Manatee Genset relocation II, hatch frame

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Joined
Oct 2, 2009
Messages
5,198
Location
USA
Vessel Name
Bucky
Vessel Make
Krogen Manatee 36 North Sea
I'm starting a separate thread here to organize a few photos of the hatch frame building process itself. This way, if you're having a contractor do your hatch frame, maybe you're not interested in the build process. If you are one to undertake the process yourself, I'll send you all I have, but suffice that this is a brief overview of the mold construction and plug process. You are building a female mold in which glass will be laid into, creating a removable raw fiberglass product which will become the finished hatch frame.

Start by studying the original factory lazarette hatch in your veranda. The shape, quality and strength should be equal or better. REMEMBER, you have cut a massive chunk of deck out of the center of your veranda. The strength of the frame and its attachment to the outer perimeter will determine whether or not your deck is solid or not. I could easily throw a piece of plywood over the cut-out and it was still more than enough strength to handle my 240 lb. frame, but near the salon doors, it's pretty skinny there. The strength of the frame has to make up for that.

The first photo is of the original lazarette hatch in your boat now. Pay attention to its construction....it's a good hatch. The second photo is of my 240 lbs. standing one foot on the newly installed frame, not even a creak. The remaining photos are of the construction process itself and the raw frame lying on the uncut deck. I chose to build the frame first so there was no mistake in the measuring of the cut.
 

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Frame construction continued:
 

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  • competed hatch frame.jpg
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OK, moving along here, the next issue is the conversion of the deck cut-out to the hatch cover itself. Teak Vinson looked at this for a long time, and in the end we decided to peal off all the balsa, all the foam, everything but the teak decking and the layer of fiberglass it was attached to, then build the rest of the hatch with divinicell coring, completely glassed over with two central mahogany reinforcement beams routed and glassed into the coring itself. The beams not only made the cover more rigid, but they also helped the whole assembly resist crowning (bowing) when all that resin soaked coring dried.

The result was an enormously strong component, something you could drive a loaded dump truck over without incident. In the end, it would have been easier and cheaper to simply build a new hatch cover. True, we saved the original teak decking, but spent a lot of time mating the decking and glass attached to the new materials. One other positive element was that with the old decking never being removed, the alignment of the deck boards never changed, and even the caulking was preserved.
 

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  • cross section showing lid base.jpg
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Continued from above, these photos briefly show the process of converting the old deck cut-out to the finished hatch cover, beginning with a 36 X 46 sheet of 2" divinycell adhered to the remaining original layer of glass and teak decking from the cut-out. For those of you who want the entire process, send me a PM, but this photo series should give you a pretty good idea of the process. Click on images to enlarge and clarify.
 

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  • rolling glass over mahogany reinforcement 3.jpg
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  • after resin 4.jpg
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  • smoothing putty 5 .jpg
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  • blocking down lid edges 6.jpg
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  • showing hatch bottom 7.jpg
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  • measuring final 8.jpg
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  • bottom of hatch lid 9.jpg
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