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

The location of the loop will have no effect on how hard the pump works, at
least not that can be measured. The easy location, close to the pump, will
have minimum backflow and will be ideal. Only possible drawback I can see
is that the engine heat will make the little rubber flapper in the siphon
break dry out and need replacement slightly sooner. This isn't the big deal
it would be with sewage. Even if it leaks a bit, you probably would never
notices.

Go for it.

Roger

In article ,
Roger Long wrote:
The location of the loop will have no effect on how hard the pump works, at
least not that can be measured. The easy location, close to the pump, will
have minimum backflow and will be ideal. Only possible drawback I can see
is that the engine heat will make the little rubber flapper in the siphon
break dry out and need replacement slightly sooner. This isn't the big deal
it would be with sewage. Even if it leaks a bit, you probably would never
notices.

Go for it.

Famous last words!

So, you think the vented loop would be fine in the engine space vs. in the transom? I don't think the engine temp will have that much of an effect. I'm also going to go to a dripless system at the next haulout.