Question about Non-Lethal Technologies to combat Piracy...

I had a quick question regarding the recent piracy incident off the coast of Somalia involving a cuise ship.

It appears that part of their defense was a device that beams a column of highly intense sound for several hundred yards.

Assuming it actually works as is supposed (i.e., inflicts significant distress in those against whom it is directed), can be mounted in such a way that is provides adequate coverage, and is available at a resonable cost, would such a device be an attractive piracy countermeasure in the megayacht market? Is the experience demonstrated by the cruise industry instructive for yacht owners and operators?

It seems to me that their are few other options available aside from creating a floating bunker or carrying weapons.