How effective are Dorade boxes?

[coopec]

I wonder if others have Dorade boxes on their yachts ?

I have had trouble with two Dorade boxes in the main cabin in that they leaked rain water (too much). I think I have found where they where leaking.

I thought I would test them yesterday as I knew they were forecasting rain. In fact we had 70mm (nearly 3 inches). The meat tray that I placed under the vent was quite moist but no pooling of water. Is that what you'd expect or do I have a way to go?

(Of course, in practice, if I expected that amount of rain I'd close the vent off)

 

[dunedin]

I would have thought zero rain should come in. It is sea water across the decks that the dorade is protecting against. Need to throw some large buckets of water at them, with as much force as possible, to give any sort of test on land.

 

[coopec]

I would have thought zero rain should come in. It is sea water across the decks that the dorade is protecting against. Need to throw some large buckets of water at them, with as much force as possible, to give any sort of test on land.

I don't think any Dorade box would stop green water across decks.

"An alternative option is available from Vetus, which allows the vent to be closed off in bad weather from below, by using a mushroom cowl on ...."
Keeping The Water Out—Deck

 

[dankilb]

A bit of rain comes in to ours in strong winds, but I love them and wouldn’t swap for the world. You can feel the air circulating through in all conditions when standing nearby. Sometimes they draw warm air out, others they channel a cool breeze in. We’ve only owned the boat during a 3 year refit so cannot comment on green water, but give us another 6 months…!

 

[rotrax]

Ours work fine, and we have taked a few big 'greenies' over the foredeck. They are quite high, well over two metres from the waterline. They are in Island Packet's OE Dorade boxes with Vetus plastic dorades.

Very expensive polished Stainless ones are an option - we dont have those, but the previous IP did. They were dry too.

 

[geem]

I wonder if others have Dorade boxes on their yachts ?

I have had trouble with two Dorade boxes in the main cabin in that they leaked rain water (too much). I think I have found where they where leaking.

I thought I would test them yesterday as I knew they were forecasting rain. In fact we had 70mm (nearly 3 inches). The meat tray that I placed under the vent was quite moist but no pooling of water. Is that what you'd expect or do I have a way to go?

(Of course, in practice, if I expected that amount of rain I'd close the vent off)

View attachment 135227

You may not have the stub duct inside high enough. Also, more than one drain hole at opposite corners will be necessary to allow for heeling. Our fly screens are below the main scupper air inlet so we can unscrew the inlet and remove the screens if we want to for more airflow. We can also screw s/s blanks in place if we know we are going to be doing a rough passage with a lot of green water.

 

[PetiteFleur]

They work on my boat - Moody33 - keeps the boat well ventilated.

 

[johnalison]

Never had water into ours, with the vent always facing aft when at sea. The hole is just small enough to be blockable with one thermal sock when the dehumidifier is in use.

 

[coopec]

Never had water into ours, with the vent always facing aft when at sea. The hole is just small enough to be blockable with one thermal sock when the dehumidifier is in use.

I deliberately faced the vent into the weather so maybe I don't have a problem?
But I think I will take Geem's advice and raise the stub vent a bit.

 

[Zing]

Rain should not get in. It’s got to be a drain or seal problem.

I’ve had water coming in mine. They are big and high, but given enough sea water they get swamped. Easy to forget to turn them around and that increases the chance of a leak. If I am likely to bury the bows, then I will fit blanking plates, but they are not perfect. They should really have O ring or rubber seals and they don’t. I have the basic Vetus units. You can get better screw down vents to go inside of dorades, but they have poor airflow. I’ve seen custom ones done. It’s not complicated. Vetus do a range of components with vents, closeable or adjustable from the inside with a range of dorade boxes and cowls. Simple to source, but not perfect. They are bloody ugly things too and catch lines, so need an ugly protection frame. It’s another one of those impossible boat compromises. No perfect solution possible.

 

[Middie H.]

Sea water could come through dorade box in, if I understood @Zing correctly…

I thought the dorade box never let water in, when the vent is facing aft.

We had a wet paper chart on the chart table after quite rough sailing 20-22 knots to the wind. Our dorade box is installed exactly upon the chart table, so it seems that the water has come from dorade box. The vent was facing aft, but it doesn’t work, obviously. We have to keep our chart table clean if we have waves

 

[V1701]

I have two of the type that can be closed off from below. Once took all the outer bits off (to paint them) & removed some silicone sealant from around part of what's inside on one of them without realising that was to stop water running across the coachroof from getting in. This one leaked quite badly in heavy rain so reasealed with silicone sealant. I don't think youd'd want or need to permanently fix them in place in case you ever wanted to swap them out. About the only thing I'd use silicone sealant for on the boat...

 

[Buck Turgidson]

Not sure how rain could possibly get in if it's correctly sealed. Mine have never let any water in even when they were washed by braking waves for hours on end.

 

[johnalison]

Sea water could come through dorade box in, if I understood @Zing correctly…

I thought the dorade box never let water in, when the vent is facing aft.

We had a wet paper chart on the chart table after quite rough sailing 20-22 knots to the wind. Our dorade box is installed exactly upon the chart table, so it seems that the water has come from dorade box. The vent was facing aft, but it doesn’t work, obviously. We have to keep our chart table clean if we have waves

I can see the logic of turning them into the wind but it might be that they work better when deployed to 'suck' air out. Of course, our little plastic versions are a pale imitation of the original ones but I think they help a fair bit, perhaps depending on whether the designer has put them in the best place.

 

[Zing]

Sea water could come through dorade box in, if I understood @Zing correctly…

I thought the dorade box never let water in, when the vent is facing aft.

We had a wet paper chart on the chart table after quite rough sailing 20-22 knots to the wind. Our dorade box is installed exactly upon the chart table, so it seems that the water has come from dorade box. The vent was facing aft, but it doesn’t work, obviously. We have to keep our chart table clean if we have waves

Rain can come from all directions as does spray - just like the wind. Dorades will drain that sort of moisture, but if your dorade drains are blocked they won't. Having learnt this the hard way it's now an annual maintenance job to inspect and clean them.