Don W brought forth on stone tablets:
Hi Everyone,

I got around to fixing problems with our Irwin 38's head recently, and
as a result, I'm seriously considering completely rebuilding the
sanitation system. For one thing, the 1-1/2" sanitation hose was
original, and it was quite brittle. For another, the holding tank is
only 8-1/2 gallons, which is ludicrously small even for just two people.

We currently have a small electric head with a macerator which pumps
through a vented loop directly to a 1-1/2" thru-hull under the floor in
the aft cabin. If you shut off the valve at the thru-hull, and open
another valve, it pumps to the holding tank in the back of the boat
(behind the aft cabin).

Right now, I'm "cogitating" (that's a Texas expression) on whether it
would be better to pull the electric head, and install a Sealand
Vacuflush head and vacuum generator while I'm re-doing everything. In
any case, I will put in a larger holding tank.

An advantage to the Vacuflush system is that I can install the vacuum
generator in the top of my starboard cockpit locker, and let it drain by
gravity into the holding tank. Since the holding tank is vented at the
top, this does away with the need for a vented loop since there would be
no way that a siphon could develop from the thru-hull. Also, since the
vacuum generator effectively "sucks" the line clean there is an added
advantage of not having anything standing in the sanitation hose--a
disadvantage of the present system.

I'm thinking that I might use an electric macerating pump to pump the
contents of the holding tank to the thru-hull when emptying at sea,
rather than relying on gravity to do the job. I'm a little concerned
about having the macerator head sitting in raw sewage all of the time.

All of this is likely to cost a few boat bucks, so I'd like to be sure
I've thought it through before commiting the money.

Any thoughts or comments you'd like to offer??

Don W.


I'd skip the use of the head hose, except as for flexible connections to
hard-mounted items, unless the runs are very short. Instead, plumb with
rigid white PVC pipe - it has an essentially infinite permeation time -
unlike the hose.

bob
s/v Eolian
Seattle