[ZenGum]

Boy, you guys sure lost your enthusiasm since talk like a pirate day.

Has anyone (else) here read The Devil's Alternative, by Fredrick Forsyth? It deals with a hijacked super tanker.

Clearly, mere regular patrols aren't working. Counter-strikes against seized ships kill hostages and in this case would either destroy, or dump into the sea, a huge amount of oil.
Two tactical responses seem like they might work: providing escorts for ships in convoy, or setting a few decoy/sting ships that look like nice easy targets but turn out to have, say, a whole commando regiment on board.