Fiberglass companionway hatch construction DONE

Paul Moir

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Nov 5, 2002
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A year and a half ago my brother lost his sliding companionway hatch from his sailboat during a hurricane. At last, we're looking at making a replacement for it. A little research showed it was a fairly simple affair, essentially a ']' shaped fiberglass section about 36" long with some simple wooden cutouts to key into the hatch slides. The only pictures I could find of a Shark 24's hatch were on pages 4 & 5 of this PDF:<br />Shark resoration photos, click here (1.2MB). <br />The original cover was a little flimsy - it would buckle if you put your weight on it, but it would bounce back to shape.<br /><br />Principally, what I would like to know is what is the best way to go about building a new one. The way I see it, I could build a mould and lay it up like the factory doubtless did. Or I could construct a flimsy core and lay a few layers of woven roving over it to make it strong and durable, then smooth and sand and I suppose paint it.<br /><br />I'm thinking of sticking with epoxy for this since it's a relatively small part so there's really no significant cost advantage with poly. I've only done a little fiberglass work in the past so I'm hoping this will be a learning experiance. In that vein if one of those two methods would be more time-consuming but also more educational, I would prefer to go with the more interesting route.<br /><br />Thanks for your advice!
 

daveswaves

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Re: Fiberglass companionway hatch construction DONE

Hi Paul, interesting project. I would not duplicate the original unless you are trying to keep the boat original. You mentioned that the original buckled when you sit on it. Here is what I would suggest, cut plywood, bowed, stringers that would run transversely across the hatch, perhaps six stringers with 6 inch space between them. Frame the stringers out with 1 X ? pine ( not sure of the latch/groove detail so use appropriate width material) Skin the resulting frame and stringers with 1/4 ply, glue and screw the ply down, pre drill for the screws so as not to split the ply. When the hatch fits and slides like you want you could glass the finished product.
 

Paul Moir

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Re: Fiberglass companionway hatch construction DONE

Thanks for the idea daveswaves!<br />I (and he) has no desire to stick with the original design if there's room for improvements. I even tried talking him into diamond-plate but he wouldn't go for it. :D <br />Before going out to measure up the boat this year, I had imagined something like that - then I gave up on it. There is a stop at the end of the travel that goes across between the two sliders. That would interfere with anything that dropped down from the original hatch underside as you slid it forward. It also stops rainwater and spray from coming into the cockpit from forward. You can see it in this photo I took:<br />
upload.JPG
Click here if you can't see it. <br />But my notes say that this stop is 1-3/8" tall at it's narrowest, and I could probably easily take 3/4" out of it and it would still be just as effective. Then perhaps design the hatch an extra 3/4" taller. That would give me enough room to use 'stringers' 1" wide or so. Which, if reinforced with fiberglass, would be far stiffer than the original hatch.<br />Glass is going to be part of the equation at some point. The topside is cambered and if I don't at least put down a protection layer, I'm worried the plywood would check along the grain.
 

daveswaves

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Mar 22, 2002
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Re: Fiberglass companionway hatch construction DONE

I see what you mean Paul, I would still be tempted to construct a stringered "lid"/hatch. Perhaps you could leave the front stop in place and have the new hatch wider and slide on the top of the existing rails instead of in the groove. Build the hatch longer so that it overhangs the front stop and drop a flat plate down (4 in total) to ride in the existing groove, the hatch could be secured either open or closed with an overcenter latch or similar set up.
 

BillP

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Re: Fiberglass companionway hatch construction DONE

Paul,<br />Most companionway hatches only have structure around the edges. This keeps headroom under the hatch at max. Strength is made up by oversizing. I would use 1" clear fir for side frames (if you use them) and same for cross frames (one at each end). Arch them to give the top strength. 1/2" or 5/8" ply on top will be plenty. Using a large radi at the edges will give it more of a molded fiberglass look.<br /><br />Now is the time to get an extra inch or two headroom under the hatch if wanted. It's hard to tell from your pics the fine details but here's a scan out of an old book that shows cross sections for wood hatch (plank construction).<br /><br /><br />
2inln8
 

Paul Moir

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Re: Fiberglass companionway hatch construction DONE

Thanks! You don't know how useful your advice is to me. :) <br />I'm really starting to picture this thing now. There's no reason not to make it a little wider than the stock size - it really won't make any difference but a better hatch. Head room isn't much of a concern since there's only about 4'4" of it. The 24' is misleading since the Shark is very narrow. The boat weighs 2200lbs - which gives a better idea of size. DavesWave might be familiar with them as they were built up in Ontario, and they're pretty popular on the Lakes.<br /><br />But clearly I can't have any beams which are likely to catch one's noggin - which is something I hadn't thought about. It sure wouldn't be good to have my work cursed! If I do use a rib, I'll make it a half-rounded over 1" sized thing like on a cedarstrip runabout.<br /><br />In the interest of turning this into a real science project, I do have a vaccum pump and was thinking about vaccum bagging it. Do you think that would be good fun, or just a waste of time?
 

