RESTRICTED 



Figure 24. — Methods of making fast the towlines when towing in ice. 



latter will invariably break, as they are not strong enough to take the 

 great strain necessary when towing a vessel tlirough ice. 



In drift ice or open pack, a ship is towed by the icebreaker using 

 a long towline. In this case, the entire towline is paid out with the 

 exception of a few turns. Such towing is used when a ship has been 

 damaged and cannot proceed under her own power. 



When navigating in close pack, with moderate pressure, a short 

 tow is used if the piloted ship cannot make headway unassisted. In 

 this case the towline is eased off to 35 to 50 feet and the vessel will 

 advance in the icebreaker's wake, where the propeller wash prevents 

 the ice from closing up immediately. If the icebreaker slows down, 

 the towed ship, which is beiiig held back by compact ice, has enough 

 time to go astern, provided the signals for reducing speed and going 

 astern are given by the icebreaker in sufficient time. If the icebreaker 

 stops unexpectedly when using the short tow, collision and damage 

 are almost inevitable. Therefore, the captain of the towed vessel must 



100 



RESTRICTED 



