Jeff, the first yachts you see are models of boats that belonged to King Carlos of Portugal (1863 to 1908) and he was the last before King of Portugal
(see here)
King Carlos of Portugal was a sail fanatic and he would comission boats from all over the World, but this I am sure he oreded many built for him in Portugal, and built in portugal.
I also know that he never sold a boat, and many either sank or were destroyed when in 1910 when we became a Republic.
Some of the boats still exist and Amelia, his most famous yacht is still there.
He was know for getting his ideas from his Royal cousins in the UK.
However, and since that was the "line" of boats in the end of the 1800's early 1900's it could very well be that his draghtsmen got ideas from Herreshoff, whoi knows, or maybe Herreshoff designed it for him...???
Nicolson was later than that, so it couldn't be.
nevertheless wish we could make boats like that today...yes sir....
One day, time permiting I will go there and see who the designers were. But pretty sure most were designe in the Alfeite Atelier de MArinha