(Remembered from family history)
Dad's destroyer sailed into Hiroshima, first American ship in harbor I believe. (#69 I think. Haha.) Nearly every man on that ship died of mesothelioma ~40 years later. Lung cancer from asbestos, which is on point. Dad said sheets of it were lashed around the pipes with duct tape and it would rain dust on them when a shell hit close by.
Same dad told me Zeros exploded like matchsticks from a close hit because they were made of balsa wood. Same dad told me he never really saw action. I think he was a bit of a liar and didn't want to glorify war to his young grandson. :)
This is what I remember from family history. Can anyone track this? I remember looking at his ship's engagements for a history project in the late 80's and it seemed that ship was in every Pacific naval engagement I had ever heard of.
I lack the know-how and resources to investigate. Was any of this true? Am I misremembering? I can find the ship number (69) and I'm pretty sure it was a destroyer. He was maybe a second or third class torpedo-man?
The US destroyer with the pennant number 69 was the USS Caldwell, launched in 1917 and struck and scrapped in 1936, which is too old to be your dad's ship. If the pennant number of his ship was 669, that would make sense for the timing -- USS Cotten, DD-669, was a Fletcher class destroyer commissioned in 1943 that was in service until 1960, and sold for scrap in 1973. It was part of the fleet that anchored in Tokyo Bay on September 3, 1945, and could well have visited Hiroshima.
There's a memoir of life aboard the ship, 200,000 Miles Aboard the Destroyer Cotten, written by C. Snelling Robinson, which may be available to you either at a local library or via ILL.
Also: As your question is related to looking for identification/information regarding military personnel, our Guide on Military Identification may be of use to you. It provides a number of different resources, including how to request service records from a number of national agencies around the world, as well as graphical aids to assist in deciphering rank, unit, and other forms of badges or insignia. While the users here may still be able to lend you more assistance, hopefully this will provide a good place to start!