I'm new to the game (haven't even sunk a ship yet, 'cept for the tutorial), but I've been adding as many old-time 1930's and 40's tracks as I can find. I've been using the SH3 commander date folders to organize them by the correct date. So far I have about...100 or so tunes. Most of them I got from
http://www.u-boot.realsimulation.com/ but I also got others from various free sites.
In fact, I just recently found this site (below) with old-time propaganda music that was transmitted over to the US, Britain, and Canada. It's Charlie and His Orchestra by Karl Schwendler. I'm not sure if U-Boat captains would listen to it, but it sets the mood for me.
http://blog.wfmu.org/freeform/2005/0...e_and_his.html