100 Million worth of crude oil. Hell would you give it a try? I might.. Especially when the ship captains tell us their best defenses ammount to a high pressure water hose. What about the Military? "Well, the ocean is so big..." they say. Understandable.

So what is the solution? Well.. Granted I get seasick watching boats on tv so call it the 'armchair solution', but seems to me there are several.
In WW2 we had shipping lanes & Military escort. Can't imagine there are too many ports a supertanker can pull into thus there are probably few routes between them. The pirates know this.. So send a couple gunships along with the tanker. Don't have a Navy? Get ahold of Blackwater. Betcha they've got boats. I know for sure they have "little-bird" helecopters.. Set one of those on the deck of your tanker. Wait for the pirates. When they show up, launch that helo & lite 'em up.

What about arming your tanker? There's a little thing called a GAU-2/A (US Air Force Designation) minigun. Six barrels, 30 caliber, 500 or 6,000 rounds a minute, selectable. Three guys can carry it & set it up. It can be mounted on anything from a SUV to a lil helecopter to even the AC 130 Gunship. Want to see it? Here ya go.
Ya if I was a pirate in a lil Swift-boat & saw that coming at me.. I would be somewhere else almost immediately.

Ok, ok.. Maybe having something that puts out that much fire sitting on the deck of your (just) slightly flammable supertanker could be a Bad Idea. The point is to protect your boatload of flammables not torch it right? But still. Protecting 100 Million Dollars of anything with a high pressure water hose? When the Bad Guys can come at you with *Anything* and the cops are nowhere to be found?

If I was the owner of that ship.. I sure as Hell would be doing something to protect my investment.

I still haven't managed to find the tactics used by the pirates. What.. Do you drive up next to the tanker & call over the radio "Throw down a ladder or we'll Huff & Puff & Blow your Boat In!" Do you put a sticky-bomb on the end of a stick & threateningly wave it at the tanker? I don't know. Maybe you chuck a rope in the water & foul their propeller, then wait for them to starve.

I do know tankers are kinda tall. Pretty much you cannot get onto one in the open ocean unless the guys already on it throw you a rope. Now you could try to Nancy Regan them & Just Say No.. But wouldn't it be better to have a sniper team on board? Or stick a Phalanx Close-In Weapon System on there. It's automated. Turn it on & go to bed... It tracks & kills anything within X kilometers of your ship.

Seems fairly cut & dried to me. Add defenses to your oil tanker.. The pirates will attack someone else. What would it cost? Well.. What's the ransom on a 100 Million dollar tanker & the crew? Spend that money on arming your ship & you only have to pay it once. Plus you get something for your it besides your ship back. Even if it costs you $100,000 a shipment to hire a crew from Blackwater.. Write it off as insurance.