Second, an Arleigh Burke class DDG is kind of a mismatch, too. They were designed as state of the art Anti-missile, Anti-air and Anti-submarine carrier escorts. Same or even more so for the Tico-class cruisers. The Bainbridge's single 5in 62 mm gun is considerably more than needed under these circumstances.
BTW; the new RIM 162 ESSM, replacing the RIM 66 SM-2, has a bigger warhead, flies better, and best of all can be 4-packed into a single Mk. 41 Vertical Launch System. Arliegh Burkes have 90 cells, you do the math. (Saving room for SM-2's for ASuW, Tomahawks for this and that, and a few SM-3's to pick off the odd ballistic missile. And maybe a few RUM-139 ASROC's for the occasional submarine. All in all, one hell of a ship, for which we have to thank the finest president in the 20th century, Ronald Reagan.
Now, for the pirates at sea I think the LCS (Littoral Combat Ship) armed with as someone suggested, a navalized Bushmaster 25mm would be ideal. Martin Marietta's LCS-1 Freedom however, is armed with a Mk 110 57 mm gun. Not as much ammo room as 25mm, but still. On the other hand, the General Dynamics version, LCS-2 Independance, armed with the proven Bofors 57mm gun has room for mission modules, one of which could be a nice Bushmaster with associated ammo in one neat box the size of a standard container. Gotta have more room for ammo than a Bradley, or a Stryker, don't you think? In spite of the New York Times article poo-pooing the concept, Somali pirates seem tailor-made to show the use of these ships.
Last, despite my being a Navy guy, I think the proper way to handle these guys would be something like Hellfire armed Predators loitering around that area, following any interesting 'fishing boats' and popping them if they try to go alongside any American Flagged merchant ships. Then, backtracking by satellite to wherever these clowns came from and sending another Hellfire through the front door. Repeat as necessary until they figure out that this is a bad idea. Offer same function to other national flagged shipping, for a nominal price. Current deficit defining level considered 'nominal'. 5% of value of ship & cargo seems about right. For our friends. Cost-Plus for the French, Germans, Chinese, and such.
Just a thought....
What we, and the rest of the civilized world, are doing in this area IS NOT WORKING!
We need some demonstration projects, and they need to be ratcheted up as necessay until the lessons are learned.
Reference 1945 if need be.
I like overkill, it reduces the chances of casualities on our side.
however the Bainbridge also two 20mm Phalanx CIWS. Still overkill, not so much so, but still enough to keep me happy. :)