Though similar in size, the current patrol boats are not descendants of gunboats from the colonial and Federation periods, due to their different functions. Gunboats provided coastal defence, whereas patrol boats perform mainly constabulary duties. The Royal Australian Navy (RAN) currently has in service eight cape class patrol boats and three older patrol boats of the Armidale type.
Patrol boats are a primary enabler of the Australian Defence Force contribution to Operation Resolute, which covers approximately 10 per cent of the world's surface and includes the Australia's exclusive economic zone, which extends up to 200 nautical miles from the Australian mainland and offshore territories. Christmas, Cocos Keeling, Heard, McDonald, Macquarie, Norfolk and Lord Howe islands also fall within the Operation Resolute boundaries.
In association with Border Force, Australian Fisheries and Australian Federal Police, Operation Resolute protects against unauthorised entry, illegal fishing, and breaches of customs, immigration and drugs legislation. The operation supports law enforcement, and preserves the integrity of fish stocks, the marine environment and other natural resources.
Patrol boat crews are typically employed on a range of constabulary duties involving tracking, stopping and boarding of other vessels, and sometimes arresting their crews and seizing cargo.