Examples from the Web for demi-cannon
The number of cannons royal, and even of demi-cannon, in the English navy was not great.A Short History of the Royal Navy 1217 to 1688|David Hannay
One demi-cannon, old casting of Manila, caliber sixteen libras, length twenty-two calibers.
The Revenge mounted forty "great ordnance" of brass, including cannon-royal, demi-cannon, and culverins for firing a broadside.The Golden Galleon|Robert Leighton
One demi-cannon cast in Manila, old style, caliber sixteen libras, length twenty-two calibers.
In the port ride two caravels--eighty tons, no more--and their greatest gun a demi-cannon.Sir Mortimer|Mary Johnston