The earliest cannons were made like barrels, with strips of metal placed around a core, then bound together by hoops. This piecemeal construction made them weak and inefficient, however, and they were replaced around the mid-17th century by muzzle-loading guns cast of solid iron or bronze. By the end of the 17th century, almost all new guns were cast of iron, due to the lower cost of manufacture.
Cannon molds were made of clay, and they had to be broken to free the finished gun. As a result, no two weapons were ever identical. Even guns made at the same foundry could vary significantly in size and other specifications. For example, guns from a single 1665 order of 9-foot demi-cannons varied in weight from 4400 lbs to 5200 lbs. More serious was the fact that nonstandardized bores often resulted in inaccuracies in aim and necessitated provisioning a ship with ordnance of varying sizes.
By the beginning of the 17th century, gunners had abandoned the inefficient, unsafe practice of ladling loose powder into guns in favor of using premade charges. With the exception of a few ready-made cartridges, gunpowder was stored in barrels. Gunners were given sheets of paper or canvas, which they filled with powder and sewed closed. Cartridges were prepared before a battle in the magazine, then brought up—often by "powder monkeys" as young as six years old—to the gun decks as needed.
While paper had the ability to burn thoroughly upon the gun's discharge, it became soggy and difficult to handle in wet conditions.
Canvas, on the other hand, did not burn completely and often left smoldering traces in the chamber, creating the danger of backfire if not thoroughly doused before reloading. Both canvas and paper cartridges were used throughout the 17th century until replaced by parchment in the 1720's, and then later by flannel.
Wads, plugs of soft material that kept the charge and shot firmly in place before firing, were also made aboard ship. A 1627 mariner's manual describes "wadding" as made of "okum, old clouts or straw." Pieces of old rope and cable, designated to be repurposed into wads, was known as "junk." A warship needed several tons of junk in order to fashion one wad for every round on board.
The slowmatch used to touch off the gunpowder was a thick cord boiled in saltpeter to keep it smoldering. The spark was often put out, however, by the flash when the gun was fired, so gunners kept slowmatch burning at both ends in the match tub and on the linstock. This is also why English Civil War soldiers using matchlock muskets would keep both ends of their slowmatch alight.
Brian Lavery (1987).
The Arming and Fitting of English Ships of War, 1600-1815. Great Britain: Conway Maritime Press
Department of the Navy, Navy Historical Center
Hand-colored illustrations: ©2002-2003 by D. Thomas Treadwell.