Long ago and in some place far away, our boat had dorades put into the deck just aft of the forward hatch. These little beauties were Nicro 3″ dorades complete with screens and little bitty air scoops. The only problem with them is that they’re ancient, cracked, leaking into the deck, and leak into the boat itself.
Old Nicro dorades

It was absolutely impossible to leave the “plates” off of them when we left the boat because rain would pour right in and onto the floor. So they were left shut. And this defeated their purpose which is ventilation. So to combat this terrible problem I decided to give some new technology a try. Enter “Air-Only” ventilators. I ordered two of these little guys from Malta to give a try and over the weekend we installed them. I figured I’d detail this process in the real world since these little ventilators are not your average trim ring and presto-ready to go.

The trim ring which inserts from the inside of the boat, was very long. This is so that you can cut it to the exact width needed for your particular deck. We slipped the ring up through the existing hole and marked out the deck level on it. Then I took it back out and cut it with a hacksaw.
Marking the
We secured the trim ring by screwing it in below and I sanded any imperfections flush with the deck level. We also cleaned up the old caulk around the hole and cleaned with soap, water, and acetone.

Next we fitted the main housing piece into the trim ring and onto the deck and drilled the holes for the screws, then proceeded to countersink all of them.
Countersinking screw holes

Finally, everyone’s favorite chemical creation returns AGAIN to seal the holes and the housing itself. We filled in the old screw holes, the gap of trim ring, and the new holes with layers of butyl tape.
Butly taping the hole for the
I often joke that we’re one day just going to rename Sundowner to Butyl. Everything we’ve ever sealed with it has never leaked again, but with caulk we’re batting about .800.

The first piece to really be secured to the deck is the base of the air-only ventilator. I pressed it into the butyl and screwed it into the predrilled holes. This squished lots of butyl out from underneath and made me confident that we have a good seal between it and the deck. There is a little lip on the bottom of it that actually fits into the trim ring. This is why it is important to get the trim ring flush with the surface of the deck.
Base of the

The next step is when the space age fun starts. You actually fit a wildly colored o-ring to the base plate, and then you get to place these little balls all around it on their own little pegs. It looks almost like a toy or something at this stage. The o-ring is hard to get on just perfect.
O-rings for the

With those neat little balls and o-ring on, you get to the next step which is apparently caging them. You slip this slotted housing ontop of the baseplate, which seals with the o-ring. It also entombs the glowing little balls. You screw it down and then add the next o-ring which goes around the opening port. This o-ring is smaller and thicker and much easier to put on.
Another O-ring

I wish I could say the same for the final o-ring but it is the hardest to get on. Not only the longest, but the thinnest, and prone to twisting as it slips into place around the top of the “cage.”
3rd O-ring

Finally this is all capped off with a “roof” that makes the apparatus appear to be some sort of flying saucer.
Top of the

So basically, here is this low profile goofy looking thing sitting on the deck that is guaranteed to not let any water in but allow air to circulate. Neat huh? But even so I couldn’t tolerate those little prisoner balls getting to see the sunlight so we went the whole nine yards and stuck the air scoops on too.

The scoops themselves come as four pieces. The windscoop itself, then two parts of a “ring” which hold the base of the windscoop, and the part that sits ontop of the ventilator.
Collar for the
Underside of the

This whole assembly was placed over the vent and screwed to the deck in the same way as before with countersunk holes filled with butyl tape. The finished result turned out pretty handsome.

The air flow suffers compared to the old wide open dorades, but I threw a bunch of water directly into the dorades and not a single drop ever made it below.

I’ll be sure to give some follow up reports on how these “new” products hold up and work. They suggested caulk to seal but we preferred butyl. As a side note (followup) the port lights which we entirely sealed with butyl have been in place almost a year now and have seen absolutely horrible rains this winter and not a single one has leaked. I hope they continue to provide many years of leak free service. Only time will tell. Tick tock tick tock.

Front view of the