BBC2: PQ17: An Arctic Convoy Disaster - Thursday, January 2nd 2014 - 21:00

Conventional submarines of the time, such as the escorting P 614 and P615, could sprint at 8 kts underwater but only for a few minutes before draining the battery. Their normal submerged speed was closer to 3 kts and their top speed on the surface was only 10 kts. In the meantime, the Tirpitz could make 30 kts and stand off 18 or 20 miles while bombarding ships with her 15" guns. Her sister ship Bismarck sank HMS Hood at a range of 14 miles.

The top speed of P611 class boats was specified as 13.75 knots surfaced and 10 knots submerged. Same conclusion, though.


War Hero
Super Moderator
Bandy, the speeds for the boats given are the max speeds, the batteries of WW2 boats wouldn't be able to sustain 10kts dived for long.
Er...I know that, which is why I said, "The top speed...", and, "Same conclusion, though."
I did spend 5 years in boats, my first acquaint was 3 weeks on Opportune, my only time on clockwork submersibles but, nevertheless, informative. The rest of my time was spent on Warspite, Dreadnought, standing by (in refit), Churchill and Renown.

You must remember, old sailors never die, they just hang around giving young sailors the shits. :thumbup:
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Book Reviewer
My understanding is that submarines were in no way integrated with surface units or the convoy, but would be assigned to an individual area in which they were assured there would be no friendly forces, e.g. in an ambush position for enemy ships. Complete success depended on the submarine managing to manoeuvre within the enemy's Limited Lines of Submerged Approach, which of course become narrower and narrower with target speed. Usually the best that can be hoped for unless the s/m gets lucky is to be able to send an enemy report, but even that might be worth spun gold.

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