I place my bets on this being nothing more than an attempt to jack up oil prices. They've learned that any threat to the oil supply results in price going up, quickly and dramatically. The break even point for oil prices to keep those bastards afloat is way, way more than the $55 we're seeing right now. It's more like $90 and they are suffering, really suffering. If it works then we're in for more disruptions, probably escalating with every one.
This is a big test. If they pull it off we fail.
Bright side is that there's simply not the demand to keep oil at $90 now. Those were the good times for the bastards and they know it.
Best response would be no response. Just let them keep the ship and the oil.
The only people who need to know of how we respond are the hijackers.
Or we could simply sign a contract with the KGB to handle it for us.