Why not just get a 20-mm cannon and blast them all to hell?
That is an intelligent question, to which I have an answer.
Due to outdated maritime laws, commercial vessels are not allowed to dock at several ports - with weapons onboard. This is to prevent a commercial vessel from leading an attack or invasion upon a port city. As I indicated - this is an out-dated law.
What I do NOT understand is why some enterprising person doesn't RENT armament to these ships. Meet them in international waters, bring on some trained Mercs with RPG's, fully automatic weapons, laser guided missels, Gernades and a very foul attitude and blow said pirates 'to hell'. Then, while the ship is at the 12 mile mark, disembard with all weapons and personnel, awaiting their next assignment.
Seems like a very lucrative business to me. I think we'd have little problem finding volunteers to hunt/kill pirates; and even less problem getting armament for these people to use.
They have those mounted on helicopters. The Coast Guard uses them as well as the Navy.
However, the only thing they are allowed to target is the engines of the target craft.
I see you've been stealing Russian navy defense policy secrets again. Niekulturky!