Water tank vent overboard or bilge
 

Hello,

I have been mulling over the idea of re-routing my water tank vents
from the bilge to an overboard thru-hull vent. I would like to stop
from filling my bilge with water everytime i fill my tanks.

Some people have expressed concern that it opens up the risk of
getting seawater contamination in heavy seas and that the boatbuilder
probably chose to do this on purpose. Since this is a power boat, I
am not worried about creating a siphon from healing over.

I was wondering if anybody has any opinions on why this is a good or
bad idea and any advice on things to consider if I go ahead with this
(such as heights, loops required etc).

Thanks in advance!

Rob

Water tank vent overboard or bilge
 

Rob,

My water tank vent empties into the galley sink. My old boat vent emptied
into the shower stall. I like this arrangement because it does not let in
salt water and we can just watch the sink for an indication as to when the
tank is full.

Cheers

Ansley Sawyer
SV Pacem

Water tank vent overboard or bilge
 

My water tank vent empties into the galley sink. My old boat vent emptied
into the shower stall. I like this arrangement because it does not let in
salt water and we can just watch the sink for an indication as to when the
tank is full.

Neither of those locations is the best place for a water tank vent.
They're both full of bacteria and can also become clogged--in a sump by
soap scum, hair etc...in the galley sink by grease, food particles etc.
Plus, if the sump pump fails or the galley drain gets plugged, shower or
galley water can back up into the vent and even the tank.

Out a through-hull is the best place for a water tank vent...into the
bilge a VERY poor second. At least both of those locations allow you to
flush out the vent by overflowing the tank out it each time you fill 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://69.20.93.241/store/customer/p...40&cat=&page=1

Water tank vent overboard or bilge
 

"orbital" wrote in message
m...

Some people have expressed concern that it opens up the risk of
getting seawater contamination in heavy seas and that the boatbuilder
probably chose to do this on purpose.

Do you get sea water into your fuel tanks? They are certainly vented
overboard!

The boats I have owned have all had the vents mounted through the hull. If
you want to assure that you don't get any seawater back in the vent then run
the vent line as high as you can, but a vented loop at the top, then run the
line back down to the hull. There is no way that any significant amount of
spray is going to migrate several feet up a hose.

Rod

Water tank vent overboard or bilge
 

"Peggie Hall" wrote in message
...


Out a through-hull is the best place for a water tank vent...into the
bilge a VERY poor second.

Why is the bilge such a poor second? The water goes in the bilge. The
bilge pumps pump it out. What's the problem?


At least both of those locations [bilge or through-hull] allow you to
flush out the vent by overflowing the tank out it each time you fill it.


Aside from the problems with galley-sink and shower that you
mentioned how do these locations disallow you from flushing the
water vent by overflowing the tank as you fill it? You overflow
the tank, it goes into the sink/shower and the vent is flushed, no?

Water tank vent overboard or bilge
 

Gary Warner wrote:
"Peggie Hall" wrote in message
...


Out a through-hull is the best place for a water tank vent...into the
bilge a VERY poor second.

Why is the bilge such a poor second? The water goes in the bilge. The
bilge pumps pump it out. What's the problem?

The problem is bilge pumps DON'T pump ALL the water out...which is why
most people do everything possible to keep as much water OUT of the
bilge as possible. 'Cuz the less water that goes into one, the less
there is to turn into a dark smelly swamp.

Aside from the problems with galley-sink and shower that you
mentioned how do these locations disallow you from flushing the
water vent by overflowing the tank as you fill it? You overflow
the tank, it goes into the sink/shower and the vent is flushed, no?

Provided you remember to turn on the sump pump--not too soon, or the
impeller will fry...too late and dirty water in the sump will combine
with the water in the vent and can get back into the tank and
overflow...break out the mop. As often as all of us just stick the hose
in the water fill and and forget it till water running out the vent
reminds us to turn it off, how many of us are that good? :)

Venting it overboard is the only solution that doesn't create more
problems than it solves.

--
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

Water tank vent overboard or bilge
 

Not sure how grease etc is going to leap out of the galley sink into
the vent. Our tanks are vented into the head sinks via a spout in
each. Easy to see when the tanks are full when filling, no problem
with contamination from salt water or anything else. Works great!

Doug
s/v Callista

"Peggie Hall" wrote in message
...
My water tank vent empties into the galley sink. My old boat vent
emptied
into the shower stall. I like this arrangement because it does not let
in
salt water and we can just watch the sink for an indication as to when
the
tank is full.

Neither of those locations is the best place for a water tank vent.
They're both full of bacteria and can also become clogged--in a sump by
soap scum, hair etc...in the galley sink by grease, food particles etc.
Plus, if the sump pump fails or the galley drain gets plugged, shower or
galley water can back up into the vent and even the tank.

Out a through-hull is the best place for a water tank vent...into the
bilge a VERY poor second. At least both of those locations allow you to
flush out the vent by overflowing the tank out it each time you fill 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://69.20.93.241/store/customer/p...40&cat=&page=1

Water tank vent overboard or bilge
 

Comments below.

