ICE LOADS AND SHIP RESPONSE TO ICE

In two previous Ship Structure Commmittee reports, the assessment of various rules pertaining to the design of ice-strengthened vessels was undertaken. Empirical recommendations were made for vessel scantlings, but the need for full-scale data was recognized. This report presents the results of obtaining full-scale local ice pressure loads near the bow of the U.S. Coast Guard icebreaker POLAR SEA as a step toward the development of local ice load criteria for icebreaking ships. The data was obtained by instrumenting a bow panel of approximately 100 sq. ft. to measure ice pressures by measuring compressive strains in the webs of transverse frames. Only events over a preset threshold strain were recorded, and there were approximately 1400 such recorded events on two deployments--one to the Beaufort Sea in September-October 1982 recording summer multiyear ice impacts, and one to the Chukchi Sea in March-April 1983 recording both first year and multiyear winter ice impacts.