Thanks.

I actually plan to skip the vented loop in this case. Because the
USCG requires these pump outs to be secured against unintentional use,
I'm going to remove the lever from the seacock. I'm also going to put
the switch for the pump right by the tank so I can watch what's going
on (like if the vent plugs and the pump starts to collapse the tank).
This is for occasional use. I may never use it but I like the boat to
be self sufficient. The idea of being dependent on shore support for
something as basic as getting the sewage out doesn't sit well with me.

A "Y" valve may not be the best solution here either. I may just put
a ball valve in the deck pump out line. The seacock will shut off the
other side of the system.

No, that's a bad idea. Sewage would sit in the overboard line, maybe
forever. With the "Y" valve, I would pump out, then let seawater back
flow briefly to clear the overboard line (everything is below the
W.L.). Then shutting off the seacock and switching the "Y" would
leave mostly seawater in the discharge line and the boat ready for
normal pump out.


--

Roger Long

My waste tank is purged to the sea or, with an external hose connected,
to the Wall Mart plaza storm sewer like RVers do it, or an external
tank, like my porta pottie from the truck, using air pressure. We
don't need no steenkin' macerator pump, nor no 'nuther pump neither,
except the 12vdc tire pump, which pressurizes the system enough (1 or 2
lbs overpressure) to blow the "ballast" out the marine discharge. I use
a plastic ball valve as a sea cock, and it doesn't leak. Nor does the
joker valve, even with pressure on.

The only time I open the cheap plastic ball valve / sea cock / port /
sea valve is when emptying the holding tank. The only valve, aside
from air vent valves in the system, is the one sea cock ball valve.
There is a tee between the head, through hull / sea cock, and holding
tank pipe.

Two minutes of pumping air into the tank with the air vents closed and
the sea cock open and it all goes out. Then, it farts to let me know
it's done.

Terry K

Hmm, I like this idea. Running that airline down into the bottom of
the tank with lots of holes would also let you aerate stuff if you
were in a no discharge zone. A 12 V air pump is 1/10 the cost.

What kind of tank do you have? I would have to pump against the head
pressure of the tank being below the waterline so would need 2 - 3 psi
which is a fair amount for a plastic tank. I would sure hate to bust
something.

--

Roger Long



"Terry K" wrote in message
oups.com...
My waste tank is purged to the sea or, with an external hose
connected,
to the Wall Mart plaza storm sewer like RVers do it, or an external
tank, like my porta pottie from the truck, using air pressure. We
don't need no steenkin' macerator pump, nor no 'nuther pump neither,
except the 12vdc tire pump, which pressurizes the system enough (1
or 2
lbs overpressure) to blow the "ballast" out the marine discharge. I
use
a plastic ball valve as a sea cock, and it doesn't leak. Nor does
the
joker valve, even with pressure on.

The only time I open the cheap plastic ball valve / sea cock / port
/
sea valve is when emptying the holding tank. The only valve, aside
from air vent valves in the system, is the one sea cock ball valve.
There is a tee between the head, through hull / sea cock, and
holding
tank pipe.

Two minutes of pumping air into the tank with the air vents closed
and
the sea cock open and it all goes out. Then, it farts to let me know
it's done.

Terry K

The devil is in the details. Thinking about it for another few minutes
last night, I realized that I don't want to subject all these plastic
hoses, joint, and screwed fittings that I'm trying to keep absolutely
odor tight to pressure. If it was a steel tank with hard piping,
maybe. Even then, I would want a pressure relieve valve and those are
very low pressures to have one work reliably.

A wad of toilet paper going up into the (too small) vent on our
plastic tank could also turn this into a bomb that you don't even want
to think about.

