As I see it....some sovereign nation issues a Letter of Marque to an NGO who then can legally conduct anti-piracy operations against designated targets described within the Letter, using defined limits, and all is above board.
Take a few Frigates out of Mothballs....Bail them to the Contractor...lease the services of some B-212's with FLIR, Radar, Dillon Mini-guns, some Ma Deuce .50 cal's....former SEAL/SBS folks with RIBS.....and Bob's yer Uncle.
Pull alongside a boat with guns, boarding ladders, and other Pirate kit....and conduct business.
Sign me up!