They used to hit large vessels all the time - as the crew had their pay on board in cash. Now, the crew is paid through direct deposit and salaried. There isn't much they can do with the oil but sell it back to a corrupt government... not that those aren't hard to find in that area.
Here's me, REALLY glad my husband isn't working over there. The money is incredible if you don't mind the possibility of not coming back. That doesn't mean being dead... it's just they disappear.