The first photograph is all the sailors in their Navy "whites". The arrow points to Hughie's head. You can see his distinctive "radar dish" ears.
Attached to the photo was a piece of notebook paper identifying all the sailors. We are so lucky he did this. Maybe we could help someone else find their granddad. Thanks Hugh!
The next photo below is all the sailors in their dress uniforms, with officers standing behind them. This is believed to be taken during the commissioning ceremony for the boat.
In the above photo, based on the list below, we can tell Hughie is on the bottom row, number 40 if you count heads down from the top left row.
...As if he wasn't thorough enough, here's all the crewmen's signatures and where they're from!