How connect two bilge pumps to ione thru hull

[rbk]

Just to clarify, are we are talking a secondary elec bilge pump here? I would assume there is an independent manual backup somewhere on a separate thru hull, primary electric another thru hull, and third high water elec pump being dumped into cockpit was my thought or T off a scupper hose.

[JPA Cate]

Originally Posted by J.Kitchens

If you ever needed both pumps at the same time the discharge would be limited by the size of the skin fitting.

The sea chest is a bad idea; you would have to make it large enough to handle the flow of both pumps and tall enough that the level never reaches the input lines from the pumps. How would you empty it? A third bilge pump? Or rely on the current pumps to pressurize the chest? Which would never work.

With check valves on each line one pump could turn off the flow of the other.

Bilge pump systems should be as simple as possible. Maybe you should check the ABYC standards for bilge pumps and share your idea with your insurance company.

This: what is highlighted above. If you ever need both pumps going at once, one small skin fitting is not going to be able to handle the flow from both pumps at once.

Ann

[transmitterdan]

I am confused. You have not one but two bilge pumps that discharges water to a hull opening that is well below the waterline? Isn't that a big design flaw in itself?

[valhalla360]

I think you need to farm the project out to Mr. Goldberg...Rube Goldberg.

Don't fix what isn't broken.

[pcmm]

Originally Posted by xxhat

Want to eliminate one thru hull.


Right now each bilge pump has its own thru hull.


Was thinking of eliminating one by having each pump go to a sea chest then the sea chest goes to the thru hull.


What are others doing ?


How else can I eliminate one thru hull ?


maybe by having one pump go to the cockpit ?


Thanks


jim

Bilge pumps ALWAYS, ALWAYS, ALWAYS get a dedicated discharge thruhull. Preferably this thruhull will also be at or just below the rubrail/sheer! If you have 2 go into one you risk pumping the water back into the boat if the discharge ever gets blocked by something. If you ever need both pumps, having 1 thruhull will limit your ability to pump. And NEVER discharge into the cockpit. least of all because bilge water occasionally get a bit oily. will make a mess on the floor and this way you are also dependant on the scuppers being clear.

Not a good plan. Keep 2 separate thruhulls at the sheer if you can.

[ranger58sb]

Originally Posted by xxhat

Want to eliminate one thru hull.

How else can I eliminate one thru hull ?

Why?

-Chris

[J.Kitchens]

Originally Posted by Uncle Bob

Firstly, if you have forgotten to turn on your bilge pump how will it spray sea water everywhere, and just where did I even mention check valves.
Ignorance reins supreme!!

Let me spell it out for you.

The boat is sinking. This fact causes the water level to rise in the sea chest. The water has no place to go once it fills up the sea chest so it goes into the bilge pump lines. Once the lines are full the sea water will back flow out of the bilge pumps.

[KeelMe]

Originally Posted by J.Kitchens

Let me spell it out for you.

The boat is sinking. This fact causes the water level to rise in the sea chest. The water has no place to go once it fills up the sea chest so it goes into the bilge pump lines. Once the lines are full the sea water will back flow out of the bilge pumps.

Don't forget the bilge pumps are below the water line so not only is the water coming out but it will be under pressure.

[KeelMe]

Originally Posted by pcmm

Bilge pumps ALWAYS, ALWAYS, ALWAYS get a dedicated discharge thruhull. Preferably this thruhull will also be at or just below the rubrail/sheer! If you have 2 go into one you risk pumping the water back into the boat if the discharge ever gets blocked by something. If you ever need both pumps, having 1 thruhull will limit your ability to pump. And NEVER discharge into the cockpit. least of all because bilge water occasionally get a bit oily. will make a mess on the floor and this way you are also dependant on the scuppers being clear.

Not a good plan. Keep 2 separate thruhulls at the sheer if you can.

100% Agreed

[Terra Nova]

Originally Posted by xxhat

Want to eliminate one thru hull.


Right now each bilge pump has its own thru hull.


Was thinking of eliminating one by having each pump go to a sea chest then the sea chest goes to the thru hull...

Such extreme foolishness.

[DLincoln3]

There is a good article in this month's SAIL magazine about this. The author points out that having 2 bilge pumps pumping through a common through-hull is not ideal. The second pump is usually there for redundancy in case the first one fails. So you could have a situation where the second pump is pumping water back down to the dead first pump and back into the bilge. I think what you currently have is the best solution and you should leave it alone, IMO.

[carlheintz]

Now we did something like this on my Sea Wolf. I ran two pumps... and hooked each of them to a check valve ( one way valve) and then to a Y fitting and off to one through-hull. No big problems, easy to do, just remember that every time you have a fitting you have a potential disaster. Double clamp everything.

[Terra Nova]

Originally Posted by carlheintz

...I ran two pumps... and hooked each of them to a check valve ( one way valve) and then to a Y fitting and off to one through-hull...

Very unwise.

[Ken Pole]

The original question did not specify the location of the current through-hulls. I have my manual and electric discharges going to separate outlets just below my toerail. Nigel Calder's 3rd edition mech/elec manual recommends that the discharge hose be "above the highest possible heeled waterline level" with a siphon break at the top of the loop. He also points out that ABYC standards prohibits check valves on discharges below the maximum heeled waterline.

[S/V Illusion]

Originally Posted by Ken Pole

He also points out that ABYC standards prohibits check valves on discharges below the maximum heeled waterline.

And yet some people still do this which is why I am often reluctant to sail on other peoples' boats.
And they rationalize it by saying they haven't had any problem. The only fault is they forgot to add the word "yet" to the end of that claim.