How did you attach the hose to the inside of the pick up you made? did you tap it ans put a fitting in it?
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How did you attach the hose to the inside of the pick up you made? did you tap it ans put a fitting in it?
Cool, Did you through bolt the one in the transom? I always like to see custom ideas rather than the cookie cutter ways of doing things. Hope you don't mind if I steal this one?
I could not through bolt it. I have NO access to the backside. I actually had to attach the hose before installing the pickup. Because I have no access, I had Parker Hose attach the hose to he barb fitting with two stainless bands. That way I dont have to worry about a clamp loosening and it fit through the hole from the outside.
Ill take a pic of the sea strainer setup later.
If you simply mount the transom pickup, what kind of psi will you get at 70mph if its not plumbed through the impeller? That is what pressure will it generate just from going 70mph?
I dont know. My guess is it would be pretty high.I know at 30 psi I can overcome the pressure of my well water pump and screw on a garden hose end although I am going to get pretty wet. I cant imagine being able to hold onto a garden hose and stick it in the water at 70mph.
I have seen plastic live well pumps and pvc valves blow off brass fittings when run at 70mph+ when a scoop strainer is used on the bottom of the boat. My guess is you might see 70-100#s of pressure. Some systems have a blow off valve on them to limit pressure to about 30#s.
Just wanted to add some pics of the final setup:
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You can use the formula for converting pitot pressure to speed to figure what your ram pressure is to your external pickup. The formula is 8.32xSQUAREROOT of pressure=MPH. At 83.2 MPH., you have 100 PSI ram pressure, which the squareroot of 100 is 10, times the 8.32 gives you the 83.2 MPH. So, you can back calculate for other speeds. 8.32*SQRT(PitotPress)=MPH
So if you know your speed, you can divide by 8.32, take that number and square it (multiply it times itself) and you get pressure. So, 70 MPH, divide by 8.32 is 8.413, times itself (8.413x8.413) is 70.778. You get 70.8 PSI for 70 MPH.
If we would have known we could use math to make stuff faster, we would have paid more attention! Hope this helps someone.
Give this man an A+!!!!! Great info! I was wondering when someone was gonna break out the math and the quantification...
I'm wondering how this would work on a V hull with a non-coned motor? I'm currently running a 200 'Rude with the propshaft about 1" below the pad, with the top two holes plugged off on the stock water intakes. I'm getting low 80's with this set up, but I know there's more there yet if I get the motor higher.
On a V-Hull you would need the pick up close the centre of the boat. Could create unwanted disturbance in the water in ft of the prop.
Dave
Chris and those running a transom pickup, At what speed do you start seeing pressure before the water pump?
I have 10 psi at idle and 25 psi at pretty much anything over idle. I have no way of knowing what the pressure is ahead of the pump though.
I may ru it some day without an impeller just to see what happens. Fire it up and get right up on plane. That would give me a pressure created by the pickup and, Ive heard its worth a MPH or so.