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takes a strain on the line secured to the ice anchor and with this addi- 

 tional pulling force the icebreaker moves astern. This maneuver 

 usually brings good results and the icebreaker is released. 



On the U. S. S. Bear in 1942 it was found to be of more advantage to 

 take out an ice anchor abreast of a mast with the heaving line to the 

 masthead. A slight force on the heaving line caused a slight list to 

 the ship which was always effective in releasing it. Damage to the 

 winch or gear usually resulted w'hen it was attempted to free the ship 

 by heaving on an ice anchor laid out astern or on the beam with the 

 hauling line leading aboard at deck level. Explosives are also used 

 to release an icebreaker. 



In continuous sheet ice, even when the icebreaker is able to maintain 

 speed through it, as she can in ice only 2 or 3 feet thick, the course is 

 likely to be erratic. As the ship hits the sheet ice, cracks radiate from 

 the point of impact, forming paths of least resistance. The ship is 

 likely to start down one of these cracks making it extremely difficult 

 to get the heading on the proper direction again. Often even with 

 full rudder the icebreaker may go contrary to the desired course for 

 a considerable period of time. 



Steering with the engines may be of some help under these condi- 

 tions, but slowing down one engine in order to swing the ship's head 

 around also may result in the loss of headway and the stalling of the 

 ship. 



There appear to be two main methods in conning an icebreaker 

 through the ice pack, both of which are dependent upon the degree of 

 initiative allowed the helmsman. In the first method, much latitude 

 is given the helmsman. Usually the officer of the deck points out a 

 distant berg or some identifying mark in the pack which lies within a 

 few degrees of the desired course. Also, he tells him the amount he 

 may vary each side of the base course. Except for an occasional bit 

 of advice the O. O. D. then generally allows the helmsman to follow his 

 own bent. In the second method the onus is placed upon the O. O. D. 

 He orders all changes of coui-se and makes all decisions in following 

 leads. In doing this he must make up his mind sufficiently well in 

 advance to communicate an early decision to the helmsman so that the 

 order may be understood and acted upon. 



Both methods have their advantages and disadvantages, and the em- 

 ployment of either is dependent upon existing conditions, the tempera- 

 ment and experience of the O. O. D. and the helmsman, etc. Mainly 

 because of the makeup of the Burton Island's bridge, her commanding 

 officer in the Antarctic in 1948 preferred the first method. As no g\'ro- 

 compass was available in the vicinity from which the O. O. D. was 



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