There are more authoritative experts in this Forum when it comes to uniforms, but I'll take a stab at it.
The standard U.S. Navy enlisted man's working uniform in World War II consisted of a light blue shirt and darker blue dungarees (i.e., blue jeans). The officer's working uniform conisted of a khaki shirt, khaki pants, and a black necktie - though I doubt very much that the c/o of a PT boat in the Solomons wore his tie very often. The navy helmet was painted a medium grey. Lifejackets could be found in several colors, but I suspect a dull, rather dark blue - about the same shade as the dungarees - would be most likely in this case.
The numerous PT boat experts here in the Forum may shoot me down; if so, by all means believe them rather than me. But I think the above is about right.
If you do a forum search on the words "PT 109" you'll find a whole lot of extremely erudite posts regarding the boat's color scheme. I won't even try to add to what's already been contributed on that subject.
Good luck.
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