Flush mount hatches?

I am working toward making my hatches flush mount.  My cover does not have quite enough curve so I am not going to be able to get the bungie system to work.  What other systems have the folks here used and what results?  I looked at the pictures here on the web site of the turn latches but could not tell, are they plastic, wood or what.  Will they compress the foam gasket significantly or does the foam have to be trimmed so that is is the proper hight?  Placing straps across the deck sort of defeats the purpose of the flush mount hatch, but I can do that if I have to.

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RE: Flush mount hatches?

It might be worthwhile to remove the offending ribs (if that is how you are holding the radius) and replace them with ones that have a tighter radius so that a bungie system will work.  A heat gun should work to remove the old ribs then you can cut new ones from any 1/4" material.  Don't rely on spring clamps when gluing the ribs to the hatch.  With a couple of well placed small wood wedges you can utilize a "C" clamp on the outer tips of the ribs to ensure a proper tight hold.  Spring clamps just can't pull the two together and I think that is where most folks lose that bit of radius that either makes or breaks a nice tight fitting flush hatch.  For my flush mounted hatches on my MC16.5, I used a full 3/4" thick centre rib and two 1/4" outer ribs.  The 3/4" stock really holds the radius and also gives you something substantial to attach a hook to hold the bungie

Hope it works out.

Chris 

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RE: Flush mount hatches?

Thor,

Which boat are you building?

I used a flush hatch for the first time on my recent Wood Duck 12 (on which the hatch is supposed to be flat so I can't help you with the curve question). The only problem I ran into was with the weather-stripping. The stuff supplied with the kit was so thick that the hatch cover sat too high unless the hold-downs were way too tight, so I split it down the middle with an exacto knife.

The turn latches on the Wood Ducks are wood. I used internal bungees so I don't know how well the latches work.

I'm also looking at replacing the weatherstripping. That stuff is open cell foam which is great for stopping air flow, but not so good for water. It turns into a soggy sponge which then drips into the cargo space. I'm looking at replacing it with closed-cell foam.

Good luck,

Laszlo 

RE: Flush mount hatches?

Good points from Laszlo.  Even with closed cell foam, I would not be too concerned that the initial thickness might be a bit substantial.  After a few days with the hatch pulled down tightly with bungies it seems to compress and have have a bit of memory.  I found this on my hatches and I'm thinking of adding a thicker strip as the ones I installed made the hatches flush at the beginning of season but had sunk some by fall (even with removing the hatches always during storage).

Chris 

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RE: Flush mount hatches?

I am building the Chesapeak 17 and I clamped the hatch properly, but made my ribs the "exact" radius of the hull as a result the edge that is not supported by the rib sits about 1\8 to 1\4 high when the center of the radius is flush.  Granted, this is not really significant but it aint perfect either.  At this point I can't start over because we have a deadline for a trip that is scheduled up in Canada.  I am using 1/2 closed cell rubber gasket and it is fairly stiff so should seal well.

RE: Flush mount hatches?

I had the same problem on my CH16's...but only on the front hatches where the radius is tighter.  After some mess'n around trial and error I finally got the ribs to the right radius and a perfect seal (had to use c-clamps - that's a must).

If your edges are flared up you may get some leakage especially with a flush mount. 

Where in Canada are you headed?

Chris 

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RE: Flush mount hatches?

Interesting, I never put ribs on my hatches.  Though they do leak a little bit, it's not nearly as bad as I would have expected.  (A couple of cups of water total for a two or three hour trip.)  I'd imagine if I'd actually put the ribs on my hatches, the boat would literally be bone dry on the inside.

 

FrankP 

RE: Flush mount hatches?

We are scheduled to paddle through the Bowron (sp?) lakes at the end of July.  Our scout troop is building 6 kayaks currently for the trip.  A total of 10 people are scheduled to go so far.  This is my first trip but I am told that it will take about 7 days to complete the circut through the 5 lakes that make up the camping tour.  We have a test run for the boats scheduled for mid June, and as you can tell, the construction on some of the boats is not yet done.  I anticipate that I will have to go with wobbly hatches until I get back and get a chance to further engineer  a solution.

RE: Flush mount hatches?

Here's a shot from inside the front hatch of my Mill Creek. I'll be installing the bungie toogle adjuster idea that someobe posted recently.

RE: Flush mount hatches?

Wow, you must be really small to be able to fit inside that hatch and take a picture.

RE: Flush mount hatches?

Here is a link to an article about our project

http://www.greatfallstribune.com/apps/pbcs.dll/article?AID=2008805270308

RE: Flush mount hatches?

Lazlo, yeah I threw out the kit supplied weatherstripping. It was useless for my Shearwater flush hatches. What I did use was the white waterproof weatherstripping, I doubled up 3/8" twice around my hatch rims. The 3/4" stuff is clearly intended for the Chesapeakes. Now my hatches are perfectly flush, and water tight and I did have the boat upside down to find out just how tight they were. I sent CLC an email about this weatherstripping situation. Didn't get a response, so I do not know if they have made corrections to kit supplied materials.

Another thing I did different from the kit was I did not carve holes on both sides of the hatches for what is referred to as 'drain' holes for the hatch rims. I could not bring myself to do that to the boat and it has proven to be unnecessary.

I can take a couple pics if someone wants to see this setup done right.

RE: Flush mount hatches?

I did flush mount hatches myself on shearwater 17 hybrid. I epoxied my wood strips on the underside lengthwise to attach the brass hooks to. I did not use the rims, just the hatch sills, then tossed the thick foam gasket supplied with the kit and used some thinner rubber foam gasket material intended for doorways that I had a roll of previously unused. I attached the gasket directly to the hatch sills and it works just fine, so far.

 

 http://drw-hobbies.blogspot.com/

RE: Flush mount hatches?

You might want to consider this unique way of securing hatches from Shearwater:

http://www.shearwater-boats.com/Knobhatchkit.htm

I used it on my Ches. 17LT and it worked fine!

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