HM Submarine Seahorse
Seahorse was part of the 1930 building programme and ordered on 16 March 1931.
She was launched on 15 November 1932 by Mrs Bowring.
The first use of the name Seahorse was in 1630 and this submarine would be the thirteenth RN vessel to have the name.
After completion she was based at Portsmouth then in 1934 she moved to Portland and was part of the Home Fleet up to 1939.
With war imminent she sailed to join the flotilla at Dundee. Seahorse made three war patrols from Dundee before moving to Blyth. Here she sailed on two patrols, the second of which would be her last. Leaving Blyth on 27 December 1939 for a patrol off Heligoland and Bight, it is believed she hit a mine on 29 December. Seahorse became the first submarine of the war to be lost with all hands. Four officers and 34 men were lost.