Just a couple of things about the latest version of RFB.
1. I just finished a patrol in my sugar boat and it is now loaded with Mk 14s - wikipedia tells me that they were incompatible with the S-boats (
http://en.wikipedia.org/wiki/Mark_14_torpedo)
2. During the dive my boat will hang around periscope depth for a few minutes before speeding up the dive to rated depth.