Press gangs were groups of men from a naval ship in a port tasked to 'recruit' men to join the ship's crew. In the Royal Navy a ship's captain was responsible for fitting out his ship, including his crew complement, so, the gang, usually headed by a lieutenant, one or more midshipmen, and a number of trusted seamen would travel around a port and seize men between the ages of 18 and 55, although that was not always adhered to. Members of the merchant service could carry exemption certificates, but they were not always honoured. The men seized would then become members of the crew.
Ships that have left port have also been known to board merchant vessels and seize members of their crew to fill out their own complement.
British Men-of-War many times pressed men from American ships, leading up to the American-British War of 1812.
- Impressment at Wikipedia.