Forget 18 knots, at least fully loaded with the ballast tank full, that is. But
it still does really well with a 50 hp motor. And it really sails well, too.
And for that reason, I say get a 9 hp motor only. The boat is a better sailing
vessel than it is a speed boat and it should be appreciated for that.

It's funny, my wife and I now sail a dinghy just about every weekend. We never
got a motor for it, because that would have only ruined it. Now that we've
learned to sail well (which we really didn't know how to do with our Mac), we
have no need for a motor.

I make this recommendation: if you've already ordered the boat with the 50 hp
motor, get it and use it as you like, but don't consider it a bad move to
remove it and switch to a 9 hp.

The Veridican