The Demi-cannon was developed in the early 17th century and often used on the lower teir of english war ships. In full the cannon fired a 42 ound ball but was very unweildy. The ships that carried these cannons fought in the Anglo-Dutch war. At 11 feet long and 6 inches wide the cannon could weigh up to 5600 ounds, requiring 18 pounds of gun powder for one sufficient shot. Its range wnet up to about 1600 feeet which was average for a cannon of its time. It was extremely inacurate except for close range shots so the ships would get as close as possible before tehy shotoff the cannons. It would usually onky take a few broadside hits to defeat the enemy ship.