[d--b]

The plan shows this had a keel though.

[ddingus]

What does that do?

Maybe allow choice of current, like where it forks?

[jussij]

I suspect the keel attempts to stops the barrel from rolling on it's axis.

If it had a tendency to easily roll it would be like trying to live in a giant tumble dryer.

[11235813213455]

stabilization, to avoid getting upside down all the time, he could have used ballasts as well