A better dorade box.

TomY

Alden Forum Moderator
Jun 22, 2004
2,758
Alden 38' Challenger yawl Rockport Harbor
Olin Stevens is reputed to have invented the dorade box ventilator shortly after DORADE (his design), was launched. Cowl vents used to pipe directly below which at sea can be a wet problem.

If you have ever spent time below in a stuffy cabin going to windward with a sea running - and you've been in the same conditions below in a boat with ample dorade box ventilators - you know dorade boxes, can't be beat.

They also keep a cabin well ventilated in a rain storm at anchor. And for a moored boat, there's no better way to ventilate and keep it dry, below decks.

I built 2 replacement boxes for the originals on my boat. The dovetails crafted originally (the old boxes to the right) were beautiful. But I'm not so sure dovetails are the best joint for pieces like this. And they are time consuming.

Plus there were a pair of added blocks to mine for tying down a dinghy and another for storing a danforth anchor. They are shot.

I kept the new ones, simple: Plain butt joints, epoxy, SS screws-plugs. Easy.

Material is an affordable tropical hardwood I can get locally($8.00/ bd. ft.) This stuff, after staining and varnishing, looks great.

To improve them, I used 1/2" thick Polycarbonate for the tops, for two reasons.

The standpipes inside that supply air to the cabin, will also act as dead lights.

We'll get extra sunlight in the head, and passageway between the saloon and forward cabin. Both those areas could use the extra light.

Plus the top or horizontal surface of anything on deck - that is bright wood, is the hardest to maintain because of UV damage. This will make the boxes much easier to care for.

Today was another rainy day on the coast of Maine; I put it to good use cutting and fitting the Lexan tops...

The Lexan front edges were cut to 20 degrees to match the boxes. Once a good fit on the front was had, the Lexan was cut 1/8" oversized, to overhang the other 3 edges.

Then: Clamp oversized piece precisely, and drill holes for screws + countersink. Fasten Lexan (dry), to boxes.

Once secured to box, trim the 1/8" off the 3 overhanging edges with a router and bottom roller trim bit.

Finish: Add a slight round over profile to the crisp edge (won't easily snag lines), hand shape the 20 degree.

Dorade boxes (1 of 1).jpg


Done. Now they're disassembled, for easy finishing. Once finished, the tops will be - bedded/ secured. I previously fine tuned the fit on the boat - check.

Here's a close up. I picked up the 1/2" Lexan from the local glass store (scraps, good deal).

The nickel plating is wearing off the 56 year old cowls and trim rings. I'll buff them up a little but by the time Xmas has a new owner, the cowls will probably be all green.

And the dog is pointing out the obvious: I need to spray the throats red, again.
Dorade boxes close (1 of 1).jpg
 
Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
Those look special, it would be nice to see a picture when they are installed.

All U Get
 
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TomY

Alden Forum Moderator
Jun 22, 2004
2,758
Alden 38' Challenger yawl Rockport Harbor
Those look special, it would be nice to see a picture when they are installed.

All U Get
I had the best help, my daughter, to install them this weekend. With the old boxes off, it was a good time to paint the cabin top. I took the handrails off too as I built and installed those a few years ago, to be easily removable. It was a breeze to put a few coats of varnish on them, sitting on a saw horse.

I'm trying my first roll of Butyl tape thanks to Mainesails advice. Those handrails are the perfect situation. I previously installed them with Boatlife Caulk which is messy.

Here's Mary Jane putting the butyl tape on the feet of the handrails.

Handrails butyl tape MJ (1 of 1).jpg


With MJ above decks and me below with drivers and fasteners, the freshly varnished handrails went back on easily.

Dorade boxes mounted  (1 of 1).jpg


Butyl tape on the dorade boxes as well and fastened from below the boat is again weather tight. The deck holes, that are the standpipes for the ventilators, used to be black holes below. Now the holes, as well as supplying a constant flow of fresh air, are lights in the ceiling. That extra light will be appreciated.
Dorade boxes mounted close up (1 of 1).jpg
 
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TomY

Alden Forum Moderator
Jun 22, 2004
2,758
Alden 38' Challenger yawl Rockport Harbor
Small detail, but here's the black hole now a deck light.
Stand pipe deck light (1 of 1).jpg
 
Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
Good idea for the light. Makes me think though, wasn't the purpose of having red throats to subdue light coming in. I got to swing into Mystic to find out.

All U Get
 

TomY

Alden Forum Moderator
Jun 22, 2004
2,758
Alden 38' Challenger yawl Rockport Harbor
Good idea for the light. Makes me think though, wasn't the purpose of having red throats to subdue light coming in. I got to swing into Mystic to find out.

All U Get
I'm curious what you find. There must be some history to the red interiors.

Painting the throats or interior of cowls red to cut light, may have been the reason - pre dorade boxes - when cowls opened directly below decks.

But with a dorade box, light - or no light - can't transmit through the cowls to the deck pipe. The design that prevents water from entering does the same to light. You have to be open to light directly above the standpipes.




The throats of cowl vents can be painted other colors (blue isn't too rare), although red seems to be the norm.
 
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May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
mine are red on the inside too. i have a question tom. what is the paper weight that is red and bronze that is holding down the cover to the mast hole?
 

TomY

Alden Forum Moderator
Jun 22, 2004
2,758
Alden 38' Challenger yawl Rockport Harbor
mine are red on the inside too. i have a question tom. what is the paper weight that is red and bronze that is holding down the cover to the mast hole?
That's just an anchor kellet, Jon. It won't do much for keeping your anchor set but it works well holding something down. :)
 
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May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
never seen one. i do not use any chain for my ground tackle here on the lakes. not even a short shot that is required to be carried for the mac races. there is nothing to chaff on on the lakes.
 

TomY

Alden Forum Moderator
Jun 22, 2004
2,758
Alden 38' Challenger yawl Rockport Harbor
never seen one. i do not use any chain for my ground tackle here on the lakes. not even a short shot that is required to be carried for the mac races. there is nothing to chaff on on the lakes.
The only time I use the kellet is in a packed, busy harbor(for instance, Block Island). The reason is to hold my nylon rode well below the surface. I have had a motor boater cut our rode once, in the middle of the night. It was on a lake in fact (Lake Champlain), and we ended up aground, briefly.

Crystal clear water, we found the anchor and what was left of the rode, in the morning.
 
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Jul 20, 2017
2
Alden 1949 32' Auxiliury Cutter Portland CT
Is the red interior just left over from the inside of Battle ships so the sailors would not notice the blood during battle?
 
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