Sorry for the tardy reply. On the Survivor 35 conversion
, the key components are the motor
) and the reciprocating saw, a Dewalt DC385B from Home Depot. You could use any reciprocating saw as long as the saw travel is 1 and 1/8" which happens to be the travel of the manual watermaker piston. I also advise to get a pwm control circuit to be able to vary the motor
speed. Also, refer to the ereplacementparts.com site for a schematic of the reciporacting saw mechanism when you work on the conversion.
Start with the circular saw
, disassemble and degrease. Then use a Dremel tool to cut out pieces of the aluminium enclosure that you do not need. Cut the bottom and drill three holes as shown in the picture. The motor will attach through these holes with M6 bolts. You may need to flatten out the bolt heads so that they do not touch the gear
. Use nuts to compress the bolts once the motor is in position, roughly aligned with the hole for the gear
assembly. Take the gear and spindle assembly and cut it at the thickest part, roughly in the middle. The spindle is 1/2" while the motor shaft is 10 mm. You need to make a sleeve in the spindle and flatten the motor shaft so that it goes in the sleeve. Then put a coupling on top of the assembly. Note that initially I just uses a coupling... it is not strong enough and it would disengage after a couple of hours of run time. Next tighten the three bolts through the gear disk to make sure everything is tight. It helps to run the motor with everything slightly loose and tighten the bolts/nuts gradually to ensure alignment.
Now work on the top part of the assembly
that houses the piston. I used 2" x 3" aluminium profile cut to the shape of the plastic part of the watermaker. You need to drill four holes for the attachment bolts (I used rods from Home Depot, 5/16"). Measure twice before drilling, make sure the holes are aligned. In the centre you need to drill a bigger 1/2" hole for the pump piston. Then you take the top part of the drill assembly, position it on the top surface of the profile and connect it to the pump piston. Mark the position with a pencil. Find at least three suitable attachment points and drill holes through the saw upper assembly and the top of the aluminium profile. Use M4 stainless steel
bolts. This part is not difficult bit the pressure the motor develops is fairly high and there should be no loose movement at all. Use nuts and counter nuts.
Assemble the two parts
and run the watermaker dry for a couple of minutes. Whatever is not in alignment, please align. Then tighten all the bolts to the max torque you can. Next test it with water
, at low rpm's first then increase the rpms. For the first couple of hours you need to babysit it, as some parts
will get loose but eventually it settles. I should probably do a disassembly/assembly video.
I am still running it with the original membrane it came with (15 years old) and I get up to 1.4 gph at max speed (around 40 rpms). The current
is oscillating from 2A to 9A depending on the position of the piston. I average around 4.1 amps per gallon. I believe this would get better with a new membrane. The water quality is around 200 ppm.
Now, before you replicate this project
, here are my thoughts. It works based on the initial design criteria. The motor gets very hot but it has not burned out yet. I am a little disappointed with the watermaker itself: it leaks
, it has a disturbing noise pitch
and it produces very little water. The noise
is similar to what you hear in the car with the windshield wipers on... yieng, tuk, yieng, tuk. It is not loud but noticeable. Then, the poor thing has to work nearly an hour to produce a gallon of water. It is not enough. It will not make you forget about saving water. You could run it off a solar
panel (possible) but do you want to listen to the noise for five six hours every day? Further You would need to buy a new membrane ($340) and possibly the seal kit ($145). All of this because it is a proprietary system. It does have benefits (small, portable, you can tuck it anywhere) but it is better suited for emergencies.
I am now thinking about producing the maximum amount of water in the shortest time
, using standard membranes. The topic has been discussed many times and I believe it is the right way to go. One 2521 membrane could give you 12-15 gph and it costs $170. I am tending towards using an engine
driven pump with a manual clutch
but have not worked out the specifics. Whatever you decide, AC-powered via generator
driven, I think it would be a more satisfying experience as the average boat
uses at least 8-10 gpd. You could do this with a two hour engine run every other day.