The Merlin-class packet boat of 1838 was a Sir William Symonds design that was approved on 2 April 1838. The vessels were to be built for steam mail packet service on the Liverpool to Dublin route. The initial two ships were ordered in autumn 1838 from Pembroke Dockyard. The third vessel (Medina) was ordered in 1839, also from Pembroke. When completed all vessels were used on the Liverpool station. In 1848 all three were in the Mediterranean on mail packet service. Merlin went to the Baltic during the Russian Was as a survey ship. Medusa went to the Black Sea. Medina remained in the Mediterranean being converted to a survey ship for Mediterranean service. Merlin served on the West Coast of Africa and was sold for commercial use in 1863. Medina was sold at Malta in April 1864. Medusa was converted to a tugboat in 1861 and remained in that service until sold in 1872.