Welcome to Subsim Foibleson.
Great Introduction. your . Silent Hunter 4 and 5 are much better and it's really a matter of preference. As U crank said, If you have any questions regarding your simulations, just ask the community here.
As U Crank and Eichhörnchen said, thanks for sharing your grandfather's experiences. As JimBuna also said, A big Salute and word of thanks to your grandfather as well.
Enjoy your time here and your sims.