F30 water tank issue

seychellois_lib · June 10, 2008, 2:24pm

Posted by seychellois_lib (mcunningham@…>)

About a year ago I first noticed a strange phenomenon related to
filling my water tank. I was on my summer cruise and was filling at an
overnight stop. I removed the water tank plate on deck and proceeded
to fill as per normal.

Several years ago I took the advice of someone on the board and cut a
small access hatch in the settee cover over the tank so I could
observe the state of fill and visually check the tank level at will.

In any event, I was filling and occasionally keeping an eye on the
fill status. I began to hear a wood cracking sound. I quickly realized
the tank was ballooning out under pressure and was causing some of the
settee assembly screws to tear out. Needless to say I stopped filling
immediately when I realized what was happening. I checked the vented
loop right away assuming that it must have become clogged. In the past
if I overfilled the excess water would simply siphon off through he
vented loop and no problem other than fresh water in the bilge. The
vented loop seemed fine, I could move air into the tank and suck water
out of the tank with a little effort but despite this I was getting
some very significant pressure inside the tank. I could swear I have
overfilled before without seeing this pressure build up and, as
mentioned, just a solid flow of overfill water out the vented loop.

Anyone got any ideas?

Note: I did replace the water pump about 17 months ago but all pump
touches is the pressurized side of the system and the water outlet
from tank to the pump. The timing of the replacement and the new
problem is suspicious but I’m struggling to make a connection. Help.

Alan_Kusinitz · June 10, 2008, 3:13pm

Posted by Alan Kusinitz (akusinitz@…>)

I’m surprised you never saw this
before. Perhaps the water pressure and rate of fill is now higher.
I see this routinely. The vent hose is a
smaller diameter then the fill hose. If I continue filling I hear a pop which
is the tank expanding outward.
See if it happens filling more slowly.
Alan F-33 Hull #51 1982

From: FreedomOwnersGroup@yahoogroups.com [mailto:FreedomOwnersGroup@yahoogroups.com] On Behalf Of seychellois_lib
Sent: Tuesday, June 10, 2008 10:25
AM
To: FreedomOwnersGroup@yahoogroups.com
Subject: [FreedomOwnersGroup] F30
water tank issue

About a year ago I first noticed a strange phenomenon
related to
filling my water tank. I was on my summer cruise and was filling at an
overnight stop. I removed the water tank plate on deck and proceeded
to fill as per normal.

Several years ago I took the advice of someone on the board and cut a
small access hatch in the settee cover over the tank so I could
observe the state of fill and visually check the tank level at will.

In any event, I was filling and occasionally keeping an eye on the
fill status. I began to hear a wood cracking sound. I quickly realized
the tank was ballooning out under pressure and was causing some of the
settee assembly screws to tear out. Needless to say I stopped filling
immediately when I realized what was happening. I checked the vented
loop right away assuming that it must have become clogged. In the past
if I overfilled the excess water would simply siphon off through he
vented loop and no problem other than fresh water in the bilge. The
vented loop seemed fine, I could move air into the tank and suck water
out of the tank with a little effort but despite this I was getting
some very significant pressure inside the tank. I could swear I have
overfilled before without seeing this pressure build up and, as
mentioned, just a solid flow of overfill water out the vented loop.

Anyone got any ideas?

Note: I did replace the water pump about 17 months ago but all pump
touches is the pressurized side of the system and the water outlet
from tank to the pump. The timing of the replacement and the new
problem is suspicious but I’m struggling to make a connection. Help.

\

Roger_L · June 10, 2008, 3:24pm

Posted by Roger L. (rogerlov@…>)

Any tank will expand and contract as it is filled. Normally there is some space left to accommodate that movement. Is it possible that debris has collected next to the wall of the tank and is forming a wedge against the settee wall as the tank “breathes”?
Roger

----- Original Message -----
From: Alan Kusinitz
To: FreedomOwnersGroup@yahoogroups.com
Sent: Tuesday, June 10, 2008 9:13 AM
Subject: RE: [FreedomOwnersGroup] F30 water tank issue

I’m surprised you never saw this before. Perhaps the water pressure and rate of fill is now higher.
I see this routinely. The vent hose is a smaller diameter then the fill hose. If I continue filling I hear a pop which is the tank expanding outward.
See if it happens filling more slowly.
Alan F-33 Hull #51 1982

From: FreedomOwnersGroup@yahoogroups.com [mailto:FreedomOwnersGroup@yahoogroups.com] On Behalf Of seychellois_libSent: Tuesday, June 10, 2008 10:25 AMTo: FreedomOwnersGroup@yahoogroups.comSubject: [FreedomOwnersGroup] F30 water tank issue

