The first 6 ships had a 2-cylinder horizontal single-expansion steam engine provided by Robert Napier and Sons and rated at 200 nominal horsepower, driving a single screw. Sylvia and Nassau were completed as survey ships and were powered by 150 nhp Humphreys and Tennant engines, and Myrmidon, the last of the completed Cormorants, received a more powerful 200 nhp Humphreys and Tennant engine.[2]
In common with all other Royal Navy wooden screw gunvessels, the Cormorants were rigged as barques, that is with three masts, with the fore and main masts square rigged, and the mizzen fore-and-aft rigged.[3]
Construction
The first 6 ships were ordered from commercial yards (Money Wigram & Sons, C J Mare & Co and J Scott Russell). A further batch of 4 ships (including Myrmidon) were ordered on 5 March 1860 and the final batch of 3 (Pegasus – Guernsey) on 25 March 1862. The first completed ships had a draught of 11–12 feet (3.4–3.7 m), exceeding the intended 8 feet (2.4 m) by a considerable margin. Since gunvessels were intended to work in shallow water while bombarding the shore, work on the later two batches was suspended.[2]Sylvia, Nassau and Myrmidon were suspended in 1862 or 1863, but were resumed, being finished as survey vessels.[Note 1] She was launched on 5 June 1867[4] and commissioned in October 1867.[2]
Operational service
Myrmidon commenced service on the North America and West Indies Station.[4] She served on the Australia Station from 14 March 1885 and undertook hydrographic surveys along the Australian coastline until she left the Australia Station in 1888.[4] In April 1887 she was involved in a collison with the troopship HMS Tyne near Sydney.
Fate
She sailed to Hong Kong and was sold in April 1889 for £3000.[4][2] Her eventual fate is unknown.
Notes
^Preston claims that Myrmidon was completed as a survey vessel; Winfield states only that she was a survey vessel by 1888.
Winfield, R.; Lyon, D. (2004). The Sail and Steam Navy List: All the Ships of the Royal Navy 1815–1889. London: Chatham Publishing. ISBN978-1-86176-032-6. OCLC52620555.