I’m still trying to figure out how they get on board the pirated vessels without any help. My merchant navy days taught me that the only way to climb aboard while at sea was up a Jacob’s Ladder, thrown by a crew member. If grappling hooks are used, well, a heavy squirt from a fire hose would take care of that. Or boiling oil if all else fails.
As it is, the answer may be to travel in convoy, and pray that the enemy doesn’t go submersible. North Atlantic all over again? Where’s Winston when you need him!