Curious Case of Bilge Pumps that can't reach the top!

[ditchcrawler]

10 minutes ago, Degobah Schooner said:

I think I'm going to suggest a second skin fitting, being added to accommodate pump two as it’s own separate installation. It seems the most pragmatic and functional - in the long run.  Yet I do love the circuit option as a quick pragmatic fix for now.

 

A good move and probably the best, but remember, if you are doing this for someone else they will come back and say there is still 15mm of water left when the pumps stop.

10 minutes ago, Degobah Schooner said:

Hypothetically and irrespective of the current problematic T situations, would a thinner pipe truly make no difference to how much fluid can travel up a pipe? - given that there would be less water being pumped and thus give the pump more power/capacity, which presumably would allow for a higher quantity of fluid to be pushed up. 🤔

You will never get the water past the TEE. Also the head (back pressure) is a function of the Hight, not volume 

[truckcab79]

You’ll have more luck with a Y fitting than a T. Even so It’s trying to push the water uphill so instead it takes the significantly easier option of going down the other branch to the other pump. 
 

That and fit one way valves before the Y.  Also have the pumps or their switches at slightly different heights so one is your main pump and one is effectively a backup. Separate float switches for each obviously   
 

edit - just scanned through and seen that these two areas are separated.  I’d join them or still do as above if when water would get to a certain height it can overspill into the other. 

Edited February 18 by truckcab79

[aread2]

I'm voting for a second skin fitting. But if you still have to use a single one it might work if the T fitting is at the skin fitting level with the two pipes joining it from above so they both can drain without water flowing down to the other pump.

[ditchcrawler]

3 minutes ago, aread2 said:

I'm voting for a second skin fitting. But if you still have to use a single one it might work if the T fitting is at the skin fitting level with the two pipes joining it from above so they both can drain without water flowing down to the other pump.

Which is how my shower and washbasin work.

[Tracy D'arth]

3 minutes ago, aread2 said:

I'm voting for a second skin fitting. But if you still have to use a single one it might work if the T fitting is at the skin fitting level with the two pipes joining it from above so they both can drain without water flowing down to the other pump.

Said that pages ago, if the junction is above the skin fitting so that both can drain without filling the other.

[nb Innisfree]

Skin fittings: When I fitted out Innisfree (2003 to 2005) I cut something like 12 or 13 holes in 6mm steel, 2 size of bi-metal hole saw, no lubrication and loads of pressure, very rapid, hole saws still sharp and now sitting in my w'shop, though mains drill never quite recovered. 

 

ETA: It took a very strenuous effort so after the first few holes I made up a spring loaded nut & bolt device to apply the pressure while drill did the turning. 

18 minutes ago, nb Innisfree said:

Skin fittings: When I fitted out Innisfree (2003 to 2005) I cut something like 12 or 13 holes in 6mm steel, 2 size of bi-metal hole saw, no lubrication and loads of pressure, very rapid, hole saws still sharp and now sitting in my w'shop, though mains drill never quite recovered. 

 

ETA: It took a very strenuous effort so after the first few holes I made up a spring loaded nut & bolt device to apply the pressure while drill did the turning. 

It took 2 drills actually, first one, 240v 700 odd watts 2 speed 'box soon burnt out, 2nd one was a 240v Dewalt single variable speed, though it smoked a few times it carried on giving good service for a few years before departing to Dewalt heaven, amazing tool RIP. 

Edited February 23 by nb Innisfree

[Peugeot 106]

16 minutes ago, nb Innisfree said:

Skin fittings: When I fitted out Innisfree (2003 to 2005) I cut something like 12 or 13 holes in 6mm steel, 2 size of bi-metal hole saw, no lubrication and loads of pressure, very rapid, hole saws still sharp and now sitting in my w'shop, though mains drill never quite recovered. 

 

ETA: It took a very strenuous effort so after the first few holes I made up a spring loaded nut & bolt device to apply the pressure while drill did the turning. 

Agreed. I’m 72 this year and I nearly dislocated my shoulder. Suggest the elderly and infirm take care and find a fit youth to do the drilling. It’s not skilled but definitely can require some strength especially if it sticks. Action and Reaction are opposite and equal

[nb Innisfree]

11 minutes ago, Peugeot 106 said:

Agreed. I’m 72 this year and I nearly dislocated my shoulder. Suggest the elderly and infirm take care and find a fit youth to do the drilling. It’s not skilled but definitely can require some strength especially if it sticks. Action and Reaction are opposite and equal

I slid a long tube over the side handle, along with my home brewed device it  turned a very physical effort into little effort. Brains, not brawn. 

 

I'm 76 now and shoulders still ok! 🙂

Edited February 23 by nb Innisfree

[Peugeot 106]

8 minutes ago, nb Innisfree said:

I slid a long tube over the side handle, along with my home brewed device it  turned a very physical effort into little effort. Brains, not brawn. 

 

I'm 76 now and shoulders still ok! 🙂

Ok you’ve made me look like a 72 year old weakling which is true. Well done to you. Also I have no side handle on my drill. I guess you took the drill bit out when you  had a centre hole  and inserted a bolt and spring. Cunning I will try that if I have to do it again.  I find with holesaws that they are not all equal and some jam less than others

i’m afraid I much preferred my 9 volt drill. I could do most jobs with it and didn’t risk getting my arms pulled off as can happen with the 18 volt one. Maybe I should use the slipping clutch more often

 

i agree with the OP putting in two skin fittings. Apart from anything else he will get much less drain back into the boat from shorter discharge pipes

 

Anyway I will make a mental note not to pick a fight with you Cheers