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[NobbySideways]

Now that it is clear that this is just "building stuff for the sake of it "(which is perfectly legitimate), one more question: when unpowered does the water pump let water go through ?

I believe so, when I pushed water through with my mouth (nice image for you all) it didn't seem difficult to overcome the pump; Its centrifugal rather than positive displacement.


Derek, I like the way you think. :)

[derekwarner]

Nobby....Camilero raises a good question here  ..surface cooling just like cars but in a marinised version!.......real ships used below hull surface water cooling tubes....for cooling of hydraulic systems

You could build a small closed loop fresh water heat exchanger with a matrix of underwater radiator tubes and powered by your diaphragm pump, this way no need for flushing the cooling water circuit after each days outing to cleanse the cooling internals of the ESC...

One must consider the thermal gradient of the exposed total external surface area of the tube matrix and the velocity or speed of the volume of sea water passing over the tubes as compared to the single slug of cooling water which is represented by the net column length of the ID of the tube from suction to discharge point

To take it to then next step in thermal efficiency you could also consider using ethelyene glycol as the cooling fluid......

For that matter you could also install a second diaphragm pump as an auxiliary .......

My only concern here is you may need to install a heater in the cooling circuit to ensure hell does not freeze over ........

It's all good fun Nobby ....solving these complex challenges.......remember if there is a simple answer.......with a little thought a technically superior solution exists.....but only waiting for our minds to stumble and be enlightened......Derek

[NobbySideways]

It's hard to know if you are serious... 


I notice the huntsman upper structure has cooling vents which Inertia designed to actually operate to aspirate the forward cabin... 

[davidm1945]

 

For that matter you could also install a second diaphragm pump as an auxiliary .......

Of course, powered by a wind turbine mounted on the cabin roof!

This is getting silly, ennit.....

[NobbySideways]

Some of the best ideas start off with the craziest statements... 

[derekwarner]

Sorry David.......& despite my OZ slant on things ....thinking backwards ....the ethelyene glycol closed loop external heat exchanger has real technical advantages  and would not be difficult to manufacture & install

In my steam build and installing a 6mm diameter x 5 mm stroke boiler make up water feed pump at first seemed OK, but was going to be limited by the low paddle shaft speed of ~~ 150 RPM.....

So to overcome this shortfall have installed an identical 6mm diameter x 5 mm stroke pump as an auxiliary drive by a 12V dc motor....which is not all that different to the original question posed by Nobby ......

Most early Australian paddle wheeler engines were non condensing, although a few engines were in fact under hull surfacing condensing.....so essentially no different to what I have suggested here 

Below are the images of both the axel driven pump & the 12 Vdc auxiliary....... Derek

[derekwarner]

Nobby....here is an example of a ships below hull surface water cooling tubes  ..... Derek

[inertia]

I notice the huntsman upper structure has cooling vents which Inertia designed to actually operate to aspirate the forward cabin... 

That was actually more to supply air for the carby (i/c engine, you see). The actual cooling was by.........................scoop and loop! In the end we punched out the front window glazing - far more effective.
DM

[NobbySideways]

Whether or not most of this is directly applicable to my application or not doesn't matter any more, I'm finding this all thoroughly interesting, thank you all.

[Martin (Admin)]

Me too!   

[sparkey]

  I say go for it Nobby and don't be put off,you never know you might find a new way of cooling motor and Esc's,the Wright brothers were told flight was impossible but they kept trying and the result is we are now all flying,anyway trail and error can be a lot of fun and you can learn a lot from it,I am always trying new things sometimes I get it right and sometimes I don't but always learn from it,if you have got the pump try it out and if does not work you can go back to just using the scoop,Ray.      

[Martin (Admin)]

 I can't quite remember the configuration of the boat but once I did find that the water pumped itself due to the 'glow' engine heating (and expanding) the the water and the outlet tubing being bigger than the inlet tubing.... or something!

[malcolmfrary]

Looking at Derek's keel coolers picture, I feel that the most effective is the external pipe one, but that this would introduce unwanted extra drag on a fast boat.  Maybe solder copper pipes to a copper or brass plate and have the plate flush to the outside of the hull bottom.
Back in the elder days, I recall a magazine article about someone water cooling a 2N3055 power transistor by mounting it through his hull.  This was before PWM was the norm, so it would be effectively a linear regulator, and need a lot of heatsinking.  Direct contact with moving water is probably as infinite a heatsink as you can get.

[Terry]

I built a Sea Commodore a couple of years ago and wanted a pumped cooling system. Not to over engineer it, but to provide a scale like appearance to the water outlet, even working when the boat was not moving. I stripped out one of those oral hygiene gadgets that pumps water to the toothbrush and found a reciprocating piston pump perfect for the job. It runs quite happily off the 7.2v main drive battery and has lasted a couple of summers so far.
Cheers, Terry.

[Netleyned]

Seen one or two at the lake .
As Terry says it looks right when
pumped.
When a big tug was done the same way
and a pipe came adrift a tug became a
submarine

Ned

[derekwarner]

Malcolm.....the images shown are in fact five different examples...your thought couples both, the 'skin over the grid' arrangement.....

One point here, when I mentioned ethelyene glycol...that was simply to draw attention as in real practical terms this fluid whilst having a higher boiling point will not adsorb a significantly greater amount of heat than plain distilled water [@ a nominal 20 degrees C]

However it does have the advantage of chemical stabilizer inhibiters used universally in motor engine cooling systems with aluminium blocks of pump components ...so any commercial radiator fluid with antifreeze would suffice

In a perfect scale model application, a small fluid header tank [open to atmosphere] would also be advantageous .....as would small lengths of semi translucent synthetic tubing fastened securely with tubing barbs....to act as a sight glass and resilient elements between the hull and pump assembly...... Derek