This is from yacht club bar gossip so we know it can be trusted implicitly.
At least it was in a cruiser area (the Royal Suva YC in Fiji) and involved long distance cruisers. One Aussie here has a relation who serves on an Australian naval ship that regularly patrols the ocean off the horn of Africa, where there are naval vessels from many nations. His comment was that he could not go into any details about what they do, just that the number of pirate vessels heading out of port is not equal to the number who return. He implied that other nations are following similar rules of engagement.
Another cruiser met a former Royal Marine in Aden who is now employed by a company that hires out to the insurance companies that pay ransoms for commercial vessels that have been seized. Their job is to go to the ship after the ransom has been paid (well-armed) and accompany the ship until it is out of harms way. He said that they were accosted by a vessel four hours out of the Somali port and a fire fight ensued with the attackers being sunk.
If these reports are true (and that is a large 'if'), it is good to remember that just because something is not reported by CNN or the BBC does not mean that it did not occur.
BTW, there are quite a few potential circumnavigators in this region who are not prepared to go around Africa at all, and will not go the Red Sea route until there is better security.