Ventilation - Dorades and ??

In port, a "ghost" is about as good as it gets for serious ventilation. No power needed. Just a simple fabric, box sail like structure whose lower end fits over a hatch.

 

Those are good, but what about rain? We also need ventilation underway. Angelique... Those stick up just like a dorade. I don't want to interrupt the boat's lines with big pipes or boxes above the deck.

So far, I am leaning toward using the unique benefits of a catamaran deckhouse to build in low profile vents like Steve suggested.

 

How about a nun;s hat or two, http://www.controlledjibe.com/tag/canvas-work/

 

I should specify... this thread is about all weather ventilation. Sorry if I wasn't clear. It's not about fabric scoops at anchor. It's about constant flow of air in any weather.

 

I used a custom made dorade box solution using floating balls to
close the vent for a project some years ago. See attached sketch. May be a solution?

 

Thanks, Tackwise. That's a nice setup. I have a spot where i can work something like that in.

 

Very clever Tackwise. Similar to two different cockpit scuppers I am familiar with.

I would add a true water trap and I don't see a drain for water in the ball chamber, also this involves a moving part.

Steve

 

It reminds me of the old ball snorkel.

 

The project I used the floating ball ventilation on was a very low profile sailing yacht.

I am trying to recall all the aspects of the project, here are some tips:

1) I used the info from http://www.winel.nl regarding ball diameter vs hole diameter. (Winel can supply the balls and gaskets loose)

2) You will need to provide restraints for any sideways movement of the ball. You can achieve this with the help of small rods (3-4) placed around the ball.

3) Be careful with the layout, as you need to keep an adequate amount of clear area for the ventilation air!

4) The floating ball only prevents flooding water from entering the vent. You will need to use the design of the lay-out and grill to prevent any splash water from entering the ventilation channel. And as Steve correctly noticed, a drainage needs to be added!

5) In case of really terrible weather you need to be able to close off the vent! I achieved that with a cover with gasket which I placed over the ventilation grill. (fixed with latches going through the ventilation grill.) However depending on the amount of room available other solutions are also possible.

Good luck!