On Mon, 07 Dec 2009 18:29:11 -0600, Vic Smith
wrote:

On Tue, 08 Dec 2009 07:15:17 +0700, Bruce In Bangkok
wrote:

On Mon, 07 Dec 2009 13:37:17 -0500, Wayne.B
wrote:

On Mon, 07 Dec 2009 09:37:30 -0800, Gordon wrote:

This filter supposedly stops odor so why not vent inside?

It will lead to problems sooner or later. Peggie is a big advocate
of freely venting the holding tank with lots of fresh air. At the
very least, the filter will impede that venting. At worst the filter
will become clogged sooner or later and cause the tank to pressurize.
Use your imagination on where that will lead.

Perhaps I miss-remember Peggy's advice but I have the distinct memory
that Peggy suggested large holding tank vents and felt that a supply
of oxygen was necessary - I seem to remember 1 inch vents?. I can't
see that adding a charcoal filter to the system is going to cause
troubles assuming that it doesn't impede air flow but why vent inside
the boat - what advantage is that going to give you?

Disadvantage. Better venting due to increased airflow outside.
Time to rant.
First, I don't have a boat, but so what?
When I get a boat, it will have an Airhead or equivalent.
Every owner account I've read has been a good review.
Not suitable for "party boats" or more than 4-5 crew, but for a couple
or a couple with a couple kids it's fine.
No holding tanks, hoses, valves, pumpouts, etc.
And no stink.
Only reason I can figure they aren't more used is simple ignorance,
and the marine head parts industry poo-pooing the idea.
Rant over.

--Vic

Ever been on a small boat with one of those. They do STINK. I'm not
kidding. It's like being in a poorly maintained horse stall.

The manufacturer mentions this deftly, so they can say you have been
warned. From their brochu

"In many cases a noticeable improvement in air quality will be
perceived upon opening the companionway hatch after lay-ups."

And you will not find many marinas that welcome folks dumping these
things into a standard commode as the manufacturer suggests.

A 6 gallon Porta Potty is just as good a solution, and costs less than
1/10th the money. The Porta Potty can either be carried ashore and
dumped in a standard commode if you can find a place that doesn't
mind, or pumped out by any conventional pumpout rig.

The holding tank for a Porta Potty remains completely sealed when you
disconnect it, so carrying a second tank on long trips is feasible.