That’s a great idea, although it may leave loops or sags in the line.
I extended(replaced) mine to lead back to the aft bilge, where filling
the tanks helps keep it clean and smelling fresh.

There is some discussion about venting to areas that are exposed to
seawater. And then there is the issue of tank pressure-the highest
point of the vent provides about 1/2 lb/ft, which translates to
pressure throughout the tank. The tanks don’t look to sturdy to me…

Bob

On 3/31/09, Syringa <> wrote:

I don’t like the settee water tanks dumping over flow water into the fwd
bilge. I have been thinking about rerouting the vent lines into the upper
anchor locker and letting them drain there. Any other ideas?

---

Don Gardner
S/V Syringa #124

/)+/)+~=:)

—
Sent from my mobile device

Bob Fine
s/v Pelican
Hull #8

Post generated from Pearson424 Forum using Mail2Forum

Bob,
I assume you ran the vents directly to the bilge, with no loop to deck level.  Sounds like a good idea.  Even the original owners manual warned of over-filling the tanks and leaving water standing in the fill tube.  I think the combined diameter of the fill (1.5″) and the vent (0.5″) tubes would produce more hydrostatic pressure than .5 lb/ft. 
Thanks, for another project.  While in the Bahamas there is no danger of me overfilling the tanks with $0.20/gallon water and watching it flow out through the bilge pump.  I monitor the filling very closely to avoid that situation.  Back in the states, with no additional charge for water at most marinas, I'm not always that careful.

John

On Wed, Apr 1, 2009 at 8:00 AM, Robert Fine < ([email][/email])> wrote:

That's a great idea, although it may leave loops or sags in the line.
I extended(replaced) mine to lead back to the aft bilge, where filling
the tanks helps keep it clean and smelling fresh.

There is some discussion about venting to areas that are exposed to
seawater. And then there is the issue of tank pressure-the highest
point of the vent provides about 1/2 lb/ft, which translates to
pressure throughout the tank. The tanks don't look to sturdy to me…

Bob

On 3/31/09, Syringa < ([email][/email])> wrote:

I don't like the settee water tanks dumping over flow water into the fwd
bilge.  I have been thinking about rerouting the vent lines into the upper
anchor locker and letting them drain there.  Any other ideas?

---

Don Gardner
S/V Syringa #124

/)+/)+~=:)

—
Sent from my mobile device

Bob Fine
s/v Pelican
Hull #8

---

To unsubscribe, e-mail: ()
For additional commands, e-mail: ()

—
Regards,
John Stevenson
http://www.svsarah.com

Post generated from Pearson424 Forum using Mail2Forum

Hi John,

No, you do need a loop, at least as high above the tank as the distance from the vent to the edge of the tank (so it doesn't siphon when heeled).  You can meet the criteria by laying the vent across the tank, looping it back to the other side of the tank and then to the bilge.  Just so water can't flow out when heeled at the maximum angle. 

As far as the fill line and vent being filled above the tank, it doesn't matter whether you have a 1-1/2″ tube or a 1/2″ tube.  The first law of hydraulics is that pressure in one point of a system is identical in all points of the system.  The pressure applied to the tank has nothing to do with the volume of water – just the height of it.  It's non-intuitive, but true.

Anyway, that's my story and I'm sticking to it.

Bob

On Wed, Apr 1, 2009 at 9:11 AM, John Stevenson < ([email][/email])> wrote:

Bob,
I assume you ran the vents directly to the bilge, with no loop to deck level.  Sounds like a good idea.  Even the original owners manual warned of over-filling the tanks and leaving water standing in the fill tube.  I think the combined diameter of the fill (1.5″) and the vent (0.5″) tubes would produce more hydrostatic pressure than .5 lb/ft. 
Thanks, for another project.  While in the Bahamas there is no danger of me overfilling the tanks with $0.20/gallon water and watching it flow out through the bilge pump.  I monitor the filling very closely to avoid that situation.  Back in the states, with no additional charge for water at most marinas, I'm not always that careful.

John

On Wed, Apr 1, 2009 at 8:00 AM, Robert Fine < ([email][/email])> wrote:

That's a great idea, although it may leave loops or sags in the line.
I extended(replaced) mine to lead back to the aft bilge, where filling
the tanks helps keep it clean and smelling fresh.

There is some discussion about venting to areas that are exposed to
seawater. And then there is the issue of tank pressure-the highest
point of the vent provides about 1/2 lb/ft, which translates to
pressure throughout the tank. The tanks don't look to sturdy to me…

Bob

On 3/31/09, Syringa < ([email][/email])> wrote:

I don't like the settee water tanks dumping over flow water into the fwd
bilge.  I have been thinking about rerouting the vent lines into the upper
anchor locker and letting them drain there.  Any other ideas?

---

Don Gardner
S/V Syringa #124

/)+/)+~=:)

—
Sent from my mobile device

Bob Fine
s/v Pelican
Hull #8

---

To unsubscribe, e-mail: ()
For additional commands, e-mail: ()

—
Regards,
John Stevenson
http://www.svsarah.com

—
Bob Fine
s/v Pelican
Hull #8

Post generated from Pearson424 Forum using Mail2Forum

Thanks, Bob.  Makes sense about the vent loop.  Avoiding the run into the forward cabin lockers will make things a lot easier and help keep moisture out of those lockers.
The hydraulics issue I'll have to think about for awhile.

John

On Wed, Apr 1, 2009 at 10:51 AM, Robert Fine < ([email][/email])> wrote:

Hi John,

No, you do need a loop, at least as high above the tank as the distance from the vent to the edge of the tank (so it doesn't siphon when heeled).  You can meet the criteria by laying the vent across the tank, looping it back to the other side of the tank and then to the bilge.  Just so water can't flow out when heeled at the maximum angle. 

As far as the fill line and vent being filled above the tank, it doesn't matter whether you have a 1-1/2″ tube or a 1/2″ tube.  The first law of hydraulics is that pressure in one point of a system is identical in all points of the system.  The pressure applied to the tank has nothing to do with the volume of water – just the height of it.  It's non-intuitive, but true.

Anyway, that's my story and I'm sticking to it.

Bob

On Wed, Apr 1, 2009 at 9:11 AM, John Stevenson < ([email][/email])> wrote:

Bob,
I assume you ran the vents directly to the bilge, with no loop to deck level.  Sounds like a good idea.  Even the original owners manual warned of over-filling the tanks and leaving water standing in the fill tube.  I think the combined diameter of the fill (1.5″) and the vent (0.5″) tubes would produce more hydrostatic pressure than .5 lb/ft. 
Thanks, for another project.  While in the Bahamas there is no danger of me overfilling the tanks with $0.20/gallon water and watching it flow out through the bilge pump.  I monitor the filling very closely to avoid that situation.  Back in the states, with no additional charge for water at most marinas, I'm not always that careful.

John

On Wed, Apr 1, 2009 at 8:00 AM, Robert Fine < ([email][/email])> wrote:

That's a great idea, although it may leave loops or sags in the line.
I extended(replaced) mine to lead back to the aft bilge, where filling
the tanks helps keep it clean and smelling fresh.

There is some discussion about venting to areas that are exposed to
seawater. And then there is the issue of tank pressure-the highest
point of the vent provides about 1/2 lb/ft, which translates to
pressure throughout the tank. The tanks don't look to sturdy to me…

Bob

On 3/31/09, Syringa < ([email][/email])> wrote:

I don't like the settee water tanks dumping over flow water into the fwd
bilge.  I have been thinking about rerouting the vent lines into the upper
anchor locker and letting them drain there.  Any other ideas?

---

Don Gardner
S/V Syringa #124

/)+/)+~=:)

—
Sent from my mobile device

Bob Fine
s/v Pelican
Hull #8

---

To unsubscribe, e-mail: ()
For additional commands, e-mail: ()

—
Regards,
John Stevenson
http://www.svsarah.com

—

Bob Fine
s/v Pelican
Hull #8

—
Regards,
John Stevenson
http://www.svsarah.com

Post generated from Pearson424 Forum using Mail2Forum

I'm back with you on the pressure vrs weight.

