The Alert, built in Dover by Henry Ladd and launched on 24th June 1777, was the largest class of cutter in the Royal Navy. Alert originally carried ten four-pounder carriage guns and six to twelve half-pounder swivel guns. She was one of fifteen cutters built for the Royal navy between 1777 and 1778. Smaller cutters were often purchased or built by private yards and then purchased by the Navy, but Alert was purpose built from the keel up.
In February 1778, Alert docked at Plymouth for an overhaul, to which some alterations were made to her hull and the ten four pounder carriage guns were replaced with twelve six pounder guns, raising her broadside weight by 30%. The guns were changed because six-pounder shot was more commonly available and, of course, they were more effective.
Because of the increase in ordnance, the crew of the Alert was increased from sixty to eighty men, and recommissioned under a new commander, Lieutenant William George Fairfax. In May 1778, Fairfax was promoted to Commander and Alert was re-classed as a sloop to comply with Admiralty requirements. (Although always remained cutter rigged)
On 17th June 1778, the Alert, in company with the frigate Arethusa, spotted and intercepted the French frigate Belle Poule and the armed lugger Coureur, with the latter overhauled by the Alert and surrendered, returning to Spithead after the action with her prize. On 8th July of the same year, whilst on an independent deployment, searching for the enemy fleet, Alert was taken by surprise and captured by the French frigate Junon. Alert is reported as lost without trace on 15th December 1779.
