Ideas for DIY hatch vent / fan with seal

[Redline452]

The square Nicro solar PowerVent were great and could be closed off. The smaller round vents could be swapped out for a cover plate.

I’ve found the quality went downhill after Marinco bought them - after 15-20 years with the Nicroa, have gone through two sets of Marinco replacements , and now the latest are wearing out. Motors wear right through their finger brushes, and/or the bearings are shot and noisy.

I have bits and parts for over a half-dozen in the hope I can find suitable replacement motors. Grrr

[Ratty1978]

Originally Posted by nfbr

I'm looking at forward cabin ventilation. Seems the solar vented hatch vents are not well regarded and cannot be closed for heavy weather.

So I'm thinking of a vent with a closeable seal, and a 12v fan, with a 3d printed adapter.

Has anyone tried similar?
Vetus vs Lewmar hatch vents?

I can do a dorade in the deck, but I like the idea of clear decks and we don't walk on hatches now.

Thanks

(1) Did a cheap "closable" vent in the cabin top using an inspection port. Used a 4" port for a 3" cowl in a first plate that let me mount the cowl but add a screen below. Remove the whole cowl, put in a second plate and it's closed. Also have an old solar vent that's good in the harbor. Did it this way because the cowl blocks the companionway hatch (it's aligned at the CG for a chain lift from the keel bolts -- 24' boat, 3200 lbs displacement) so a flat plate needed. (2) Did the 3d print duct and old computer fan, but put it in a vertical companionway board. Can swap boards for a solid one when out of the harbor. Obviously, these are cheap solutions for a smallish (but seaworthy, keel) boat. At sea, on the foredeck, I'd opt for a fully closable plate or proper Dorade vent.

[Bowdrie]

Not cheap, that's why Airstream uses them.

https://inlandrv.com/product/dometic-fantastic-fan/