Questions re leak-proofing hatches, CD31

[Dean Abramson]

Our CD31 has two Bomar hatches.

What is the best sealant to use to fill tiny cracks in the existing sealer that surrounds the Lexan? This work will be done on the cabin top, from the top side of the hatches.

Exactly what type of gasket material do I buy to replace the rubber gasket in the groove on the underside of the hatch?

In researching this, we have found there are cast Bomar hatches and extruded Bomar hatches. I would guess ours is cast, but to be honest, I am not totally sure what this refers to. To me "cast" and "extruded" are terms referring to metal. But one thing I read seems to say that it refers to the Lexan part, and I have no ides what that could be about. ???

Can anyone help me out here? Help us be drier this year!

[Jim Walsh]

http://www.capedory.org/board/viewtopic.php?f=9&t=34245

If they are original they are cast Ocean Series Bomar hatches. They still make them today for a grand or so apiece. The component parts are all available if in need of replacement. Bomar sells a great replacement gasket by the foot which has a stripe of glue already in place. Just remove the old gasket, clean the surface, peel the tape covering the glue, and press in place. At the joint where the two ends meet just put a dab of contact cement on both ends and hold together for a few seconds.
You can also purchase gasket material, which is a 1/2” round EPDM cord from McMaster Carr, it comes on a reel, not by the foot. If you go that route it does not have the glue stripe so you will have to apply the contact cement yourself.
In my opinion the Bomar product is superior for use on the hatches. It is 9/16” not 1/2”. It is available at Defenders and other sources.
https://www.defender.com/product3.jsp?p ... &id=834163
I have not had to fool with the lenses so I have no advice to share.

[Frenchy]

For bedding lexan, I used GE SCS2000 Silpruf. There is one other product recommended for this application but I don't
recall what it is offhand. I'm not sure how to go about patching an existing installation either. I'm pretty sure this stuff
doesn't stick to itself when already cured. It's a silicone product.
If the lens is leaking, I would remove it, clean the lexan and aluminum really well, wipe with isopropyl alcohol and rebed. - Jean

[Dean Abramson]

Thanks, Jim and Frenchy. Your assistance is much appreciated.

[John Stone]

Dean
We looked into this when we rebuilt the Far Reach. I don’t remember all the species. What I do remember is the sealant needs to be compatible with the lexan. I recall what was recommended was a two part sealant. Might have been made by Sika but not sure. End the end, we sent them off to hatchmasters. We upgraded from the the thin lexan to a thicker stronger acrylic. It stands a little proud of the frame which we wanted. Hatchmasters work was perfect. The hatches were totally rebuilt...like new. The price included a new gasket as well. The cost was about 2/3rds the price of a new hatch.

[Dean Abramson]

Thanks, John.

[Frenchy]

Yes, John is referring to Sikaflex 205. It needs a primer and an activator for the primer. The GE doesn't need either - Just a
wipe with isopropyl alcohol. - Jean

[Dean Abramson]

Thanks, Jean.

What I've got are extremely small fissures in the sealant around the Lexan. I think I will TRY forcing a bit of silicone into the cracks. My guess is that it can't hurt to try . . . ???

Before doing this, does anyone recommend wiping with anything in particular? Really, I'd be wiping the surrounding areas, because there is no wiping in these tiny cracks.

The boat launches in three weeks; I can't send the hatches away. And I am not ready to re-bed, because I'm not sure I'm even getting leaks from the sealant part. We are going to replace the rubber gaskets on both hatches, and see where we are after that. We do not have bad leaks at all. In fact, this half of the crew thinks they are quite tolerable . . .

[Frenchy]

Doing an internet search on painting silicone caulk, I found a suggestion to wipe the caulk with alcohol (this supposedly
roughens it up a bit) then apply a siliconized acrylic latex caulk. The acrylic latex will stick to the silicone, from what I read.
It is paintable. Personally, I wouldn't trust it for sealing leaks, though. Good luck in any case - Jean

[Dean Abramson]

Thanks, Jean.

Do you know of a brand of siliconized acrylic latex caulk? I ask because I have less than zero knowledge of chemistry, and my experience is that often product descriptions online or on packaging don't always have the exact words I'm looking for.

My chemistry teacher passed me solely to be rid of me the following year.

[Dean Abramson]

Jean, I found some of that caulk online.

Thanks again for your help.

[Sea Hunt Video]

Hello Dean:

In the March 2019 issue of Practical Sailor there is a 4 page article reviewing various adhesive sealants (they rate 10 - 3M, Sika, etc.). I am not sure if this is exactly what you are looking for but I am happy to send the article to Marvo. If she wants to give it to you that would be her decision.

[Dean Abramson]

That’s okay, Robert. I’m all set. Thanks.

[Gary M]

Years ago I tried this on leaking forward facing windows of a pilot house sail boat.

https://www.westmarine.com/buy/captain- ... nt--243990

It worked and the leak was still gone 8 or 10 years later when I sold the boat.

Good Luck

Gary

[Dean Abramson]

Thanks, Gary. I have heard of that stuff, but not in a very long time. But seems like I had heard positive reports before.

Did you use the Tolley's on cracks in the existing sealer?