comparing water pickups

[Cooper]

Yup, I had a build where I debated the size of hull pickups, (made my own) for the above reasons, wanted the larger diameter at the start of the system, more pressure, reference to a garden hose with a nozzle on the end vs. just the hose. And this would have a greater effect of shooting water out the exhaust (for visual purposes-I like to see a good stream of water). Well stated run with scissors. !!!

Lol I even think I stated my redneck physics there too, got a degree in blowing things up and a minor in repairs ,,,lol.

[tlandauer]

Yes finned would be a benefit, there would be more surface are to exchange heat, more hot metal for the water to pass over.
Think of a one inch sugar cube- having a total surface area of 6 square inches, cut it in half and you add two more square inches of surface area. Now to the extreme crush it up to microns and possibly have a football field sized surface area.

I agree, the fins would increase surface area to dissipate/exchange heat more efficiently.

[St3alth_Frenzy]

hey, I have an idea. Why dont we all submit this as a myth to mythbusters? Like, if we all where to submit it, it might get through.
http://dsc.discovery.com/tv-shows/my...-duct-tape.htm

[iridebikes247]

yah not a bad idea actually lol. I made this post a few weeks ago I came back and this is what I see lol. I suck at physics I'm an accountant to me it just makes sense to really cool as much as you can. I will say though the water pickup can be picking up too much and if it is you could be going faster. I will say I don't have the guts to restrict water flow and check temps something tells me I'll be kicking myself for awhile lol.

[Cooper]

Agreed, if the cooling system is too big (too much drag, too much added weight) that would contradict its function too. And this is also a good debate as every boat system is different and the goal is to cool things as much as possible without adding too much drag. I've always wanted to try and measure the amount of pressure any pick up makes when going in excess of 80mph. It's got to be pretty high, have blown off cooling lines before. That is one problem with having the larger diameter at the start of the system. I always consider the size of the cooling system by the narrowest part, usually the jacket fittings are the most restrictive. An idea for anyone to take on to find out what kinds of pressure are in these systems. Flow would be easy, just put a container inside to collect flow. Humm maybe a project ill try this summer.

[iridebikes247]

Yah the pressure is definitely high I have blown off cooling lines too. I hate using the hose clamps that can slice through the tubing now I just add the smallest drop of CA to the fitting in areas where a razorblade can easily flake off the glue once I remove the tubing. (if need be). Keith Bradley sells black fuel tubing on his site and its unlike anything I've used before. Very very stiff and hard to get on and off but impossible to kink and no way you can blow one of these off.

[Eodman]

Does the guy have a thermometer, has he checked his temps .... if not that's where he should start! Then we would be pissing on everyone! If the temps are OK and comes back cool why all the nonsense?

[Cooper]

.... if not that's where he should start! Then we would be pissing on everyone! ?

???

[iridebikes247]

Started thread to compare flush mount vs rudder vs brass rod transom pickups. The flush mount pickup works differently. The thread sorta turned from one thing into another. Flush mount relies on water pressure as Fluid said, works a bit differently from the more conventional pickups. So on a SAW boat they're great but on a boat that doesn't go over 40, won't work as well. I'm happy this thread went in the direction it did though nothin wrong with having to think once in awhile haha.

[sundog]

Flush mount relies on water pressure as Fluid said, works a bit differently from the more conventional pickups. So on a SAW boat they're great but on a boat that doesn't go over 40, won't work as well.

No, I'm afraid you didn't get the gist of it. On a SAW running for best time/speed, you won't want any pickups because of drag, and because you don't run long enough to matter. Flush mount pickups work great, if you install them in the right location. Fluid was mistaken. He has said before (I see it has been edited) that the water needed to be slowed down enough for the water to absorb the heat. That is wrong. He said in the earlier pages of this post that you should put flush mount pickups under the transom for best results, and that is wrong if you have a modern, stepped hull. Go back and re-read this thread - there is some good info in this thread. You have your flush mount pickups where they won't give optimum results - they should be at the rear of the first step on the sponson(s). Or try a different style pickup, like one that hangs behind the transom, or in the prop wash, or go to a rudder pickup. Just don't locate your flush-mount pickups under the transom of a modern, stepped hull.

[iridebikes247]

interesting sundog. Thanks for the advice. This thread has gotten a lot of gears turning thats for sure.

[Cooper]

Just to point out some things, rudder pickup are probably the most effective for water. Reason being the intake "hole" is directly inline with the direction of the boat. Opening is perpendicular to the direction of travel.
Think of a garden hose,,,ever take a drink from one? Usually you hold the hose perpendicular to your mouth and some of the fast moving water enters your mouth, still allowing you to drink. Now if you held that hose directly facing your mouth (and the hose is turned on full blast for both instances ) and try to take a sip, well you would be lucky if you didn't choke.
Now for a flush pick up it is more like the sipping from the side of the garden hose. Still getting a drink but not choking. I agree for a fast moving boat that sipping should be adequate. (Don't confuse that statement with me saying less water is better because there are more variables-drag)
Now for a protruding tube pick up, that's where the drag can start to be realized, something protruding into the water will create drag.
All of the water systems are creating drag, adding weight, and slowing our boats down. But we need it so it up to each system and circumstance to find the optimal one.
Sun dog I'm just wanting to know where you were saying the more effective location was, towards the front of a boat or towards the back of a boat, wasn't sure where you might be starting at first step. Bow to stern or stern to bow? And agree for the saws really no need for cooling, at least none for the motor. (I do anyway though :).

[sundog]

Sun dog I'm just wanting to know where you were saying the more effective location was, towards the front of a boat or towards the back of a boat, wasn't sure where you might be starting at first step.

Have a looksee at post 34, the pictures will explain it better. Same with stepped mono's, especially those that are fast enough to lift the transom at high speed.

[Cooper]

Ah, I see your logic. If it was mainly running on that area wouldn't it be running really really wet? And set up adjusted? (I'm not doubting you as I'm not at mono guy, all cats for me. I do have several but not that technical with them. ).