guard R-class icebreaker

This paper presents the results of resistance and propulsion tests in level ice of a 1:20 scale model of the Canadian Coast Guard R-class icebreaker at two ice-hull friction coefficients, performed at several ice testing facilities in various countries under the aegis of the Committee on Performance of Ships in Ice-covered Waters of the International Towing Tank Conference (ITTC). There is good agreement overall among the test results obtained at the various facilities. The differences that do remain should be attributed to differences in experimental techniques and types of model ice used at the participating laboratories. An increase in hull roughness led to an increase in ice resistance as expected, but had no effect on the propeller characteristics. While the thrust coefficient in ice was nearly the same as in clear water, the torque coefficient and thrust deduction factor were much greater in level ice than in clear water and nearly constant. Full-scale ship performance predicted from the resistance test results of the rougher model and the propulsion characteristics in clear water was in good agreement overall with available field trial data. Predicted performance using the ice resistance of the rougher model and the model propeller characteristics in ice was usually below that observed at full scale. This would indicate that ice-propeller interaction is excessive during model propulsion tests, or that the effect of ice entrainment on propeller performance is greater at model scale than at full scale. Ice-propeller interaction remains a domain where further research is needed.Peer reviewed: YesNRC publication: Ye

Erste eisbrechtechnische Expedition mit F.S. Polarstern Schlussbericht. Bd. 3

TIB: AC 9385 (3) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman