Our holding tank is about 10 gallons and is located under the
starboard settee. The connection for the vent hose is at the
forward end of the tank. The hose runs back to an outlet about 3
feet aft and 2 feet above the tank. This gives a rather curvy,
mostly horizontal hose run of about 6 feet. Air can enter and
leave the tank for filling and emptying, but there isn't any real
"air circulation" to prevent odors. It looks like there might be
room to put a new connection at the aft corner of the tank which
would shorten the hose run by 2.5 to 3 feet. The tank is
fiberglass or some kind of very hard plastic. (It's been painted
so it's difficult to tell what it's made from.) We think the tank
is probably 20 years old and was custom made for the boat when it
was built. The vent hose appears to be 1/2 inch ID.

So here are my questions:
1. Would shortening the hose by this amount make any real
difference in the air circulation?
2. Would modifying the tank cause any problems with its
structural integrity?
3. Assuming the answer to 1 is "yes" and 2 is "no", how should we
go about adding the new connector and removing the old one?

Thanks

Cindy

Cindy Ballreich wrote:
Our holding tank is about 10 gallons and is located under the starboard
settee. The connection for the vent hose is at the forward end of the
tank. The hose runs back to an outlet about 3 feet aft and 2 feet above
the tank. This gives a rather curvy, mostly horizontal hose run of about
6 feet. Air can enter and leave the tank for filling and emptying, but
there isn't any real "air circulation" to prevent odors. It looks like
there might be room to put a new connection at the aft corner of the
tank which would shorten the hose run by 2.5 to 3 feet. The tank is
fiberglass or some kind of very hard plastic. (It's been painted so it's
difficult to tell what it's made from.) We think the tank is probably 20
years old and was custom made for the boat when it was built. The vent
hose appears to be 1/2 inch ID.

Cindy, your best solution may be to re-route the vent line to a new
thru-hull forward of the tank. The fitting on the tank is already in the
best place for it...running the vent line forward in the shortest
straightest line possible would help a lot, especially if you can still
keep the rise under 45 degrees and the line length at 3' or less.

Where in the boat is the tank? If it's under the v-berth, a vent line
forword is definitely the best plan.


So here are my questions:
1. Would shortening the hose by this amount make any real difference in
the air circulation?

The shorter and straighter the vent line the better...however, running
aft, shortening it up prob'ly won't make much difference.

2. Would modifying the tank cause any problems with its structural
integrity?

No...new fittings are installed in tanks all the time. But without
knowing for certain what the tank is made of, I can't tell you how to do it/

3. Assuming the answer to 1 is "yes" and 2 is "no", how should we go
about adding the new connector and removing the old one?

I wouldn't remove it...I'd send it to a new thru-hull forward of the tank.

--
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://69.20.93.241/store/customer/p...40&cat=&page=1

If the tank is about 20 years old, I suggest you change it. This is a waist
tank, you do not want it to leak! Listed below is a list of links you should
checkout and read the FAQ and technical info.



http://www.raritaneng.com/



http://www.oceanlinkinc.com/sanitation/index.asp



http://www.groco.net/



http://www.trioniccorp.com/



"Cindy Ballreich" wrote in message
...
Our holding tank is about 10 gallons and is located under the
starboard settee. The connection for the vent hose is at the
forward end of the tank. The hose runs back to an outlet about 3
feet aft and 2 feet above the tank. This gives a rather curvy,
mostly horizontal hose run of about 6 feet. Air can enter and
leave the tank for filling and emptying, but there isn't any real
"air circulation" to prevent odors. It looks like there might be
room to put a new connection at the aft corner of the tank which
would shorten the hose run by 2.5 to 3 feet. The tank is
fiberglass or some kind of very hard plastic. (It's been painted
so it's difficult to tell what it's made from.) We think the tank
is probably 20 years old and was custom made for the boat when it
was built. The vent hose appears to be 1/2 inch ID.

