|Mort the Cleverly Named|
I'd go with Abadar. God of Merchants and Law, really hates pirates. Actually has an organization called "The Sea Dragons" just to hunt them. They are called "merciless," and being LN it can be argued Abadar's Paladins could be a bit less "Good" and a bit more "Lawful" when it comes to enemies. His Paladin Code even refers to Bandits (so, pirates), as a plague and that those that won't submit to justice "will come under the power of my sword." Yikes.
Really can't think of a more appropriate deity. Even if James Jacobs hadn't smote the Paladins of Asmodeus I'd still go with Abadar.