Now here's an interesting little thing worth trying...I was discussing this with Nigel (AMS Chairman) and between us we came up with this idea. May well be worth a try..
Ok, so we know that if Lipo batteries get wet, there will be a big bang in your wtc, which by it's very nature won't do your boat much good. And if your boat has been down a while, there's every chance that when it's rescued there will be water in the wtc...maybe it's not found it's way to the battery pack as yet, but as soon as it's tilted, the water may run to where the battery pack is...resulting in aforesaid big bang which may well cause damage to the rescuer as well as your boat.
Now, we also know that dropping a Lipo battery pack into salt water will kill the battery completely and render it harmless.
Ok, so how about adding salt to your wtc? No, I don't mean getting the salt cellar out of the kitchen and sprinkling everything with salt, but adding salt into water soluble bags and placing a couple at either end of the wtc...see what I mean? You can buy water soluble bags in any fishing tackle shop, or you can empty out a couple of dissolving tablets and fill them with salt.
Now, if your boat develops a major leak and water enters the wtc, it will start off a reaction which will melt your water soluble container, be it a bag or a tablet case, and the salt will mix with the water, which in theory will kill the battery pack before the big bang happens.
Please note that this theoretical and as yet hasn't been tested, but it may well be worth a try...it may well save your boat from destruction at the cost of a battery pack. Sounds like a good deal to me.