If you follow the link I provided there are some comments from Halsey:
"The Eagle was planned and first built in the early 70s by Nowak & Williams of Bristol, Rhode Island, my home town. Initially, we designed the Herreshoff America catboat that proved to be a sturdy yacht of rather conventional catboat proportions but with a bit more sail than traditionally.
The Eagle hulls came from the same mold, but the rig was very different, having an effective headsail and optional topsail that enhanced performance in light air conditions. As expected, the Eagle proved a much better sailor than the Herreshoff America. I sailed these boats quite a few times. They were popular, but I dont remember how many were built by Nowak & Williams or the successor companies, Squadron Yachts of Bristol, Rhode Island or Nauset Marine of Orleans, Mass."