Well, if you are referring to the Legend of Zelda and the Twilight Princess game, then you have to get the cannon out of the basement of the hut in Kakariko Village then warp it to the lake, then get the guy to repair it for 300 rupees.
This is also in the wrong section, it should be under the "Stuff We Play" section. Just to let you know so people dont get confused lol.