As Sea Demon says you need to use your High Frequency sonar to navigate around the ice wall. If I remember correctly you are also up against a time limit on this mission. When I did it I ran my boat at around 8-10 knots keeping more or less parallel to the ice wall until a break appears that I could navigate through (very much like an ice maze). I think there might be mines to avoid as well and again this is where the HF sonar comes in very useful. It took me three or four attempts at this mission before I successfully completed it so don't be put off if you don't complete it first time.
Nemo
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"I'm afraid there is no disguising the fact that King's obsession with the Pacific and the Battle of Washington cost us dear in the Battle of the Atlantic".
Sir John Slessor GCB, DSO, MC, DL
AOC-in-C Coastal Command RAF
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