According to Google, "Hy" is also an abbreviation for Henry. In this context, I think that name may be more likely. In the image you shared of the yacht registry, his last name is spelled with two "o"s. (You typed his name as Walcott in your post.)

Using that registry name, and an old newspaper database, I find that there were probably several "Henry S. Wolcott"s running around during the turn of the century. Adding the word yacht to my search, did not turn up anything. The most prominent one was a Republican politician who ran for governor of Colorado in 1898. Promising candidate, but Colorado has no coast or very large lakes, so maybe a dead end.