On Wed, Apr 1, 2009 at 11:32 AM, John Stevenson < ([email][/email])> wrote:

Thanks, Bob.  Makes sense about the vent loop.  Avoiding the run into the forward cabin lockers will make things a lot easier and help keep moisture out of those lockers.
The hydraulics issue I'll have to think about for awhile.

John

On Wed, Apr 1, 2009 at 10:51 AM, Robert Fine < ([email][/email])> wrote:

Hi John,

No, you do need a loop, at least as high above the tank as the distance from the vent to the edge of the tank (so it doesn't siphon when heeled).  You can meet the criteria by laying the vent across the tank, looping it back to the other side of the tank and then to the bilge.  Just so water can't flow out when heeled at the maximum angle. 

As far as the fill line and vent being filled above the tank, it doesn't matter whether you have a 1-1/2″ tube or a 1/2″ tube.  The first law of hydraulics is that pressure in one point of a system is identical in all points of the system.  The pressure applied to the tank has nothing to do with the volume of water – just the height of it.  It's non-intuitive, but true.

Anyway, that's my story and I'm sticking to it.

Bob

On Wed, Apr 1, 2009 at 9:11 AM, John Stevenson < ([email][/email])> wrote:

Bob,
I assume you ran the vents directly to the bilge, with no loop to deck level.  Sounds like a good idea.  Even the original owners manual warned of over-filling the tanks and leaving water standing in the fill tube.  I think the combined diameter of the fill (1.5″) and the vent (0.5″) tubes would produce more hydrostatic pressure than .5 lb/ft. 
Thanks, for another project.  While in the Bahamas there is no danger of me overfilling the tanks with $0.20/gallon water and watching it flow out through the bilge pump.  I monitor the filling very closely to avoid that situation.  Back in the states, with no additional charge for water at most marinas, I'm not always that careful.

John

On Wed, Apr 1, 2009 at 8:00 AM, Robert Fine < ([email][/email])> wrote:

That's a great idea, although it may leave loops or sags in the line.
I extended(replaced) mine to lead back to the aft bilge, where filling
the tanks helps keep it clean and smelling fresh.

There is some discussion about venting to areas that are exposed to
seawater. And then there is the issue of tank pressure-the highest
point of the vent provides about 1/2 lb/ft, which translates to
pressure throughout the tank. The tanks don't look to sturdy to me…

Bob

On 3/31/09, Syringa < ([email][/email])> wrote:

I don't like the settee water tanks dumping over flow water into the fwd
bilge.  I have been thinking about rerouting the vent lines into the upper
anchor locker and letting them drain there.  Any other ideas?

---

Don Gardner
S/V Syringa #124

/)+/)+~=:)

—
Sent from my mobile device

Bob Fine
s/v Pelican
Hull #8

---

To unsubscribe, e-mail: ()
For additional commands, e-mail: ()

—
Regards,
John Stevenson
http://www.svsarah.com

—

Bob Fine
s/v Pelican
Hull #8

—
Regards,
John Stevenson
http://www.svsarah.com

—
Regards,
John Stevenson
http://www.svsarah.com

Post generated from Pearson424 Forum using Mail2Forum

Water tank vent should go up from the tank with a smaller hose and then
loop down and dump into a larger tube, leaving an air gap, and thus a
siphon break.

John Stevenson wrote:

Thanks, Bob. Makes sense about the vent loop. Avoiding the run into
the forward cabin lockers will make things a lot easier and help keep
moisture out of those lockers.
The hydraulics issue I’ll have to think about for awhile.

John

On Wed, Apr 1, 2009 at 10:51 AM, Robert Fine <
> wrote:

Hi John,

No, you do need a loop, at least as high above the tank as the
distance from the vent to the edge of the tank (so it doesn’t
siphon when heeled). You can meet the criteria by laying the vent
across the tank, looping it back to the other side of the tank and
then to the bilge. Just so water can’t flow out when heeled at
the maximum angle.

