The Andromeda sub-class was a slightly enlarged and improved version of the Druid sub-class, with a more powerful armament.[1] Seahorse had a length at the gundeck of 159feet and 133feet at the keel. She had a beam of 41feet, a draught of 14feet and a depth of hold of 13feet. The ship's tonnage was 1211 tons burthen.[2] The Andromeda sub-class was armed with twenty-six 18-pounder cannon on her gundeck, ten 32-pounder carronades and a pair of 68-pounder guns on her quarterdeck and four more 32-pounder carronades in the forecastle. The ships had a crew of 315 officers and ratings.[3]
Seahorse, the ninth ship of her name to serve in the Royal Navy,[4] was ordered on 9 January 1823, laid down in November 1826 at Pembroke Dockyard, Wales, and launched on 22 July 1830.[3] She was completed for ordinary at Plymouth Dockyard in August 1830 and completely roofed over.[2]