Sir Gregory Hall, Esq. wrote:

That catamaran will not go directly to weather under wind
power alone. Just can't be done. There are simple accepted laws of physics
involved which the ignorant always wish could be circumvented but may not
be.

The ignorant fail to understand the simple accepted laws of physics,
and then misapply them. In considering the question whether a catamaran
can go directly upwind, using a propellor powered by a windmill, if it
were the case that this would violate the laws about conservation of
energy and/or momentum, or any other "accepted" laws, then it would
indeed be impossible.

But it doesn't, and therefore it is not necessarily impossible.

If you wish to claim that it would violate any laws, then let's see
you back up that claim with some acceptable reasoning.

You won't, because you can't.