20 lashes wrote:

Yipes, $65usd for a frickin' plastic valve at Waste Marine? I think
the pipe on my handsome, gleaming hand pump toilet is 1 3/8" or 1
1/2". Can't you use something from the hardware store? I want to Y the
waste to the thru-hull or the waste tank. I guess you need one Y-valve
and one stop valve. Hmm. Thanks as always and keep up the good work.

I used one large plastic ball valve from Home Hardware to close off
the marine discharge, replacing the old through hull valve that
would have been ok, but was really getting stiff, worn and balky. It
cost $19.00. The flush hose is teed to the marine discharge valve
and the holding tank. When the discharge ball valve is closed, the
effluent goes to the tank with it's air vent hoses open.

With holding tank air vent hoses closed by cheap plastic ball valve
shutoffs, ($5.00 each) air pressure builds up in the tank and with
the discharge valve open caused effluent to go out the marine
discharge. (Two vents, on opposite sides of the hull, encourages
oxygenation of the holding tank, reducing anaerobic odour significantly)

It is far cheaper than a marine "Y" and can have the same effect,
overall.

Introduction of a very little excess air pressure into the sealed
tank vent line purges the holding tank, with the hoses set up right
and a lift of only a foot or two. The shraeder air valve (tire
valve) installs using an R.V. purge air adapter in the 1" vent line
between the tank and the vent shutoff. ($3.00) The air pump is a 12
Volt tire inflator, ($9.00, on sale) but a manual balloon pump from
the dollar store should work as well.

To dump the tank at sea, I close the 2 air vents, open the marine
discharge valve, and pump air into the tank. Two minutes, all gone!
Be certain your duck bill, or "joker" valve in the head flush pump
does not leak back significantly. If it does, it needs replacement.
One should always have an extra duck bill aboard.

For safety, it is now convenient to leave the marine discharge
through hull closed and use the holding tank, until opening it only
long enough to purge the tank before returning to port. It does not
interfere with normal deck suction pumpout, so long as the vent is
open. This scheme also removes any need to have a self pumpout pump
in the toilet hoses, something less to worry about. Coincidentally,
it also enables easy tank dumps on the trailer at an R.V. dump
plaza, or street grate using a tail pipe rammed or threaded into the
marine discharge, or not. Eww!

Terry K