Dorades

I know I’ve been very remiss in writing lately, and there is a ton to catch up on. But just because we haven’t been updating, doesn’t mean the progress has stopped! So with the cold weather upon us, it’s time to play catch up and tell you about some of the projects we recently completed.

Installing our dorade boxes has long been at the top of our list. Originally designed by Rod Stephens and named for the first boat on which they appeared in the early 1930s, dorades are a great way to increase airflow down below, especially when you are underway or in heavy weather.


Basic design of a dorade box. Air (and possibly water) flow into the cowl vent and into the dorade box. Water is (hopefully) blocked by the through-deck pipe, and then exits through a drain hole. Air is shuttled down below through the deck pipe.

We decided to go with 6, 4-inch dorade vents – 2 in each cabin, all of which Bill made out of Brazilian teak (camaru). Bill made baffled dorade boxes for the forward and main cabins.
 

Inside foredeck dorade box with baffles

The 2 on the main cabin were sized to maximize 4-inch cowl vents. The 2 on the foredeck are taller and larger so they can accommodate 5-inch cowlings if we want to upgrade down the road. The taller dorade also helps catch more air that could otherwise be blocked by the bullwarks and bowsprit.



Checking for placement of foredeck and main cabin dorades. Note the size difference between the two sets

Since we have less deck space to play with on our aft cabin top, Bill made straight dorade boxes (no baffles) for this location with mushroom vents underneath so we can close them off as needed.


Mushroom vent without box on top

Constructing the boxes were just part of the process – the real fun came with the installation! We used schedule 40 PVC pipe with a 4-inch ID for the through-deck pipe, and needed a 4 ½ inch hole saw to allow for the OD of the pipe. To help minimize the drill kickback with this size hole saw, Bill drilled the holes with the motor in reverse. It was a slower, yet safer way to drill through the deck (though make sure your hole saw is very sharp).


Box placement taped and pilot hole marked -- ready for drilling

No kickback here!



Deck thickness removed

Once the holes were cut, we sealed the deck with epoxy, then dry fit the pipe to check for fit.



Checking for fit

The top of the pipe was then cut with a “French green bean” cut to help keep any water out of the pipe. The finished through-deck pipe was caulked into place, and we were ready to cover the pipes with the dorade boxes.


Through deck pipe cut and caulked in place

To allow for easier removal of the boxes in the future (for maintenance, deck repairs, repainting, etc.) Bill affixed camaru strips to the deck to serve as cleats for the boxes, and screwed the boxes to the cleats. A nice bead of caulk around the base of the boxes sealed them, and they were ready for 3 coats of Cetol (Natural).



Cleated, caulked and Cetol

Since we have a ton of mud wasps here in the Chesapeake in the summer, we purchased Nicro insect screens and installed them on the inside of the cowling vents. We’ve seen many boats install them in the ceiling down below, but in most cases, the wasps simply next inside the box and/or pipe – not only creating a mess and a nuisance, but reducing (sometimes totally blocking) the much needed airflow in the process.



Screens in place at the dock. They are easily removed when underway or at anchor to increase airflow

And to finish the look, down below, we installed teak trim rings to the ceiling.



Mushroom vent in the ceiling without the trim ring



Teak trim ring

Now that they are in place, I can definitely say that they look great and you can feel some increase in airflow; though it’s still only a fraction of what you would get from a well placed hatch or opening port. If you had to choose between the two, we would recommend going with a hatch with a good sea hood rather than a dorade. But if you have the deck space or want them as part of an overall ventilation system, they are well worth the chore of installation.

We still need to make dorade guards for the two vents on the foredeck to prevent the sheet leads from catching on the cowlings, but that will be another story...