A demi-cannon or half-cannon was a 17th Century naval gun which fired a 32-pound solid shot. A full cannon fired a 42-pound shot. 42-pounders were discontinued as they were seen as too unwieldy in the 18th Century. The lower tier of 17th Century English battleships were usually equipped with demi-cannons. Ships featuring demi-cannons included HMS Sovereign of the Seas, HMS Resolution and HMS James, which fought in the Anglo-Dutch naval wars.

See also

• Culverin
• Demi-culverin