Flush hatches: mixed success

Thanks to good advice and encouragement here in forum I’ve done my flush hatches and the spacers and mounting ring. 

Did them in sequence, as I’ve learned to do in this project, so that mistakes can be learned from and adjustments made.  As an outcome, second hatch (forward) is practically perfect without any rework – a clean cut, fair lines, drops into the spacers perfectly, and perfect camber.  Camber was slightly different on the for’d and aft edges and neither is exactly the spec, so it took some finagling building the form.  I’m all set to do “invisible” closure with bungees and have this literally “disappear into the woodwork”.

Went first with the aft hatch, where I learned a few things…  Only ongoing concern is that the camber is just a tad flatter than the deck.  It’s rigid as heck after lamination.  I’m thinking I need to go with dogs around the edge to pull the edges down the mm or so…  I don’t think “invisible” (which pulls from the middle) would work out well.  but I’m bothered by the thought of having invisible forward and dogs aft.

The options I see:

-Could try an invisible bungee system that pulls on the edges?

-Get over the esthetic quandry and finish the boat with two different systems

-Dogs forward and aft

-Delaminate the aft hatch and try again (ugh!)

Thoughts from the group?

3 replies:

« Previous Post       List of Posts       Next Post »

RE: Flush hatches: mixed success

Hi Andrew, 

first, don't get over the aesthetics....it's important to you and that's ok. 

i would look for a system that pulls down by the edges......and frankly, even if i did not have the problem you are describing, i would want my system pulling the edges, and not the center.

the only other idea i have for you (and its tough becuase you did not include a picture), is if the hatch has a little form to lock the camber in, i would try removing the form, shape it to adjust the camber and reglue the hatch to the form with, obviously, some pressure to increase the camber.   this can probably address something in the neighborhood of a couple mm of misalignment.




RE: Flush hatches: mixed success

I put the wooden hooks towards the edges of my WD12 hatch cover and it's worked fine for 13 years.


RE: Flush hatches: mixed success

   I've done invisible bungee hold-downs on a Chess 17 and a Shearwater Sport.  The basic set up looks very much like Laszlo's.  The Shearwater was easy, as the hatches are flat.  The Chess was much more difficult due to the highly cambered deck, but not all that bad. On the Chess I completely built and glassed the boat prior to cutting out the hatches, then pretty much self-manufactured the hatch under-rings even though I started with the “invisible” kit.  I included an area for the gasket and an inner lip to support the hatch at the correct (flush) height when snugged down.  On the larger hatch I even glued a strip of thin ply (about 1 inch wide) under the deck further forward and aft of the hatch ring that extended from edge to edge all the way across the boat, just for (probably unnecessary) added strength.

The hatch lids sprung back flatter when cut out.  Prior to gluing stongbacks onto the hatch lid I carefully observed the curvature of the strongbacks with the hull, trying all kinds of eyeballing and taped-on cardboard methods. I manufactured extra, smaller strongbacks and put one towards either end of the hatch lid, and cut my hold-down hooks right into the outer ends of the center strongback. If you do this, use a dremmel or something to cut the hooks in AFTER after the hatch is completed, otherwise the ends of the strongback will become too weak to help shape the lid when gluing up – I found this out the hard way, and thus spoiled and had to re-cut a new strongback.  Of course, you could make separate hooks as pictured by Laszlo, and as I did on the Shearwater.  On one end the boat the curvature of the as-supplied kit strongbacks was a good match.  On the other they required some modification, and even so, once I glued the thing up I still wasn’t happy with the fit, and used a heat gun to remove a stronbgack, re-shape and re-glue. Lots of creative clamping required throughout the process.

I’m not sure how Laszlo’s bungee system works.  For mine I put 2 small blocks of wood with two holes in each, one glued at the turn of the “bilge” near each chine.  Then the bungee forms a continuous loop through the two blocks. This helps open up the storage area below, as you stack stuff right on top of the bungee.  I suppose a whole lot of stuff crammed in there might create a stronger hold-down force/make it harder to engage the loops under the hatch, but I’ve never noticed any big difference.  I also spent a long time in the Ace hardware aisle (better selection) choosing some gasket material that appeared to be just the right thickness, density and sealing surface edge (some have nice little ridges from which to choose). 

Bottom line, I really like my invisible hatch hold downs and have never shipped water. It does take a little bit of experience to get the knack of reaching in under the lip of the hatch to place the bungees during the closing/opening process, but no big deal. If I was going to paddle open ocean to Alaska or something I might go for some over-straps or toggles to ensure that no wave could possibly knock the hatch off, but for my purposes these hold securely and have been absolutely leak free.  


« Previous Post     List of Posts     Next Post »

Please login or register to post a reply.