Hi
You can carry a handgun, if you are alowed to carry one in the USA, if you go into international waters, and stop at a forign port, customs will ask if you are carrying any fire arms, they will then ask you to surrender them, and they will give you a receipt, when you are leaving that country, you can then pick them up. When i made the trip out to bermuda, they even took the flare pistol, (which i got a receipt for, and they give you it back, along with any other firearms you have) Customs guy told me, you can put a sleeve in a flare gun, and fire a 45 out of it. If you dont declare you have a gun on board, and they find it even a few mins later, you are in big trouble, and in bermuda, posession of a gun gets you ten years, posession of one bullet, gets you a year, even the cops there dont have guns. Pretty much whatever you have in your boat, that is legal in your country, is ok in another country, but, they may take it off you for safe keeping until you leave, or if they cant be bothered taking it, they may bond it by puting a seal on it, until you leave. I was in the british merchant navy, we went into a saudi arabian port, we had a bar on the ship, and plenty of booze, the saudis (booze is illegal there) came aboar, got us to put every bit of booze in the ships bond, then they put their own seal on it, we were there a week, and they came back and checked the seal, before we left. If that seal had been broken, we would have probably all got twenty lashes.