I will be installing A through-hull for the overboard discharge soon. I
would like it to be as far forward as possible.I presume that having it
face forward at all would not be a good idea as water will be forced
into it when underway. Is the depth of the discharge a consideration
i.e. just under the waterline or 2 feet underthe waterline.
Tony

TB wrote:
I will be installing A through-hull for the overboard discharge soon. I
would like it to be as far forward as possible.

It should be aft of the head intake. When the discharge is forward of
the intake, waste can be pumped back in and recirculated through the toilet.

If you're installing it to flush the directly overboard at sea, it
should be within 6' of the toilet...because that's as far as bowl
contents will move in the amount of time 99.999% of people will spend
flushing.

If you're installing it to dump the tank, it's necessary to put it
within the pump specifications--how far it can pull and push waste
depending on bends etc. If you're installing an electric macerator pump,
it's especially important that the pump be close enough to the tank to
prime quickly, or the impeller will "fry"...and still be close enough to
the thru-hull to push the waste overboard.

I presume that having it
face forward at all would not be a good idea as water will be forced
into it when underway.

It would, but the thru-hull shouldn't even be open while underway except
when the toilet is actually in use...which is another consideration: in
order for it to be possible to keep it closed except when actually in
us, it should be readily accessible in the head. But why would you want
to "shoot" waste forward anyway??? It should go aft.

Is the depth of the discharge a consideration
i.e. just under the waterline or 2 feet underthe waterline.

Since the waterline on a sailboat changes depending on degree of heel,
it should be low enough on the hull to be at least a foot under water at
any angle of heel. And there should be a vented loop in it that's at
least 8-12" ABOVE the waterline at any angle of heel.

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://www.seaworthy.com/html/get_ri...oat_odors.html

Thanks Peggie, I will be emptying the holding tank not direct discharge.
The through hull will be on the oposite side to the head intake but will
be forward of the engine intake, That means that pumping the tank with
the engine running will be a no-no.

Peggie Hall wrote:

TB wrote:

I will be installing A through-hull for the overboard discharge soon.
I would like it to be as far forward as possible.


It should be aft of the head intake. When the discharge is forward of
the intake, waste can be pumped back in and recirculated through the
toilet.

If you're installing it to flush the directly overboard at sea, it
should be within 6' of the toilet...because that's as far as bowl
contents will move in the amount of time 99.999% of people will spend
flushing.

If you're installing it to dump the tank, it's necessary to put it
within the pump specifications--how far it can pull and push waste
depending on bends etc. If you're installing an electric macerator pump,
it's especially important that the pump be close enough to the tank to
prime quickly, or the impeller will "fry"...and still be close enough to
the thru-hull to push the waste overboard.

I presume that having it face forward at all would not be a good idea
as water will be forced into it when underway.


It would, but the thru-hull shouldn't even be open while underway except
when the toilet is actually in use...which is another consideration: in
order for it to be possible to keep it closed except when actually in
us, it should be readily accessible in the head. But why would you want
to "shoot" waste forward anyway??? It should go aft.

Is the depth of the discharge a consideration i.e. just under the
waterline or 2 feet underthe waterline.


Since the waterline on a sailboat changes depending on degree of heel,
it should be low enough on the hull to be at least a foot under water at
any angle of heel. And there should be a vented loop in it that's at
least 8-12" ABOVE the waterline at any angle of heel.

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://www.seaworthy.com/html/get_ri...oat_odors.html

TB wrote:
Thanks Peggie, I will be emptying the holding tank not direct discharge.
The through hull will be on the oposite side to the head intake but will
be forward of the engine intake, That means that pumping the tank with
the engine running will be a no-no.

A little highly diluted liquified waste shouldn't be a problem for your
engine intake, esepcially if you're moving--even just at idle--while you
dump the tank. But it's still important that the thru-hull be readily
accessible so that it can be kept closed except when dumping the tank.
'Cuz even if the thru-hull doesn't face forward, water can still be
pushed up the hose into the tank by the pressure of the water against
the hull when you're underway...the macerator or pump will slow it down,
but it won't block it. I'd also recommend that you put y-valve, not just
a tee fitting, in your pumpout line...'cuz pumps never fail when a tank
is empty, so you want to be able to cut off the flow from the tank to it.

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://www.seaworthy.com/html/get_ri...oat_odors.html

You wouldn't be worried about the engine sucking in little bits of macerated
toilet paper? Guess it should have dissolved by then, eh?

--


Keith
__
One tequila, two tequila, three tequila, floor.
"Peggie Hall" wrote in message
...
TB wrote:
Thanks Peggie, I will be emptying the holding tank not direct discharge.
The through hull will be on the oposite side to the head intake but will
be forward of the engine intake, That means that pumping the tank with
the engine running will be a no-no.

A little highly diluted liquified waste shouldn't be a problem for your
engine intake, esepcially if you're moving--even just at idle--while you
dump the tank. But it's still important that the thru-hull be readily
accessible so that it can be kept closed except when dumping the tank.
'Cuz even if the thru-hull doesn't face forward, water can still be
pushed up the hose into the tank by the pressure of the water against
the hull when you're underway...the macerator or pump will slow it down,
but it won't block it. I'd also recommend that you put y-valve, not just
a tee fitting, in your pumpout line...'cuz pumps never fail when a tank
is empty, so you want to be able to cut off the flow from the tank to it.

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://www.seaworthy.com/html/get_ri...oat_odors.html

Keith wrote:
You wouldn't be worried about the engine sucking in little bits of macerated
toilet paper? Guess it should have dissolved by then, eh?

It should be...be even if it's not quick-dissolve TP, any "bits" of it
big enough clog up the engine water intake pump most likely would
already have clogged up the macerator.

--
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://www.seaworthy.com/html/get_ri...oat_odors.html

I would hope that there would be a raw water strainer prior to
the engine raw water pump.

Doug
s/v Callista

"Peggie Hall" wrote in message
...
Keith wrote:
You wouldn't be worried about the engine sucking in little bits of
macerated
toilet paper? Guess it should have dissolved by then, eh?

It should be...be even if it's not quick-dissolve TP, any "bits" of it
big enough clog up the engine water intake pump most likely would
already have clogged up the macerator.

--
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://www.seaworthy.com/html/get_ri...oat_odors.html