Tripp and Morgan had much in common. The Tripp Columbia 43, hull #1 had the Columbia 50 deck on it with that same cabin style. I own hull #4 for the last 40 years. Lots of info on the 43 here:http://hagothlog.blogspot.com/2012/07/columbia-43-little-history.html
Tripp did some interesting work with Dolf Le Comte back in the days like the ALC 35 MK 2, a lovely boat in my opinion. http://sailboatdata.com/viewrecord.asp?class_id=1647 They build them in the Netherlands and I believe that's where Koopmans got his style from.
Tripp's list of designs view_designer.asp