Need help with vents (pics)

[drewpster]

I need help deciding what would be best to do with my engine compartment vents. Originally the vent pipes were routed into open spaces behind the panels covering the inside of the cockpit area.


You can see the end of the vent pipe protruding through the floor next to the helm. Flat panels originally covered this area. The panel had a cutout in it allowing air to escape this area through the pipe.


Here you can see the aft vent pipes up through the floor as well. These originally vented into the open area where the fuel tank is. (tank going by-by)I am not sure what the idea was here as I can see no way for fresh air to reach these vents.


Here you can see where the stbd vent pipe has been removed to accommodate the waste tank pumpout and vent hoses.
I would like to vent all these pipes to open air. The aft vents are no a huge problem. They can be brought up through the transom deck and attached to clamshells if needs be.


Its these forward vents that give me greater concern. I thought I might make openings in the hull sides and use exterior louvered vents with collectors. But as you can see, the stbd vent hole has waste piping in it. Could I get away with inclosing this area leaving the piping in place and cut an exterior vent into this area? Can I use standard plywood coated with epoxy to make the doublers for the vent cutouts in this dry area?

[tashasdaddy]

i see now reason why not, ask long as you have the fan inline on one of the stern outlet, for starting and slow cruising. we use to use seal trunk spaces in home construction to move air, with a duct on the end, i see no reason if you seal the area with the exterior collector with the open hose in it. the air will get there.

[Chris1956]

Drew. A lot of boats had the clam shell vents on top of the gunwale. Usually one facing forward to scoop the air and one facing aft to exhaust the air. if you install them on the side of the hull, facing forward, they may scoop some water or wetter air, which is undesirable.

[drewpster]

I will be using clamshell vents on the transom deck for the aft vents and louvered vents on the hull sides. I was told today I did not need all four vents for an engine compartment the size of mine. I tend to disagree. What do you think, all four, or just the two aft vents with clamshells?

my side vents,'
http://www.iboats.com/Louvered_Ventu...-view_id.38742

[tashasdaddy]

i think the more air you can get there , the better you are. air helps keep the bilge dry, mildew down. besides the safety thing.