The Probert Encyclopaedia of Ships

ULTIMATUM

HMS Ultimatum was a British Ursula Class submarine of 540 tons displacement launched in 1941. HMS Ultimatum was powered by two Davey Paxman diesel engines providing a top speed of 11 knots surfaced and two electric motors providing a top speed of 9 knots submerged. She carried a complement of 31 was armed with one 3 inch gun; three machine-guns and four 21 inch bow torpedo tubes.
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