When I first heard about these Pirate attacks a few months ago I had an idea that seemed to me would stop it in its tracks. It seemed so simple that I assumed it or something like it would be implemented right away. It was not, so I am going to put it out here for your and anyone else's consideration, plus my second idea which I feel is just as good, if not better than the first one!
The first idea was simply to put an electric fence around the perimeter of each ship, quite easy and inexpensive I would think. It could even be compartmentalised so that it could be turned off in various areas for work to be carried out. Let them try climbing over the edges of an electrified ship!
The second idea is to make the ships travel in very tight shipping lanes, instead of wandering all over the Gulf they have to travel through on certain lanes. This way it would be easier for "Guard ships" to watch them, overhead pilotless lookout planes could track small ships and the Guard Ships would have a relatively small distance to go to investigate them. A few ships could be stationed every 10 or 20 miles or so and maybe they could even have a helicopter on board that would be able to reach a ship being attacked quickly and sink the offending pirate with a few well placed shots. End of problem