HMS Triton was a submarine of the Royal Navy named for the son of Poseidon and Amphitrite, the personification of the roaring waters.

At 1955 on 10 September 1939, Triton had surfaced, fixed a position off the Obrestad Light, set a slow zigzag patrol, and began charging batteries.

Lieutenant Commander Steel, having verified that the area was clear and having posted lookouts, gave the bridge to the officer of the watch and went below, leaving orders that he was to be called if anything unusual appeared.

Steel ordered propulsion shifted to the main motors, the signalman to the bridge, and torpedo tubes 7 and 8 readied for firing.

Oxley was out of position, Triton had acted correctly, and the first Allied submarine casualty of World War II was due to "friendly fire."

On 10 April 1940, she sank the German steamers Friedenau, Wigbert, and the patrol vessel Rau 6 in the Kattegat.

During her first patrol in the Gulf of Genoa, Lieutenant Watkins, now Triton's commanding officer, decided to enter the harbour of Savona.

She found a supply ship at anchor in the harbour, at which she fired a single torpedo and claimed an 8,000-ton kill, though the sinking could not be confirmed.

The submarine began shelling a large factory and a gas works on the shore, damaging both of them before departing.

The Italian Navy claimed that Triton was sunk by torpedo boats, probably Confienza, possibly by Clio, but the date cited was several days after contact was lost.