1-1/8" hose size??

[AHoy]

I am replacing a submersible bilge pump with a diaphragm pump. I want to reuse the output hose which is 1-1/8". The output of the new bilge pump is 3/4". I am having no luck finding a barbed adapter between the two. Any ideas how to make this work?

On a side note does anyone now why 1-1/8" is common on bilge pumps?

[peghall]

Are you 100% certain the hose is 1-1/8?" 'Cuz I suspect that's its OUTSIDE diameter. Hose sizes are always stated using the INside diameter....for two reasons: hose wall thickness can vary quite a bit...and they have to fit onto the OUTside of hose fittings? So your bilge pump hose is likely to 1". If the outlet fitting on your new pump really is 3/4 (which would be its OUTside diameter, but that info should be in the manual/instructions), you should be able to get a 3/4-1" adapter.


--Peggie

[model 10]

Every bilge pump I've ever had was 1-1/8", ID. There are Nylon hose adapters that do what you want, you might need to use 2.

[Stu Jackson]

Originally Posted by Ecos

Every bilge pump I've ever had was 1-1/8", ID. There are Nylon hose adapters that do what you want, you might need to use 2.

Me, too. Odd size, but that's it. Good advice on the transition. Good luck.

[peghall]

I'll be darned...I learn something new every day!



--Peggie

[jimbunyard]

I'd just go to the hardware store and cobble something up in the pvc pipe section but if you want something not homemade...

https://www.wakemakers.com/hose-barb-reducer.html



or

https://www.plumbingsupply.com/inser....html#coupling



or

[Privilege]

As an (ever so slightly) thread thrift, you realize that a 3/4" diaphragm pump is going to pump significantly lower water than a 1 1/8" centrifugal pump?

[AHoy]

Originally Posted by Privilege

As an (ever so slightly) thread thrift, you realize that a 3/4" diaphragm pump is going to pump significantly lower water than a 1 1/8" centrifugal pump?

I have a Whitby 42 which originally had a keel fuel tank that are known to leak. The previous owner removed it which left me with a very deep narrow bilge that is nearly impossible to clean. The centrifugal pump didn't move much water because it had a lot of head to overcome and failed shortly after I purchased the boat. The new one will move less water but it should be much more reliable. I also have two centrifugal pumps in the normal accessible bilge area to do the heavy lifting.

From what I can find for adapters, it looks like most people are using a 1" to 3/4" and just clamping it tightly which should work. I haven't been able to find an actual 1-1/8" adapter. It would be nice if bilge pump manufactures would use a standard size of either 1" or 1-1/4".

[Stu Jackson]

Originally Posted by AHoy

I have a Whitby 42 which originally had a keel fuel tank that are known to leak. The previous owner removed it which left me with a very deep narrow bilge that is nearly impossible to clean. The centrifugal pump didn't move much water because it had a lot of head to overcome and failed shortly after I purchased the boat. The new one will move less water but it should be much more reliable. I also have two centrifugal pumps in the normal accessible bilge area to do the heavy lifting.

From what I can find for adapters, it looks like most people are using a 1" to 3/4" and just clamping it tightly which should work. I haven't been able to find an actual 1-1/8" adapter. It would be nice if bilge pump manufactures would use a standard size of either 1" or 1-1/4".

Have you considered a diaphragm pump instead?

[Privilege]

Great, it sounds like you have everything in hand...except for your adapter. I have a similar set-up to yours in that my diaphram pump cleans out the last bit of bilge. I run it to my shower sump so it doesn't need to sit with a large volume of water in the hose.