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the dream of dawn

How not to retrofit a hatch: Prelude

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Here I replace the old Ericson factory wooden box hatch with a new Lewmar #50 medium-profile hatch that I bought the last time they were on sale at WM. The complexity of this fiasco probably cannot be conveyed adequately in the three-photo limit. If it is to have any value, it would be in revealing what the inside of the structure looks like, for those who are tempted to try this in the future, on boats of similar vintage. So, this looks like another of those multi-part posts. Spoiler: it all works out in the end. More or less.

Problem: The old wooden box hatch always looked like an absurd mistake by a previous owner. But I guess it came that way. It was time to re-finish the wood again. I previously added the solar ventilator to it, but the fan is now dead too, even with fresh batteries. And the wood parts themselves are getting increasingly brittle and perhaps rotten in places.

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One obvious solution was simply to build a new wood hatch. But I opted to leap into the 20th century and put in a modern aluminum hatch, even though the cost makes it a "major" project in my Old Boat Budget world. Of course, it might be less than the cost of dinner at the club for some Yotties. The old hatch was secured to the boat by nothing more than a few wood screws securing the hinges into the deck. And some very tiny screws (and, apparently, a dab of 5200) securing the latch.

A note here for others with the old hatch: I hadn't previously paid a lot of attention to these hinges, but the relatively beefy hinge pins are held in with tiny, and in my case, fully corroded cotter pins that crumbled away when addressed. It is easy to imagine the whole hinge assembly falling away during adverse conditions, to disastrous results. Inspect your hinge pins! Inside the hatch, the deck rises to an inch-high lip that acts as a baffle to keep water out, and might even have a watertight gasket, on some boats. The first problem in fitting the new hatch is to cut away this lip and fabricate a new flat platform that will accept the new hatch in its place.
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The next problem is what to do on the interior. The interior liner has a little "riser" that mates into the riser of the deck, which forms the hatch platform. Nothing at all about this riser is straight or flat in any way. Whoever fashioned it in the first place must have felt quite smug and artistic about it. But it turns out to be a significant problem for future DIYers. A band of (rotten) wood trim hides the union of the deck and liner here. So a key issue is what lies beneath there, and what to do about it. Another key issue that will arise is how this area will be re-worked to trim-out the new hatch. All this and more will be revealed in the next episode!

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Spoiler: While I wasted quite a lot of time and thought trying to retrofit the existing structure, I now think that the best solution is to cut away the entire inner "riser" at the outset. Give yourself room to work and a nice clear space to build up new structure. Which I may do at the next haul-out when I hope to do extensive work on the deck. But that is not what happened this week...

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Updated 09-21-2018 at 10:52 AM by toddster

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  1. toddster's Avatar
    I see that other threads brought up but left unaddressed the issue of “medium profile” vs”ocean hatch.” The lens material, I believe, was the same thickness (and thicker than the “low profile” hatch) while the aluminum frame is thinner and probably not as robust. However two features pointed me toward the medium profile:
    1. The medium frame can be disassembled in the field to replace the lens, while the ocean hatch must be returned to the factory (per the Lewmar manual.)
    2. It was on sale for quite a lot less.