Copper sheathing, first applied to the Alarm, was a huge force multiplier for a navy with a maritime strategy based on blockade. Copper sheathing diminished marine growth, keeping vessels out of the dockyards and at sea maintaining usefull speed capability for extended periods and prolonging hull life by keeping out "the worm".
Most are aware of the galvanic corrosion issues associated with copper sheathing, but the most unusual issue I have found is from Capt. John Byron's journal of his circumnavigation of the world in the 24 gun ship Dolphin (third vessel to be coppered) in the 1760's. Even though he thought that copper sheathing was "the finest invention in the world", it did create a hardship on the crew, because Byron blamed the Dolphin's shortage of fresh meat at sea to the copper scaring the fish away!
I dont think I need to discuss the carronade's effects at close range. Its first use is credited both to a Carron Company commercial vessel (the Paisley in May 1779 per Peter Padfield) and to a Liverpool privateer (the Spitfire in "early 1779" per Brian Lavery).
The first mounting to a RN vessel is obscure, with trials beginning in May 1779 on several ships.
But, sources are consistent in identifying the carronade's first success in the RN, the taking of the French 32 gun Frigate Nymphe (26 X 12, 14 X 6) by the English 36 gun frigate Flora (26 X 18, 9 X 9, 1 X 18c). Based on the weight of metal, the odds were stacked in the Flora's favor, but the effect of the carronade in the battle was astounding; the single carronade, manned by the bosun and a boy "created havoc" amongst the "unsuspecting" French crew. The Nypmhe lost 139 killed, compared to 26 fatalities on the Flora.
The carronade had been initially rejected by many RN officers in the "peacetime navy", the Admiralty relenting to pressure and arming vessels with carronades only at a captain's discretion (many RN officers questioned its efectiveness and were convinced that it would set fire to the rigging). The success of the carronade in actions during 1780 and 1781, and the lack of rigging fires, led to its rapid adoption within the RN.
SeaRat, the floor is yours.