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Can't remember the episode but "Myth Busters" had a show involving a harpoon gun and - it was a modified martini shooting a 4' long harpoon with rope spooling off the bottom.

Found 2 real interesting places for the martini- first was the WW-2 HD movie(documentary) on Netflix about the Solomans Is just before the war and there were native troops marching round the British...