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strength of ice increases markedly with the approach of frost and 

 the fall of air temperature. 



The danger of the fore part of the vessel striking against sharp 

 corners of ice must always be guarded against. If collision with cakes 

 is necessary, try to take the impact on the stem. Newly formed young 

 ice is dangerous to wooden ships, as it may cut right through the hull 

 planking at the waterline unless the vessel has been sheathed with 

 ironbark or steel plating. 



^Vliile working through the ice, a ship makes use of every weak spot 

 en route and is, therefore, frequently required to make sharp turns. 

 If in trying to save time, these turns are made at all possible speed, 

 the stem may be thrown against ice edges. Sometimes the blows are 

 very heavy and a broken blade or shaft results. Sometimes breakage 

 results from metal fatigue caused by the propeller hitting the ice 

 frequently over a long period of time. In such cases, the loss of the 

 blade or the entire propeller may occur almost imperceptibly. When 

 navigating in deeply submerged old ice, the conning officer should 

 therefore endeavor to make slow turns and prevent the stern from 

 striking sharply against the ice. Wlien maneuvering astern, a look- 

 out should always be kept on the fantail with direct communication 

 to the bridge and a warning system worked out. Most damage to 

 propellers and rudders happens at the end of the navigation season 

 when ships are working at night in heavy ice. 



Wlien forcing a passage through the ice by ramming, it is necessary 

 to pay strict attention to the loss of headway at the moment of running 

 into the ice. If it is evident that as a result of the run taken the 

 obstacle will not be overcome and the ship will stop, it is then neces- 

 sary, to avoid being embedded, to go full speed astern even before 

 she stops. At the moment when way is lost the engines should already 

 be going full speed astern. It is not advisable to continue forcing a 

 passage if the channel so made does not considerably exceed the beam 

 of the vessel, so that she can move freely out astern. Moving forward 

 in such a channel may cause the vessel to become beset or even even- 

 tually crushed. 



A vessel may sometimes be beset and yet be saved from pressure. 

 When the besetting ice has underwater spurs, due to the melting back 

 of the uppermost 2 or 3 feet of ice, these may act as a cradle for the 

 ship. 



RELEASE OF A VESSEL 



In endeavoring to avoid getting fast in ice it sometimes happens 

 that taking a run at the ice may result not in the breaking of the 



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