Engine Driven Watermaker Pump

[mvmojo]

Originally Posted by SailingAdrift

Hi all,

Does anyone have any experience with an engine driven watermaker pump? Seems like a nice little solution to a Genset to get decent output while charging batteries/ motoring, etc....

Any thoughts would be great!

I ran an AquaMarine engine driven watermaker pump making 20 gph for 6 years while in the Caribbean. It had an electric magnetic clutch and worked great! At anchor we ran it every day for an hour and ran it underway whenever we wanted to top off the tanks, wash the decks, etc. The high pressure pump was belted to the front of a Lehman 80 hp diesel in a Whitby 42 sailboat using a bracket that I designed out of cardboard and then had fabricated from 1/4" steel plate. Per the recommendation of Dan Forrest at AquaMarine I tee'd off the engine raw water loop between the oil cooler and the heat exchanger to feed the water maker. This eliminates the need for a boost pump since the engine water pump">raw water pump does that job. Additionally, it pre-heats the water which increases the efficiency of the water maker membrane. We also had a 105 amp alternator and an engine driven refrigeration/freezer compressor on the same engine. Again, worked great. In an hours running time we could make 20 gal of water, keep the freezer at <5 deg F & make 75-80 ah of electricity for the batteries. I knew two other cruisers with engine driven water maker high pressure pumps and they were happy with them as well. So yes, it is a workable substitute for a genset and an electric motor to drive the pump.

[cansley99]

I've had an engine driven pump for years. It has an electric clutch, and has been trouble free. The watermaker delivers 80 litres/hour. The pump is a US brand, but mine came as part of the Open Ocean package: simple and cheap. Very pppular here. See www.openocieanwatermakers.co.nz

[gpeacock]

I have been using an engine driven 20 GPH watermaker system for the past 10 years on our main engine. It was a fiddly to get the high pressure pump mounted properly on the engine and I think this is why most watermaker companies dont sell it as an option... Too much custom work.
I will say that if you are running an older engine like mine with a non electronic governor you must either have a High pressure switch or some device other than the needle valve to keep the pressure constant. With many engines, as the load is increased or reduced, the RPM's change which then changes the pressure. This can be due to the boat surfing, a puff of wind in the sails or alternator load changes. Other than that I've had zero issues with it or the engine.
Mine has a high pressure switch which shuts off the watermaker when the pressure increases above 810 PSI. It works fine but I've pretty much given up motor sailing while running the watermaker and if I were to do it again I would use my big inverter to power an AC motor instead of mounting the pump directly on the engine. Either that or find a way to have a constant pressure valve in the system.

[Thonglor]

Can I change the engines RPM while the watermaker is running?

Yes. ECHOTec. belt driven watermakers are equipped with a patented automatic pressure regulating valve, that ensures constant working pressure at changing engine RPM without the need of any adjustment.

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