We vented through what was previously the vent for the old holding tank and ran the hose directly through the under-sink cabinet.  The opening through the hull has proven adequate for the air flow.

Ralph

We encountered the same concerns when laying out the installation of our Nature's Head.  While we fully embraced the composting concept, we did not want the hoses to be an over powering visual to the boat.  We had two head compartments to considered on the WS42, and, thankfully, had convenient cabinetry to work with.

However, our choice of deck venting would dictate many things including placement on the cabin top and hence the routing of the hoses.  After considering our experience with solar vents, we chose the passive Vetus mushroom vent and connected the fan to our house battery bank:  the 1.8 amp daily draw was miniscule and would be covered by an eventual solar array.

The Vetus mushroom vent allowed us a smaller hole and a better location with respect to the inner cabin layout.  I have included two pictures of the hose installations.  The clear hose offered a fairly could blending with our white painted bulkheads.  I hope these help with design configurations - the Airhead "plumbing" should be very similar to the Nature's Head.

The forward head is pictured here: 

 The Aft Head is pictured below:

Greetings,

The link below is from an article we wrote on the installation of our Airhead for Southwinds Magazine, in June 2013. It begins on page 36 with some pics and a narrative on how we installed our unit. Hope it helps!

http://www.southwindssailing.com/pdfs-issues/southwindsjune2013.pdf

Jeff & Wendy                                                                                                               Calypso #44

That is interesting to read about the C-Head, a churnless composting toilet. We have the Airhead, but we use it in a different way to what was specified. We put in a 1-2 inch layer of coir peat, and then add a couple of scoops after each donation, just like the churnless toilet. After a week or so we start to churn it. We found using the toilet as recommended by Airhead we ended up with a large amount of un-mixed coir peat around the sides and bottom of the container. 

We have been using it this way for a few years now and it works for us. Being able to line the bucket with a plastic bag would make emptying easier. But then we sometimes just empty our toilet into our home composting unit ( great tomatoes, and rhubarb), or bury it in the bush so plastic would be a pain.

Cheers Wendy

I recently emptied our Nature's Head and noticed that there was a small amount of peat moss that escaped agitation.  I agree that Wendy's process works and helps with the agitation.  The last 2 months represented our first time using the composting head and we love the ease and no-smell attributes.  However, experience showed me that I had not filled the base with enough peat moss when we started using it.  After having added more the agitation was more complete.

While I do expect some rebellious peat moss or coconut coir to hide in the corners, we like the simplicity of using the head as directed by the manufacturer.  The "stir stick" concept when emptying would work fine, too, and eliminate a step during use.  But, to each his own.

The manufacturers of both the Airhead and the Nature's Head explain how easy the emptying process is.  However, I was amazed at just how easy it was the first time I did it. From start to finish it took me less than 15 minutes and that included removing and re-installing the unit.  It was actually shorter than what it would take to pump out a holding tank.

Additionally, we had guests on board recently.  We all know how intimidating a standard marine head can be for the uninitiated.  Throw in a composting unit and terminal constipation is a sure possibility.  However, these guests found using the composting head easy and comfortable.  That included both men and women.  Of those guests, one was a boat owner and he was so impressed with the ease of use, he is considering removing his existing system with holding tank and adopting composting.

We're sold.