I owned a Holder 20 many years ago and lake sailed it in New Mexico. I really liked the boat and really wish I had never sold it. Nice sailing boat. The keel is a drop down that bolts in place so it is like having a keel boat when it is down. The only thing I didn''t like about our particular boat was that the companion way hatch was kind of difficult to secure.
If I find one for sail locally someday, I might just buy another one!