Help, Anybody know Fluid dynamics,water flow, Pickup Tube ?

[Strip Poker 388]

Is Anybody knowledgeable about fluid flow dynamics? I'm working with a Water pickup tube for my innercoolers on my Hustler. It has 90 degree mandrel bends. I've been told that full down is 1 psi per1 mph,and that the pickup will have to much pressure.

The inlet and outlet hasnt been cut yet
Whats going to be the deference on these 2 pieces of lower tubing? Both are 90's, one has a 1.5 radius and original is 2.5.

The reason I replaced the 2.5 to the 1.5 is to make it shorter,It will not fit my knotch and I have to have it 90 degrees to the bottom,its got to look right tooI've got it cut to fit and have adjustiblity of 1.800 up and down. Highest setting is .125 hanging down below the edge of the transom picking up water.

How much drag would it be if adjusted down over 50%, MPH?

Here are some pictures what I'm working with , one is a complete long version with the 2.5 radi. I bought a short version kit not assembled which was still to long by a inch.So I bought a 1.5 peice to raise up the inlet.

Also the new water pickup will be for sale when Im finished.

lower tube is 1.375 od 1.250 id
upper tube is 1.500 od 1.400 id

then to a hose barb 1 1/4 rubber hose

thanks for any help
Rob




http://www.pipeflowcalculations.com/...drop/index.htm


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[Strip Poker 388]

The pictures of the pickup thats welded together is their long version,my version is around 2 inches shorter.and they said it could not be done


I found out the hard way, 1 3/8 od is real hard to find in this radius.

[Griff]

I understand what you're doing, but I have never seen a water pick that faces forward to that extent. I would think that just running it straight down with the trailing edge a 1/4 lower would flow plenty.

[Strip Poker 388]

This is my old one ,it had zero pressure and had about a 1/3 of water ruining thru the sea strainer.the faster the less water and worse aerated

YouTube Video

[Strip Poker 388]

Originally Posted by Griff

I understand what you're doing, but I have never seen a water pick that faces forward to that extent. I would think that just running it straight down with the trailing edge a 1/4 lower would flow plenty.

its not cut on that end yet. It will be like the other one, flush with the transom. It will look like the completed one on the inlet and outlet.sorry for leaving that out.

YouTube Video

[CB-BLR]

This is some interesting stuff.

It is obvious that the innercooler isn't getting a good supply with that setup by looking at your video's.

Chris

[Frequency]

Rob,

I don't think flow equations are gonna solve this for you. Too much variation is possible at the inlet. Water conditions, load, and running attitude will all effect how much you are picking up. I would rather pick up plenty and then dump the excess or choke the flow before the intercooler.

Greg

[WARPARTY36]

We had some issues with blowing braided Stainless lines from too much water pressure at high speeds. Make sure you have a valve near the pick up in case that happens, or a box of tampons to plug the hose. We didn't at the time, and took on water faster then the bilge pumps can keep up with

[TxHawk]

Going to be hard to do without installing it and trimming/testing. I watched this same process on a 42 Fountain. I could not believe how much the smallest adjustments made. A lot depended on the attitude of the boat. When complete, you would have never thought the pickup would take water based on the way it looked on the trailer.

[BBB725]

Rob I took these of a cat at the Miami Boat show, I hope these help