ButterFly Hatch

[Tony Bilello]

I finally started my Butterfly Hatch.
I have a few questions…First question is, When the ‘wings’ are closed, what is the best way to seal out the rain? Do I make a false inner lip and route out a recess on the wing / door or do I just add strip as an overhang or what other alternatives do you suggest. This is not a very big hatch. It is roughly
22 ½ inches square.
My next question is regarding the lexan. Do I just rabbit out the wings/doors and set the lexan in place flush with the surface? . What would I use for caulking? The individual windows are only about 6” X 8”, will ¼” be strong enough? Should I add Stainless Steel bars as a guard above the Lexan?

Thanks in advance.

[Frank Hagan]

I don't have any experience with the butterfly hatch, other than hearing they are a bear to get waterproof. Can't be of much help there!

But for setting the lexan, I would use a sealant designed for boat use, such as LifeCaulk, etc. You do have to avoid polysulfide and polyurethane based sealants that will cause the lexan to crack (see this article by expert Don Casey on sealants). The exception is when the label says you can use it on lexan ... 3M 4200 says its OK for "most plastics", but it is a polyurethane, so I'm not sure its acceptable for lexan.

Guards on top of the hatch are to deflect things like gin poles, heavy shackles, etc. that might smack the hatch and crack the plastic. And for looks, of course.

[David Sharp]

Most marine hatches that I've seen and built are like the drawing on the right with a rabbit around the outside of the base and a rabbit on the inside of the top. You might want to use safety glass. Lexan does not look too good after a couple of years in the sun, unless it has improved. I got out of the boat bus. about 20 years ago. I'm down the coast in Freeport-lake jackson. I'm not a big fan of 3m 5200 if you ever need to get it apart your @#$ed. I'd second the idea on lifecaulk. Are you going to use stainless piano hinge?

[Tony Bilello]

Frank: Thanks for the link on sealants. It will be very helpful. I think I will go with the Lifecaulk.

David: We are close enough to be neighbors in a texas size state.
I have been kicking around the safety glass idea, since I been to busy to get back to my project, I have a little more time. I will be using Stainles Steel piano hinges and have some rough ideas I received from others about using a split pipe as a trough of sorts to catch the leaking water through the piano hinge and running it to the ouside of the 'box'.