Strap-on Escort Blisters

Security ports are entered on either side of waters known to be Pirate active where ships are fitted with temporary gun emplacement blisters.

The gun emplacement blister hangs off the side of large ships (with another directly opposite for balance) and are manned by trained Naval personnel.
The guns are .50 cal anti-aircraft & a small cannon - 3" or so? I don't know the limit of what would be possible in this configuration.
Naval personnel are volunteered by various countries and assigned by the UN to escort shipping concerns by piggy backing their gun emplacements directly on the commercial ships.
I think this would prevent the commercial enterprise from having to deal with legal issues if the Naval escort happened to put several holes in a ship failing to follow their orders to maintain a proper distance, but I'm not sure.

The Escort Blister is removed at the port on the other side of known pirate waters to be transfered to the next ship crossing through them.

This idea was inspired by my recent tour of the USS Texas, a WWI / WWII battleship. I was chilled at the horrifying lethality of it and it last served over 60 years ago, so I know the lethality of battleships has probably not lessened in that time. I imagined that if I were in a ship / boat & was told to do something by someone in control of that ship, I would certainly not hesitate to do what I was asked.
I know there's a kind of amusement with pirates here, and there's also that global warming correlation, but maybe this could be considered as an idea to weed out the dumb pirates.