Author(s): E. Karulin; M. Karulina
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Abstract: In planning and performance of marine operations it may well be required to assess the icebreaking capabilities of icebreaking ships involved in these operations. The icebreaking capability of a ship is defined by the maximum thickness of solid level ice that the ship in question can negotiate at the minimum steady speed (2-3 knots) under full power. This characteristic depends on the ship hull form and propulsion system details as well as power output. This paper presents an approach intended to derive a simple criterion to assess such capability for icebreakers. The formula for icebreaking capability criterion is structured based on simple physical considerations: icebreaking capability is proportional to the total shaft power of propellers and inversely proportional to the ship beam on waterline. The formula coefficients are found using the least-square treatment of actual data collected from known icebreakers. Icebreaking capability assessments are done for vessels not included in the reference data samples. Specific aspects related to extension of the formula from icebreakers to commercial ice-class carriers and supply vessels are considered. It is shown that the said criterion is useful in prompt icebreaking capability evaluations for practical decision-making tasks like choice of suitable vessels for certain icebreaker operations related to convoy assistance, towage or ice-management operations.
Year: 2020