The 18 pounder long gun was an intermediate caliber artillery piece found on warships in the day of sail. It served as the main armament on the typical Royal Navy frigate of the Revolutionary period. This smooth-bore gun was 9 feet long and weighed 4,760 pounds. It could fire a 5.3-inch 18-pound round shot up to a mile, although accuracy was greatly diminished as the range to target increased.