Lewmar Superhatch rebuild and lens replacement

[Williwaw_]

I’m rebuilding the Lewmar Super Hatches on my new to me 1986 Cal 33-2. I learned a lot from this site, so wanted to leave what I’ve learned in one place as it didn’t really exist all together anywhere else. Hoping this might help someone trying to do the same thing.

1. Remove hatch lids, all hardware and hinges and old lenses. The hinge pins can be knocked out gently with a hammer and a punch. Hinge removal is straight forward, but a bit tricky. A large, wide flathead will help with the T-nuts. Use a razor blade to separate the old silicone sealant from between the frame and lens, then pry the lens off the butyl tape that holds it into the top frame. Scrape as much silicone and butyl as possible, then clean with mineral spirits and fine grip sand paper. Try not to damage the factory anodizing on the aluminum frame. No great pictures here are is was messy, but here is how my lenses looked before:



2. I damaged the anodizing a bit during the sanding process and also noted that Lewmar used some type of greenish primer where the silicone is used. It was probably zinc chromate, nasty stuff. I sanded a lot of it off, and then masked and resprayed with a zinc phosphate primer I was able to find at West Marine made by Moeller.




3. Next was installing the new hatch seals. I bought it from hatchmasters.com along with the bonding cyanoacrylate. Using some plastic levers intended for car interior work helped a ton. Links here:

https://hatchmasters.com/product/lew...er-hatch-seal/
https://hatchmasters.com/product/si-...and-activator/

You simply cut them to length as squarely as possible (I used a new razor blade), and super glue them together. I found that cutting them just a little long, and then letting them compress together when they glued gave a nice joint. CA glue will not bridge a gap well, so get the cuts as close as possible.



4. The hatch seal combined with the lower flange in the frame provide the bonding surface for the new lens. I used new Bed-It butyl tape to bed the lens in. It’s sold by Hamilton Marine is Maine, good stuff.
https://shop.hamiltonmarine.com/prod...roll-4482.html


5. I brought my old lenses to be used as templates to a local plastics supplier/fabricator. The original lenses were a blue tint, which is not broadly available. I think if you care enough, you can still find places that can get the blue, but I switched over to gray for ease of access. Lewmar used 12mm thick cast acrylic lenses. I ordered ½” thick cast acrylic in medium gray (color number 2064). 2412 is also common and is a medium bronze. Oddly, the nominal thickness of ½” is actually 0.472” which = 12mm. I assume it’s actually 12mm acrylic. Being cast is important as opposed to extruded. Cost was very reasonable, and they cut them to shape for me and drilled them for another $80 in labor. Push the new lenses into the bedding butyl.


6. I re-masked the lenses, used a razor to cut away the tape over the channel between the acrylic and frame that needs to be silicone, and left them gently clamped overnight to seat the lenses into the butyl.


7. The next day I re-caulked the lens in place with Dow 795 in black. This stuff was generally the recommended product. One tube was enough to do the 3 hatches. I found the best way to fill the gap was to apply the silicone like spot wells, and move a ¼” at a time around the lens. Wait for it to slightly overfill and bubble over the top, them move on. I used my finger to smooth the joint.


8. peel masking, have a beer. The best tip I read as I researched was to “mask like a pro.” Arrange your tape with pull tabs and so that you can remove most of it with one continuous pull. I was covered in silicone, and the stuff forms a skin pretty quickly. You need to remove the masking as soon as you’re done smoothing the caulk.

Will post pictures when they’re back on the boat, but have a few other projects to finish up first, including a core repair from a leak around one of these hatches.

[lehulei]

Hi! I am looking to do the same to my hatches or replace them. I have an island packet 31 with 2 same size hatches and 1 small 10x10 like hatch.

Did you find an equivalent hatch to replace the super hatch?

[Febrio]

Thanks
I have 2 hatches, on my boat from 1984, that is leaking and it has been a serious problem finding gaskets for them, not to mention instructions how to replace them.
Then finding information where to by gaskets and everything else I need + the full process description to replace them ... pure happiness

[bstreep]

As the OP says, try www.hatchmasters.com. Tony is the best. He'll do them for you, if you like. Hatches can be "challenging". Great job!

[tkeithlu]

You do really pretty work, Williwaw. Thanks for posting.