Peggie Hall writes:

On a powerboat, no....'cuz powerboats don't heel. But on a sailboat,
if the inlet fitting on the tank is toward the hull instead of toward
the centerline of the boat, a loop--though not necessarily a vented
loop--is a good idea to prevent tank contents from running back toward
the toilet when you're heeled.

It's not necessary if the inlet and vent fittings are toward the
centerline because waste in the tank runs to the side away from the
fitting on one tack, the hoses run uphill on the other tack. Worth
remembering when you spec out an installation.

--
Peggie

Peggie,

thanks for all the great work you are doing! I read may of your
postings in different forums and benefitted a lot from your knowledge
in the installation of my holding tank.

However, this one I don't understand. When I read it first I thought
'shoot, my fittings are on the wrong side' since they are towards the
hull. But then I thought again and I don't see what's wrong about it.

Why is holding tank contents more likely to run out of the tank with
the fittings towards the hull than towards the centerline? Let's say
the fittings are on the hull side on the port side (as in my case).
Then, at a certain heel angle to port, the level of liquids inside the
tank will reach the fitting and overflow may occur (yuck). But if the
fittings were towards the centerline, why wouldn't the same occur when
the boat heels by exactly the same angle to starboard??

--Ernst
Columbia 32

Why is holding tank contents more likely to run out of the tank with
the fittings towards the hull than towards the centerline? Let's say
the fittings are on the hull side on the port side (as in my case).
Then, at a certain heel angle to port, the level of liquids inside the
tank will reach the fitting and overflow may occur (yuck).

Yep...because stuff runs downhill...So when you're heeled to port, if
fittings are on the port side of the tank, contents can spill out the
vent or run back toward a head on the port side. But if the tank
fittings are toward the centerline, contents will run to the port side
of the tank when you're heeled to port, but have no place to go because
the lines are on the other side of the tank.

But if the
fittings were towards the centerline, why wouldn't the same occur when
the boat heels by exactly the same angle to starboard??

No, because stuff DOESN'T run UPhill...your head and vent fitting are
still on the port side...right? So when you're heeled to starboard, it's
an uphill run from the centerline to a head and vent thru-hull on the
port side of the boat.

Liquid in a tank is always gonna run toward the low side of the
boat...so it's always gonna run away from any fitting that's toward the
centerline on one tack... any hoses running across the tank from the
side toward the centerline are gonna be running uphill on the other tack.

If the tank is set on the centerline--for instance, a bow-shaped tank
under the v-berth--the fittings should ideally be on the top and in the
center of the tank. But even if they're on the end, tank contents will
run to one side or the other, never toward the hoses, when you're
heeled...the boat would have to be stood on its stern to create a
downhill run in either direction.


--
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

Peggie Hall writes:

But if the
fittings were towards the centerline, why wouldn't the same occur when
the boat heels by exactly the same angle to starboard??

No, because stuff DOESN'T run UPhill...your head and vent fitting are
still on the port side...right? So when you're heeled to starboard,
it's an uphill run from the centerline to a head and vent thru-hull on
the port side of the boat.

Liquid in a tank is always gonna run toward the low side of the
boat...so it's always gonna run away from any fitting that's toward
the centerline on one tack... any hoses running across the tank from
the side toward the centerline are gonna be running uphill on the
other tack.


OK, maybe I understand it now. Do you propose to have the outlet
fitting towards the centerline and the hose then OVER the tank? I
guess that would work, then the 'stuff' would have to run uphill to
get out of the tank.

That would have been hard to achieve in my situation, the tank is
pretty much shoehorned in, to give max. volume. I guess I'll have to
pay attention to not overfilling the tank when on starboard tack...

I have a Lavac toilet (with which I am so far extremely happy). Does
this make me more or less vulnerable to this kind of problem?
Although the outlet valve of the Henderson pump seemed pretty sturdy,
it is my only line of defence, right? Once liquid gets through the
pump, it can flow right out of the toilet.

--Ernst

brain wrote:
OK, maybe I understand it now. Do you propose to have the outlet
fitting towards the centerline and the hose then OVER the tank?

Yes...or across the end of it if there isn't room above it.

That would have been hard to achieve in my situation, the tank is
pretty much shoehorned in, to give max. volume. I guess I'll have to
pay attention to not overfilling the tank when on starboard tack...

If the tank is on the port side and your tank fittings, vent thru-hull
and toilet are too, I think you mean a port tack.

Runback toward the toilet can be solved with a loop in the line.
Depending on how much you heel, preventing waste from overflowing out
the vent can be harder to do.


