got its name from the famous
racing yacht Dorade,
designed by Olin Stephens in the
The cowl vent has long been regarded as one of the best way to get air
However, the cowl on its own was just as efficient at funneling rain
as it was air, until Stephens' innovation.
of the Dorade
Box is to allow the air to
pass below while trapping any water and allowing it to drain
The amount of air flowing below is dependent on the size
of the bell shaped cowl opening.
There is a formula for working
out how much ventilation
will be provided by a particular size of cowl.
However, the number of vents
you have and where they are
sited on deck will determine what areas of your boat will be aired.
A pair of cowls will create a
flow of air throughout the
boat if fitted at either end of the boat with one facing forward and
But in practice where you fit
the vents and how many you
have will depend on the size of your boat and the space available.
As with most things on a boat it will
probably be a compromise.
Suffice to say that the more
you have and the larger the
cowl opening the more air will flow below.
a small boat where deck
space is limited it is worth
considering the plastic dorades such as those made by Vetus.
They come in a variety of
sizes and are light,
functional, compact, the flexible plastic is less likely to foul lines
more friendly to bare shins and toes.
One problem with the plastic
ones is that they tend to
discolor in strong sunlight, fortunately this can be remedied by
the paint used for coating vinyl plastic and PVC.
However, if you are reluctant
to spoil the looks of your
wooden with plastic bits on her deck, a wooden dorade box complete with
cowl will be an ornament to be proud of.
Or you could compromise by
fitting a 'toe friendly' plastic
cowl to a wooden box.
The shape and size of your box will have to depend on the space
where you want to site it.
But it will need to be of,
Have an internal baffle,
Have sufficient drainage to
allow water to out without
unduly reducing the air flow,
A method of controlling the
air flow from the
A mesh screen to filter the
Cowl necks long enough to
avoid any deck
The scoops should be free
to turn through 360
With a bit of thought, at the
design stage the box could
double up as a place to site your navigation lights or with a couple of
somewhere to store the boat hook or any non load bearing hardware.
“The cruising life isn't for all of us.
It isn't even for most of us, but it is for some of us, and for a few of us it is essential to survival.”