HMS Triad (N53)

HMS Triad (N53) was a T-class submarine of the Royal Navy. She was laid down by Vickers Armstrong, Barrow and launched in May 1939. So far she has been the only ship of the Royal Navy to bear the name Triad.

Career
Triad had a relatively short career, serving in the North Sea and the Mediterranean. In April 1940 she sank the German troop transport Ionia and attacked, but failed to sink the German depot ship Tsingtau.

Mediterranean and loss
Shortly after, she was assigned to the Mediterranean. On 9 October 1940 she sailed from Malta to operate in the Gulf of Taranto, with orders to reach Alexandria on completion of her patrol. She failed to make port and by 20 October the submarine was declared overdue. She was believed to have been lost in a minefield or sunk by Italian anti-submarine aircraft. New evidence suggests that Triad was engaged and sunk on the night of 14/15 October by the Italian submarine Enrico Toti.

It was assumed that the Enrico Toti had engaged and sunk HMS Rainbow, which was thought to be operating in the same area.

Last action
At 0100 hours on 15 October, the Enrico Toti sighted a large submarine 1,000 metres to port: both boats manoeuvred into attack position but the British opened fire first, supposedly scoring two hits, one on the conning tower, the other on the bow (Italian accounts claim all of Triad's shells missed). She also fired a torpedo which Enrico Toti avoided by turning sharply, then closed on the enemy submarine at top speed, firing as she approached. Soon, machine gun fire compelled the British gunners to abandon the exposed deck. As the British submarine started to dive, Toti fired a torpedo and hit the British submarine with two shells. The boat rose vertically then disappeared without survivors. The entire action had lasted less than 30 minutes

Rainbow had been ordered to leave the area on 13 October, she would have been gone 26-30 hours before the action described above began. Even at the modest speed of 6 kn, Rainbow would have been 200 nmi away from the spot at the time of the action. The only boat in Toti's vicinity was Triad.