As far as the fill line and vent being filled above the tank, it
doesn’t matter whether you have a 1-1/2″ tube or a 1/2″ tube. The
first law of hydraulics is that pressure in one point of a system
is identical in all points of the system. The pressure applied to
the tank has nothing to do with the volume of water – just the
height of it. It’s non-intuitive, but true.

Anyway, that’s my story and I’m sticking to it.

Bob

On Wed, Apr 1, 2009 at 9:11 AM, John Stevenson
< > wrote:

Bob,
I assume you ran the vents directly to the bilge, with no loop
to deck level. Sounds like a good idea. Even the original
owners manual warned of over-filling the tanks and leaving
water standing in the fill tube. I think the combined
diameter of the fill (1.5″) and the vent (0.5″) tubes would
produce more hydrostatic pressure than .5 lb/ft.
Thanks, for another project. While in the Bahamas there is no
danger of me overfilling the tanks with $0.20/gallon water and
watching it flow out through the bilge pump. I monitor the
filling very closely to avoid that situation. Back in the
states, with no additional charge for water at most marinas,
I’m not always that careful.

John

On Wed, Apr 1, 2009 at 8:00 AM, Robert Fine <
> wrote:

That’s a great idea, although it may leave loops or sags
in the line.
I extended(replaced) mine to lead back to the aft bilge,
where filling
the tanks helps keep it clean and smelling fresh.

There is some discussion about venting to areas that are
exposed to
seawater. And then there is the issue of tank pressure-the
highest
point of the vent provides about 1/2 lb/ft, which
translates to
pressure throughout the tank. The tanks don’t look to
sturdy to me…

Bob

On 3/31/09, Syringa <
> wrote:

I don’t like the settee water tanks dumping over flow

water into the fwd

bilge. I have been thinking about rerouting the vent

lines into the upper

anchor locker and letting them drain there. Any other

ideas?

---

Don Gardner
S/V Syringa #124

/)+/)+~=:)

—
Sent from my mobile device

Bob Fine
s/v Pelican
Hull #8

---

To unsubscribe, e-mail:

For additional commands, e-mail:

—
Regards,
John Stevenson
http://www.svsarah.com <http://www.svsarah.com>

—
Bob Fine
s/v Pelican
Hull #8

—
Regards,
John Stevenson
http://www.svsarah.com <http://www.svsarah.com>

Post generated from Pearson424 Forum using Mail2Forum

Don,
The upper anchor locker can flood in heavy seas if water comes over the bow faster than it can drain out that little drain hole. I wouldn’t suggest putting your vent lines in there. If you haven’t already done it, I suggest sealing the small space under your toe rail above the forward bulkhead to keep water from entering the forward cabin.

A friend with a Vagabond has his vent lines run up inside his stanchions. That’s kind of neat since it keeps them out of the way.

Regards
Rich
BlackSheep #47

Post generated from Pearson424 Forum using Mail2Forum

Basic physics question. Does a column of water 4″ in diameter 4′ high exert the same pressure as a 1″ column 4′ high?

Linus

<.. snip>

Post generated from Pearson424 Forum using Mail2Forum

Short answer: Yes – it is the column height that makes the pressure.

Bob

On Wed, Apr 1, 2009 at 1:28 PM, Linus Martinez < ([email][/email])> wrote:

Ah, but does a 4″ column of Cruzan rum exert the same force as a quart of Mount Gay? This is the question that has plagued Caribbean sailors since the days of yore, or at least since April Fool’s Day.

Tor
~~~~~~~~~~~~~~~~~~~~~~~
Silver Heels, P-424 #17
http://www.SilverHeels.us
~~~~~~~~~~~~~~~~~~

The holding tank vent on my old Catalina 30 went up into a stanchion. It had a pipe welded to the bottom of the stanchion that went through the deck. I like that idea so much, I added another stanchion just like it to vent the water tank.
alan

— On Wed, 4/1/09, <> wrote: