I have a 1965 T 27 hull #130 and there were no gaskets. I rebeded mine with butel tape. I unassembled the portal; outside aluminum extrusion, inside extrusion, barrel nuts and lense. I put the outside extrusion on my picnic table to work and filled the boatside of the aluminum with putty from the butel tape with the outside portion of the barrel nuts in place bedding around them. Hung the lenses in place with masking tape on the inside of the boat. Put the outside extrusion in place with the barrel nuts going through the holes around the opening. Put the inside extrusion on the inside with the other side of the barrel nuts meeting their counter parts on the outside and tightened them all going around a few times to make sure of evenness. I removed the tape leaving the unseen little bit under the inside extrusion. Two years; no leaks. If you use something like black G/E silicone from a tube which is fine if not better, leave a half turn on the barrel nuts to be tightened after cure for a good seal. You don't do that with the butel ( bad spelling I know ) tape because it doesn't cure. It stays soft. Hope this helped.
I'm getting some water leakage through one of the windows on my '76 Tartan 27. I'm planning to re-seat it and assume I'll find a crusty old seal or gasket under the frame. Any advice for replacing this?