About a year ago I first noticed a strange phenomenon related tofilling my water tank. I was on my summer cruise and was filling at anovernight stop. I removed the water tank plate on deck and proceededto fill as per normal. Several years ago I took the advice of someone on the board and cut asmall access hatch in the settee cover over the tank so I couldobserve the state of fill and visually check the tank level at will.In any event, I was filling and occasionally keeping an eye on thefill status. I began to hear a wood cracking sound. I quickly realizedthe tank was ballooning out under pressure and was causing some of thesettee assembly screws to tear out. Needless to say I stopped fillingimmediately when I realized what was happening. I checked the ventedloop right away assuming that it must have become clogged. In the pastif I overfilled the excess water would simply siphon off through hevented loop and no problem other than fresh water in the bilge. Thevented loop seemed fine, I could move air into the tank and suck waterout of the tank with a little effort but despite this I was gettingsome very significant pressure inside the tank. I could swear I haveoverfilled before without seeing this pressure build up and, asmentioned, just a solid flow of overfill water out the vented loop.Anyone got any ideas?Note: I did replace the water pump about 17 months ago but all pumptouches is the pressurized side of the system and the water outletfrom tank to the pump. The timing of the replacement and the newproblem is suspicious but I’m struggling to make a connection. Help.

katorpus1 · June 10, 2008, 3:55pm

Posted by katorpus (jrb@…>)

I doubt that what you are experiencing is any
significant “pressurization” of the tank…unless you have some kind
of “seal” between the supply hose and the inlet port on the deck.

Water won’t compress (measurably), but the air in the void space
above the water level will. This air will “whoosh” out of the vented
loop, relieving any pressure unless the rate of inflow exceeds the
flow capability of air in the loop, in which case, it will “bubble
back” through the column of incoming water between the tank and the
inlet port.

You won’t be experiencing any significant pressurization of the tank
until the tank is full, at which point you will experience
pressurization equal to the pressure of the incoming flow MINUS the
outflow through the vented loop.

It sounds like to me that the static pressure of the weight of the
water in your tank is causing the tank walls to bulge. My tanks are
aluminum and baffled…I don’t know what yours are made of.

If there are internal baffles, I suspect that they may have failed
and the tank walls are flexing from weight alone. If that is the
case, and if the cabinetry is of insufficient strength to contain the
tank without “disassembling itself”, then you will sooner or later
develop a leak in the tank from the flexing and ultimate failure of
tank walls/seams.

Note that this is not something that will be going on ONLY when
filling the tank, but will occur during normal “pounding” of the hull
while sailing.

My tank was built with inspection ports. By your statement of the
need to “cut an access hatch” it sounds like yours was built without
these ports.

My recommendation is to figure out how to strengthen the cabinetry to
the point at which it is not permitting the tank walls to bulge at
any time…otherwise, you’re looking at eventual sudden failure of
the tank which might be very inconvenient if you’re off cruising at
the time.

— In FreedomOwnersGroup@yahoogroups.com, “seychellois_lib”
<mcunningham@…> wrote:

About a year ago I first noticed a strange phenomenon related to
filling my water tank. I was on my summer cruise and was filling at
an
overnight stop. I removed the water tank plate on deck and proceeded
to fill as per normal.

Several years ago I took the advice of someone on the board and cut
a
small access hatch in the settee cover over the tank so I could
observe the state of fill and visually check the tank level at will.

In any event, I was filling and occasionally keeping an eye on the
fill status. I began to hear a wood cracking sound. I quickly
realized
the tank was ballooning out under pressure and was causing some of
the
settee assembly screws to tear out. Needless to say I stopped
filling
immediately when I realized what was happening. I checked the vented
loop right away assuming that it must have become clogged. In the
past
if I overfilled the excess water would simply siphon off through he
vented loop and no problem other than fresh water in the bilge. The
vented loop seemed fine, I could move air into the tank and suck
water
out of the tank with a little effort but despite this I was getting
some very significant pressure inside the tank. I could swear I have
overfilled before without seeing this pressure build up and, as
mentioned, just a solid flow of overfill water out the vented loop.

Anyone got any ideas?

Note: I did replace the water pump about 17 months ago but all pump
touches is the pressurized side of the system and the water outlet
from tank to the pump. The timing of the replacement and the new
problem is suspicious but I’m struggling to make a connection. Help.

Al_Lorman1 · June 10, 2008, 4:22pm

Posted by Al Lorman (ajl@…>)

When
I filled the water tank on my former F30, I found that the air vent loop (brilliantly
located behind the electrical panel) had an almost complete kink in it, so it was
possible to pressurize the tank because the air could not escape. I
solved the problem by making a U out of copper plumbing pipe and attaching the
vent hose to both ends.

Al
Lorman

From:
FreedomOwnersGroup@yahoogroups.com [mailto:FreedomOwnersGroup@yahoogroups.com] On
Behalf Of katorpus
Sent: Tuesday, June 10, 2008 11:56 AM
To: FreedomOwnersGroup@yahoogroups.com
Subject: [FreedomOwnersGroup] Re: F30 water tank issue

\

I doubt that what you are experiencing is any
significant “pressurization” of the tank…unless you have some kind
of “seal” between the supply hose and the inlet port on the deck.

Water won’t compress (measurably), but the air in the void space
above the water level will. This air will “whoosh” out of the vented
loop, relieving any pressure unless the rate of inflow exceeds the
flow capability of air in the loop, in which case, it will “bubble
back” through the column of incoming water between the tank and the
inlet port.

You won’t be experiencing any significant pressurization of the tank
until the tank is full, at which point you will experience
pressurization equal to the pressure of the incoming flow MINUS the
outflow through the vented loop.

