Nothing wrong with helicopters, and amphibious assault ships often have very many helicopters. But one of the main issues with dealing with small craft is separating friend from foe: is that small Somali boat a bunch of pirates or are they fishermen? (they probably are both, depending on where the best catches of the day can be found). Helicopers are pretty vulnerable at the disctance you need to go to ID the potential perps, even against light weaponry like machine guns and RPG's.

Another problem is that big ships are pretty clumsy, especially close to shore where the small craft operate. The big ships (destroyers etc) often have relatively big guns which can't be brought to bear against small craft.

Small craft are best fought either with medium sized ships (corvettes or small frigates displacing a few hundred tons up to a bit over 1000 tons), or preferably by destroying the pirate base (hey, that would make it a pirate "cove", right?). Aaargh! ;-)

Peak oil is not an energy crisis. It is a liquid fuel crisis.