Oops, my bad - you did write grandfather and his age at the time. But yes I'm referring to beginning of WWII. I'm not exactly sure of when my dad got that job - obviously a lot younger than your Grandfather. He would have been 22 in 1940.
My grandfather was working at a US Naval ship yard so his circumstance was a bit different than your father who was working as an employee of a private company providing service to the US Navy.
Your fathers credentials would have all been handled by Bethlehem Steel, not the USN.