Tompion found in a cannon from the Queen Anne’s Revenge, before 1718
In 1627, a tompion was defined as a wooden plug inserted into the muzzle of the cannon and sealed with tallow to protect the contents from rain and sea water so that the cannon could remain loaded when not in use. This has not changed much over the years. In 1677 they were only issued in two sizes, a large and a small, suggesting that they were not intended to fit with great accuracy. In the 1770s they were made in different sizes for each calibre of cannon.










