Using dorade vents

The Pilothouse I have is nicely shaded, but originally, it had a split, tilt-out lower section in the windshield for ventilation at the helm. It was eliminated by the previous owner. Rather than redo the windshield, I'm thinking that dorade vents mounted on the cowl might be the ticket, particularly during rain when the dorades can be swiveled around and still draw ventilation air from the high-pressure area at the base of the windshield. Screens to filter bugs could be added if need be. It seems like a pretty easy mod. Am I not thinking of something obvious? We don't see dorades much anymore. Here's an example of a cowl mounted dorade.

They usually are mounted on a box with drains and water dams to allow air but keep out water. Not good for much IMO.

I put half moon zippered smileys in the top of my lexan windows.

I've always liked them . I built teak boxes with drains and baffels for my old sailboat . The Alaskan 49 I looked at the other day had four . Two on the forward deck that I think were for the anchor well and two on the roof for pilothouse . I think Ted took some off of his boat during his short haul refit .

Seems like dorades fell into disfavor as HVAC systems began appearing on more recreational yachts (sail and power), and as said vessels started spending their lives in marinas instead of at anchor or on a mooring. They are nice traditional features, though, functional and salty-looking, IMO. "Bayview" is right to note that they must drain and be configured to prevent water as well as undesirable fauna from entering. OTOH, they require less periodic maintenance than your average heat or a/c system!

I think solar vents do more than the traditional Dorades. I have used the mushroom vents and been VERY disappointed.

I had dorade boxes and vents on my 32' Halvorsen and if they provided any advantage at all, it went completely unnoticed by me. They are sexy looking though!

An opening pilothouse window provides lots of ventilation underway. Still, I've rarely needed/used it.

My IG has an original IG/Kong & Halvorsen teak dorade box with vent, mounted on the forward hatch. It works well, air gets in, but no water.
At one time I removed it and fitted a so called dorade vent with wind/water separation function,replacing the box with vent mounted on top. Big mistake, water entered the cabin via the vent,that never happened before, so the refinished dorade box and a replacement plastic vent were refitted, hey presto,no more water entry. The vent comes with a screw on cap to replace the cowl if conditions require.

Pack Mule said:

I've always liked them . I built teak boxes with drains and baffels for my old sailboat . The Alaskan 49 I looked at the other day had four . Two on the forward deck that I think were for the anchor well and two on the roof for pilothouse . I think Ted took some off of his boat during his short haul refit .

Click to expand...

I originally had 4 on my boat, 2 on the trunk cabin roof and 2 on the pilothouse roof. The premise of the air in and water diverted is a good one until the water content exceeds the drains capacity. The starboard one passed some water spray / high moisture content into my cedar lined closet on a rough crossing of Chesapeake Bay. So the lower trunk cabin ones were removed.





I left the ones on the pilothouse roof as I thought they added a nice touch and think it unlikely I'll be seeing any significant spray up there.



Larry, I think you would be fine with them at the pilothouse level, not the forward deck level.

Pack Mule, if you still want them, I'll make you a present of them.

Ted

I bought a Fan-tastic vent from Amazon ($120) -- the least expensive single direction motor. There is one that pushes and pulls air. I was right when I surmised the company would buy just one motor and reverse the polarity to make it go the other way.

It's the same principle as your windlass.

Anyway, I put the power to it and was very pleasantly surprised how much air it pulled out. Mine faces aft as my forward cabin hatch opens to the bow. The theory was the two would set up an air-draft situation.

There are three speeds and high is too high. It really chilled the galley/dinette area quickly.

I'll have an article about what type of on-off-on switch to buy and how to wire it.

I just bought the screws I needed to finish up. Between the start of the project and finish, I managed to lose the screws.

If you've got a place to open a small hatch up top, you might opt for that. Mine doesn't leak. Still, your dorade idea is great. I love the looks of them too. Very salty! And those brass ones are gorgeous. Note they will get H-O-T to the touch.

Good luck, and have fun.

I mounted a solar powered fan onto the Bomar hatch in my pilothouse. Its a Solar Star, normally used on houses to vent attic spaces.

It works a treat to suck air out in summer, it really stops the PH from turning into an oven when closed up at the dock. For times of the year when I don't want to lose heat I can put a canvas cover over the top to cover the solar cells, and also slip some insulation offcuts into the opening from below as they just sit on the hatch cross-bars. The white base come up about 4", and the black dome is a larger diameter and is about 1" lower than the top of the circular white section. Rain proof for sure, and spray proof to date! And the hatch still opens as normal, if required.

Dorades work quite well at bringing air below and not water,

They do require a bit of breeze to function.

The internal down pipe has to be larger than the external funnel to make up for the bends in the air flow.

If screens are required the down pipe has to be even larger.

We found that 24V computer fans operated on 12V are super quiet , should the vent be in a sleeping cabin.

These fans can not be reversed.

Our technique was to install 6 inch hard plastic covers with a hole chopped in the middle and hot glue a trimmed computer fan in the center.

Easy to remove and screw in the air out if you dont like the temperature of the air coming in.

Of course in the South a 12v unit will use more electric , but bring in 4x the air, and when there is ice on the deck, the solid lid works great to help seal the boat.

Using a second deck plate on the top of the internal down pipe helps seal the pipe should the Dorade be swept off.

And insulate in winter.

http://beckson.com/dckplt.html

Larry: I like the look plus there functional. We have 2 on Hobo on the bow built into the bench/ rope locker/ escape hatch that gives us air exchange in the master. Not as fancy as yours with just a metal grate but we like the air circulatin. We've never flooded them. I'd highly recommend them.

Dorades on Alaskan 49

The engine room stern vent on top of the salon room has them. The engine rooms side port Windows alow air in so the warmer air rises to the ceiling and up the vent. When the emgines are not running, keep a white 5 gallon bucket over them, which are mostly hiden by the storage box. The buckets allow air flow.

I need some ventilation under my aft deck ( the old fish hold ) . I wonder if dorades mounted on pilot house roof plumbed to aft deck against pilot house aft wall would work ?

Pack Mule said:

I need some ventilation under my aft deck ( the old fish hold ) . I wonder if dorades mounted on pilot house roof plumbed to aft deck against pilot house aft wall would work ?

Click to expand...

Our is run on the inside in the corners, so they are not notice and out of the way. I have seen them on the outside also. You could put an inline fan.

I like the ceiling fan, good idea.

Pack Mule wrote: "I wonder if dorades mounted on pilot house roof plumbed to aft deck against pilot house aft wall would work?"

Seems as though it should work fine. Like Phil Fill, I have seen that arrangement on the outside of the aft bulkhead of the deckhouse, especially on flush deck fishing vessels.

My dorades are split between the forward berth area and in the head, so I draw fresh air into the forward berth and exhaust it through the head. It helps to keep the bathroom aired out and the berth area dry and fresh. It seems to me that having them in two separate areas of the boat would make them work more efficiently. I can close the door to the head and then the gaps around the cabin doors exhaust the air the berth dorado draws in. I keep one facing forward and one facing aft.

I am really happy with them, when the wind howls I drop a neoprene coozie down the hole from the outside to close it off. It has bug screens so no insects enter. The boxes are on the rotten side and I am a low maintenance kind of guy, so I am looking to replace the teak boxes with fiberglass ones in the near future.

The only down side for me is that when I get the kayaks off the roof, the vents are in danger. I am looking to build guards to protect them from that sort off activity. I saw a beautiful set of guards on a sailboat that I plan to emulate.