Pirates?
The cost of the lives of the crew is alone worth whatever monetary loss incured. Those ships cost multi- millions, that does not include the value of the cargo, even more millions. Now lets think just a little, the pirates will not release the crew or ship for less than a million dollars, how many men and guns could you hire for that amount. Let the pirates know you've got enough fire power and men to blow them out of the water a hunddred yards before they even get near your ship and they will stop. The pirates only attack because they can, kill a bunch of them and they will stop. They are not worried about who they hurt, if we had the same attitude things would change very fast. My mother always said," if someone is nice to you, be nice to them, if someone is bad to you--kill them," mom didn't have many friends, but everyone one who knew her either respected her or was afraid of her. Lesson learned !!!!!!!!
For the love of GOD turns off your capslock.
Now for your question, "How many men and guns could you hire for that amount (1 Million Dollars)?". It is actually fairly simple to do the math so lets take a look.
The M2 Browning 50 cal machine gun has a replacement cost of about $15,000 ( according to this ). That is for the US Military though, the civilian market would cost more. Let's assume a decent markup, plus the cost of related hardware (like mounting) that the cost is $25,000. Don't forget that you need something to shoot, lets keep enough ammo for at least 1,000 rounds at each station. The bulk cost for 50 cal is $4 a round. So: 10 Stations * $25,000 (a gun) + (1,000 rnds of ammo * $4 each) = $290,000
Now let's take a look at the men. You want "highly trained marksmen" so lets get some E-7 w:Sergeant First Class's with 22 years of experience. That will cost $4,142.10 a month, or roughly $50,000 a year. Now this is just base salary, any specialties on top of that (like scout sniper) are going to earn them more. Plus the US Army has a lot of benefits. In reality to lure them away from the military, you're going to have to pay them a lot more (after all, they are mercenaries now), lets say $125,000 a year (Though I've heard PMCs in Iraq earn as much as $1,000 a day). Remember, we needed 15 men from the earlier post. So: 15 men * $125,000 a year = $1,875,000
Adding it all up. $290,000 for guns + $1,875,000 for men = $2,165,000. Over 2 MILLION Dollars for one ship, for one year. You can't forget that the men are paid salary, so that cost is just going to keep going up. Plus guns constantly exposed to sea water are going to need constant maintenance and replacement parts. Oh, and the men will need to train too so you'll have to buy more ammo. See where this is going? It isn't cheap to equip a ship with men and guns.
So lets answer your question now, "How many men and guns could you hire for that amount (1 Million Dollars)?". Half of a ship, half of the time.
It's also worth considering what would happen if pirates did manage to take over an armed tanker - which might become the target, itself, because it's not like taking a naval vessel. And being an oil tanker, you can't just sink it if it's taken and starts terrorizing the area.
It seems like hiring trained personnel would be a better use of the ship owner's money than outfitting the ship itself. It's a more flexible option, since your defense is still functional even if the ship is boarded. It's expensive, to be sure, but no company wants to lose cargo and the lives of their employees - even if it's only for the sake of maintaining a healthy public image. That being said, the issue shouldn't have to be resolved by private companies. Global entities like the United Nations are supposed to be the ones addressing these issues through united action in defense of their citizens. I'm not saying that to express some form of desperate idealism - it's more an observation of the systemic failure of contemporary government to respect the rights and needs of honest people. I certainly feel that if government isn't willing to step up to solve the problem, they should step aside and let private contractors deal with it instead.
There are 27 navies from around the world engaged in anti-piracy operations in Somali waters, many of which form combined task forces and regularly share intelligence; since this is an "infringement of [Somalia's] sovereignty" they have the permission of the United Nations to carry out these operations. Many countries have also authorized shipping companies to use private security measures, and some security firms specialize in anti-piracy. So you do have government trying to fight piracy, and you do have the private sector trying to fight piracy.
They could use that ultra sound system. I forget what its called but the machine sends out a ultra high frequency that is supposed to hurt the ear drum. Why cant they just put a few of those on the boats instead of hiring men?
Well from what I remember, those aren't public available yet and I think they may have fairly limited range. Sure they might work out to 100 feet or so, but you want to drive away the pirates BEFORE they get in RPG range. Secondarily, even if you were to have those on the boats instead of guns, you'd still need to have multiple units spread around the boat (for full coverage) and you'd need people to operate them. It isn't just simply a matter of having someone at the controlls of these weapons, it is having the people out there to SPOT the pirates in advance and use whatever weapon you have. We're not talking about a fishing trolley that is 20 or 30 feet stem to stern, we're talking about super tankers that are 1200+ feet in length. The world record for the 400m dash (just slightly longer than the boat) is 43 seconds. So it isn't like you can just say "they'll spot them from the controls tower and run out to the forward guns", that would take far far too long.