[PaulK]

It does not seem to be any of the designs between 21 and 22 feet long in the Sailboatdata listings. Another picture of the boat from the side, showing the profile and the whole mast and boom might be helpful.  If the sail has an insignia on it, that might provide another clue.  Did you look for a HIN number?  They are usually on the upper starboard side of the transom.  HIN numbers were started in the 1970’s, so boats that don’t have them would be before then. They indicate the builder, the design and when they were built.  In any case it  looks like the first thing to do is to wash the bottom. The growth there is really slowing you down!!