Retract my original guess. The V21 did not have a pop-top. I'm now going with a MacGregor V22. I've also restored one of those...

here are some pics.
Does this boat have a raised gunwale on the foredeck (bow)? If so then it is a V22-2. Does it have a front window on the cabin?
If it is a V22 then the keel is 600# of cast iron and the winch would be just on the inside of the companionway hatch. The V21 has the winch in the cockpit. That should help you figure it out. But from the picture you posted, this looks like it has a pop top and the V21 did not have that feature.
I know that boat looks really nasty but truth is a good pressure wash will do it a wonder of good. On all the old boats I've restored, I'd rip out all of the rotten wood inside, then go inside with the shop vac in one hand and the pressure washer in the other. A few hours of work and I had a clean boat. Then cut some new bulkheads using the old ones as templates and you have a new boat. One long weekend of work plus a second to paint her once she is clean.