[Kielanders]

I've done a Sailnet and Google/Sailnet search, and didn't find this discussed. If the subject has been broached, apologies - just point me to the right thread, and nuke this post.

I'm looking at new ventilators to replace my dorade boxes.

I like these closeable flush mounts by Vetus:

VETUS closable deck ventilator UFO2, SS, incl. plastic trim ring

I'm a 26' LOD, swaging at about 900 cubic feet under deck, I'd be installing one forward, one aft, where the dorade cutouts already exist. I live in a cold climate.

I purposely do not want the version with the solar fan, just more stuff to break.

Any thoughts, experience, advice?

Thanks

 

[paulk]

I'd start by going with the solar fan. They work, even when there's no breeze, so that going below can be tolerable on even the hottest days. We've had ours for 12 years, and have had to replace the batteries (drumroll)... once. One of the reasons they come with fans is that their low profiles keep them from moving as much air as standard cowl funnels. A question, however: are you replacing the dorade boxes or just the ventilator funnels? Replacing the boxes will likely leave marks on the deck where they were. The marks will probably not be covered by the new vents, so you will have to repair, paint over, or otherwise hide them If you are just replacing the funnels, or only have funnels (no dorades) and are simply trying to keep things dryer below, the flush ones should be easy to install. I would get the fans, though.

 

[mad_machine]

solar fans are as simple as they come. There is one on my Sea Sprite from when I bought it last year. The boat came to be abused and in much need of a full refit.. yet the Solar vent on the fore hatch, even with all it's chrome gone, still spins on a sunny day

 

[Faster]

Since you precluded the use of solar, these will have the benefit of being closeable.. do your current cowls have proper boxes? or do you have to remove them and install a deck plate to close things off?

It's hard to beat the ventilation of properly oriented dorades (properly installed on boxes) but they do require a breeze. These you're looking at will be rather passive ventilation in comparison.

 

[Kielanders]

I'd start by going with the solar fan. They work, even when there's no breeze, so that going below can be tolerable on even the hottest days. We've had ours for 12 years, and have had to replace the batteries (drumroll)... once. One of the reasons they come with fans is that their low profiles keep them from moving as much air as standard cowl funnels. A question, however: are you replacing the dorade boxes or just the ventilator funnels? Replacing the boxes will likely leave marks on the deck where they were. The marks will probably not be covered by the new vents, so you will have to repair, paint over, or otherwise hide them If you are just replacing the funnels, or only have funnels (no dorades) and are simply trying to keep things dryer below, the flush ones should be easy to install. I would get the fans, though.

The dorades will be removed, less to trip on or break on such a small deck. The deck and hull need to be rebuffed anyway. I had read, though didn't bookmark, that the fans were prone to breakage/failure. It sounds like you've had good luck. Heat during the summer here is not a problem.

 

[Kielanders]

Since you precluded the use of solar, these will have the benefit of being closeable.. do your current cowls have proper boxes? or do you have to remove them and install a deck plate to close things off?

It's hard to beat the ventilation of properly oriented dorades (properly installed on boxes) but they do require a breeze. These you're looking at will be rather passive ventilation in comparison.

I had read some mixed reviews on the solar powered vents. Two responses here indicate that they are reliable.

Yes, the Vetus vents I linked can be made water tight.

I calculate that, given my estimated interior volume, I would need about 5.5 CFM to fully exchange the air over the course of 3 hours per the ASHRAE standard for office environments. So it seemed that 4.5"^2 on each vent intake, would allow for more than enough passive circulation.

I live in a cold climate, so summer heat isn't a concern. Managing air quality and humidity in the cabin is a concern.

Question: Can the fans on the solar powered units be adjusted or switched off?

 

[JoeLena]

Question: Can the fans on the solar powered units be adjusted or switched off?

The Nicro solar vent I have can be switched off, or reversed easily. It is quiet and pretty unobtrusive. I have only had it one season, so cannot comment on real long term life span, but happy so far.

 

[mad_machine]

I will be adding some Dorades to my sprite.. and a couple of mushroom vents on the aft deck.

I think properly built and oriented, they should fit right up against the front of the cabin and not be a trip hazard

 

[Kielanders]

The Nicro solar vent I have can be switched off, or reversed easily. It is quiet and pretty unobtrusive. I have only had it one season, so cannot comment on real long term life span, but happy so far.

They look nice. Do you have the stainless or the plastic? Does the construction seem pretty durable in case accidentally kicked or steped-on?

 

[Kielanders]

I will be adding some Dorades to my sprite.. and a couple of mushroom vents on the aft deck.

I think properly built and oriented, they should fit right up against the front of the cabin and not be a trip hazard

The dorades I removed to redo the hull took a lot of real estate. I'm not a complete klutz, but given their placement, I did find myself bumping them quite a bit. I also didn't like that they weren't able to be made water tight without modification.

I really like the mushroom vents, and the prices are very reasonable, but they just seem vulnerable.

I'd be using the existing dorade holes, and the forward vent would have to be mounted right on the deck in a 'high' traffic area, just about 2' aft of the bowsprit/hull junction.

If I have my mind on other things, I'm concerned about just kicking the top of the mushroom off.

Apologies if I'm overthinking this.

 

[RainDog]

Question: Can the fans on the solar powered units be adjusted or switched off?

I just replaced my dorades with Nicro Day Night Plus solar vents. They run all the time and move a lot of air. They can be shut off, and switched from intake to exhaust easily. Ideally you have two, one on intake and one on exhaust. If you do this it will move air really well through your boat when it is closed up.

The downside I have seen so far is there is not way to make the water tight. In rain, I do not think they will leak, but in a hurricane or if you have green water over the boat, I think they will be a real problem without me fabricating a way to seal them off. I am not to happy about this and will need to figure out a solution before next hurricane season.

They are certainly lightly built compared to the 20 year old Vetus units they replaced. I will try to avoid stepping on them, but I think they will last 10 years no problem.