These ships would be escorted by an icebreaker under adverse ice conditions, so their beam must be narrower than the icebreaker in order to be able to pass through the open water channel created by the icebreaker. Currently the largest icebreaker in service along the NSR is the Arktika class, with a beam of 28m. Because ships with ordinary hull forms break ice slightly wider than their breadths, an escorted ship can enjoy a channel slightly wider than the breadth of an escorting icebreaker; in the Arktika's case, about 30m. Accordingly INSROP decided that the escorted ship should be no more than 30m wide. To obtain the right displacement under the limitations on the draft and beam, the ships must feature a high length-to-beam ratio. Some key particulars of the three ship types used in the simulations are given below. For more detailed information, please see the data in Section 5-2.
