New Japanese "electric sailboat". I had high hopes but I'm STILL...

waiting for someone to do what seems obvious to me.....

integrate the batteries into the ballast/keel design.

Either one central box keel, maybe with a center board and a box keel fat enough for the board and a row of bats on either side....

or

bilge keels.

I don't think having the bats down under the water line in the keel or bilge is a big design issue, any more than low mounted engine. Just put them in tough water tight bags with schnorkle with the power cables.


http://www.zenboat.jp/category/electric/

 

How do you service batteries that deep in the hull, and relative to the normal ballast weight, the batteries just aren't a significant amount of weight.

I see this as an interesting idea, but not worth the effort. To little gain for too many problems.

 

Best to put the batteries low in the hull itself, under the cabin sole, if possible, but not in the keel. They will definitely add to stability, as they are heavy. But they are not heavy enough for outside ballast.

Remember. A ballast keel adds buoyancy as well as counter weight. The volume of such must be multiplied by the weight of water then subtracted from the actual weight of the keel. What is left is how much effective counterweight you're going to have, as long as the keel is immersed. Ballast keels are almost always made of the densest materials available for this reason.