The Probert Encyclopaedia of Ships

POSEIDON

HMS Poseidon was a British Parthian Class submarine of 1475 tons displacement launched in 1929 and sunk as a result of a collision occurring in 1930. HMS Poseidon was armed with one 4-inch gun; two machine-guns and eight 21-inch torpedo tubes. She had a top speed of 17.5 knots surfaced, 9 knots submerged and carried a complement of 50.
Research Poseidon