Homerjack, here is what I did recently on my 1989 22.
1. Removed hatch, 12 screws plus 6 more at hinges
2. Scraped all old sealant off cabin roof, didn’t seem like enough?
3. Cleared underside of hatch of old sealant
4. Injected “gitrot” into balsa surrounding the Full opening, some soft spots, didn’t want to pull it all out and re-do with new balsa as soft spots were only in one corner. Also brushed gitrot around complete opening to seal balsa.
5 When gitrot dried, sealed opening with 5200 to keep water out since cutout was larger than hatch.
6. Over drilled the 12 holes and filled with epoxy.
7. Re-drilled the holes down through bottom layer of glass to use bolts vs screws. Used hatch as guide.
8. Placed a layer of “butyl tape” on under side of hatch
9. Inserted screws through hatch/butyl and wrapped the protruding part with small amount of butyl.
10. Filled pre-drilled holes with 4200
11. Placed hatch in position and pushed bolts through
12. Tightened bolts/nuts to firm, waited 24 hours then re tightened, butyl squeezed out slightly, so I knew I had good seal. Used stainless nuts and bolts , with medium sized washer.
Now I need to tackle the leaking wood handrail screws, winter project. Never ending, the joys of an older boat!
Curt