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and Barter Island. The type of ice floes in this area requires it to 

 make continuous approaches at steerage way. Moreover, icebreakers, 

 because of their peculiar hull form, create a strong stern suction 

 that swirls ice in behind them. Because of the running start required 

 by the icebreaker in breaking heavy ice and the nonhomogeneity of 

 the pack, it is impossible for an LST to follow closely enough behind 

 the icebreaker to take advantage of the lane she makes. As it is 

 necessary to make contact with the ice at bare steerage way in order 

 to minimize damage to the LST, an average speed of only 1 to 2 

 knots can be maintained in heavy, close pack. Damage to LST's may 

 be sustained by swinging into one piece of ice while trying to avoid 

 another. It was found that the LST immediately behind the ice- 

 breaker is subject to more punishment than the last one in a column. 

 From this fact, it may be concluded that a reasonable number of 

 LST's could follow single file behind an icebreaker in the type of 

 ice encountered in this area. However, when the icebreaker cannot 

 maintain a straight course, the consequent twisting and turning of 

 the LST's make their conning exceedingly difhcult. 



It is believed that convoying cargo ships through ice of the Alaskan 

 coast presents certain features which may not hold in other Arctic 

 areas and which are assuredly different from the task in Antarctic 

 areas. 



VESSELS FOR ALASKAN AND CANADIAN WATERS 



The vessels used at present for navigation in the waters east of 

 Point Barrow have evolved from many years of accumulated expe- 

 rience in that region, which began with the whalers in the 1850's. 

 They commonly winter in the area. The desirable characteristics 

 of such vessels are listed by a veteran navigator as follows : 



1. Strength. — Strength of construction is of vital importance for 

 obvious reasons. A wooden vessel should be sheathed for 4 to 6 feet 

 abaft the fore edge of the stem with either plates or strakes of V2-inch 

 steel, flush-fastened. Strakes are preferable to plates on account of 

 the ease of renewing them if damaged. The hawsepipes should be 

 constructed so as to allow the bower anchors to stow flush with the 

 ship's side; otherwise, the projecting flukes will act as an obstruction 

 in ice. Where this cannot be accomplished, anchors should be catted 

 prior to entering the ice. 



2. Power. — Diesel power is preferred because fewer engine per- 

 sonnel and no boiler feed water are required. Fuel supplies are readily 

 available at Norman Wells, Fort Smith, and other points in the 

 region. 



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