Water, water everywhere and not a drop to drink. The idea of being at sea began when I was very young and enraptured with stories in a survival book, frequently of downed airmen adrift in the ocean.

Water enters the sea chest and is strained. It then passes through a ball valve, two pre-filters, one 20 and the next 5 microns to remove particles, the to the saltwater pump, or boost pump. The boost pump draws the water through the prefilters and ensures there is some positive pressure for the seawater entering the high pressure pump. The high pressure pump is just below the waterline but not enough to the necessary pressure and flow required to feed the high-pressure pump.

Boost Pump Options:

Pump 29 gpm, max head 39 ft $420 Blueline 70 HD

16 gpm @ 3ft, 15 @ 10 ft. $332 Little Giant 5MD-SC

Pump 29 gpm, max head 39 $260 Pan World 200PS

Stainless Steel, Liquid-Fillable, 15 psi $90 Industrial Pressure Gauge

– If we add a boost pump it would supply saltwater for research projects, wash down, and plumbing so it would be convenient to have an automatic pressure switch. Pressure Switch

Pre-filters for Watermaker water only, not the wash down supply path.

Pleated Sediment Cartridge (12 GPM, 12 sq ft Media) $21 Harmsco Polyester-Plus 20″ × 2¾”, 20 Micron

Pleated Sediment Cartridge (12 GPM, 12 sq ft Media) $21 Harmsco Polyester-Plus 20″ × 2¾”, 5 Micron

$65 x 2 = $130 Pentek 150560, 3G 20″ Clear Filter Housing

High Pressure Pump Motor

– 1HP 1800RPM 56CFR 1PH TEFC $250 North American (F56C1S4C) Electric Motor

High Pressure Pump:

Plunger Pump, 3.6 gpm, 1/2″ FNPT Inlet x 3/8″ FNPT Outlet, 1200 psi $1485 Cat Pump 247

RO Membrane:

4 – Sea Water 300 GPD RO Membrane Element $195 x 4 $780 Filmtec SW30-2521

Membrane Housing:

4 – 3″ 316 Stainless Steel Sch 40, 84 inches x 2 $700 and 4 – 3″316 Stainless Steel sch 40 end caps and plugs $250 Total aprox $1000

$305 each $1220 HCTI Seawater Vessels PV-2521-SW

Resources:

“Watermaker: Doing It Yourself”

How to make a 30 gallon per hour watermaker using off the shelf parts.

Seawater Pro Watermaker Kits