We're doing the marine electronics thing. The best way we've discovered to make stuff water/bomb proof is encapsulation epoxy
(Looking around to see if the moderators are watching..)
Here's an example..
We use aluminum or delrin molds. We like delrin better. The trick is to solder m/f standoffs to the PC board then use these to bolt the pc board into the mold. Pour in the resin, let it kick and the mounting screws end up being your contacts.
Another example, from my past life is the water injection valve for performance boats : Injection valve construction.
There's also potting boxes you can get from different electronic houses. We've used those as well. Put in your electronic goodies and pour the resin in filling up to the top.
A potting box example would be (Also from Banderlog) :
These are nice because here is no tooling to develop. Just choose size fits your stuff.
If you ned to pass a wire out of a resin block you will need some kind of protection for where it passes out of the block. A simple way to do this is with heat shrink. A few layers of heat shrink makes a nice cushion for this.
Heat shrink cushion.
Expresspcb.com, they are the bomb! We use them for everything. Really tough to beat their service.
Anyway, hope this helps.