Someone invents a windmill powered "sailboat". This windmill generates
electricity that, in turn, charges batteries which are used to drive an
electric motor that turns a propeller in the water. The windmill can be
swiveled an any direction to face the wind.

What is it? I'd say it was a motorboat when underway using the electric
motor and the water propeller. But, if the windmill was turning charging up
the batteries and the boat's electric motor was turned off and it is
underway on a broad reach powered by the wind on the air propeller then it's
a sailboat.

Machinery is in use but not "propelling" machinery. Or since the windmill is
a machine can it be said that it is propelling machinery? If so, is not a
sail that winds up on the forestay or inside the mainmast also "machinery"
especially if it's wound up using electric motors which is often the case on
larger yachts. So should those yachts with roller furling be labeled
motorboats by virtue of the fact that propelling "machinery" is being used
to propel the vessel?

Now, do you see how lame is the contention that a yacht sailing alone with
working sail while the motor is idling and used to charge batteries while in
neutral is considered by the rules to be a motorboat. See how stupid your
argument is.

I hope this helps. I should have been a lawyer.

Wilbur Hubbard