Watermaker Bike

[Owly055]

https://www.jovoto.com/projects/greenpeacechallenge/ideas/31465

     I've long thought about the possibility of a pedal powered watermaker.   This is a picture of a project in the town of Faza on Pate Island off the coast of Northern Kenya.   It is designed to purify brackish water, rather than being an actual marine watermaker.   A long way from how I would design one for a cruising sailboat, yet the idea is there.   The claim of 60L per hour is preposterous as far as I'm concerned.   That's almost 16 gallons per hour.   I would expect one would be lucky to get a quarter of that, at least with salt water.   On passage, the exercise would be excellent...... I can see pedaling up enough fresh water for a fresh water shower each day......... A nice reward for an hour of pedaling!   I envision a direct drive pump purpose built using pressure washer technology, but designed to fit directly between the pedals.   It would be a modular system with quick couplings, and be designed to rest directly on the cockpit sole, with comfortable pedaling position that was incorporated right into the cockpit seating.  The large RO filter would rest where ever was practical.......... cockpit locker?  Pre-Filtration woiuld be a separate process, and would probably also be human powered, and provide both pre-filtered water for the watermaker, and filtered seawater for use in the boat.
     While this is a some distance from what I had envisioned as far as specifics and application, it is gratifying to see someone else thinking along the same lines...

                                                                                H.W.

[Owly055]

   Just as additional note on horsepower to desalinate water.    I've read figures that say that a water maker operates on about 900 PSI.    Having a background in hydraulics, I can translate that into horsepower easily using the following formula.   (Pressure in PSI * Flow in GPM) / 1710 = horsepower

  15 gallons per hour equals 1/4 gallon per minute times 900 psi / 1710   equals only .13 horsepower   A human can produce about .06 HP sustained over a period of time.  The good news is that this works out to 6.9 gallons per hour of fresh water, although realistically one should expect to get half or less of that amount unless you want to work really hard for an hour.   3 gallons of water would make a nice fresh water shower though..........

     My math says it is entirely realistic..........

                                               H.W.

[CharlieJ]

Some interesting ideas here. But I can assure you very few if any  long term cruisers would blow 3 gallons of hard earned fresh water on a shower. We used this sprayer from Duckworks ( they no longer sell them)

Holds 2 gallons and we typically got 2 showers each from it. Often, in clean waters, we'd wash first in salt, then rinse with the warm fresh  water Always in the cockpit- I'd not have a shower below in a small boat- recipe for mildew ;)

[Owly055]

Some interesting ideas here. But I can assure you very few if any  long term cruisers would blow 3 gallons of hard earned fresh water on a shower. We used this sprayer from Duckworks ( they no longer sell them)

Holds 2 gallons and we typically got 2 showers each from it. Often, in clean waters, we'd wash first in salt, then rinse with the warm fresh  water Always in the cockpit- I'd not have a shower below in a small boat- recipe for mildew ;)

     I didn't mean to imply 3 gallons would be a typical shower for a cruiser........ It would be an incredible luxury.   The point is that producing several gallons of fresh water manually is not a an unreasonable task, and has the added advantage of giving one some much needed exercise.    Typical usage on passage seems to be half a gallon per day per person.......... What else to do beyond replenishing tankage with 3 or 4 gallons of fresh water except the luxury of a long fresh water shower?

                                                                        H.W.