Boat owners, especially on a world cruise face a multitude of laws and regulations in each port of call. That said, your future canoe venture north bring a favourite rifle immediately to mind, The British SMLE .303 . You have a 10 round, rapid fire weapon equally capable of dropping a surly moose , south seas pirate or putting a round into his search light. Ammunition is still fairly common ( especially Canada,) the weapon is robust, built to take abuse and still relatively inexpensive. Mine sits in the closet with the bolt secreted nearby. This business of "go bigger" has merit, but like anything you pay for it on both ends and at some point the returns diminish. The post about a 12 guage's acoustical damage is case in point, along with recoil and controllability. I once went to the range with a prewar, 6" model 10 Smith & Wesson in .38 spl. I had a recent police academy grad next to me. He had some hi capacity shiny thing in the latest wonder round. He looked at my old wheel gun with a sad look while putting on his recoil gloves, yellow shooting glasses and laying out multiple magazines before croutching in some stance stolen from a Pilotti studio. I rapid fired 6 rounds of 200 grain super police from a camp Perry stance before he could bring his 3 dot ,glow in the dark sights to bear. I put them in the torso target's head to. He was not amused. Big isn't much use if you miss big with it. I have an even better home defense system though. My tomcat confronted a maintenance man who forgot to knock once. Now that was messy <img src="/images/graemlins/blush.gif" alt="" />. Have you considered a small, yappy dog? Burglars hate them <img src="/images/graemlins/grin.gif" alt="" />