A friend of mine’s nephew is in the Navy. He’s getting training working on Diesel engines. Diesel engine repair may not be the most glamorous job out there but when he gets out, if he plays his cards right could make damn good $$$ especially if he one day owns a repair business.
Here’s a career clue for your friend’s Navy nephew: natural gas compression - large diesel engines are used at compressor stations to move the gas to market. They are also used to drive gas through the super-cooling process that turns it into CNG for fuel and transportation. Tell him to check out this link: http://go.osuit.edu/academics/energy_technologies/overview