How do you get the cannon on legend of Zelda phantom hour glass?
Go to the island southwest of Mercay Island, and go all the way
around it and to a shop. You can buy it there. Though, you must
have completed the first dungeon on Ember Island, and you can know
whether or not you can buy it when you dock on the island you
started out on and a guy will ask you to talk to him. If he
inquires about a canon, you can go buy it from the guy on canon