Caca snipped.

Arm every merchant vessel with a 50 cal. machine gun along with a
qualified gunner. When the pirates come into the effective range of
that .50 (about 2000 yards), a short burst should easily dissuade
anyone from being a threat. You could also have another gunner with a
50 cal M107 (probably what the Seals used in rescuing our captain).
If they insist, the gunner could cut the small craft in half with such
a weapon and the M107 gunner could pick and choose the threats. Works
for me. Leave the ships alone and the pirates can live as long as
they want. Really simple when you think about it.

And, there are plenty of mercenaries world-wide that would/could do
the job.

Dave