RESTRICTED 



of tow be minimized. In other words, the icebreaker should have 

 a long fantail so as to permit snubbing of standard-type vessels into 

 the crotch of its stern. 



A 214-inch plow-steel wire bridle and a towline swivel are recom- 

 mended equipment for all ships. Towing arrangements must be in 

 full readiness before the convoy sails. Just before entering the ice, 

 the ship's anchors must be secured on deck to prevent them from strik- 

 ing the ice while passing hummocks and thereby damaging the hawse- 

 pipes, as well as to enable the ship fo take the towlines from the ice- 

 breaker through the hawsepipes at any time. It is not necessary, 

 however, for a vessel with a high bow and considerable freeboard 

 to cat her anchors; it is sufficient for such a vessel to rig a towing 

 bridle forward with a shackle of size to mate with the towing cable 

 of the icebreaker. Althoug*!! a bridle should be used for towing in 

 pack ice, the towing hawser should be shackled to the anchor chain 

 for towing in the open sea. 



The ship's personnel must know how to take aboard a heavy towline 

 as quickly as possible and to secure it so that it can be slipped with 

 minimum delay, when so signaled by the icebreaker. "Wire rope 

 messengers must be led through the hawsepipes in advance, to which 

 the straps of the icebreaker's towlines are to be secured. The wire- 

 rope messengers are then brought to the winch and the straps of the 

 towlines hauled up on deck and secured. Figure 24 shows two methods 

 of securing the towlines in the towed ship. One is to pass a manila 

 line through the two straps, the two towlines being thus secured on 

 deck by several turns of manila. Wlien ordered to slip the tow, the 

 turns are cut and the two straps released. The disadvantage of this 

 method is the rapidity with which the manila rope wears out, resulting 

 in the parting of the tow. Therefore, when towing in very heavy ice 

 where jerking is unavoidable, the best method is to secure the straps 

 to a wooden beam. When the straps are brought up on deck through 

 the hawsepipes, the timber is passed through both eyes. To cast off, 

 the straps are eased up. the beam is pushed out of the eyes, and the 

 towline is cast off. If soft wood is used for securing, the wood is 

 scored during the stretching of the towline and the towline eats into 

 it. In such a case, when casting off it is necessary to cut the wood 

 until the ends are free. 



A large slip can be used for joining the eyes of the two towlines, 

 but if incorrectly secured it may get twisted and deformed, making a 

 quick release difficult. There are other methods of securing towlines, 

 but on no account must the tow straps be made fast to the bitts. The 



RESTRICTED 99 



