Solar Hatch Vents and Cowls

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Nov 17, 2012
6
Can anyone speak to their experiences with solar and or cowl vents installed through. Deck hatches and specifically to how effective the built in seals/plugs are when operating in open ocean? Thanks
 
Dec 19, 2006
5,821
Hunter 36 Punta Gorda
No Leaks

I can tell you that I have had one in the front vee berth hatch since about 2007 and did sail down from Ny to Florida all ocean and have made a few trips to the Keys and dry tortugas and have not had any problem with water leaking into the vee berth.
They do a good job helping keep the cabin smelling fresh but about 6 months ago it did stop working and after replacing the battery it still would not work so I put a 12volt fan like a ccomputer fan into it and it now works off my 12 volt system all the time with a on and off switch,I have solar panels to keep batteries charged.
Nick
 
May 24, 2004
470
Hunter 33.5 Portsmouth, RI
We have used a Nicro 2000 Solar/Battery vent installed in the center of the Vee Berth Hatch for quite a few years now. I set it to "Exhaust" (it comes with 2 blades - one for exhaust and one for intake). I also installed a horizontal strip vent in the top most pin board in the companionway. The vent fan exhausts air out and draws in fresh air from the companionway vent (Non-powered). I has worked very well form day one. keeps the boat smelling much fresher and significantly reduced "boat smell". The gasket with it keeps out the rain or ocasional sea spray. We have taken the boat throughout Narragansett Bay, RI Sound, Vinyard Sound, etc. and never had a problem with water getting in. All in all, very satisfied with it.
 
Oct 29, 2005
2,362
Hunter Marine 326 303 Singapore
If I cannot balance the intake air to outlet air, for effective ventilation, should I have more intake or more outlet air flow?
 

Webone

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Apr 30, 2010
50
Jeanneau 45.2 Saugatuck, MI
Just one more tripping hazard on deck. Mine do not leak, but always seem to be right where I want to step. Stick up about 2 1/2" above hatch. Does keep some air moving in the cabin while closed up.
 
Sep 5, 2007
689
MacGregor 26X Rochester
If I cannot balance the intake air to outlet air, for effective ventilation, should I have more intake or more outlet air flow?
I'm not sure what you're asking. For steady-state air flow, the intake air flow rate will match the exhaust. It has to - if they don't match, the pressure inside the boat will be increasing or decreasing, but sooner or later (sooner, really), they'll match again.

If the intake is restricted severely, the exhaust fan will simply not be able to move as much air as it would with an unrestricted intake - fans have a performance curve where flow rate depends on flow resistance, or static pressure difference across the fan. Induced draft ventilators work the same way, including cowl vents on dorades.

Some folks use two powered vents, one intake and one exhaust, but if you have adequate passive intake area (like around the sliding hatch/companionway hatch boards, which is rarely gasketed), you'll probably get more bang for the buck by exhausting both. But that also depends on what the air is doing and how the boat is oriented to the prevailing winds. If a lot of air is escaping around the hatch board/hatch interface when at anchor or at the dock already, due to that area being in the lee of the prevailing winds (a smoke wand will tell you this), then adding more area for air to get in may be all you need. Or the reverse, if air is trying to get in there, and exhausting (powered or passive) would be called for.

And don't forget to orient cowl vents to draw air out or push it in, depending on which is more effective. If all your existing vents are trying to suck air out already, adding more that suck air out isn't going to help. Turning cowl vents to bring air in, or adding additional intake vents somewhere, may be all you need.

My last boat (Hunter 340) had two ports in the stern berth, one of which opened into the cockpit. I added a smoked plastic louver/screen unit (standard Beckson option) to replace the original screen, and left it open all season. It was under the bimini, but still exposed to weather. Never got water in through it, but it really helped move air through the boat as witnessed by the sudden lack of 'boat smell'. Best $10 I ever spent (found it on a clearance table in a WM), but I'd have spent full price if I had known it would be so effective. No moving parts, either, but needs some breeze to do its work. Point being, of course, there are many ways to skin this cat, some of which are not always so obvious until you do it.

I had also added a louver to one of the hatch boards, but that didn't have as much effect, by the way. And the cowl vents on an H340 are just for show, as they only vent into the space under the 'hood' (Hunter's term), and that's open front and back anyway, along with two little openings to the cabin, so virtually no air was brought in or exhausted through those little flexible pvc cowl vents no matter what as it just came in the front and through the cowl vents and went out the back. :doh:
 
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