Improving Cabin Ventilation

[sailingdog]

Trantor-

I would just use the gasket. Many sealants will attack the plastic that the hatch and vent are made of. If you've snugged the screws down properly, the gasket should be all that is necessary IMHO.

[phallo153]

SEMIJim,

Good info below on the intent of these vents... to me the primary purpose in putting one in was maintenance ventilation, to prevent mildew and mold by changing the air at least once an hour. That's not a rate that is really going to provide "comfort" ventilation... at least, it doesn't in SE Louisiana in August The goal is to minimize the differences between temperature and humidity to prevent condensation.

Comfort ventilation would be more difficult to achieve with one of these, or even two, at least by themselves.

http://www.marinco.com/docs/guides/n_vent_guide.pdf

[pegasus1457]

On my previous (25') boat, there was always a persistent bathroom smell [from decaying marine life in the head inlet] when opening the boat after it had been closed up for a few days.

I installed a Nicro solar fan in the hatch over the head, in "blow" mode, and a louver in the companionway hatch board.

The smells went away and stayed away.

[Trekka]

I put a 3in "Nicro Day/Night Plus Solar Vent" in my boat's head. It helps a lot, but I wish I had gone the extra inch. Yet, even in saying that, I am not so impressed with the 4in regarding reliability. The first one I put in a main cabin hatch failed after 2 months. The next is still running after a year and a half but has become noisy.

There are two very old style day/nights on my boat and after cleaning them and replacing the "c" nicads they are running great. One is noisy but the other as silent as can be while running top speed. Both have to be at least 10 years old.

My previous boat was a 26 ft Westerly. I made two 4in dorades for the main cabin - which made a tremendous difference. Later I added two 3ins for the fwd cabin. I was very happy with the ventilation on that boat.

[sailingdog]

The four inch vents are a much better buy than the three-inch vents, since they move a lot more air. I've had both of mine for two years at this point, and they're still both going strong.

[E38]

I installed the 4" stainless steel model in my head (replaced passive vent) last spring. The fan didn't run overnight and Marinco was very good about sending me a replacement (said that possibly the charger was bad). The new fan also does not run overnight (I haven't tried to determine how long it runs after the sun goes down). I haven't tried to get it replaced. At least it runs well during the day. One of the reasons for SS was because it is in front of the mast and I wanted to be able to remove it and install the deck plate if conditions warranted.

[sailaway21]

The Nicros use 'c' cell rechargable batteries which can be purchased at the hardware store or camera dept. of a department store for much less than "marine" locations.

[trantor12020]

Originally Posted by sailingdog

Trantor-
I would just use the gasket. Many sealants will attack the plastic that the hatch and vent are made of. If you've snugged the screws down properly, the gasket should be all that is necessary IMHO.

Thanks for info. I've mounted mine with the gasket & small bolts & nuts. Made sure the bolts/nuts is tight enough to compressor the gasket for good seal. We'll know if it leaks next couple of weeks.

[therapy23]

Originally Posted by sailingdog

The four inch vents are a much better buy than the three-inch vents, since they move a lot more air. I've had both of mine for two years at this point, and they're still both going strong.

Now they sell this one.

http://www.defender.com/product.jsp?path=-1|6880|45749|320600&id=860942

Frankly I was surprised that the manual/ad said they had NiCd batteries. That is pretty old technology. I would think at least NiMh like the above.

[sailingdog]

I believe the reason they use NiCd rather than NiMH batteries has a lot to do with the chemistry of the batteries. NiMH batteries tend to not do as well if not properly charged up to full. NiCd batteries can take the abuse of charging via a small solar cell far better IIRC. Also, IIRC, NiCd batteries have more charging cycles and tolerate deep discharge far better than do NiMH batteries.