It sounds like to me that the static pressure of the weight of the
water in your tank is causing the tank walls to bulge. My tanks are
aluminum and baffled…I don’t know what yours are made of.

If there are internal baffles, I suspect that they may have failed
and the tank walls are flexing from weight alone. If that is the
case, and if the cabinetry is of insufficient strength to contain the
tank without “disassembling itself”, then you will sooner or later
develop a leak in the tank from the flexing and ultimate failure of
tank walls/seams.

Note that this is not something that will be going on ONLY when
filling the tank, but will occur during normal “pounding” of the hull

while sailing.

My tank was built with inspection ports. By your statement of the
need to “cut an access hatch” it sounds like yours was built without
these ports.

My recommendation is to figure out how to strengthen the cabinetry to
the point at which it is not permitting the tank walls to bulge at
any time…otherwise, you’re looking at eventual sudden failure of
the tank which might be very inconvenient if you’re off cruising at
the time.

— In FreedomOwnersGroup@yahoogroups.com,
“seychellois_lib”
<mcunningham@…> wrote:

About a year ago I first noticed a strange phenomenon related to
filling my water tank. I was on my summer cruise and was filling at
an
overnight stop. I removed the water tank plate on deck and proceeded
to fill as per normal.

Several years ago I took the advice of someone on the board and cut
a
small access hatch in the settee cover over the tank so I could
observe the state of fill and visually check the tank level at will.

In any event, I was filling and occasionally keeping an eye on the
fill status. I began to hear a wood cracking sound. I quickly
realized
the tank was ballooning out under pressure and was causing some of
the
settee assembly screws to tear out. Needless to say I stopped
filling
immediately when I realized what was happening. I checked the vented
loop right away assuming that it must have become clogged. In the
past
if I overfilled the excess water would simply siphon off through he
vented loop and no problem other than fresh water in the bilge. The
vented loop seemed fine, I could move air into the tank and suck
water
out of the tank with a little effort but despite this I was getting
some very significant pressure inside the tank. I could swear I have
overfilled before without seeing this pressure build up and, as
mentioned, just a solid flow of overfill water out the vented loop.

Anyone got any ideas?

Note: I did replace the water pump about 17 months ago but all pump
touches is the pressurized side of the system and the water outlet
from tank to the pump. The timing of the replacement and the new
problem is suspicious but I’m struggling to make a connection. Help.

\

Fargo_Rousseau · June 10, 2008, 10:09pm

Posted by Fargo Rousseau (fargo_r@…>)
Al:I also found that nifty location for potential leaks…and also the filler deck fitting can contribute to leaks over the electrical system. Would always reseal the deck fitting if getting into that area for inspection and work… FargoEx F30 #12Al Lorman <ajl@…> wrote: When I filled the water tank on my former F30, I found that the air vent loop (brilliantly located behind the electrical panel) had an
almost complete kink in it, so it was possible to pressurize the tank because the air could not escape. I solved the problem by making a U out of copper plumbing pipe and attaching the vent hose to both ends. Al Lorman From: FreedomOwnersGroup@yahoogroups.com [mailto:FreedomOwnersGroup@yahoogroups.com] On Behalf Of katorpus Sent: Tuesday, June 10, 2008 11:56 AM To: FreedomOwnersGroup@yahoogroups.com Subject: [FreedomOwnersGroup] Re: F30 water tank
issue I doubt that what you are experiencing is any significant “pressurization” of the tank…unless you have some kind of “seal” between the supply hose and the inlet port on the deck. Water won’t compress (measurably), but the air in the void space above the water level will. This air will “whoosh” out of the vented loop, relieving any pressure unless the rate of inflow exceeds the flow capability of air in the loop, in which case, it will “bubble back” through the column of incoming water between the tank and the inlet port. You won’t be experiencing any significant pressurization of the tank until the tank is full, at which point you will experience pressurization equal to the pressure of the incoming flow MINUS the outflow through the vented
loop. It sounds like to me that the static pressure of the weight of the water in your tank is causing the tank walls to bulge. My tanks are aluminum and baffled…I don’t know what yours are made of. If there are internal baffles, I suspect that they may have failed and the tank walls are flexing from weight alone. If that is the case, and if the cabinetry is of insufficient strength to contain the tank without “disassembling itself”, then you will sooner or later develop a leak in the tank from the flexing and ultimate failure of tank walls/seams. Note that this is not something that will be going on ONLY when filling the tank, but will occur during normal “pounding” of the hull while sailing. My tank was built with inspection ports. By your statement of the need to “cut an access hatch” it sounds like yours was built without these ports. My recommendation is to figure out
how to strengthen the cabinetry to the point at which it is not permitting the tank walls to bulge at any time…otherwise, you’re looking at eventual sudden failure of the tank which might be very inconvenient if you’re off cruising at the time. — In FreedomOwnersGroup@yahoogroups.com, “seychellois_lib” <mcunningham@…> wrote: > > About a year ago I first noticed a strange phenomenon related to > filling my water tank. I was on my summer cruise and was filling at an > overnight stop. I removed the water tank plate on deck and proceeded > to fill as per normal. > > Several years ago I took the advice of someone on the board and cut a > small access hatch in the settee cover over the tank so I could > observe the state of fill and visually check the tank level at will. >

