Well, it has to be a very well designed yacht, it has to be very well sailed and the modern boat has to be very poorly sailed, but yes you can say that.
That is about the same as saying that a very good driver can go faster on a twisting road with an old VW (you know the one from the 60's) than a poor driver with a brand new Porsche.
That is no proof that the 60's VW is faster then the Porsche, only that it is not enough to have a fast car, it is also needed to know how to drive it. The same with the boats.
Or, the new porsche is very difficult to drive fast as it is very demanding and uncomfortable (and breaks down a lot) and the old vw that is comfortable and reliable is easy to drive faster.