Harpoon cannon

These are used in modern whaling, with the exception of many Norwegian cannons which utilize an improved muzzle-loading design, with a breech firing system.

With a trigger mounted on the back of a steel handle which would lever a thin rod up to the firing device in the horizontally sliding breechblock.

The breechblock would be opened by rotating a handle on the top of the breech, and the spent cartridge case removed, to be reloaded with powder and wadding.

Iceland uses 90 mm cannons built by Kongsberg Våpenfabrikk (KV) in the fin whale hunt by Hvalur HF.

Japan uses 75 mm cannons, built by Miroku Manufacturing in its pelagic whaling in the North Pacific and Antarctic research hunts.