Surplus Watermaker Testing
We recently had an opportunity to thoroughly test four hand-operated watermakers, all made by Katadyn, and it has changed our perception of life raft survival. We first tested a 13-year-old Survivor 06, made by Recovery Engineering (now part of Katadyn North America). Katadyn recommends testing their watermakers annually, and if it meets the design specification, you "pickle" it and put it back in storage.
This particular watermaker had been purchased in 1990 and put aboard the boat a BWS staffer was taking around the world. They came back, the watermaker was never used, and it sat in a box full of gear removed from the boat, unserviced, untouched, for eight more years. At 13 years of age, we took it out and tested it against two new 06 models from Katadyn, the standard 06 civilian model and the military model, the MROD-06-LL (as the military calls it), and the Survivor 35, a larger (much) version of Katadyn's manual watermaker.
We were very interested in the performance of the 13-year-old 06. There was some slight staining in the saltwater hoses, but it otherwise looked as good as new. It is identical in nearly every respect to the newer model, and we dropped the paired saltwater hoses into Narragansett Bay. After some 30 strokes of the handle, water began to come out, and then we pumped an additional 80 strokes to clear the pump's membranes, the recommended procedure when first using it. We gave a tentative taste to the water, and it was sweet and good, very much to our surprise.
"You may see some reduction in the output," said Alan Lizza, director of Katadyn North America, "probably because the membranes have dried out. We've never tested one thisold, so we would be interested in the performance."
We were suitably impressed. It put out water that was perfectly good, as good as any water you would buy in a bottle, but indeed the output was less. We gave it 100 strokes, and the veteran put out less than an ounce of water. We pumped as fast as we could, taking two minutes and 30 seconds. Pumping slowly, taking just over three minutes, the output was the same. It also leaked salt water, a leak that slowly diminished, but after an overnight rest the leaks returned. They weren't serious leaks, but enough to get salt water on the pumper's arms and legs.
We then fired up the new 06, and it took fewer strokes to begin putting out water. Twenty strokes had water dripping from the small output hose, and after another 80 strokes we put it to the test. After 100 strokes, we had just under two ounces, slightly more than twice the amount produced by the old 06. Pump faster, get more water. Neither of the two new 06 models had any leaks at all.
Our three-person testing crew all decided that pumping the 06 was a fair bit of work, with the short handle not providing much leverage and requiring both hands to use it.
The MOD-06-LL has an extendable handle for the pump arm, and an extendable bracket on the pump body that straps to your leg using a Velcro band. The effort was much less, almost easy, but the output was compromised at times because the intake hoses collapsed when they were bent. The hoses of the military model are made of very soft silicone tubing, whereas the civilian models have stiffer, clear, vinyl hoses, much less prone to kinking when bent. The flexible hoses and the resultant kinks resulted in less water being put out unless care was exercised in the placement of the hoses. Water quality was similar, although the testing/tasting crew opined that the water from the older model tasted slightly better. We concluded that was because we had pumped a lot more water through the older model, and perhaps it had more thoroughly rinsed the pump's innards. The water was perfectly drinkable, though, and testing the new models again the next day bore out our thesis. The water quality improved with more water having been pumped through it.
The real star of our tests was the Survivor 35. It is larger, measuring 22.5 inches long as opposed to the 06's eight inches. The 06 weighs as much as three pints of water, and the 35 weighs as much as seven pints of water.
The 35 took about the same number of strokes to begin pumping, and we cleared it with 80 strokes before testing began. It put out a steady stream of water, and 100 strokes produced just over seven ounces of water, with much less effort than 100 strokes of the 06 and slightly less effort than 100 strokes of the 06-LL. By unanimous agreement, the water was best from the 35. That is not to say the water wasn't good from the other pumps, it was, but you could bottle and sell the water from the 35, water pumped directly from Narragansett Bay.
The rate of pumping had an effect on the output of the 35. The reason requires some knowledge of how a watermaker works. The Katadyn uses a reverse-osmosis system, forcing water through a semi-permeable membrane under very high (as much as 1,000 p.s.i.) pressure, just like any other RO watermaker, but what makes them different, and better, is that some of that pressure, once it is used to push roughly 10 percent of the saltwater through the membrane, is used to aid in the next stroke, reducing the effort required by some 85 percent. The excess water, returned to the sea with a raised salinity, is taken from the pump by the second hose, paired with the intake hose, which terminates in a weighted (to keep it submerged) fine mesh screen at the intake.
When you pump the 35 quickly, some of the return water exits from a relief valve, and this can produce a fair bit of water on the pumper. It's easily avoided by pumping at a reduced rate, and we found that a rate of 30-50 strokes per minute worked perfectly.
After use, if the 35 is going to be unused for more than a week, it needs to be pickled, a simple process that takes about 10 minutes using the chemicals provided. If it is used regularly, you just use it. The very complete instruction manual lists the procedure for a complete overhaul, using the factory-supplied kit, and appears to be a straightforward process, although we did not perform an overhaul. Besides the kit, you only need two Allen wrenches, needle-nose pliers and a slot-head screwdriver.
We concluded that the 06, whether the civilian or the military version, is only suitable for survival. It will produce the water you need in a life raft, and you won't die of thirst, but it is a tiresome, slow process. Driven by thirst, it would be quite tolerable, but the quantity produced places it squarely in the category of emergency equipment. Given its small size, we decided it absolutely must be in any well-equipped life raft.
The 35 is quite another story. We would carry one on the boat as a backup for the boat's water supply. You could produce the daily water requirement for a four-person crew, a nearly luxurious three gallons a day, with roughly one hour of pumping daily, perhaps slightly longer if the chore weren't spread among the entire crew. It's very nearly a must-have, as you literally would never have any worries about running out of water on your boat. Like its smaller cousins, it is wonderfully well made, of glass-reinforced thermoplastic and stainless steel. The design has passed some very tough tests devised by the U.S. Navy, including surviving a drop of 65 feet, cycling the unit in temperatures between -70 degrees F and 160 degrees F for 60 days, and then sprayed with saltwater for 500 hours while being continuously pumped with a mechanical actuator. It should work fine on your boat, stuck in the Doldrums, running out of water with no diesel left in the tanks.