In any event, I was filling and occasionally keeping an eye on the > fill status. I began to hear a wood cracking sound. I quickly realized > the tank was ballooning out under pressure and was causing some of the > settee assembly screws to tear out. Needless to say I stopped filling > immediately when I realized what was happening. I checked the vented > loop right away assuming that it must have become clogged. In the past > if I overfilled the excess water would simply siphon off through he > vented loop and no problem other than fresh water in the bilge. The > vented loop seemed fine, I could move air into the tank and suck water > out of the tank with a little effort but despite this I was getting > some very significant pressure inside the tank. I could swear I have > overfilled before without seeing this pressure build up and, as > mentioned, just a
solid flow of overfill water out the vented loop. > > Anyone got any ideas? > > Note: I did replace the water pump about 17 months ago but all pump > touches is the pressurized side of the system and the water outlet > from tank to the pump. The timing of the replacement and the new > problem is suspicious but I’m struggling to make a connection. Help. >

michel.capel · June 11, 2008, 8:43am

Posted by michel.capel (michel.capel@…>)

I had the same thoughts as Katorpus, a torn baffle in the tank. My
tanks are PE (1981 F44) and I don’t know if there are baffles. I do
know that my cabinetry surrounding the tanks is much heavier that
the rest of the cabinetry. I now understand why.

michel

— In FreedomOwnersGroup@yahoogroups.com, “katorpus” <jrb@…>
wrote:

I doubt that what you are experiencing is any
significant “pressurization” of the tank…unless you have some
kind
of “seal” between the supply hose and the inlet port on the deck.

Water won’t compress (measurably), but the air in the void space
above the water level will. This air will “whoosh” out of the
vented
loop, relieving any pressure unless the rate of inflow exceeds the
flow capability of air in the loop, in which case, it will “bubble
back” through the column of incoming water between the tank and
the
inlet port.

You won’t be experiencing any significant pressurization of the
tank
until the tank is full, at which point you will experience
pressurization equal to the pressure of the incoming flow MINUS
the
outflow through the vented loop.

It sounds like to me that the static pressure of the weight of the
water in your tank is causing the tank walls to bulge. My tanks
are
aluminum and baffled…I don’t know what yours are made of.

If there are internal baffles, I suspect that they may have failed
and the tank walls are flexing from weight alone. If that is the
case, and if the cabinetry is of insufficient strength to contain
the
tank without “disassembling itself”, then you will sooner or later
develop a leak in the tank from the flexing and ultimate failure
of
tank walls/seams.

Note that this is not something that will be going on ONLY when
filling the tank, but will occur during normal “pounding” of the
hull
while sailing.

My tank was built with inspection ports. By your statement of the
need to “cut an access hatch” it sounds like yours was built
without
these ports.

My recommendation is to figure out how to strengthen the cabinetry
to
the point at which it is not permitting the tank walls to bulge at
any time…otherwise, you’re looking at eventual sudden failure of
the tank which might be very inconvenient if you’re off cruising
at
the time.

— In FreedomOwnersGroup@yahoogroups.com, “seychellois_lib”
<mcunningham@> wrote:

About a year ago I first noticed a strange phenomenon related to
filling my water tank. I was on my summer cruise and was filling
at
an
overnight stop. I removed the water tank plate on deck and
proceeded
to fill as per normal.

Several years ago I took the advice of someone on the board and
cut
a
small access hatch in the settee cover over the tank so I could
observe the state of fill and visually check the tank level at
will.

In any event, I was filling and occasionally keeping an eye on
the
fill status. I began to hear a wood cracking sound. I quickly
realized
the tank was ballooning out under pressure and was causing some
of
the
settee assembly screws to tear out. Needless to say I stopped
filling
immediately when I realized what was happening. I checked the
vented
loop right away assuming that it must have become clogged. In
the
past
if I overfilled the excess water would simply siphon off through
he
vented loop and no problem other than fresh water in the bilge.
The
vented loop seemed fine, I could move air into the tank and suck
water
out of the tank with a little effort but despite this I was
getting
some very significant pressure inside the tank. I could swear I
have
overfilled before without seeing this pressure build up and, as
mentioned, just a solid flow of overfill water out the vented
loop.

Anyone got any ideas?

Note: I did replace the water pump about 17 months ago but all
pump
touches is the pressurized side of the system and the water
outlet
from tank to the pump. The timing of the replacement and the new
problem is suspicious but I’m struggling to make a connection.
Help.

ron_barr · June 11, 2008, 3:14pm

Posted by ron barr (rwhb@…>)

Anybody know where the vented loop is on the F32?
Normally on a boat it should vent overboard? I can’t
understand why Freedom didn’t put an inspection hatch in the plywood!
Ours seems to overflow somehow into the bilge – I haven’t
had the plywood off yet.

Ron
Hoyt F32
Newport RI

Al_Lorman1 · June 11, 2008, 4:35pm

Posted by Al Lorman (ajl@…>)

By any chance, do you have a clean out access port on your water tank? Since
almost nothing sticks to polyethylene, I know from experience that if you over
fill the thank, water will escape from under the access port and flood the sole.

