I have been talking to Hollis/Oceanic tech support about an unrelated problem, and I ended up mailing the whole thing in to them to deal with that problem. (Fairly expensive postage, BTW ) As a part of our discussions, I mentioned this problem, and it sure seemed to be a surprise to the tech to whom I was speaking. I told them that it seemed to me that the whole problem could have been solved by making the body maybe an inch or so longer and moving the battery out that extra inch or two to balance it off. He really did seem interested. He said that if no one wanted to take the scooter into a cave because of that negative buoyancy, it sure would not do much to help their sales figures. He said he would pass my thoughts along to the engineering department.