I am singlehanding in the Med since a couple of years.
If you have weapons onboard, I think you must declare them to the
authorities upon entry to each country, at least in Europe. They will most
likely be confiscated for the time you spend in the country, and returned to
you when you are leaving the country. Failure to do so is upon discovery
likely to get you into BIG trouble.

As an example, in the summer of 2004 I was boarded at sea by the French
customs in the English Channel. Three armed officers boarded my boat and
spent 1 hour searching my boat, all while sailing 5-6 knots. Discovery of a
weapon would likely have caused me lots of trouble.

Also, with a weapon you have to be prepared to use it without slightest
hesitation, and you might find that you just killed a couple of fishermen
trying to earn a dollar or 2.
Martin

--
i'm wondering about guns on board too. the subject comes up a lot in
different books and articles and things i've been reading about
cruising, and in the cruising forums, and there are plenty of piracy
reports out there to read too. i don't have a clear opinion on it yet,
i'm still thinking about it.