The Trailer, I believe is a Tee-Nee. The rail the boat keel sits on is on almost all Tee-Nees. The winch support and round pipe under it look like there may have been some home-brew modifications, or someone may have swapped some Tee Nee structure onto something else.. Click on the link below and scroll down for brochures:
Dave
https://www.feathercraft.net/fc-info/10-catalogs/87-vintage-trailers
