"Jonathan Ganz" wrote

I took a look at the WM site and found an example of a vented loop. Looks
like it might fit, but I'm not sure where yet. It can either be within a
foot or so, or it would have to be at least 3 feet away in the engine
space. I'll have to check it out.


The vent has to be above the discharge and waterline for there to be any
point to it. "within a foot or so" would be OK if you just mean the lateral
distance and not the hose length. The loop should be just as high in the
boat as you can get it, ideally, just under the deck. If your bilge
discharge is high enough above the waterline, you don't really need a vented
loop except to keep surveyors happy. My bilge discharges are just ahead of
the transom and nearly a foot above the water line so I haven't added vents
to the lines which loop even higher under the cockpit coaming. It's
something I'll probably do before going very far off shore though. If the
boat was low in the water due to flooding and the pumps stopped, a back
siphon could be created.

--
Roger Long

"Roger Long" wrote in message
...
"Jonathan Ganz" wrote

I took a look at the WM site and found an example of a vented loop. Looks
like it might fit, but I'm not sure where yet. It can either be within a
foot or so, or it would have to be at least 3 feet away in the engine
space. I'll have to check it out.


The vent has to be above the discharge and waterline for there to be any
point to it. "within a foot or so" would be OK if you just mean the
lateral distance and not the hose length. The loop should be just as high
in the boat as you can get it, ideally, just under the deck. If your
bilge discharge is high enough above the waterline, you don't really need
a vented loop except to keep surveyors happy. My bilge discharges are
just ahead of the transom and nearly a foot above the water line so I
haven't added vents to the lines which loop even higher under the cockpit
coaming. It's something I'll probably do before going very far off shore
though. If the boat was low in the water due to flooding and the pumps
stopped, a back siphon could be created.

--
Roger Long


Good grief! More vented loop idiocy. STOP THE INSANITY!!!!!!

You vented loop people are confused. Vented loops are a good thing in a
sewage system so your toilet doesn't flood out of the bowl and fill up your
boat. They are a safety device to break any possibility of a siphon on the
intake side of a toilet. The intake side is necessarily placed under the LWL

To put one on a bilge pump is folly - pure folly. In order to keep a bilge
pump from siphoning all one needs do is have the bilge pump discharge above
the LWL of the vessel.

Place the discharge thru-hull about two feet up from the LWL and on the
transom and you have ABSOLUTELY NO NEED for a vented loop. Duh! But, that
idiot drug sponge Ganze will probably install one anyway since he has my
wisdom kill filed. Somebody else please clue the loser in.

Tarnal hell but you Rubes have no business anywhere near the water. Joe
juniors all of you!

Wilbur Hubbard

In article ,
Roger Long wrote:
"Jonathan Ganz" wrote

I took a look at the WM site and found an example of a vented loop. Looks
like it might fit, but I'm not sure where yet. It can either be within a
foot or so, or it would have to be at least 3 feet away in the engine
space. I'll have to check it out.


The vent has to be above the discharge and waterline for there to be any
point to it. "within a foot or so" would be OK if you just mean the lateral
distance and not the hose length. The loop should be just as high in the
boat as you can get it, ideally, just under the deck. If your bilge
discharge is high enough above the waterline, you don't really need a vented
loop except to keep surveyors happy. My bilge discharges are just ahead of
the transom and nearly a foot above the water line so I haven't added vents
to the lines which loop even higher under the cockpit coaming. It's
something I'll probably do before going very far off shore though. If the
boat was low in the water due to flooding and the pumps stopped, a back
siphon could be created.

This is an area that I need to investigate. I was down at the boat and took some time to look at the situation that develops. It looks like there's enough back-pressure on the line that it ends up jamming the flapper against the body of the valve enough to cause it to jam (not every time, but often enough, obviously). When I get in there with a screwdriver and force it open, the water that's trapped comes shooting out with a fair amount of force.

The discharge is well above the waterline - at least 18" or so, which would mean the loop (as you point out) would have to go higher. It's not a problem at the transom... plenty of room to do that via the stern laz. I definitely need to have something to prevent backflow. We typically get following seas, even coming back from someplace local. Come back through the the Gate, as I did last Sunday, and you definitely get a big following sea.

