I don’t know how old is the one in this movie, but they were young indeed.
In the original Das Boot book by Lothar Buchheim the kaleun was around 30 if i recall well, but in the movie the actor seemed more around 40...
But some as Lehmann were younger (28 in 1939)
Prien was 31 in 1939...
As the war was going on, and with the losses, the olders were gone (sunk) and the recruitment was among young blood i believe