Doug
s/v Callista

"Rod McInnis" wrote in message
...

"orbital" wrote in message
m...

Some people have expressed concern that it opens up the risk of
getting seawater contamination in heavy seas and that the boatbuilder
probably chose to do this on purpose.

Do you get sea water into your fuel tanks? They are certainly vented
overboard!

Not necessarily. Current school of thought is to vent them in the cockpit.
No problem with overflow overboard (big fine). No problem with
sal****er infiltration. There was an article about it in the past year or so
in Cruising Worls or PS or ON.

The boats I have owned have all had the vents mounted through the hull.
If
you want to assure that you don't get any seawater back in the vent then
run
the vent line as high as you can, but a vented loop at the top, then run
the
line back down to the hull. There is no way that any significant amount
of
spray is going to migrate several feet up a hose.

Spray isn't the problem. Immersion is the potential problem.

Rod

Water tank vent overboard or bilge
 

Doug Dotson wrote:
Not sure how grease etc is going to leap out of the galley sink into
the vent

Prob'ly won't if you never fill the sink to wash dishes or allow any
dirty dishwater to go down the drain.

Our tanks are vented into the head sinks via a spout in
each. Easy to see when the tanks are full when filling...

As long as you're in the head while they're filling... or there's no
plug in the sink if you aren't.

I think the vent should go out the hull. But hey...they're YOUR boats,
so whatever floats 'em for YOU is fine with me.

--
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

Water tank vent overboard or bilge
 

Comments below.

Doug
s/v Callista

"Peggie Hall" wrote in message
...
Doug Dotson wrote:
Not sure how grease etc is going to leap out of the galley sink into
the vent

Prob'ly won't if you never fill the sink to wash dishes or allow any
dirty dishwater to go down the drain.

You don't understand how the vents are installed. They are not
plumbed into the drains. Just empty into the basins.

Our tanks are vented into the head sinks via a spout in
each. Easy to see when the tanks are full when filling...

As long as you're in the head while they're filling... or there's no
plug in the sink if you aren't.

I suppose that not leaving a plug in the drains is a requirement.
Not really a problem.

I think the vent should go out the hull. But hey...they're YOUR boats,
so whatever floats 'em for YOU is fine with me.

To be really safe, put them in the cockit. That way they will drain
out the scuppers and not be so prone to taking in sal****er. Another
option is to put them up the mast a bit. I know someone that did this.
Overflow will go out the fill rather than out the vent. Problem solved
forever.


--
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

Water tank vent overboard or bilge
 

Doug Dotson wrote:

To be really safe, put them in the cockit. That way they will drain
out the scuppers and not be so prone to taking in sal****er. Another
option is to put them up the mast a bit. I know someone that did this.
Overflow will go out the fill rather than out the vent. Problem solved
forever.

I set my water tank vents on the outside of the cockpit coaming just
down hill from the deck fill. When the tank is full water flows across
the side deck and out the scupper. You do have to be careful to locate
the vents so that the overflow will not flow back into the deck fill.

Chartered a boat once that had the vent lines run up inside the
stantions with a vent hole just under the top lifeline. Worked great
but if you were holding the hose when the tank overflowed it would spray
you in the face. :-)


--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Water tank vent overboard or bilge
 

Air vents for the water tanks are just for venting air (to allow air to
enter when water is being pumped out and to allow air to escape when
filling the tank) not for water escape. If you are using them for water
escape, be very careful. WHen filling the tanks you better NOT have too
much pressure. Even .5 psi can put a lot of pressure on the tops of
tanks - 2'x 5'lid = 24"x 60" = 1440 sq in x .5= 720 pound of pressure,
enough to cause the lid to buckle and separate.

When filling, we always remove the input vent on the top of our tanks
and 'watch' the water filling. Even the exhaust vent in the tanks can
cause pressure.


Hanz

Glenn Ashmore wrote:


Doug Dotson wrote:

To be really safe, put them in the cockit. That way they will drain
out the scuppers and not be so prone to taking in sal****er. Another
option is to put them up the mast a bit. I know someone that did this.
Overflow will go out the fill rather than out the vent. Problem solved
forever.


I set my water tank vents on the outside of the cockpit coaming just
down hill from the deck fill. When the tank is full water flows across
the side deck and out the scupper. You do have to be careful to locate
the vents so that the overflow will not flow back into the deck fill.

Chartered a boat once that had the vent lines run up inside the
stantions with a vent hole just under the top lifeline. Worked great
but if you were holding the hose when the tank overflowed it would spray
you in the face. :-)

Water tank vent overboard or bilge
 

Not likely that too much pressure can build in the vent while
overflowing out the fill.

Doug
s/v Callista

"hanz" wrote in message
...
Air vents for the water tanks are just for venting air (to allow air to
enter when water is being pumped out and to allow air to escape when
filling the tank) not for water escape. If you are using them for water
escape, be very careful. WHen filling the tanks you better NOT have too
much pressure. Even .5 psi can put a lot of pressure on the tops of
tanks - 2'x 5'lid = 24"x 60" = 1440 sq in x .5= 720 pound of pressure,
enough to cause the lid to buckle and separate.

