Design
Propulsion
The first 6 ships had a 2-cylinder horizontal single-expansion steam engine provided by Robert Napier and Sons and rated at 200 horsepower#Nominal horsepower, nominal horsepower, driving a single screw. ''Sylvia'' and ''Nassau'' were completed as survey ships and were powered by 150 nhp Humphrys, Tennant and Dykes, Humphreys and Tennant engines, and ''Myrmidon'', the last of the completed ''Cormorant''s, received a more powerful 200 nhp Humphreys and Tennant engine.Armament
The main armament, which was principally intended for shore bombardment, was originally designed with two 68-pounder gun, 68-pounder and two 32-pounder muzzle-loading smoothbore guns. They were finished, however, with a single RBL 7 inch Armstrong gun, 7-inch/110-pounder Armstrong breech-loading gun and a 68-pounder gun, 68-pounder muzzle-loading smoothbore gun. A pair of broadside RBL 20 pounder Armstrong gun, 20-pounder Armstrong breech-loading guns were also fitted. The 68-pounders were later replaced by a pair of 64-pounder muzzle-loading rifled guns.Sail plan
In common with all other Royal Navy wooden screw gunvessels, the ''Cormorant''s were rigged as barques, that is with three masts, with the fore and main masts square rigged, and the mizzen fore-and-aft rigged.Construction
The first 6 ships were ordered from commercial yards (Money Wigram & Sons, Thames Ironworks and Shipbuilding Company, C J Mare & Co and Millwall Iron Works, 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 , exceeding the intended 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. ''Sylvia'', ''Nassau'' and ''Myrmidon'' were suspended in 1862 or 1863, but were resumed, being finished as survey vessels.Preston claims that ''Myrmidon'' was completed as a survey vessel; Winfield states only that she was a survey vessel by 1888. She was launched on 5 June 1867Bastock, p.91. and commissioned in October 1867.Operational service
''Myrmidon'' commenced service on the North America and West Indies Station. 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. 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. Her eventual fate is unknown.Notes
References
*Bastock, John (1988), ''Ships on the Australia Station'', Child & Associates Publishing Pty Ltd; Frenchs Forest, Australia. *, p. 157 * {{DEFAULTSORT:Myrmidon (1867) 1867 ships Ships built in Chatham Cormorant-class gunvessels Victorian-era gunboats of the United Kingdom