The problem is how do you tell some fishermen wanting to trade fish for cigarettes or booze, from pirates?
and as far as I know, there is no navy for rent.
but Blackwater, er Xe, might be willing for a price.
There is one thing I would do, if I choose to arm myself. put a laser on the weapon.
Everyone knows a laser dot means a gun is pointed at them... that could be an effective weapon, short of shooting into the air.
-in the previous photo, I'd have shot a warning shot.. into the air... just so everyone knows I meant business.