I have a Lavac toilet (with which I am so far extremely happy). Does
this make me more or less vulnerable to this kind of problem?

That depends on where the pump is mounted, but it should make you a bit
less vulnerable in any case. But not to waste overflowing out the vent.
That can clean to a blocked vent line, so it's important that you
remember to backflush the vent every time you pumpout AND every time you
wash the boat.

Although the outlet valve of the Henderson pump seemed pretty sturdy,
it is my only line of defence, right? Once liquid gets through the
pump, it can flow right out of the toilet.

INTO the toilet. A good reason to pay close attention to any needed
maintenance.

--
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

Peggie Hall writes:


Runback toward the toilet can be solved with a loop in the
line. Depending on how much you heel, preventing waste from
overflowing out the vent can be harder to do.

A loop would be difficult to install. The tank is installed relatively
high, with most of it over the waterline. Two reasons for that: one
because it fits nicely where it is (under the sink in the head), and
the second because it allows me to drain the tank by gravity: There is
a second outlet at the bottom which is connected to the original
thruhull. Of course, this is padlocked to make it legal within 3 miles
of the coast.

If I wanted to install a loop, it would either stick right into the
room over the sink, or I would have to butcher a nice nearby teak
cabinet really badly. Neither seems appealing. (OK, the idea of tank
contents seepage isn't exactly appealing, either...)


I have a Lavac toilet (with which I am so far extremely happy). Does
this make me more or less vulnerable to this kind of problem?

That depends on where the pump is mounted, but it should make you a
bit less vulnerable in any case.

Pump is very close to the tank, at the level of about the top of it.

But not to waste overflowing out the
vent. That can clean to a blocked vent line, so it's important that
you remember to backflush the vent every time you pumpout AND every
time you wash the boat.

Good ideas, but in THAT case I actually did follow your advice: the
vent fittings (yes, I DO have two of them, and they are led to the
bow, port and starboard) are sitting on the top of the tank, in the
centerline. So I should be safe with regard to that.

Although the outlet valve of the Henderson pump seemed pretty sturdy,
it is my only line of defence, right? Once liquid gets through the
pump, it can flow right out of the toilet.

INTO the toilet. A good reason to pay close attention to any needed
maintenance.


Well, that was kind of my point: If it can flow INTO the Lavac toilet,
it can flow OUT of it, right? (the tank is higher than the toilet)
There is no valve or anything in a Lavac that would hold it back.

And the only maintenance I can think of is to make sure the rubber
parts in the Henderson pump are OK, right?

This lack of necessary maintenance/rebuilding was one of the reasons I
picked the Lavac.

--Ernst

Well, that was kind of my point: If it can flow INTO the Lavac toilet,
it can flow OUT of it, right?

Well...ok. If more than the bowl can hold flows in, it'll flow out of
the bowl.


And the only maintenance I can think of is to make sure the rubber
parts in the Henderson pump are OK, right?

Yep.


This lack of necessary maintenance/rebuilding was one of the reasons I
picked the Lavac.

I always have to grin when people tell me the Lavac needs no
maintenance, that only the pump requires occasional--about every 5 years
or so--rebuilding. I don't know of any other toilet BOWLS that require
any maintenance either...MAYBE a new seat/lid every 10 years or
so--which is usually less often than the Lavac needs a new seal. Nor
does any decent quality toilet pump require rebuilding any more often
than about once every 5 years or so as long as it's kept lubricated.

But there's something about putting the pump 2-5' from the bowl instead
of right next to it on the same base that changes everything in people's
minds.

I'm not knocking the Lavac...it's an outstanding toilet--though not
necessarily the right toilet for everyone. But I can't help wondering if
it would have even a fraction of the appeal it has, if it worked exactly
the same way, but the pump and bowl were side-by-side on a single base.

--
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

Peggie Hall writes:

This lack of necessary maintenance/rebuilding was one of the reasons
I
picked the Lavac.

I always have to grin when people tell me the Lavac needs no
maintenance, that only the pump requires occasional--about every 5
years or so--rebuilding. I don't know of any other toilet BOWLS that
require any maintenance either...MAYBE a new seat/lid every 10 years
or so--which is usually less often than the Lavac needs a new
seal. Nor does any decent quality toilet pump require rebuilding any
more often than about once every 5 years or so as long as it's kept
lubricated.

But there's something about putting the pump 2-5' from the bowl
instead of right next to it on the same base that changes everything
in people's minds.