When filling, we always remove the input vent on the top of our tanks
and 'watch' the water filling. Even the exhaust vent in the tanks can
cause pressure.


Hanz

Glenn Ashmore wrote:


Doug Dotson wrote:

To be really safe, put them in the cockit. That way they will drain
out the scuppers and not be so prone to taking in sal****er. Another
option is to put them up the mast a bit. I know someone that did this.
Overflow will go out the fill rather than out the vent. Problem solved
forever.


I set my water tank vents on the outside of the cockpit coaming just
down hill from the deck fill. When the tank is full water flows across
the side deck and out the scupper. You do have to be careful to locate
the vents so that the overflow will not flow back into the deck fill.

Chartered a boat once that had the vent lines run up inside the
stantions with a vent hole just under the top lifeline. Worked great
but if you were holding the hose when the tank overflowed it would spray
you in the face. :-)

Water tank vent overboard or bilge
 

On Sat, 26 Jun 2004 10:03:56 -0400, hanz
wrote:

WHen filling the tanks you better NOT have too
much pressure. Even .5 psi can put a lot of pressure on the tops of
tanks - 2'x 5'lid = 24"x 60" = 1440 sq in x .5= 720 pound of pressure,
enough to cause the lid to buckle and separate.

I was thinking of writing along this line because I had that issue
with my fuel tanks. It's easy to get a lot of pressure. Say a water
tank vent outlet (or filler cap) is 6 feet above the tank. By the time
water comes out the vent or filler cap you have about 1/5 atmosphere
or 3 psi in the tank. Fuel is similar, probably 75% of that pressure.
My tank vents are fairly high up a coaming on a center cockpit and the
fuel tanks are under the sole. There's 7-8 feet of head. My tanks
oozed around some fittings that were not used to pressure and around
an inspection port that wasn't really adequately gasketed.

Water tank vent overboard or bilge
 

Peggie Hall wrote in :


The problem is bilge pumps DON'T pump ALL the water out...which is why
most people do everything possible to keep as much water OUT of the
bilge as possible. 'Cuz the less water that goes into one, the less
there is to turn into a dark smelly swamp.


When Geoffrey bought Lionheart, an Amel Sharki ketch, we were horrified to
find that all the sinks, shower, everything but the head, of course, dumped
all that grey water into the BILGE! Geoffrey wanted to put through-hull
fittings under the sinks to get it overboard, directly, but other things
needed doing, first, so it got put off.

After using this arrangement since last August, including a couple of sea
voyages, we've found that this Amel smells a LOT better than his Endeavour
35 sloop BECAUSE of all the grey water sloshing around in the sump down in
the full keel, instead of that little trickle of rain and seawater making
its way into the "biological soup" of the Endeavour.

I think the advanced biology growing in the Endeavour's bilge is killed off
by the antibiotic soap the dishes are washed in that also cleans the oil
and scum out of the Amel's bilge! Amel has a BIG manual electric bilge
pump but the previous owner put in a BIG Rule 4000 gph and a float switch
way down in the bottom. The Rule doesn't do well with food solids that
make it into the bilge, but I just pull the power to it and flush out the
solids with soapy water and the big Amel OEM bilge pump ever so often, when
I think of it.

For some crazy reason, this arrangement works BETTER! Any ideas why,
Peggie?

Larry

Water tank vent overboard or bilge
 

by the antibiotic soap the dishes are washed in that also cleans the oil
and scum out of the Amel's bilge! Amel has a BIG manual electric

Nowdays doesn't the Coast Guard frown on soap being dumped into the water. I
know that they really frown on spilling fuel in the water and spraying Dawn on
it to break the sheen.

Chunks of food and shower water in the bilge if left long enough seem like they
would attract maggots. Don't really know.

Water tank vent overboard or bilge
 

Larry W4CSC wrote:
For some crazy reason, this arrangement works BETTER! Any ideas why,
Peggie?

If it does work better, it definitely isn't due to any "antibiotics" in
dish soap...there aren't any, in dishwashing liquids or any other
"antibacterial" products. It can only be because you have to flush all
that garbage out the bilge fairly regularly to unclog the bilge
pump...which doesn't happen on the Endeavor. Any boat will smell a LOT
better if the bilge is actually flushed out a few times a year instead
of only relying solely on periodic doses of bilge cleaner and the bilge
pump.

--
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

Water tank vent overboard or bilge
 

"Doug Dotson" wrote in message
...

Do you get sea water into your fuel tanks? They are certainly vented
overboard!

Not necessarily. Current school of thought is to vent them in the cockpit.
No problem with overflow overboard (big fine). No problem with
sal****er infiltration.


Who's school of thought is it to vent gas tanks into the cockpit?

It is certainly illegal to have portable tanks (which place the vents inside
the boat) on anything other than an open boat with an outboard. I would
think that it would also be illegal to vent the tank inside the boat. It
certainly doesn't seem like a wise idea.

A properly installed vented loop will prevent any back flow of sea water
into a line. No need to create additional problems and/or hazards.


Rod