G'day Geoff! Love what you're doing here but unfortunately I haven't really got the time to get involved at the moment.
In regards to the request in your first post though, Neal posted this great link to a USN training film about the construction of a WWII era diesel/electric sub:
It covers some of the fundamentals of a sub such as ballast ect.
I imagine you're fairly well along now but I hope it maybe of some use to ya.
