Gunlocks
A gunlock was a flintlock mechanism that fired a cannon. They were a significant innovation in naval gunnery and were first used by the Royal Navy in 1745. Their use spread slowly as they could not be retrofitted to older guns - the French had still not generally adopted them by the time of the Battle of Trafalgar (1805).
The earlier method of firing a cannon was to apply a linstock - a wooden staff holding a length of smoldering match at the end - to the touch-hole of the gun, that was filled with loose, priming powder. This was dangerous and made accurate shooting from a moving ship impossible, as the gun had to be fired from the side, to avoid its recoil, and there was a noticeable delay between the application of the linstock and the gun firing.
The gunlock was operated by pulling a cord, or lanyard. The gun-captain could stand behind the gun, safely beyond its range of recoil, and sight along the gun, firing when the roll of the ship lined the gun up with the enemy and so avoid the chance of the shot hitting the sea or flying high over the enemy's deck. Loading the gun was faster and safer as the gunlock didn't use loose, priming powder, the main charge was ignited by a quill filled with priming powder that was pushed through the touch hole during loading and pierced the cartridge bag, containing the main charge of gunpowder.
After the introduction of gunlocks, linstocks were retained, but only as a backup means of firing.
Read more about this topic: Flintlock Mechanism