Slightly off the subject:

I remember a shipyard here in Maine needing to fill the built in tank
in a
just completed fishing dragger with water to test it. The water at
the
dock was off so they ran a long hose down the hill from the shop and
connected it to the tank. They were smart enough not to hook it up to
city
water pressure and ran the water into a funnel. They weren't smart
enough
not to hard mount the hose to the tank and the vent hadn't been
installed
yet. The weight of water in the hose, with a vertical drop of about
25
feet, bowed the top of the tank up about 3 inches. Since this was
also the
floor of the crew's quarters, all the accommodations had to be ripped
out
and a huge section of the boat cut out and rewelded. It cost about
$100,000
to fix.

--

Roger Long

Somebody should stuff Terry K down a storm sewer...
That's just plain ignorant. But with a "plastic ball valve" for a
seacock, it's just a matter of time till his boat sinks, and then it
will be fuel and oil that he'll be fouling the waterways with, not just
sewage...sheesh! A marelon valve is ok as a seacock, but judging by his
statements, I suspect Terry is more of a PVC from Home Depot kind of
guy...
And if you skip the vented loop with your system below the water
line, You stand a good chance of sinking your boat as well, Roger. Do
yourself a favor and check out this link to see how a system should be
constructed, instead of over/under engineering it in your head. This
tutorial will answer all your questions, and it has drawings of all
common configurations....
http://www.westmarine.com/webapp/wcs...tionsystem.htm

....And if you see some dipstick dumping his boat OR RV in a sewer,
call 911 and turn the idiot in..

markvictor wrote:
...And if you see some dipstick dumping his boat OR RV in a sewer,
call 911 and turn the idiot in..

Actually, unless he's sticking a hose down a storm drain--and maybe not
even then, other than aesthetics (which have never seemed to concern
Larry)--there's nothing wrong with it. In fact, it's a lot more
environmentally friendly than dumping a tank at sea. Everything on land
including bird poop ends up in the sewer...and everything in a
sewer--including the contents of all the holding tanks that are pumped
out--ends up in a sewage treatment plant.

I know quite a few people who have trailer boats who've installed
connections to their sewer lines at home so they can dump their tanks.


--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/books...ku=90&cat=1304

Terry K wrote:
My waste tank is purged to the sea or, with an external hose connected,
to the Wall Mart plaza storm sewer like RVers do it

Peggie Hall wrote:

Actually, unless he's sticking a hose down a storm drain--and maybe not
even then, other than aesthetics (which have never seemed to concern
Larry)--there's nothing wrong with it. In fact, it's a lot more
environmentally friendly than dumping a tank at sea. Everything on land
including bird poop ends up in the sewer...and everything in a
sewer--including the contents of all the holding tanks that are pumped
out--ends up in a sewage treatment plant.

You may be a marine sanitation "specialist", but your knowledge of
waste and run-off is blatantly lacking...There IS something wrong with
it...(unless you feel there is nothing wrong with committing a
misdemeanor), bird poop,and Larry"s Wal- Mart deposits, and, as you put
it, "everything on land" does not end up in the sewer, I don't know
what part of Idaho you're from, but in California, the vast majority of
runoff goes to storm drains, barrancas,flood control channels,streams
and rivers, and discharges directly to the harbors and ocean...
nearshore or onshore, about 3 miles shy of the 3 mile limit..Our
beaches are routinely closed by the Health dept. due to elevated levels
of fecal coliform bacteria; bad enough from the"bird poop".. the last
thing we need (or will tolerate) is morons dumping waste in the storm
drains. How you could possibly think that dumping sewage to a storm
drain is more environmentally friendly than at least taking it 3 miles
away from where people live, work, swim, surf, etc. is beyond logic.
Perhaps you've got stock in a gammaglobulin manufacturer...I'm sorry
Peggy, you may be adept at odor control, but your knowledge of
sanitation stinks....
So, I guess it's OK to pee in YOUR pool...

Terry K wrote:
My waste tank is purged to the sea or, with an external hose connected,
to the Wall Mart plaza storm sewer like RVers do it

Peggie Hall wrote:
Actually, unless he's sticking a hose down a storm drain--and maybe not
even then, other than aesthetics (which have never seemed to concern
Larry)--there's nothing wrong with it. In fact, it's a lot more
environmentally friendly than dumping a tank at sea. Everything on land
including bird poop ends up in the sewer...and everything in a
sewer--including the contents of all the holding tanks that are pumped
out--ends up in a sewage treatment plant.