Al Lorman

Law Office of
Alvin J. Lorman
1629 K Street, NW, Suite 300
Washington, DC 20006
Tel/Fax: 202.263.1100
Cell: 202.236.2359

Sent from my BlackBerry Wireless

-----Original Message-----
From: “ron barr” <rwhb@…>

Date: Wed, 11 Jun 2008 11:14:57
To:<FreedomOwnersGroup@yahoogroups.com>
Subject: [FreedomOwnersGroup] Re:F30 water tank issue

Anybody know where the vented loop is on the F32?
Normally on a boat it should vent overboard? I can’t understand why Freedom
didn’t put an inspection hatch in the plywood!
Ours seems to overflow somehow into the bilge – I haven’t had the plywood off
yet.

Ron
Hoyt F32
Newport RI

Thomas_Wales · June 11, 2008, 6:35pm

Posted by Thomas Wales (twales@…>)

I believe mine goes into the bilge as well. I
have not removed the plywood to inspect either. When you do, please report.
Thanks
TW
Anoush Koon
Pemaquid, ME

At 11:14 AM 6/11/2008, you wrote:

Anybody know where the vented loop is on the F32?

Normally on a boat it should vent overboard? I
can’t understand why Freedom didn’t put an inspection hatch in the plywood!

Ours seems to overflow somehow into the bilge –
I haven’t had the plywood off yet.

Ron

Hoyt F32

Newport RI

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Checked by AVG.
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Release Date: 6/11/2008 8:32 AM

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sward1 · June 12, 2008, 1:23am

Posted by Sward (swardfullsail@…>)
Mine does that too. I have taken the plywood off, but no opening port like the v-berth. I don’t know how it ends up in the bilge either.
“Life is a Reach, then you Jibe”

SWARD— On Wed, 6/11/08, ron barr <rwhb@…> wrote:
From: ron barr <rwhb@…>Subject: [FreedomOwnersGroup] Re:F30 water tank issueTo: FreedomOwnersGroup@yahoogroups.comDate: Wednesday, June 11, 2008, 11:14 AM

Anybody know where the vented loop is on the F32?
Normally on a boat it should vent overboard? I can’t understand why Freedom didn’t put an inspection hatch in the plywood!
Ours seems to overflow somehow into the bilge – I haven’t had the plywood off yet.

Ron
Hoyt F32
Newport RI

michel.capel · June 12, 2008, 8:10am

Posted by michel.capel (michel.capel@…>)

I have inspection ports in the plywood covers over the hose
connections. no claening ports however. I have one 25 gln tank under
the port settee and one 175 gln tank under the forward double berth.
I too was surprised to find the vented loops inside the boat, in my
case (F44) in the mast/chain locker in the bow. This is the highest
point in the boat, so even if the fill hole is overflowing, no water
comes out of the vent loops. Advantage of inside venting that it’s
impossible to get seawater in the tanks. My (unused) black water
tanks are vented outside, without odor filter.

— In FreedomOwnersGroup@yahoogroups.com, “ron barr” <rwhb@…>
wrote:

Anybody know where the vented loop is on the F32?

Normally on a boat it should vent overboard? I can’t understand
why Freedom
didn’t put an inspection hatch in the plywood!

Ours seems to overflow somehow into the bilge - I haven’t had the
plywood
off yet.

Ron

Hoyt F32

Newport RI

michel.capel · June 12, 2008, 8:13am

Posted by michel.capel (michel.capel@…>)

A friend with F44 #5 (1981/2) made a cleanout port in his PE main
watertank. Guess what? After 25 years there was nothing to clean!

— In FreedomOwnersGroup@yahoogroups.com, “Al Lorman” <ajl@…>
wrote:

By any chance, do you have a clean out access port on your water
tank? Since almost nothing sticks to polyethylene, I know from
experience that if you over fill the thank, water will escape from
under the access port and flood the sole.

Al Lorman

Law Office of
Alvin J. Lorman
1629 K Street, NW, Suite 300
Washington, DC 20006
Tel/Fax: 202.263.1100
Cell: 202.236.2359

Sent from my BlackBerry Wireless

-----Original Message-----
From: “ron barr” <rwhb@…>

Date: Wed, 11 Jun 2008 11:14:57
To:<FreedomOwnersGroup@yahoogroups.com>
Subject: [FreedomOwnersGroup] Re:F30 water tank issue

Anybody know where the vented loop is on the F32?
Normally on a boat it should vent overboard? I can’t understand
why Freedom didn’t put an inspection hatch in the plywood!
Ours seems to overflow somehow into the bilge – I haven’t had the
plywood off yet.

Ron
Hoyt F32
Newport RI

seychellois_lib · June 13, 2008, 2:24pm

Posted by seychellois_lib (mcunningham@…>)

Thanks for the responses. I don’t think I have the right answer yet.
The tank is definitely coming under pressure as I fill albeit low
pressure I’m sure. it is clearly not static water load because the top
of the tank is ballooning and I can press down upon the top and feel
strong resistance - similar to a pressurized balloon. I actually stood
on the tank in an attempt to force water out of the vented loop
overfill with no success. The obvious answer seems o be the vented
loop is plugged or kinked but I seem to be able to blow air through
it. I have filled the tank (poly by the way) many many times in the
past and only began to notice this “pressurization” since I replaced
the water pump. I am obviously missing something simple, wish I knew
what it was!!

