Adding a vent to supply fresh air into the sleeping cabin?

[Esteban]

I am going to run a couple of fresh air vents out thru the floor. Not sure exactly where yet though. Since they will exit under the floor, I'm not really worried about appearance. I think I am just going to use shower floor drains screwed to the bottom of the floor. Openings should be small enough to keep any varmints out.

Sent from my XT1080 using Tapatalk

Maybe some screening to keep out insects...I plan on doing similar, but will incorporate fine screening to keep out bugs. I also will try to make the vent kind of a pyramid shape with screen on bottom and fan near top. This will allow surface area to compensate for the screening. the muffin fan will be slightly below the floor so I can make a flush cover for it

A Replacement Exterior Half-Moon Trailer Vent for 3" Diameter Hole or something similar, could be used to keep the rain out of a wall vent. I remember seeing photos of teardrop trailer doors with small clamshell vent covers installed in the top part of the doors to provide a little source of fresh air. Clam shell vents could be installed in walls or floors too.

Per Halfdome Danny's suggestion I'm going to install clam shell vents atop the side walls of my galley.

[KCStudly]

I plan on using a piece of "polyester filter media roll" (Google search link) mounted behind a small trim frame to make a furnace filter like arrangement for the inlet. I like that half moon vent as a protective outer cover, too, and since mine will be mounted under the floor appearance is not important; but I'm not sure if I will have room for the flange since my opening will be close to a frame xmbr.

The advantage of the polyester gauze like media is that it is airy enough to provide very little obstruction to air flow, but has enough of a labyrinth effect to catch dust and exclude bugs; compared to regular window bug screen it is thicker and has much better dirt catching/holding ability. I'm pretty sure that it would also be a deterrent to rodents, but will also have an adequate grill. Some varieties of the gauze have antimicrobial properties, which really isn't a factor for this application, but gives a slight tackiness, like an oiled filter would have, and I think makes them a better dust catcher. Comes in bulk so easy to cut a fresh piece whenever needed.

I use the stuff at work so usually have lightly used pieces left over, otherwise one might be able to buy in small quantity from any local HVAC installer/equipment provider.

[Esteban]

This discussion lead me to search for and discover the http://www.sea-dog.com/groups/1321-cowl-vent-with-base which probably can be used with a computer fan and filter fabric like KCStudly suggests using.

I may use a Sea Dog Cowl Vent on the outside walls of my galley. On the inside walls I may use a DRAIN COVER or a FLUSH THRU VENT. They would help dissipate the heat from an ac/dc chest fridge/freezer lower in the galley.

A cowl vent under the galley floor may work well as the fresh air inlet for the cabin area hit and miss vent.

Cowl Vents could be useful in the sleeping cabin area too.

I really like how this discussion is evolving my/our thinking to help us come up with better and better ventilation ideas and designs!