The United States Coast Guard is responsible for completing all of its statutory missions in U.S. waters surrounding Alaska. In the past, patrols in these waters have been limited to areas outside of the seasonal sea ice boundary, plus one or two icebreaker patrols per year. Recently, due to reduced sea ice areal coverage and the associated increases in commercial activity, demands for a Coast Guard presence in the Alaskan Arctic have increased significantly. In addition to ongoing efforts to increase the size of the icebreaker fleet, these demands have caused the U.S. Coast Guard to operate non-ice-strengthened cutters in areas where sea ice could be encountered, and to evaluate the capabilities of these cutters to operate in ice. This paper presents results of engineering studies completed over the past several years to evaluate the capabilities of current and future cutters for operations in ice and cold temperatures. These studies, which are also applicable to naval combatants, include: (1) definition of sea ice characteristics variations with season and geographic location; (2) evaluation of the ice-transiting capabilities of non-ice-strengthened hull structures; (3) analysis of potential increases in safe operating areas for different levels of ice strengthening; (4) evaluation of the capabilities of existing rudders, propellers, struts and shafting to withstand ice impacts; (5) assessment of possible cold temperature operating issues for deck equipment; and (6) analysis of the capabilities of HVAC, electrical and seawater systems to operate in cold air and water temperatures. Findings for each of these studies are discussed and results are presented. In addition, lessons learned from actual operations are included where appropriate. Finally, recommendations are offered for future class-specific engineering evaluations and operating considerations when non-ice-strengthened vessels are assigned to operating areas where sea-ice and cold temperatures may be encountered.

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