Unfortunately they've made it very VERY clear that they aren't going to release the source code. I think there may be some "CLASSIFIED" stuff in there or something that they use in the actual navy training sims that they make that they don't want to get out.
I'm not entirely sure of the reasons, but they've made it clear that they don't want ANYONE modifying their source code.
Anything not source code (New ships/aircraft/models/weapons/sensors/database stuff is okay. Drivable platforms though, they made it VERY clear that adding those is a BIG no no.)
I would LOVE to see a Dangerous Water II, but I doubt it's going to happen considering what's going on with Sonalysts now. I don't think we can expect many "public" sims released from them anymore. Unfortunately, Dangerous Waters also flopped on the market so there's not much finacial push for another one either.