I've been on both a German and US WWII sub(U-505 and USS Silversides).
My hat's off to your FIL, I could never have made it on a sub.
Guess we will have submarine sandwiches today...(Groan...too corny?).
Thanks to all who serve on subs. My neighbor is on a sub so I have first hand knowledge of the particular sacrifices they and their families make for our Country.