I'm wondering if there'll be so much backflow that the pump will continue to cycle. What do you think about a vented loop near the transom as you suggest, plus a check valve near the pump? Seems like this would prevent the flooding/back siphon and give the pump a break.

"Wilbur Hubbard" wrote

To put one on a bilge pump is folly - pure folly. In order to keep a bilge
pump from siphoning all one needs do is have the bilge pump discharge
above the LWL of the vessel.


I assume though, that he is looking for a solution that doesn't involve
hauling the boat to relocate a through hull fitting.

With a long hose run, a vented loop can cut the amount of back flow
considerably if placed close to the pump. This makes for a less water in
the bilge even if back flow cycling is not a problem.

As far as keeping the discharge above the waterline, it has to be above the
HEELED waterline. This means near the centerline, thus the stern, on any
boat which is sailed hard which brings up the long hose run issue. The
heeling problem might not be apparent on a 27 foot boat that just sits in
one place but, if you really sail, a discharge near any probable bilge pump
location could start a back siphon while driving hard if the pump goes on
and stops. On a long tack, such as might be done on a passage, you could
end up with a significant amount of water in the boat if the pump failed to
restart.

--
Roger Long

"Jonathan Ganz" wrote

The discharge is well above the waterline - at least 18" or so,

But where longitudinally? It, or the top of the loop, has to be above the
waterline when the boat is heeled to the deckedge. You many not sail that
hard much, but you want the margin. If you are sailing that hard because of
trying to get off a lee shore or being unable to make sail reductions, the
last thing you need is some bilge flooding.

I definitely need to have something to prevent backflow. We typically get
following seas, even coming back from someplace local. Come back through
the the Gate, as I did last Sunday, and you definitely get a big following
sea.

The amount of water a following sea will push back down the hose isn't
likley to be significant. A plain loop up to deck level at the transom will
take care of that.

What do you think about a vented loop near the transom as you suggest,
plus a check valve near the pump?

Repeat after me, NO Check Valves, except in hose ends of hand bilge pumps to
speed priming. They will always have enough crud in them to let the water
flow back slowly and increase the chances of clogging in the other
direction. Standard electric bilge pumps don't have enough pressure head to
push crud through. They can barely clear air locks.

Check first that you really have a back flow problem. Just replace the
check valve with a nipple connector and run it. If it doesn't cycle when
you shut it off, don't worry about it.

It sounds like your discharge is in the transom, if so, just add enough hose
to create a loop right there. I wouldn't worry about the siphon break for
sailing around the bay. If you get in a situation where you are flooded
enough to bring the static waterline down 18", you'll be on the radio
anyway. The waves coming up astern are not going to push enough water into
the hose to get over a high (unvented) loop and start a siphon.

The water comes up the counter and actually immerses the bilge pump
discharges on "Strider" at full power. I once flooded the bilges a bit and
started the pumps to see if I could get a siphon going. Didn't happen.
Flow past the openings at 6.5 knots makes it pretty hard for water to flow
back into the hoses after the pumps shut off.

--
Roger Long

In article ,
Roger Long wrote:
"Wilbur Hubbard" wrote

To put one on a bilge pump is folly - pure folly. In order to keep a bilge
pump from siphoning all one needs do is have the bilge pump discharge
above the LWL of the vessel.


I assume though, that he is looking for a solution that doesn't involve
hauling the boat to relocate a through hull fitting.

You assume correctly. (Neal is just as ass.) See my other post if you haven't already.

With a long hose run, a vented loop can cut the amount of back flow
considerably if placed close to the pump. This makes for a less water in
the bilge even if back flow cycling is not a problem.

I have two choices about where to locate a loop. One is near the transom. The other is in the engine space, which is perhaps 3 feet from the pump. I'm inclined to think that the latter would make it much more difficult for the pump, having to overcome the height in short distance. The former solution might cause some backflow/pump cycling, but I can't know until I try it. It's certainly easier for the former solution.

As far as keeping the discharge above the waterline, it has to be above the
HEELED waterline. This means near the centerline, thus the stern, on any
boat which is sailed hard which brings up the long hose run issue. The
heeling problem might not be apparent on a 27 foot boat that just sits in
one place but, if you really sail, a discharge near any probable bilge pump
location could start a back siphon while driving hard if the pump goes on
and stops. On a long tack, such as might be done on a passage, you could
end up with a significant amount of water in the boat if the pump failed to
restart.