So here are my questions:
1. Would shortening the hose by this amount make any real
difference in the air circulation?
2. Would modifying the tank cause any problems with its
structural integrity?
3. Assuming the answer to 1 is "yes" and 2 is "no", how should we
go about adding the new connector and removing the old one?

Thanks

Cindy

SBC wrote:
If the tank is about 20 years old, I suggest you change it. This is a waist
tank, you do not want it to leak! Listed below is a list of links you should
checkout and read the FAQ and technical info.

Not necessarily...the older tanks are often a lot more durable than
anything made today...many were made of extra thick-walled cross-linked
poly, whereas most water and waste tanks today are made of relatively
thin--1/4" or even less--low density linear poly. In fact, the holding
tank was the only part of the sanitation system I didn't replace on my
own 20 yr old "project boat"...it was so thick I suspect it would only
bounce if dropped off a cliff. That tank will last at least as long as
the hull, if not even longer.

--
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://69.20.93.241/store/customer/p...40&cat=&page=1

Why not just add a second vent line?

--


Keith
__
Would a fly without wings be called a walk?
"Peggie Hall" wrote in message
...

Cindy Ballreich wrote:
Our holding tank is about 10 gallons and is located under the starboard
settee. The connection for the vent hose is at the forward end of the
tank. The hose runs back to an outlet about 3 feet aft and 2 feet above
the tank. This gives a rather curvy, mostly horizontal hose run of about
6 feet. Air can enter and leave the tank for filling and emptying, but
there isn't any real "air circulation" to prevent odors. It looks like
there might be room to put a new connection at the aft corner of the
tank which would shorten the hose run by 2.5 to 3 feet. The tank is
fiberglass or some kind of very hard plastic. (It's been painted so it's
difficult to tell what it's made from.) We think the tank is probably 20
years old and was custom made for the boat when it was built. The vent
hose appears to be 1/2 inch ID.

Cindy, your best solution may be to re-route the vent line to a new
thru-hull forward of the tank. The fitting on the tank is already in the
best place for it...running the vent line forward in the shortest
straightest line possible would help a lot, especially if you can still
keep the rise under 45 degrees and the line length at 3' or less.

Where in the boat is the tank? If it's under the v-berth, a vent line
forword is definitely the best plan.


So here are my questions:
1. Would shortening the hose by this amount make any real difference in
the air circulation?

The shorter and straighter the vent line the better...however, running
aft, shortening it up prob'ly won't make much difference.

2. Would modifying the tank cause any problems with its structural
integrity?

No...new fittings are installed in tanks all the time. But without
knowing for certain what the tank is made of, I can't tell you how to do
it/

3. Assuming the answer to 1 is "yes" and 2 is "no", how should we go
about adding the new connector and removing the old one?

I wouldn't remove it...I'd send it to a new thru-hull forward of the tank.

--
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://69.20.93.241/store/customer/p...40&cat=&page=1

Keith wrote:
Why not just add a second vent line?

From her description of the installation and current vent path, I don't
think a second line would accomplish any more than one relocated to a
new forward through-hull. Adding a second vent line would still require
a new thru-hull, but moving the existing one eliminates the need for a
new fitting in the tank.

--
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://69.20.93.241/store/customer/p...40&cat=&page=1

Peggie Hall wrote:

From her description of the installation and current vent path, I don't
think a second line would accomplish any more than one relocated to a
new forward through-hull. Adding a second vent line would still require
a new thru-hull, but moving the existing one eliminates the need for a
new fitting in the tank.


I don't think we'll be able to move the vent through-hull. Right
now the tank is under the starboard settee, just aft of the head
compartment. We've discussed getting rid of the current tank and
puting a bigger tank under the V-berth. If we do that then we'd
have to install a new vent - although I'm not sure where we could
put it that it wouldn't be submerged from time to time. (The
foredeck can be *very* wet.)

I guess we'll just leave well enough alone for the time being.
Odor-loss seems to be controling the odor. We'd like to do
everything we can reasonably do to keep the head system working
as well as possible.

Cindy