"Flying Pig" wrote in
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" Sir Gregory Hall, Esq·" åke wrote in message
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The Y valve to the toilet and holding tank (I hear you have installed one
of those, yourself, even),

Heh. I was referring to a toilet and holding tank, WRT your opening
comment.

Got it!

I don't have a Y-valve. All I have is a 1 1/2"ball valve at the thru-hull
fitting and an in-line, 1 1/2", ball valve on the holding tank side of
the T from the discharge side of my ElectroScan, US Coast Guard
approved Type I MSD. One side of the T goes to the thru-hull while
the other side goes to the 1 1/2" plastic ball valve on the holding
tank side. IOW, in a no-discharge zone I have the option of directing
the flush to the holding tank which will then contain *treated* sewage
which I can legally discharge outside of the no-discharge zone. No
need for pump-out costs and hassles.


I have no leaky hose clamps in the system. My system must be air
tight as to empty the holding tank overboard I use air pressure from
a tire pump on a vent hose Shrader valve fitting to pressurize the
holding tank. Then when I open the hull discharge valve, the treated
tank contents get pushed out of the thru-hull fitting/valve.

That's pretty cool - but, having now gone to that extent, how do you prove,
if boarded, that you have an exclusion from dumping, if it's a regular ball
valve?

The state statutes require the overboard discharge valve (ball valve in
my case) to be closed and secured with a lock, tie-wrap or some other
method to keep somebody from casually opening it.

My ball valve has been fitted with a padlock and is locked to a nearby
bulkhead into which an eyebolt is fitted. Since I have a Type I MSD the
only place where it must remain closed and locked is in do-discharge
zones. Anywhere else the discharge ball valve may be legally left open
as treated sewage from the Type I MSD is allowed to be pumped
overboard.

My holding tank is an adjunct and not required by law as it is a Type
III device. One has one's legal choice of a Type I, II, or III or a
combination.

If one combines a Type I or II with a Type III one is still required to secure
the overboard discharge valve in no-discharge zones. But unlike having
ONLY a Type III device one may keep the overboard discharge valve
open legally in other than a no-discharge zone because it is legal to
discharge treated sewage.

Our holding tank is a bladder so wouldn't do well with your setup, I don't
think.

It would not.

However, it DOES address the ability to dump when your tank is under the
water line.

How can you do that without somehow pressurizing it? My ridgid
holding tank is under the waterline so I have to pressurize it above
what occurs at the depth of the discharge thru-hull which is about
two feet below the surface.

Do you have a valve in your vent line, as well, to allow for incoming volume
(wouldn't want to be pumping the head against a pressure already there)?

You're right. At this time, I've embraced the simple solution. No valve.

The vent fitting in the hull is in the side of the vessel in the heads.
It is right out in plain sight just above a fiddled shelf. The vent hose
is slid on the hose barb without a hose clamp. To pressurize the
holding tank I simply slide the hose off the hose barb and insert a
Shrader valve/hose barb fitting to the hose.

Then I screw my little Taylor Made fender pump to the Schrader
valve using the included Schrader valve hose and pump to about
fifteen pounds which is sufficient to push the tank contents out the
discharge thru-hull.

There is only one 1 1/2 vacuum hose fitted to the holding tank. It fits
to a n 1 1/2 hose barb on the side of the tank at the top. There is
another vac hose fitted to the inside of the hosebarb. This vac
hose is of sufficent length to lie in the bottom corner of the holding
tank. Sewage goes in and out the same hose. The air space on top
of the treated sewage, when pressurized, expands and pushes out the
liquid - all but about an inch or so.

And, ditto that about the ES. Do you have a large-volume pump you
pressurize with (a holding tank holds a lot of volume of air, too!)?

It's only a ten-gallon tank. The little fender pump only takes about fifty
strokes to pressurize an almost full tank adequately. The holding tank
is also fitted using another plastic tee with a pumpout fitting on the
hull. The tee is between the toilet and the ElectroScan. I've not tried
a pumpout station yet but I suspect I need a rubber ball to place in
the toilet so it doesn't suck air through the toilet instead of sucking
the contents of the holding tank. But, my needs for a pumpout are
about nill as it's only about a quarter mile from the boundary of the
no-discharge zone so I can simply sail or motor out on a fine day
and discharge the treated sewage legally overboard. There is no
requirement to go out three miles into international waters.

--
Sir Gregory