Fargo_Rousseau · June 13, 2008, 2:48pm

Posted by Fargo Rousseau (fargo_r@…>)
I have been following this thread over the last week but was a bit distracted. I cannot remember if you have told us where your vent loop is located. My F30 (#12) vented the water tank directly into the bilge from somewhere near the top of the tank, with no elevated portion…as I remember. If we filled the tank slowly enough, it just filled up the bilge and we never saw water back up the filler line to the deck level. I think some F30s had an elevated loop. If the vent line is elevated a few feet from the top of the tank(let us take 3 feet as an example), then the pressure pushing up on the top of the tank would be just under 200 pounds per square foot, or more than 1500 pounds pushing up over the whole
top of the tank (feet of head of water divided by 2.3 equals pressure in PSI). Could this be it???FargoEx F30 #12— On Fri, 6/13/08, seychellois_lib <mcunningham@…> wrote:From: seychellois_lib <mcunningham@…>Subject: [FreedomOwnersGroup] Re: F30 water tank issueTo: FreedomOwnersGroup@yahoogroups.comDate: Friday, June 13, 2008, 10:24 AM

Thanks for the responses. I don’t think I have the right answer yet.
The tank is definitely coming under pressure as I fill albeit low
pressure I’m sure. it is clearly not static water load because the top
of the tank is ballooning and I can press down upon the top and feel
strong resistance - similar to a pressurized balloon. I actually stood
on the tank in an attempt to force water out of the vented loop
overfill with no success. The obvious answer seems o be the vented
loop is plugged or kinked but I seem to be able to blow air through
it. I have filled the tank (poly by the way) many many times in the
past and only began to notice this “pressurization” since I replaced
the water pump. I am obviously missing something simple, wish I knew
what it was!!

\

Skipper_Skip1 · June 14, 2008, 12:43am

Posted by Skipper Skip (skipperf33@…>)

OK, this is a bit of a stretch, but is it possible that something has crushed the vented loop and caused it to break?

The crushed portion could still be sealed allowing pressure to build in the tank, while the lose end would allow you to freely blow air through it! Are you sure the air you are blowing into the vented loop is actually making it to the tank?

Not trying to insult your intelligence, just grasping for straws here! You said yourself that you might be missing the obvious:) Is it possible that what you think is the vented loop to this tank, is actually something else? (Ouch!)

Skip:)— On Fri, 6/13/08, seychellois_lib <mcunningham@…> wrote:
From: seychellois_lib <mcunningham@…>Subject: [FreedomOwnersGroup] Re: F30 water tank issueTo: FreedomOwnersGroup@yahoogroups.comDate: Friday, June 13, 2008, 7:24 AM

Thanks for the responses. I don’t think I have the right answer yet.The tank is definitely coming under pressure as I fill albeit lowpressure I’m sure. it is clearly not static water load because the topof the tank is ballooning and I can press down upon the top and feelstrong resistance - similar to a pressurized balloon. I actually stoodon the tank in an attempt to force water out of the vented loopoverfill with no success. The obvious answer seems o be the ventedloop is plugged or kinked but I seem to be able to blow air throughit. I have filled the tank (poly by the way) many many times in thepast and only began to notice this “pressurization” since I replacedthe water pump. I am obviously missing something simple, wish I knewwhat it was!!

katorpus1 · June 14, 2008, 3:02am

Posted by katorpus (jrb@…>)

Uh…Fargo…not to be picky here, but you kinda blew the math on
that one…

Assuming static equilibrium (no flow)…

A column of water 33 feet high and 1" in cross section (a very
generously sized vent hose) weighs 14.7 lbs. Divide that by 11 for a
3 foot high vent loop, and you get 1.34 lbs total of water weight
contained in the vent loop.

The weight of that water is distributed (evenly) over every square
inch (or foot) of the sides, bottom, and top of the tank, adding an
infinitesimal amount of pressure to that which is being exerted on
the tank walls, bottom, and top when the tank is just “level full”.

You DIVIDE the weight of the water over however many square inches of
tank area it’s pushing against…It doesn’t add 1.34 pounds to EVERY
square inch of the tank.

Note that atmospheric pressure (14.7 psi at sea level) is disregarded
here, since the same pressure exerted against the top of the water
column by the atmosphere is being exerted against the walls and top
of the tank from the outside of the tank.

It’s just like you standing on your feet. If you weigh 200 lbs and
your foot has an area of 30 square inches, then you are exerting a
pressure of 6.67 psi when standing still on one foot and HALF that
when standing still on two feet. That’s why snowshoes work.

— In FreedomOwnersGroup@yahoogroups.com, Fargo Rousseau
<fargo_r@…> wrote:

I have been following this thread over the last week but was a bit
distracted. I cannot remember if you have told us where your
vent loop is located. My F30 (#12) vented the water tank
directly into the bilge from somewhere near the top of the tank, with
no elevated portion…as I remember. If we filled the tank slowly
enough, it just filled up the bilge and we never saw water back up
the filler line to the deck level.

