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[TomHugill]

Hey folks I'm looking for a water pump to cool the esc in my moonraker. When I bought the boat a pump had been fitted but hadn't been wired in, on it's maiden voyage I hooked up the pickups to esc to see if passive force induction would work. Looks like at the speeds I was running this will be insufficient.

So my question is does anyone know of a pump capable of supplying enough water to two esc and ok to run continuously. The pumps I've seen are all for very intermittent use.

[Subculture]

Where were your pick-ups?

You need pickups in front of the prop blades, as close as you can get to the tips of the blades for maximum effect. With those you'll have all the cooling you require.

Having said that, with a decent quality modern controllers and on modest output, normal air convection will suffice.

[TomHugill]

The moonraker is a jet drive boat; the arrangement of the rear nozzles is going to make it very tricky to have the inlets in the nozzles. For the motors I'm considering these (the top one) one for each motor:

http://www.cornwallmodelboats.co.uk/acatalog/water_cooling.html

The other reason for a pump is so I can cool the esc between speed runs when I'm cruising slower.

[Subculture]

Can't you put a pick a pickup tube in the nozzle just in front of the prop, they usually run fairly inboard on waterjets.

Also have you measured the current draw of the motors? You probably don't need any water cooling unless the ESC's you are using are old, or  cheap rubbish with high resistance FET's.

[TomHugill]

I'll have a better look when I get in but I think there a box built in the transom which the jets fit through. I could get pickups quite far down the jets toward the nozzle but I've found this arrangement not to pull the volume through I'd like.

[TomHugill]

Regarding current I've not tested under load and only have the manufactures specs which would suggest the esc running the two outer jets will be under decent if not punishing loads. I have two robbe 570 navy esc 70A. One is running two speed 700 neodyms (outer jets) the other driving one of the same motors.

[Subculture]

You won't need much flow to very effectively cool the heatsinks on the ESC's. Water is much more effective at dealing with heat than air.

[essex2visuvesi]

I am using a small gear driven pump to cool my huntsmans Esc and motor.... I have a cooling coil round the pump motor as well
http://www.ebay.co.uk/itm/Good-Mini-Water-Gear-Priming-DC-3-12V-RS-360SH-Spray-Pumping-Motor-Aquarium-Z/201129006050?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D24061%26meid%3D8472727542916374120%26pid%3D100005%26prg%3D10244%26rk%3D3%26rkt%3D6%26sd%3D181467979500&rt=nc


I actually have mine linked 3 position switch on the tx with its own Esc, this gives me off, on at scale flow and extreme flow.
The water flows from the pickup to the pump coil, to Esc to drive motor mount.

[TomHugill]

Thanks folks, that actually the pump installed in the moonraker. Out of intrest what radio are you using with a three way switch? I've been thinking one would be very useful for controlling the ballast tank on my sub!

[essex2visuvesi]

Jr 9503x but it's 2.4ghz so no good for subs


there's a laser 6 tx in the for sale section which is the same as I use for my sea wolf sub, I have modified it to give a 3 position switch where the dial control was.
It's an easy job if you're confident with a soldering iron.

[Time Bandit]

Watercooling with the inlet on the pressure side of the jet tunnel should work without a pump.
Never had a problem with my Moonraker.

I use those pumps on 5V in my boats to cool down electrical equipment.
http://www.ebay.de/itm/12V-DC-CPU-Cooling-CAR-Brushless-Water-Oil-Pump-Waterproof-Submersible-System-HY-/151167840455?pt=LH_DefaultDomain_2&hash=item23324e30c7

Advantage is, that you canīt hear them and 30.000h lifetime 
They seem absolutely watertight so far. Never had any leakage in 2 years.
Bad thing is, you have to install them below the waterline, otherwise they are not working, so you should still install the inlet inside the hull that it gives pressure when you run fast.
I glued the the tube (6mm diameter) directly into the outlet of the pump.
Inlet tube is bigger, I think 10mm.

One additional advice use a filter in front of the pump.

[Bill D203]

I use a 12 volt car washer pump in my lifeboat. Now the trick is to feed it via a brushed ESC. Then I use a spare channel switch type and set the end point to run the motor at 65%. The pumps MUST have water in it. So i don't turn it on till some water has been naturally forced up the pickup pipe work. So far  3 years, it work fine and motor on the pump dose not get to hot.