-Can you put the TL in a box ?
- Are there charging TL systems ?
I'll bet you could get a TL brain in an ebox. Prolly stick the relay in there or the coil, but not both. Waternut has expressed ideas of fabbing a clear, polycarbonate box with o'ring type seal for a TL setup. This would make it free and clear in salt...except for any connections you make downstream. I'd imagine it could be done without too much hassle.
Charging and TL are at opposite ends of the spectrum. I've never heard of such a wonderful, magnificent beast that provides TL programmability, hot spark, bottom end punch AAAAAND charges the battery as well. I'll ask Santa for one this Christmas.