Ventilation

Orion is a damp boat. There's a leak through the centerboard case into the cabin I'm still trying to track down, there's water in the flotation and I'm still trying to solve the problem of a totally leak-proof centerboard bolt without having to go crazy with 3M 5200. It takes a long time for mildew to form, but I never like to open the cabin hatch and find a lot of stale air inside with water droplets still on cushions from a week before. It was time to address getting proper ventilation into the cabin.

Solar Power: Active or Passive?
I had already told myself I was going to get a solar-powered vent to put somewhere on the boat. But I had to decide whether I wanted active ventilation or passive ventilation. Active vents force air down into (or out of) the boat, whether they are solar-powered or hooked up to a boat's battery. Passive vents are totally dependent on wind movement - the wind, rushing over a passive vent, is what turns the fan. I didn't like the idea of a passive vent, since if there is no wind, there is no ventilation. There are active/passive combination vents, where a solar-powered fan runs during the day and lets passive air take over at night. I didn't like that idea, as many times the wind stops during the night. I wanted constant ventilation - call me greedy, but that's that. An active vent it was. And since I don't have a battery onboard Orion, the solar power would have to suffice for both day and night.

Which model?
After looking at several models, I chose the 4” Nicro Day/Night PLUS vent which I later replaced (2023) with a newer Marinco model after Marinco bought out Nicro. Marinco/Nicro has been around since the 1960's, and they know a thing or two about ventilation systems. The solar charge from the day was supposed to last a whole night, and even beyond with a complete charge. Several Mariner owners already owned one and swear by them, including Rich Weston (#2290 Sweet Caroline) who wrote to me: "I have the Day/Night solar vent. It has been running strong for at least seven years. It's great for keeping out mildew. When it gets a full charge... the fan will run the entire night on the day's charge. So my fan runs 24/7 in the summer." I read other reviews that mentioned Nicro replaced their vents quickly and for free if they seized up. Plus, the new model has some features the old one didn’t have, like a switch to reverse fan direction from intake to exhaust (as well as a shut-off) and even a small LED light. With all this information, I was sold!

Where to put it?
Believe it or not, I agonized over where to put it almost more than I did choosing the darn thing. Most boats, Mariners or otherwise, put their vents on their forward hatch, which makes a lot of sense. However, I had custom-ordered my forward hatch to be translucent, and I was darned if I was going to drill a hole through that and lose some of that light. Plus, I didn't think I was going to like the look of a vent protruding from the hatch, either from underneath or on top. So I looked at the cabin deck. That was a no-go, since there wasn't anyplace in the centerline of the deck where I wouldn't run into some deck/mast tabernacle reinforcement underneath, and I wouldn't compromise that. I couldn't put the vent off-centered, because that would simply drive me crazy.

I finally decided to put it on the foredeck, as close to the cabin front as I could. With the roller-furling jib, I rarely go up on the foredeck anymore, but I did want a place to stand when dealing with the anchor. I found the perfect spot between two deck-reinforcement "ribs".

The process
After marking where I wanted it, I took a deep breath and drilled a 4 1/2" hole through the deck. I hate putting holes anywhere, and I had to pace back and forth for a few minutes before working up the nerve - this was a big hole. Although the original Nicro vent instructions actually called for a 4 3/4" hole, I found that was only necessary if installing a trim ring, something I planned to skip. A 4 1/2" hole was plenty big enough, so that's what I did.

When I bought the updated Marinco vent in 2023, I found the outer diameter was a full inch bigger than the old Nicro vent, and it was just too big. So, I returned the 4” and went with the smaller 3”, which has the same 9” outer diameter of the old model. While the 4” vent is supposed to move up to 1,000 cubic feet per hour, the smaller 3” vent can move up to 800 cubic feet per hour, and I can live with the difference. Unfortunately, though, it meant having to close up some of the hole in the deck since it was previously drilled to 4.5” and it needed to be only 3.75”.

After removing the old vent, I sealed the hole from inside the cabin with wax paper taped to the underside, I mixed epoxy thickened with fairing filler. Making sure to wet out the area first with unthickened epoxy, I glopped the mixed epoxy all around the hole, smoothing it out as best I could, realizing I would sand away any high spots once it cured. The next day, I did just that using sandpaper tacked to a block of wood, then marked the new 3.75” hole and cut it with a jigsaw. I’d say it came out pretty well!

From there, it was a very straight-forward installation of the base, drilling pilot holes for the screws and using 5200 sealant around the screw holes and base. Then, setting the large gasket in place, I screwed the whole fan assembly down into the hole until it was nice and snug. Done!

Here is what it looks like inside the cabin. When it gets warmer, I plan to paint all around where the epoxy and filler can be seen so everything looks dressed up. You can see the fan blades behind the removable bug screen, and the small LED light in the center is turned on by the smaller black switch on the left. The black switch on the right changes the fan direction from exhaust to intake, and if the switch is kept in the middle, it shuts the fan off yet allows the battery to continue charging.

So, there you have it. The manual recommends having some kind of intake vent (like a clamshell vent) somewhere in the back of the boat to facilitate the passage of air, but Orion isn't very airtight, and it hasn't been a problem.

That being said, I was quite pleased with the original vent's performance as it seemed to do its job circulating air into the cabin. In the past, water droplets would have remained on cockpit cushions placed inside the cabin until the next week when I would go sailing again. With the original vent, the cushions were dry by the time I got to the boat after a week, so I was pleased with that and expect the new Marinco vent will perform the same. I’m hoping it will last for a while, and only time will tell whether or not it was a good investment. But, if it works as advertised, it should really help to keep ORION’s cabin mildew-free.