University club maintaining old submarine (1-4)

I believe the answer is:

u-boat

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(Other definitions for u-boat that I've seen before include "German World War One or World War Two submarine" , "German wartime submarine" , "About (anag)" , "Submersible warship of WWII" , "Submersible warship armed with torpedoes" .)

I've seen this clue in The Independent.

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