BillP

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Re: Fiberglass companionway hatch construction DONE

I remember Sharks by Hinterholler(sp), they made him famous and kicked butt on the racing circuit. Back in the mid 70s I met a solo sailer in the Bahamas on one. He cruised all through the Caribbean islands on his.<br /><br />I made wooden boat hatchs as above with fir and ply. Hammered them together with bronze ring nails and punched their heads down. Epoxy was used to glue before nailing. Then filled the head recesses and coated the entire hatch with epoxy sans glass fabric (I've also done it just coating with poly resin but it only lasted a few yrs before cracking). You can add pigment to the resin and have a no paint surface. A nice finishing touch is non skid added in the resin. I personally wouldn't worry about glass fabric or vacuum bagging...but there are many ways to make hatches.
 

Paul Moir

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Re: Fiberglass companionway hatch construction DONE

Great, thanks! I'll leave my glass education for another day then. Frankly, that really simplifies the project. What I really needed was a fiberglass-like look with a durable finish. I take it the pigments provide the UV protection the fiberglass needs?<br /><br />My brother's Shark is cosmetically in rough shape, but it's been getting better every year since he bought it - except for the hatch naturally, and the trailer (that's another story though which belongs in Stupid Human Tricks). But if you look closely at that picture you can see the mylar/kevlar mainsail poking out from under it's cover. It's kind of fun to have a 'sleeper' of a boat like that. But I think it would take a real masochist to want to live aboard one!
 

daveswaves

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Re: Fiberglass companionway hatch construction DONE

Paul, you should stick that yellow beast in your driveway on the back and see how fast she'l go. :D
 

Paul Moir

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Re: Fiberglass companionway hatch construction DONE

Well, I've almost got this project complete now. I don't want you to think that I ask for advice and then not follow it, but I ended up making it a fair bit lighter. My plan was to build it up until I felt it was strong enough and then encapsulate. I was able to walk across it without it deforming appreciably. And with no creaks or groans. This happend at about 3/8" thick with two peices of ply laminated together. <br /><br />For fun, I made up a little article over on the wonderful shareaproject.com website. Here's a link to it:<br /> Hatch project, click here.
 

tengals123

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Re: Fiberglass companionway hatch construction DONE

i think you did a nice job of it.<br /><br />cheers
 
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Re: Fiberglass companionway hatch construction DONE

Yes Paul, nice person, nice work. It has always been a dream of mine to visit Prince Edward Island. Do you think you could show me around if I make it back that far? It appears that it wasn't :eek: :eek:
 

Ralph 123

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Re: Fiberglass companionway hatch construction DONE

Nice work Paul. It's good to know that the eopxy alone will allow the wood to maintain a curve...that will come in handy some day I bet...
 

Paul Moir

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Re: Fiberglass companionway hatch construction DONE

Thanks folks! I brought it down for it's first fitting today (with my fingers crossed). I knew there was at least one cut to make but it looks like two instead. Which is not bad considering I just took a bunch of measurements in March and haven't been out to the boat since.<br /><br />technostupeedo, I'd be glad to show you around but I hardly ever get up to PEI anymore. It's very beautiful but odd corner of the world. I've been stuck to the eastern shore of NS for a while now for some reason...
 

BillP

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Re: Fiberglass companionway hatch construction DONE

Nice work Paul.
 

Paul Moir

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Re: Fiberglass companionway hatch construction DONE

Finally done! Four coats of Interlux Brightsides & spar varnish over epoxy. Came out real nice in the end and bagged a few compliments. (My favorite, "Did you have that fabricated locally?")<br />Thanks again BillP & daveswave for the ideas!<br /><br />
douvdh.jpg
<br /><br />Shareaproject site updated:<br /> http://www.shareaproject.com/pages/projectThumbs,p,93,00.html
 

Realgun

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Jul 31, 2003
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Re: Fiberglass companionway hatch construction DONE

Paul very nice job indeed now you have to paint the rest of the boat to match. <br /><br />Groan!!!! :D
 
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