ventialation

[mj81]

had a problem last summer with ventilation or lack thereof in the forecabin of my GK24 which we also use as our main berth. i am considering fitting a solar vent to the hatch. My question is threefold.........

1. What is the best way of cutting the hole in the hatch?

2. Are the solar vents really 100% sealed when closed, we take quite a bit of water over the bow when beating in bad weather. would it stand up to it?

3. How good are the solar vents, anybody have past experiance?

 

[sarabande]

Solar vents are a bit of a con. If you do the maths needed to make n changes of air in a cabin, plus the power to draw in the replacement air from the other end of the boat, you'll be better off with ventilator powered from the main batts.


The dinky vents are not really up to serious water, but there's a firm in Malta

http://www.air-onlyventilators.com/main/?page=ventDsd

whose tech spec seems pretty robust.

 

[MoodySabre]

Solar vents from ECS got the thumbs up in ST this month for winter ventiliation and are supposedly quite. Don't know how effective they would be in warm weather though. Ordinary ECS vents are watertight but don't vent much!

 

[jerryat]

They are complete and TOTAL rubbish! /forums/images/graemlins/mad.gif Keep your money, do a search on here, and consider the alternatives that are suggested!

 

[MarkGrubb]

The best way to cut a hole is probably to use a hole saw, like the one shown here
http://www.screwfix.com/prods/18557/Drill-Bits/Holesaws/Holesaws/Holesaw-127mm

you'll also need an arbor and then attach it to a drill. They come in various sizes, there are also kits that contain different sizes:

http://www.screwfix.com/prods/93131/Drill-Bits/Holesaws/Sets/Titan-Holesaw-Set-15-Pc

handy for all sorts of boaty jobs, including making neat backing pads for deck hardware. I used them for cutting hatches in my galley top by drilling the four corners with a holse saw and then joining them up with a pad saw. Made a neat job of it.

They are pretty beefy though, and can kick the drill out of your hands if they catch while you're drilling (probably because the drill tilted off the vertical/horizontal), so take care: plenty of speed and a firm grip, especially as the saw approaches the surface you're cutting, or it will grind to a halt or kick the drill out of your hand. Have a practice first.

For vents, I was advised that anything much less than 10cm won't really shift much air, so make sure they are large enough.

You could put a nice big cowl on the forepeak, that'll let plenty of air in while the boats left on the mooring. Something like this for example:

http://www.force4.co.uk/ProductDetails/m...23-27c358cdada4

They come with a fixing that you bed to the deck, and the cowl or blanking plate simply screw into the fixing. Take care not to over tighten, and make sure you test fit it first so that when the cowl is screwed and tight it faces the way you want.

If you put it right up front then you'll get the air flow right through the forecabin. When you sail the boat simply remove the cowl and screw in the blanking plate.

I've similar problems on my boat. The first ventilator is near the forehatch and there seems to be little airflow in the area forward of it: condensation takes a lot longer to disperse than in the rest of the boat. I plan to put a cowl just behind the bow roller (taking care to make sure it's sensibly sited and won't interfere with the anchor chain etc.), right at the front, and will simply blank it off when at sea. I could of course fit some sort of dorado box, but with the vent so far forward I'd prefer something that can be properly sealed.

Hope that gives you some ideas.

Cheers,

Mark.