bentley998 brings up a good point about using sound to deter pirates.
One problem is that LRAD units are pretty huge for a 40ft sailboat:
http://www.atcsd.com/site/content/view/15/110/
I should have mentioned more clearly that I'm all for using the VHF and Loud Hailer in tandem to warn off tailing craft. But, once they get inside a certain boundary (and they have proved that they won't be deterred),
There has always been a big debate about carrying arms at sea, whether is makes it more likely to survive (either by intimidation or an actual firefight), or more likely to escalate an attack. While I think this is a valid argument on merchant marine vessels where the pirates are most interested in taking valuables and cash/crew to be held for ransom (their life is worth something). It appears that the trend is different on small pleasure craft where there is no big shipping company (or insurance company) on the other end of the line, willing to fork over $100k-$250k per person. As a result, the crew of small pleasure craft are of little redeemable value to the pirates, therefore nothing but an extinguishable barrier to the ship's stores, electronics, women, etc... What happens to these boats? They (and their crew) just disappear. Period.
What is crazy to me is how brazen the pirates are, even attacking convoys to 5-10 yachts, betting on the fact that most Europeans won't have guns on board (only about 1-in-30 yachts in the Yemen and SE Asia are American) There are a couple of great stories online where the only weapon that the victims had was to turn their boats on the pirates to ram them (a 20 ton ketch can effective against a 1/2 ton fishing skiff).
If LRAD sound devices become more compact and cost effective, I'd be all for using it to replace my loud hailer. But, at the end of the day, an LRAD is no match to a Malaysian 50 yards out spraying the hull with fire from an AK47.
Thanks guys, I'm going to keep thinking through the Rifle/Shotty approach, with tactical plans well rehearsed (a lot of time on our hands in the South Pacific). If you think of any great ideas, let me know.