I think some F30s had an elevated loop. If the vent
line is elevated a few feet from the top of the tank(let us take 3
feet as an example), then the pressure pushing up on the top of the
tank would be just under 200 pounds per square foot, or more than
1500 pounds pushing up over the whole top of the tank (feet of head
of water divided by 2.3 equals pressure in PSI).

Could this be it???

Fargo
Ex F30 #12

— On Fri, 6/13/08, seychellois_lib mcunningham@… wrote:
From: seychellois_lib mcunningham@…
Subject: [FreedomOwnersGroup] Re: F30 water tank issue
To: FreedomOwnersGroup@yahoogroups.com
Date: Friday, June 13, 2008, 10:24 AM
        Thanks for the responses. I don't think I have the

right answer yet.

The tank is definitely coming under pressure as I fill albeit low

pressure I’m sure. it is clearly not static water load because the
top

of the tank is ballooning and I can press down upon the top and feel

strong resistance - similar to a pressurized balloon. I actually
stood

on the tank in an attempt to force water out of the vented loop

overfill with no success. The obvious answer seems o be the vented

loop is plugged or kinked but I seem to be able to blow air through

it. I have filled the tank (poly by the way) many many times in the

past and only began to notice this “pressurization” since I replaced

the water pump. I am obviously missing something simple, wish I knew

what it was!!

Fargo_Rousseau · June 14, 2008, 1:10pm

Posted by Fargo Rousseau (fargo_r@…>)
I’ll stand by my calculations. It is not the weight of the water in the vent loop that is spread evenly over the internal tank surfaces…it is the PRESSURE of the water. But we still don’t know where this vent loop is located in the problem boat or how high it is. In any event, the tank and attached plumbing was all designed to be safe well above the pressure that would be developed by a completely full fill pipe…full all the way up to the deck. On our F30, I removed the plywood cover over the tank and stored our chart books and other flat things in the space above the tank. Our tank was foamed in place all around the sides…but smooth and bare on top. When completely full to the
deck, it did bulge a bit…but no harm was done… and this condition did not last long (because of the overflow/vent to the bilge). Fargo— On Fri, 6/13/08, katorpus <jrb@…> wrote:From: katorpus <jrb@…>Subject: [FreedomOwnersGroup] Re: F30 water tank issueTo: FreedomOwnersGroup@yahoogroups.comDate: Friday, June 13, 2008, 11:02 PM

Uh…Fargo… .not to be picky here, but you kinda blew the math on
that one…

Assuming static equilibrium (no flow)…

A column of water 33 feet high and 1" in cross section (a very
generously sized vent hose) weighs 14.7 lbs. Divide that by 11 for a
3 foot high vent loop, and you get 1.34 lbs total of water weight
contained in the vent loop.

The weight of that water is distributed (evenly) over every square
inch (or foot) of the sides, bottom, and top of the tank, adding an
infinitesimal amount of pressure to that which is being exerted on
the tank walls, bottom, and top when the tank is just “level full”.

You DIVIDE the weight of the water over however many square inches of
tank area it’s pushing against…It doesn’t add 1.34 pounds to EVERY
square inch of the tank.

Note that atmospheric pressure (14.7 psi at sea level) is disregarded
here, since the same pressure exerted against the top of the water
column by the atmosphere is being exerted against the walls and top
of the tank from the outside of the tank.

It’s just like you standing on your feet. If you weigh 200 lbs and
your foot has an area of 30 square inches, then you are exerting a
pressure of 6.67 psi when standing still on one foot and HALF that
when standing still on two feet. That’s why snowshoes work.

— In FreedomOwnersGroup@ yahoogroups. com, Fargo Rousseau
<fargo_r@… > wrote:

I have been following this thread over the last week but was a bit
distracted.& nbsp; I cannot remember if you have told us where your
vent loop is located. My F30 (#12) vented the water tank
directly into the bilge from somewhere near the top of the tank, with
no elevated portion…as I remember. If we filled the tank slowly
enough, it just filled up the bilge and we never saw water back up
the filler line to the deck level.

I think some F30s had an elevated loop. If the vent
line is elevated a few feet from the top of the tank(let us take 3
feet as an example), then the pressure pushing up on the top of the
tank would be just under 200 pounds per square foot, or more than
1500 pounds pushing up over the whole top of the tank (feet of head
of water divided by 2.3 equals pressure in PSI).

Could this be it???

Fargo
Ex F30 #12

— On Fri, 6/13/08, seychellois_ lib mcunningham@ … wrote:
From: seychellois_ lib mcunningham@ …
Subject: [FreedomOwnersGroup ] Re: F30 water tank issue
To: FreedomOwnersGroup@ yahoogroups. com
Date: Friday, June 13, 2008, 10:24 AM

Thanks for the responses. I don’t think I have the
right answer yet.

