The Alert is an example of an early form of naval brig. She was the first vessel of the type to be built expressly for the Royal Navy, previous ships having been purchased outside the service. Designed by Sir John Williams, she was the one of the first of a class of eight similar ships built between 1775 and 1783. Acting as a fleet auxiliary, the brig could also be used for general scouting, patrolling and despatch duties and it also made, with an armament of anything up to sixteen 32-pounders, a useful convoy escort, a duty much in demand during the French wars when various convoy acts were passed forcing merchant vessels to sail in company under naval protection. We believe she is the 10-gun cutter launched at Dover in 1778 and captured by the French ship Diligente in September 1780 in the Bay of Biscay. The prize was valued at Lt52,405. In French service she was armed with six 8-pounder guns and twelve 18-pounder howitzers. Perseverance recaptured her in North American waters on 7 December 1781 ‘after a strong resistance’. Re-armed 1790 with 14 6-pounders. There is a picture of the hull construction of this vessel at the Science Museum, Kensington, London, England.