I would never try to discharge on the side. It's a stern discharge now, and it will remain that way.

"Jonathan Ganz" wrote in message
easolutions...
In article ,
Roger Long wrote:
"Wilbur Hubbard" wrote

To put one on a bilge pump is folly - pure folly. In order to keep a
bilge
pump from siphoning all one needs do is have the bilge pump discharge
above the LWL of the vessel.


I assume though, that he is looking for a solution that doesn't involve
hauling the boat to relocate a through hull fitting.

You assume correctly. (Neal is just as ass.) See my other post if you
haven't already.

Poor Ganz is soooo confused. Not only that, but he is a liar. For, he wrote
the following in this very same thread: "The discharge is well above the
waterline - at least 18" or so, which would mean the loop (as you point out)
would have to go higher."

I ask you how can 18" above the LWL under the water line? Besides, only an
idiot would locate the discharge from a bilge pump below the waterline. Not
even Ganz is that stupid.

Please inform Ganz that he can't have it both ways. Duh. And they gave this
guy a Captain's license? Crying shame.

Wilbur Hubbard

In article ,
Roger Long wrote:
"Jonathan Ganz" wrote

The discharge is well above the waterline - at least 18" or so,

But where longitudinally? It, or the top of the loop, has to be above the
waterline when the boat is heeled to the deckedge. You many not sail that
hard much, but you want the margin. If you are sailing that hard because of
trying to get off a lee shore or being unable to make sail reductions, the
last thing you need is some bilge flooding.

It's about two feet (perhaps a bit more) off centerline.

You can see it he

http://picasaweb.google.com/SailNOW....45247473780210

And here from the port side:

http://picasaweb.google.com/SailNOW....20053195620770

I definitely need to have something to prevent backflow. We typically get
following seas, even coming back from someplace local. Come back through
the the Gate, as I did last Sunday, and you definitely get a big following
sea.

The amount of water a following sea will push back down the hose isn't
likley to be significant. A plain loop up to deck level at the transom will
take care of that.

If that's the case, then I should try it without the vent.

What do you think about a vented loop near the transom as you suggest,
plus a check valve near the pump?

Repeat after me, NO Check Valves, except in hose ends of hand bilge pumps to
speed priming. They will always have enough crud in them to let the water
flow back slowly and increase the chances of clogging in the other
direction. Standard electric bilge pumps don't have enough pressure head to
push crud through. They can barely clear air locks.

No Check Valves.

Check first that you really have a back flow problem. Just replace the
check valve with a nipple connector and run it. If it doesn't cycle when
you shut it off, don't worry about it.

Well, there is a considerable amount of pressure after I clear the current valve with a screwdriver.

It sounds like your discharge is in the transom, if so, just add enough hose
to create a loop right there. I wouldn't worry about the siphon break for
sailing around the bay. If you get in a situation where you are flooded
enough to bring the static waterline down 18", you'll be on the radio
anyway. The waves coming up astern are not going to push enough water into
the hose to get over a high (unvented) loop and start a siphon.

I'll try it. I don't mind putting in a vented loop, however. Is there a significant down-side?

I'm more concerned about the big following seas found just offshore. We were surfing a week ago.

The water comes up the counter and actually immerses the bilge pump
discharges on "Strider" at full power. I once flooded the bilges a bit and
started the pumps to see if I could get a siphon going. Didn't happen.
Flow past the openings at 6.5 knots makes it pretty hard for water to flow
back into the hoses after the pumps shut off.

Interesting..

Here's another pic of the discharge. Not sure why I said it before, but the discharge is on the starboard side, not the port side. The port side is engine discharge. I must be dyslexic today.

http://picasaweb.google.com/SailNOW....20431152743042

"Jonathan Ganz" wrote in message
...
Here's another pic of the discharge. Not sure why I said it before, but
the discharge is on the starboard side, not the port side. The port side
is engine discharge. I must be dyslexic today.


Druglexic more like it. And not just today, everyday.

--
Gregory Hall