Impressment by the Royal Navy in Nova Scotia happened primarily during the American Revolution and the Napoleonic Wars. Guard boats patrolled Halifax harbour day and night and they boarded all incoming and outgoing vessels. The Navy always struggled with desertion in Nova Scotia, and it often threatened to use impressment as a punishment for communities that harboured and assisted deserters. The Navy used guard boats as floating press gangs, conscripting every fiftieth man out of ships entering the harbour. It even pressed Americans from cartels and prison hulks. Warships shot at vessels to bring them to, damaging their sails and rigging, and at least one fisherman was pressed while checking his nets.