Re: Electric Horn Hook Up
battery + to one side of switch, from other side of switch to horn +,then wire from battery - to other side of horn and you are done.
Now, all boats are a little different, you may have a power block or everything may wired directly to the battery so where you pull your power from might change but that is how you do it, very simple.
Alot of boats have a main buss, positive and negative power from the bow to the stern that things branch off of so may be able to tap into one of those but without actually seeing the boat no one can tell you exactly where yo get your power from.
Maybe google "basic wiring" and get some education before you start, a 2 wire switch is pretty basic.
Also check your local regulations before you mount it, were I am a horn has to be open to the air so you can't put it under the console or anything like that.