HMS Infernal (1757)

HMS Infernal was an 8-gun bomb vessel of the Royal Navy, constructed in 1757 and in service until 1763. Designed by Thomas Slade, she was the prototype for six subsequent Infernal class bomb vessels which saw service in the Mediterranean and the West Indies during the Seven Years' War with France. In 1760 she was refitted as a sloop and returned to active service in the Caribbean.

Infernal was paid off at the conclusion of the War in 1763, and sold out of Navy service in 1774.

Construction
Infernal was the first of seven bomb vessels designed by Surveyor of the Navy Thomas Slade to strengthen the Navy's shore bombardment capacity during the Seven Years' War. Admiralty Orders for her construction were issued on 5 October 1756, followed by a contract to master shipwright Henry Bird to build the vessel at the civilian dockyard in Northam, Southampton. Under the contract, Infernal was to be launched within six months in return for payment of £11.5.0 per ton. Neither requirement was met, though Bird was subsequently engaged to build a second similar vessel, HMS Blast (1759).

Her dimensions were in keeping with other vessels of her class, with an overall length of 91 ft, a beam of 27 ft and measuring 307 $39⁄94$ tons burthen. Construction costs were ₤3,355 with an additional ₤2,082 for fitting out. Slade's design included a narrow stern, bluff bow and broad beam, creating a short, heavy vessel capable of supporting the recoil of the mortars. A consequence of this design was that her sailing qualities were very poor, as she lacked both speed and the ability to sail to close to the wind.

Infernal was ketch-rigged, and intended for a crew of 60 men. She was initially equipped with eight six-pounder cannons for ship defence, and twelve $1⁄2$-pounder swivel guns to ward off boarding parties. Slade's design specified that two mortars be installed, one capable of 10-inch shot and the other of 13-inch, for use against fortifications. The mortars were also capable of being loaded with around one hundred one-pound projectiles at a time, for use against enemy personnel.

Bomb vessel construction ended on 11 July 1757, but by Admiralty Order the newly launched ship was immediately returned to Northam dockyard for refitting as a sloop. The mortars were removed and replaced with an additional six six-pounder cannons, and additional quarters constructed for an enlarged crew totaling 110 men.

Naval service
Infernal was commissioned into the Navy in July 1757, as a 14-gun sloop under Commander James Mackenzie. She was immediately attached to Admiral Edward Hawke's fleet for the capture of Île-d'Aix on 23 September, and the subsequent Raid on Rochefort. In April 1758 she was sailed to Portsmouth and restored to her original function as a bomb vessel at a cost of ₤884. Six of her cannons were removed and the original 10-inch and 13-inch mortars and were restored. Her crew was reduced to 60 men, though James Mackenzie retained his command. A unit of Army gunners was brought aboard to oversee the use of the mortars.

In May 1758 she bombarded the French ports of St Malo and Cherbourg, and was also present at the Battle of Saint Cast. On 12 November she was assigned to service off the Leeward Islands as part of British plans to seize the French naval base at Martinique. In 1759 she engaged in bombardments of both Martinique and Guadeloupe, but her usefulness as a bomb vessel was hampered by Britain's defensive position in the Caribbean. By Admiralty Order, on 20 March 1760 she was again fitted out as a sloop and assigned to cruising the Caribbean in search of French merchant vessels. She was present during the British landings at Belleisle between April and June 1761, and raids on Martinique in January and February 1762.

James Mackenzie died in April 1762 and was replaced by Commander Charles Roche, with Infernal continuing her Caribbean patrols. In company with six other ships she took part in the capture of a single French ship, Post de Nantz, for which prize money was paid the following year.

In February 1763 the Treaty of Paris brought an end to the war, and Infernal was returned to Deptford where she was paid off and her crew assigned to other vessels. A marine survey was conducted on 19 May 1763, and another on 31 January 1770, but there were no orders for repairs. On 26 October 1774, after nine years at Deptford dockyard, the increasingly decrepit vessel was sold into private hands for ₤350. Her fate thereafter is unknown.