I missed your last 2:16 posts last night, I know I posted after it but I think i was already asleep.
I am of the tape and string school of engineering - ok hackery.
Thanks for your comments they have provoked more thought:
To paraphrase what I read in your comments
- silca gel can only keep mostly dry air dry, it can not soak up the ocean.
- I dont need to keep pressurised water out, just deal with splashes, and slow drips.
The bits in your comments that I am not sure how to implement are:
- the o-ring; all the places I have seen them used there has been a molded fitting into which they fit
- the long drive shaft - i can not work out how to remove the belt drive cog that came on the motors
, so fitting a shaft coupling is two stages beyond me I think.
However, a mixture of bilges and water drains seems possible. Could you pass your eye over this and comment?
1) have a relatively leak free hull, with a bilge pump in the hull if it leaks fast enuf to upset me during my day of playing. I expect some water carried into the winch area by the strings, and a tiny amount through the rudder seal.
(the small toy I play with now leaks about 1/2 inch of bilge water a day, but the electric components are raised 2 inches above the bilge, so stay dry). (this sounds worse than it is, as the hull narrows towards the bilge, it would need 10s as much water to get to 1 inch in the bilge and more again to be 2 inches deep).
2) have batteries in a sealed box in the bilges for best stability; since the batteries are rechargable just seal them in with bathroom sealant. Bend the wires in an S pattern to help them shed water from outside before they reach the seal.
3) put some foam low in the hull and above the bilge to ensure the boat floats when swamped. I think my toy would actually sink as it has a weighted keel and no pasative bouancy.
4) have isolated plastic boxes with control circuitry placed on the mid line of the hull so they lie above the swamped water line - each box with a drain hole in the bottom that drains into the central bilge, so water that follows wires into the box drains into the bilge. Again use S patterns between the box entry and the boards to shed water before it reaches the boards.
5) for the motors... use a drive cord to deliver the torque from inside the box at midline to the winche barrel mounted below them. Most of the water should follow the sail control cords onto the winch and drain into the bilge. Only a very small amount of water should transfer onto the drive belt to the motor. A thin plastic spray barrier between the drive cog and the motor should convince any that does make it into the motor box to fall to the bottom of the box and drain out the bottom.
ok enough of the elaborate plans for now,
Thanks very much for the suggestions,