The tank is definitely coming under pressure as I fill albeit low

pressure I’m sure. it is clearly not static water load because the
top

of the tank is ballooning and I can press down upon the top and feel

strong resistance - similar to a pressurized balloon. I actually
stood

on the tank in an attempt to force water out of the vented loop

overfill with no success. The obvious answer seems o be the vented

loop is plugged or kinked but I seem to be able to blow air through

it. I have filled the tank (poly by the way) many many times in the

past and only began to notice this “pressurization” since I replaced

the water pump. I am obviously missing something simple, wish I knew

what it was!!

\

Dwight1 · June 14, 2008, 3:50pm

Posted by Dwight (descalera1@…>)

Stick by your calculations Fargo, you correct.
A small pressure over a large area is an example of why hydraulics can be so
powerful.

We are talking pressure here not
weight. The weight of the column of water exerts a pressure per unit area.
For a solid material the shape remains constant, the unit area will remain
constant and the pressure applied to the floor will be the weight divided by
the surface area. If water acted like this, you would be crushed if you
stuck your head 1 foot below the surface of the ocean. 64# per cubic foot
times how many square miles of ocean divided by the surface area of your head,
ouch! Instead you feel the 64# evenly distributed over the entire surface
of your head. You will feel this same pressure regardless of how large the
ocean or small (3/4” dia hose) the body of water is. The deeper you
go the greater the pressure. This is why it is the height of the vent
hose that is important to calculating the pressure. If you open the
faucet and drain the vent hose, approximately 3 fluid oz per foot of hose
length, then this pressure will be released.

This is a drawback to hydraulics.
You can generate great force but sometimes it’s hard to harness it.

Dwight Escalera
Wakefield, RI

From:
FreedomOwnersGroup@yahoogroups.com [mailto:FreedomOwnersGroup@yahoogroups.com] On Behalf Of katorpus
Sent: Friday, June 13, 2008 11:02
PM
To:
FreedomOwnersGroup@yahoogroups.com
Subject: [FreedomOwnersGroup] Re:
F30 water tank issue

Uh…Fargo…not
to be picky here, but you kinda blew the math on
that one…

Assuming static equilibrium (no flow)…

A column of water 33 feet high and 1" in cross section (a very
generously sized vent hose) weighs 14.7 lbs. Divide that by 11 for a
3 foot high vent loop, and you get 1.34 lbs total of water weight
contained in the vent loop.

The weight of that water is distributed (evenly) over every square
inch (or foot) of the sides, bottom, and top of the tank, adding an
infinitesimal amount of pressure to that which is being exerted on
the tank walls, bottom, and top when the tank is just “level full”.

You DIVIDE the weight of the water over however many square inches of
tank area it’s pushing against…It doesn’t add 1.34 pounds to EVERY
square inch of the tank.

Note that atmospheric pressure (14.7 psi at sea level) is disregarded
here, since the same pressure exerted against the top of the water
column by the atmosphere is being exerted against the walls and top
of the tank from the outside of the tank.

It’s just like you standing on your feet. If you weigh 200 lbs and
your foot has an area of 30 square inches, then you are exerting a
pressure of 6.67 psi when standing still on one foot and HALF that
when standing still on two feet. That’s why snowshoes work.

— In FreedomOwnersGroup@yahoogroups.com,
Fargo Rousseau
<fargo_r@…> wrote:

I have been following this thread over the last week but was a bit
distracted. I cannot remember if you have told us where your
vent loop is located. My F30 (#12) vented the water tank
directly into the bilge from somewhere near the top of the tank, with
no elevated portion…as I remember. If we filled the tank slowly
enough, it just filled up the bilge and we never saw water back up
the filler line to the deck level.

I think some F30s had an elevated loop. If the vent
line is elevated a few feet from the top of the tank(let us take 3
feet as an example), then the pressure pushing up on the top of the
tank would be just under 200 pounds per square foot, or more than
1500 pounds pushing up over the whole top of the tank (feet of head
of water divided by 2.3 equals pressure in PSI).

Could this be it???

Fargo
Ex F30 #12

— On Fri, 6/13/08, seychellois_lib mcunningham@… wrote:
From: seychellois_lib mcunningham@…
Subject: [FreedomOwnersGroup] Re: F30 water tank issue
To: FreedomOwnersGroup@yahoogroups.com
Date: Friday, June 13, 2008, 10:24 AM

Thanks for the responses. I don’t think I have the
right answer yet.

The tank is definitely coming under pressure as I fill albeit low

pressure I’m sure. it is clearly not static water load because the
top

of the tank is ballooning and I can press down upon the top and feel

strong resistance - similar to a pressurized balloon. I actually
stood

on the tank in an attempt to force water out of the vented loop

overfill with no success. The obvious answer seems o be the vented

loop is plugged or kinked but I seem to be able to blow air through

it. I have filled the tank (poly by the way) many many times in the

past and only began to notice this “pressurization” since I
replaced

the water pump. I am obviously missing something simple, wish I knew

what it was!!

\

seychellois_lib · June 14, 2008, 5:43pm

Posted by seychellois_lib (mcunningham@…>)

This may be the answer. The vented loop on my 30 hull #3 is looped up
almost to deck level inside the hull and, as someone else noted,
conveniently behind the electrical panel which is a pain to remove for
inspection of the top of the loop. I figured this arrangement might be
at the root of the problem I am seeing however it makes me wonder why
I never saw it before I replaced the water pump.