I'm not knocking the Lavac...it's an outstanding toilet--though not
necessarily the right toilet for everyone. But I can't help wondering
if it would have even a fraction of the appeal it has, if it worked
exactly the same way, but the pump and bowl were side-by-side on a
single base.

--
Peggie

You are absolutely right! I never thought of that but it is true,
psychologically it makes a difference. Or, as they say: It is all in
the head

--Ernst

Peggie Hall writes:

This lack of necessary maintenance/rebuilding was one of the reasons
I
picked the Lavac.

I always have to grin when people tell me the Lavac needs no
maintenance, that only the pump requires occasional--about every 5
years or so--rebuilding. I don't know of any other toilet BOWLS that
require any maintenance either...MAYBE a new seat/lid every 10 years
or so--which is usually less often than the Lavac needs a new
seal. Nor does any decent quality toilet pump require rebuilding any
more often than about once every 5 years or so as long as it's kept
lubricated.

But there's something about putting the pump 2-5' from the bowl
instead of right next to it on the same base that changes everything
in people's minds.

I'm not knocking the Lavac...it's an outstanding toilet--though not
necessarily the right toilet for everyone. But I can't help wondering
if it would have even a fraction of the appeal it has, if it worked
exactly the same way, but the pump and bowl were side-by-side on a
single base.

--
Peggie

You are absolutely right! I never thought of that but it is true,
psychologically it makes a difference. Or, as they say: It is all in
the head

--Ernst

Well, that was kind of my point: If it can flow INTO the Lavac toilet,
it can flow OUT of it, right?

Well...ok. If more than the bowl can hold flows in, it'll flow out of
the bowl.


And the only maintenance I can think of is to make sure the rubber
parts in the Henderson pump are OK, right?

Yep.


This lack of necessary maintenance/rebuilding was one of the reasons I
picked the Lavac.

I always have to grin when people tell me the Lavac needs no
maintenance, that only the pump requires occasional--about every 5 years
or so--rebuilding. I don't know of any other toilet BOWLS that require
any maintenance either...MAYBE a new seat/lid every 10 years or
so--which is usually less often than the Lavac needs a new seal. Nor
does any decent quality toilet pump require rebuilding any more often
than about once every 5 years or so as long as it's kept lubricated.

But there's something about putting the pump 2-5' from the bowl instead
of right next to it on the same base that changes everything in people's
minds.

I'm not knocking the Lavac...it's an outstanding toilet--though not
necessarily the right toilet for everyone. But I can't help wondering if
it would have even a fraction of the appeal it has, if it worked exactly
the same way, but the pump and bowl were side-by-side on a single base.

--
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

Peggie Hall writes:


Runback toward the toilet can be solved with a loop in the
line. Depending on how much you heel, preventing waste from
overflowing out the vent can be harder to do.

A loop would be difficult to install. The tank is installed relatively
high, with most of it over the waterline. Two reasons for that: one
because it fits nicely where it is (under the sink in the head), and
the second because it allows me to drain the tank by gravity: There is
a second outlet at the bottom which is connected to the original
thruhull. Of course, this is padlocked to make it legal within 3 miles
of the coast.

If I wanted to install a loop, it would either stick right into the
room over the sink, or I would have to butcher a nice nearby teak
cabinet really badly. Neither seems appealing. (OK, the idea of tank
contents seepage isn't exactly appealing, either...)


I have a Lavac toilet (with which I am so far extremely happy). Does
this make me more or less vulnerable to this kind of problem?

That depends on where the pump is mounted, but it should make you a
bit less vulnerable in any case.

Pump is very close to the tank, at the level of about the top of it.

But not to waste overflowing out the
vent. That can clean to a blocked vent line, so it's important that
you remember to backflush the vent every time you pumpout AND every
time you wash the boat.

Good ideas, but in THAT case I actually did follow your advice: the
vent fittings (yes, I DO have two of them, and they are led to the
bow, port and starboard) are sitting on the top of the tank, in the
centerline. So I should be safe with regard to that.

Although the outlet valve of the Henderson pump seemed pretty sturdy,
it is my only line of defence, right? Once liquid gets through the
pump, it can flow right out of the toilet.

INTO the toilet. A good reason to pay close attention to any needed
maintenance.


Well, that was kind of my point: If it can flow INTO the Lavac toilet,
it can flow OUT of it, right? (the tank is higher than the toilet)
There is no valve or anything in a Lavac that would hold it back.

And the only maintenance I can think of is to make sure the rubber
parts in the Henderson pump are OK, right?

This lack of necessary maintenance/rebuilding was one of the reasons I
picked the Lavac.

--Ernst