harpoon gun

a small cannon for shooting harpoons.

Origin of harpoon gun

First recorded in 1810–20

Greener's harpoon-gun is a kind of wall-piece fixed in a crutch, which steps into the bow-bollard of the whale-boat.

The Sailor's Word-Book |William Henry Smyth
They go out in large open boats, six men to a boat, and shoot the harpoon 220 into the whale from the harpoon-gun.

Bancroft's Tourist's Guide Yosemite |A.L. Bancroft
This harpoon-gun is now used all over the world, and has made whaling a wonderfully profitable business.

Harper's Round Table, July 16, 1895 |Various
Looking at Hank, he saw that the old fighter of the seas had dropped the harpoon-gun and was holding poised the long lance.

The Boy With the U. S. Fisheries |Francis Rolt-Wheeler

As respected the second mode, the use of the harpoon-gun, there was no novelty in that certainly.

Abridgement of the Debates of Congress, from 1789 to 1856 (4 of 16 vol.) |Various