Mv Ikaluk Level Ice Performance Trials

Author : Gulf Canada Resources Inc
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (947 download)

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Download or read book M.V. Ikaluk Level Ice Performance Trials written by Gulf Canada Resources Inc and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The major objective of the level ice performance trials was to assess the vessels' performance capabilities in level ice: first to demonstrate to the Canadian Coast Guard the Arctic class IV capabilities of the M.V. Ikaluk and M.V. Miscaroot and to obtain full Arctic class IV certificates; second, to provide BeauDril with a better knowledge of the vessels' capabilities in level ice. The trials program took place in early January 1984, and the Canadian Coast Guard certified the ships as full Arctic class IV on January 13, 1984. Subsequent analysis of the trials results has led to the following conclusions: The vessels are capable of moving continuously through 1.3 metres (4.25 ft.) of level ice, and are likely to be capable of moving continuously through 1.4 to 1.5 metres (approx. 4.5 to 5 ft.) of level ice; There is no significant reduction in ice resistance when operating either the bubbler system or the bow thruster (operating at low speed with both butterfly valves open, port and starboard) in level ice up to one metre thickness. Further, operating either bubbler system or the bow thruster consumes approximately 450 kw of power that would otherwise be available for propulsion, therefore reducing ships transitting speed. Transitting in a newly formed broken channel is up to 40% more efficient than transitting level ice. (i.e., either 40% higher speed for same power level, or 40% reduction in power for same transit speed). However, when channel begins to refreeze, the increase in efficiency reduces, dependent upon outside temperature and how long the channel has had to refreeze. After two to three weeks at temperatures around -20° C, transitting the refrozen broken channel becomes less efficient than transitting the level ice. During turning circle manoeuvres, at full power, the vessel was unable to turn more than 10° - 15° from original heading, in ice thicker than 0.5 metres. This is due to the near vertical side of the stern quarter, at the waterline, butting up against the unbroken level ice edge, preventing any lateral movement of the stern. When ramming an ice feature at full power from a broken channel, it is inefficient to back further than three shiplengths (240 m) to obtain maximum impact speed (approximately 12 knots). A backing distance of two shiplengths will give an impact speed of approximately 10.5 knots and one shiplength approximately 8.5 knots. There is not significant hull strain in the instrumented area of the bow when operating in level first year ice or broken channels"--Leaf [1].