You may be a marine sanitation "specialist", but your knowledge of
waste and run-off is blatantly lacking...There IS something wrong with
it...(unless you feel there is nothing wrong with committing a
misdemeanor), bird poop,and Terry"s Wal- Mart deposits, and, as you put
it, "everything on land" does not end up in the sewer, I don't know
what part of Idaho you're from, but in California, the vast majority of
runoff goes to storm drains, barrancas,flood control channels,streams
and rivers, and discharges directly to the harbors and ocean...
nearshore or onshore, about 3 miles shy of the 3 mile limit..Our
beaches are routinely closed by the Health dept. due to elevated levels
of fecal coliform bacteria; bad enough from the"bird poop".. the last
thing we need (or will tolerate) is morons dumping waste in the storm
drains. How you could possibly think that dumping sewage to a storm
drain is more environmentally friendly than at least taking it 3 miles
away from where people live, work, swim, surf, etc. is beyond logic.
Perhaps you've got stock in a gammaglobulin manufacturer...I'm sorry
Peggy, you may be adept at odor control, but your knowledge of
sanitation stinks....
So, I guess it's OK to pee in YOUR pool...

It may not be such a bad idea (I'm not taking Terry seriously about the
storm sewer), IMHO.
I came up with the same idea because of head system odors that I was
convinced came through the thin diaphragm of the manual pump installed for
pumping out the tank. I was going to use my dinghy pump. But I ended up
relocating the manual pump to a cockpit locker and that was the end of the
odors...in the cabin.
I appreciate thinking outside the box.

"markvictor" wrote in message
ups.com...
Somebody should stuff Terry K down a storm sewer...
That's just plain ignorant. But with a "plastic ball valve" for a
seacock, it's just a matter of time till his boat sinks, and then it
will be fuel and oil that he'll be fouling the waterways with, not just
sewage...sheesh! A marelon valve is ok as a seacock, but judging by his
statements, I suspect Terry is more of a PVC from Home Depot kind of
guy...
And if you skip the vented loop with your system below the water
line, You stand a good chance of sinking your boat as well, Roger. Do
yourself a favor and check out this link to see how a system should be
constructed, instead of over/under engineering it in your head. This
tutorial will answer all your questions, and it has drawings of all
common configurations....
http://www.westmarine.com/webapp/wcs...tionsystem.htm

...And if you see some dipstick dumping his boat OR RV in a sewer,
call 911 and turn the idiot in..

"markvictor" wrote

And if you skip the vented loop with your system below the water
line, You stand a good chance of sinking your boat as well, Roger.

Yeah, that's what I would say to anyone else myself while wearing my
boat designer's hat. In this case though, some part of the piping is
going to be above the waterline anyway. A slow siphon into the tank,
back through the joker valve, and out the bowl is possible but would
be pretty slow. This isn't part of the system for operation by head
users. It's just an emergency provision for if we get far enough
downeast that we aren't near a pump out. In that case, we'll nip
offshore and do the deed. I'll be doing all the pumping. The seacock
gets opened just before the pump goes on and closed just after pumping
is finished. The pump will have pulled air into the line so a siphon
can't start even if the seacock should be opened by mistake. I'll
take the handle off of this seacock after closing as double insurance.

Sure, I could sink my boat but I would have to turn off the pump
before the tank was empty and then just walk away so that the lines
would be full enough for the reverse siphon to start. I might be that
absent minded but, when I fly my plane, I look at switches that I
could do thousands of dollars of damage and maybe even kill myself by
flipping at the wrong time so I think I can handle it.

In this case, a siphon break would not add significantly to safety and
would be another potential odor leak and maintenance point.

--

Roger Long