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Author Topic: Water cooling, pick-up positioning  (Read 1257 times)

Paul R

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Water cooling, pick-up positioning
« on: August 28, 2008, 06:33:03 PM »

I have a large retro speed boat (planing hull) 1.1mtr's in lenght with a 3 blade 40mm brass prop powered by a speed 700BB turbo 12v. Where would be the best position to place the pick-up for the water cooling??? I know it needs to go behind the prop , but where exactly... Does the inlet to the pick up tube need to be level with the top of the blades on the prop or does it need to extend further down towards the bottom of the blades on the prop,
 if you know what I mean...

Any help on this matter would be gratefully received.

Paul R
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Peterm

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Re: Water cooling, pick-up positioning
« Reply #1 on: August 28, 2008, 06:50:57 PM »

Paul, on my lifeboat the intake is positioned about half way between the top of the prop and its centre, and about 20mm behind the prop, the intake hole facing the prop.   This works for me.  Pete M
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John W E

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Re: Water cooling, pick-up positioning
« Reply #2 on: August 28, 2008, 08:14:51 PM »

Hi there Paul R

The position of the water pickup should be about level with the centre of the prop about 1/3 of the way in from the tip of the propeller, and, it should be placed on the same side as the rotation of the propeller, in other words - the rotation of the propeller helps to force water up the pickup; I do hope this scribble helps to explain.

aye
john e
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Paul R

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Re: Water cooling, pick-up positioning
« Reply #3 on: August 28, 2008, 11:22:51 PM »

Thanks John, Peter thats great.. I think mine is positioned to far down towards the bottom of the prop, so I'll now make some adjustments, now where did I put my hammer...!

Regards

Paul R
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funtimefrankie

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Re: Water cooling, pick-up positioning
« Reply #4 on: September 01, 2008, 08:25:40 PM »

Could it go in line with the rudder, between the prop and rudder? so there is only one obstruction to the flow from the prop.
Could an intake be built into the rudder shaft?
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TCC

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Re: Water cooling, pick-up positioning
« Reply #5 on: December 05, 2008, 08:40:54 PM »

Hi John
does this slow the boat down?

I ask as I once tried to make water spurts appear from both ides of a MTB hull... I think it was the cooling water from the engine? being expelled both sides? Anyway, I thought a stream of water coming from the port on the hull side would look cool.

So I made a scoop from some 1" plastic (plumbers) pipe and cut the scopp out of that, glued it under the hull behind the point that leaves the water as it planes, cut a hole in the hull and had pipes from that hole to a 'T' connector and whence to these ports.

I got nothing for my trouble exept a hole to fill and a hull to re-paint after it was all removed. I'm just wondering would I have had more success with the pick-up placed like you describe and also would I have entailed a great speed reduction?

Thanks
Paul
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