Not the thread I was hoping to find, but a good one:

https://www.sailnet.com/forums/gear-m...e-windows.html

A lot of it will come down to what is holding the windows in place. Are they bolted or held by some other fastener? If so teh butyl tape may work, but personally I would not use it. If any structural integrity comes from the adhesive (the 4200 that came int eh kit) then you are not going to get them from the butyl tape.

Windos also tend to move, which is a point in favor of butyl tape actually, since it remains goopy forever.

Well, the re-bedding job is done. I used the butyl tape, and I think I achieved a good, water-tight seal all around each window. The butyl was very easy to work with, and clean-up of the residue was a cinch.

On the C22, the outside frame is pulled inwards by the use of screws that go from the inside frame to the outside frame thus bringing the two frames snug against the cabin sides. The screws are not exposed to the outside of the cabin, and they don't go through the cabin sides. I'm guessing that butyl will be a good choice for this job because of the flexing that most likely happens routinely on a boat such as the Catalina 22. When I removed the windows at the start of this project, two of the four windows had never leaked since I've owned the boat for 13 years. And the previous bedding compound (it might have been the original from the factory) was still gooey. Not bad for a 27 year old boat.

Our dockmaster here uses butyl tape for all similar applications, just as Maine Sail has discussed in previous threads. Time will tell if butyl tape was the right choice for this job.

Just wondering, should the window bolts be tightened just as much as deck hardware? For bedding deck hardware, you can't leave a 'gasket' by under tightening. Presumably there will be less movement if the bolts are snugged down.

I wouldn't overtighten the windows though. I have homedesigned bolts and nuts on my C&C 24 windows and don't seal well. I used 3M Ultra Glaze sealant and it is black and messy but sealed well. I wouldn't use 4200 or any silicone sealant as they don't work well on windows but I've heard nothing bad about butyl tape.

Since my windows are secured with Phillips-type screws, they can't be torqued down very much with an ordinary screwdriver. Thus the risk of squeezing out all of the sealant is minimized. But they appeared to have been tight enough to prevent them from shifting around too much.

As I stated earlier, two of the four windows had never leaked, and the sealant was still pliable. And the screws were about as tight as you would hope them to be. With my deck hardware, OTOH, they are through-bolted and torqued down pretty hard. Apples and oranges on this boat, I think. It might be different on a boat with through-bolted windows/ports.

There are acceptable silicones such as DC 795 - generally the silicones to avoid are those that smell like vinegar - like most available at Home Depot, for example.

Something else to look for while at the Depot, is window glazing shims or spacers. They keep the frame spaced away from the glazing at the thin edges, (see how they're usually used in this illustration by Lamateck) and they'll also keep the frame away from the flat glazing surfaces as the frame is tightened onto the glazing if used on the flat surfaces of the glazing at the edge. Cut them to appropriate size, or maybe wrap them around three sides at the edge of the glazing if they're flat and flexible.

The edge of the frame open to the elements needs a continuous bedding around it, so the spacers should be set back from this edge. With the spacers in place on both sides, inside and outside, of the glazing, tighten all you want (within reason ) and you won't squeeze out all the bedding, which would give a dry joint but one that leaks

The spacers are very important if you have glass glazing rather than Perspex (avoid Lexan - it clouds) as they allow flexing of the hull without stressing the glazing.

If you direct bolt the glazing onto the hull, oversize the holes in the glazing to avoid stress cracking/breakage of the glazing caused by hull flexing. Countersink the outside (top) of the hole, and pack with butyl tape to seal. (See Maine Sail's excellent write-up.)

Good luck and no leaks!