HMS Simoom was an iron frigate converted to an iron screw troopship. She was laid down in October 1845; however, on 23 April 1847 her frigate design was abandoned as this type of iron warship was considered to be unsuitable against cannon fire and she was ordered to be completed as a troopship. She was launched by Robert Napier and Sons in Govan, Yard No 17, on 24 May 1849, then sold to Collings, Dartmouth in June 1887.