MacGregorSailors.com

Sounds like it’s time for a bit of actual engineering science vs. our conjecture….
Sorta along the lines suggested earlier… Just how much effort is actually required to operate the darn thing?

Assuming the Down stroke compression pushes the salt water towards the Reverse Osmosis (RO) filter is the hardest part and that the Up stroke is recharging the pump with new salt water is a lower force. Knowing what these two are is the minimum amount of information needed at a fixed position on the handle. Knowing the travel distance of that fixed position of the handle Up-to-Down gives the drive stroke needed.

Next bit is to determine the relative capability of the device to suction salt water up to the device (assuming that it can….otherwise yer gonna have to be hanging over the edge …. talk about awkward). Generally suction can be a real problem for these types of pumps. The gunwales of a Mac26 is about 3 feet above the waterline so it would be nice to know that the device can handle that lift without duress or a significant increase in force needed.

Closely followed is the the bit about how high a discharge the device can provide so one can conveniently collect the fresh water. It would be nice to know one could feed the discharge up and into some sort of collection container, say a Jerry Can which would be about 2 foot tall, without duress or a significant increase in the force needed.

If one were to want to mount this cabajil on the top deck then that increases the suction to almost 5 feet factoring in some practicality margin aspects.

Just a humorous thought that came to mind… one could always hook it up to a rocking chair… that way one could relax while pumping away …just a funny thought along the lines of a Rube Goldberg creation…..

That Solar Still or Water Boiler is looking better and better…….. Ya know one could rig up a solar panel to battery to heating element to boil a batch of sea water and then have a toilet tank like float valve to refill the boiler which turns on a small electric pump that suctions up the seawater….with a battery charge controller that maintains the minimum/maximum battery charge level for the system…then a float switch to shut the whole thing down in the collection tank so it doesn’t overfill ..there’s a cartoon somewhere in there someplace…..

Best Regards,
Over Easy

I happen to be a hobby cartoonist.
Maybe I’ll think of something.

According to Wikipedia the average human can output .1 horsepower indefinitely or 1.5 briefly.
An actual horse actually produces about 5 HP

I would imagine rowing a dinghy would be an example of the .1 HP type of effort.

The average horse will gallop 25 to 35 mph.

It can’t pump a 160 dollar RO unit though!

I was not suggesting that 1HP was the actual value. My gut feeling is that is is probably closer to .25 horsepower with all of the inefficiencies included but that is just a WAG. If we had some of the numbers that Overeasy mentioned then the actual HP and torque needed could be estimated more accurately. It might even move into the realm of a SWAG.

Hi All!

Just for reference on some professional systems:
https://seawaterpro.com/?wbraid=ClQKCQj ... tNsbRoCLjo

Best Regards,
Over Easy

That’s more like it. 180 watts for five gallons is possible even with my current power system.

Ix

I came here to say I thought we were talking about a diesel engine and desal was a typo. I say this in case I am not alone

Been a very interesting read just the same

Hi Kingtoros!


That’s an interesting starting perspective for this thread!
I must admit I’ve done similar things only to have the light bulb go on after I was well into it….

Now there is a concern with diesel or gasoline and water contamination but I don’t think that I could ever convince myself to ever reprocess that separated water into something drinkable….

Best Regards
Over Easy