Megaera was the second named vessel since it was used for a 14-gun Fireship, launched by Teague of Ipswich in May 1783 and sold to J. Darkin on 3 April 1817.

She was completed for sea at Sheerness on 30 March 1838 at a cost of £27,778[Note 1] including £15,161 for the hull and £8,983 for the machinery.

[2] She was commissioned on 13 December 1837 under the command of Lieutenant Hugh Coville Goldsmith, RN for service as a packet vessel in the Mediterranean.

At this point she underwent a refit starting at Limehouse, then continuing at Woolwich and finally completing at Deptford from March to December 1842.

[3] On 10 November 1842 she was commissioned under the command of Lieutenant George Oldmixon, RN for service on the North America and West Indies Station.