Downeast, I get your thought process. My own follows it to some extent... The part about making sure the bad stuff happens to someone else, not you and yours. And the concept of being able to (in a totally legal fashion) make a show of force that would deter some percentage of bad guys is appealing.
My own common sense tells me it would work. After all if *I* were going to make a hit on a boat I would plan on doing it when I hoped no one was aboard. The appearance of someone toting a formidable weapon would cause me to rethink my plan and I would be making my way to shore or back to my own boat post and haste.
But the point here might be that it is not someone like you or I who we would be facing. and every person I have ever discussed the options of armed vs unarmed has had some consistent comments.
Don't carry a weapon if you don't know how to use it.
Don't carry a weapon if you are not prepared to use it.
The thought seems to be that the presence of weapons may escalate the tension in a situation. If you pull your gun, they may pull their gun (or knife or whatever) and then what are you going to do? Hit them over the head with the stock of your fake?
I don't know.
The idea of a perfectly legal and common flare gun that you can convert to an up close shotgun seems more appealing to me. Getting it thru customs shouldn't present a problem. Some brief research reveals that the company which was making the adapter seems to no longer be in business/offering that product. So that may not be a viable option, I don't know.
This got me reading a bit and there have been some pretty grim situations with private yachts being attacked, but I would guess petty and or amateur attacks at anchor are more common risks than high speed chases with pirates in the
gulf of Aden. Against a group of professional baddies very few of us would stand a chance. Good reason to not sail that area unaccompanied. That would be the "making yourself safe" part of my philosophy.
This IS a complicated subject. And there is no clear *right* answer, as there is no way to know exactly what you are preparing to face. And hindsight will always be so 20/20, if you are alive to see it.
I don't know what I want to do when we head out. We will be (most likely) sailing the Pacific and Caribbean. There is some tiny chance of a trip to Australia, but that is in the very faintest stages of possibility. In those areas I don't know...
One interesting idea is that you carry a very CHEAP gun until you get to port and then you throw it away. Avoids the customs issue. but only good for the first leg of the trip.