[Public-list] Centre Hatch on 1965 A30

[Gordon Laco]

Hi Roger - 

The amount of ventilation you get through dorades is quite minimal.  However
a skylight hatch will blast a draft of wind down below, some people feel the
best set up is to have the skylight hinged forward so the when open the unit
tends to suck air out.  Combine that with the fore hatch open and scooping
air in and you have dramatically improved circulation.

The companionway tends to draw air in due to its being partly in the break
of the cabin... 

Gord #426







> I am trying to understand the need for an additional hatch in the main
> cabin.  With those four "picture windows", certainly there is plenty of
> natural light.  As for ventilation, the main hatch has to be at least 20% of
> the area of the overhead.  I suppose a second hatch would add to cross
> ventilation but so would a cowl vent with a dorade which could be used in
> all but the worst weather while under weigh.  Would it be feasible to
> install a dorade box (or two) at the aft end of the lower cabin top that
> ventilates the main cabin?
> 
> Roger 148
>


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