Peter Rattenbury wrote: - >Huw, we have similar problems in Oz. I have a PuR 35, >which you will see from the web site already posted, is >a larger manual version than the O6 model. I traded off >the larger weight and bulk of the 35 for ease of >operation. Harold wrote: - >I've heard several say that they'd rather die of thirst >than again try to provide water for themselves with the >06 because it is more energy-consumptive G'Day, Trying to think who else would face this sort of problem and guess it would have to be the military. Does anyone know if they have access to energy efficient, portable, desalination. I'm very interested in fitting solar powered (electrical or thermal) desalination to a kayak - fresh water being the single most volume consuming item I can think of for a long trip through arid coastline. All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
> Trying to think who else would face this sort of problem and guess it would > have to be the military. Does anyone know if they have access to energy > efficient, portable, desalination. >fresh water being the single most volume > consuming item I can think of for a long trip through arid coastline. Arthur Hebert had to do some serious watermaking on his gulf of Mexico crossing. Arthur, if you're out there, shed some light on this issue please. Larry Koenig Baton Rouge,LA *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
> Trying to think who else would face this sort of problem and guess it would > have to be the military. Does anyone know if they have access to energy > efficient, portable, desalination. I believe the company that makes the Pur products supplies the same desalinators to the military as to the public. So, no, there doesn't seem to be an easier solution. Chuck Holst *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
From: "cholst" <cholst_at_bitstream.net> > > Trying to think who else would face this sort of problem and guess it would > > have to be the military. Does anyone know if they have access to energy > > efficient, portable, desalination. > > I believe the company that makes the Pur products supplies the same > desalinators to the military as to the public. So, no, there doesn't seem to > be an easier solution. Based on Peter's original post, I asked myself "How hard could it be to make a reverse osmosis desalinator with a solar powered pump?" Well, after a couple of days on the web, I realize that the solution isn't just connecting a RO membrane in a pump and connecting a power regulator and photovoltaic cell array. While the concept is simple, actually creating the beast, with a meaningful flow rate (say, 1 litre per hour - hence a few hours on the deck of the kayak per person), coupled with the pressures required (high quality, low power pump that can run dry without damage and survive kayaking conditions) and the need to make a good quality membrane ends up being non-trivial in a big way and not very cost effective. Sigh... Now I know why the Pur units are so pricey and not electric. The only pure solar desalinator designs I know of off-hand are distillation units and aren't designed to be moved around. Sigh again. Perhaps we can be genetically mutated into salt tolerant critters... Boy, am I glad I paddle the Great Lakes region (i.e. fresh water)! Mike *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Peter O Wrote; > > Trying to think who else would face this sort of problem and guess it > would > > have to be the military. Does anyone know if they have access to energy > > efficient, portable, desalination. > >fresh water being the single most volume > > consuming item I can think of for a long trip through arid coastline. > > Arthur Hebert had to do some serious watermaking on his gulf of Mexico > crossing. Arthur, if you're out there, shed some light on this issue please. > Larry Koenig > Baton Rouge,LA > I have used the PUR 35 as my sole water supply for a 15 days of a 20 day open water crossing. The manufacturer states a 1.2 gallon output per hour, that was probably in perfect factory conditions with several young bucks taking turns pumping, using fresh water (just guessing of course, no scientific data to prove that statement :>). There is an considerable difference of force needed to pump salt water as compared to fresh water using the PUR-35. One must be in clear ocean water for the best efficiency, which as sea kayakers we will have to paddle offshore to get into the cleaner deeper water off the shoreline. Of Course this means we are pumping water from our kayak. The best method I found was to have the unit between your legs resting on bottom of your vessel and one end of the PUR-35 wedged under the front of the kayak seat. This helped to minimize the effort needed to hold the unit still while pumping. Once you start pumping the unit you must continue to pump non stop. If you stop pumping during the process you must pump 60 times to get rid of the brine and then start over again. I was only able to pump 32oz in approx.. 20 minuets, this was no fun after paddling 10 to 12 hours. I played a dangerous balancing act maintaining adequate hydration. My primary water source was the Pur Survivor 35 ($1,400 US). It is my understanding ( I could be wrong??) PUR no longer manufactures the Survivor 35, although some distributors may still have some in stock. On the next crossing I will purchase the electric PUR 40 which can also be operated manually. There's obviously a weight concern of 25 lbs.. for the unit itself not including the power source, not to mention the finical hit of $2200 US. I would back up the PUR 35 for it's reliability. I think they are practical in a survival situation, a lot of work after or during a hard day paddling. To actually use the PUR 35 for your main source of water for cooking and drinking would entail much energy and time. During the Gulf of Mexico crossing I had a Pur Survivor 06 as a back up ($500 US). Fortunately for the 20 days at sea I never had to use the PUR 06. The PUR 06 with it's 2 pints per hour out put of fresh water, would be for survival only. A LOT of work for little water. Of course to have a 06 water maker in your safety arsenal, would be nice. The 06 would surly be my last possible resort for hydration. Arthur Hebert Louisiana www.lacostadelgolfo.com www.seacajun.com *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
At 2:56 AM -0500 10/13/01, Arthur Hebert wrote: > > I have used the PUR 35 as my sole water supply for a 15 days of a 20 day >open water crossing. [SNIP] OK, this may be a stupid question (remember, there are no stupid questions, just stupid people), but would it be at all feasible to create a small solar still (ie evaporate saltwater into a collector) to make a bit of fresh water. Seems like it might work especially in a region with a lot of heat or sun. I doubt it would be able to evaporate much water, but maybe enough that after a long day of paddling you'd have a bit to drink before initiating the Herculean task of pumping. Thoughts? Anyone here ever a Scout and do something like this? -Patrick (never a Scout of any sort) *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Patrick Maun writes: > OK, > > this may be a stupid question (remember, there are no stupid questions, > just stupid people), but would it be at all feasible to create a small > solar still (ie evaporate saltwater into a collector) to make a bit of > fresh water. Seems like it might work especially in a region with a lot of > heat or sun. I doubt it would be able to evaporate much water, but maybe > enough that after a long day of paddling you'd have a bit to drink before > initiating the Herculean task of pumping. Thoughts? Anyone here ever a > Scout and do something like this? > > -Patrick (never a Scout of any sort) > I once tried fitting a classic solar still using black and clear sheets of plastic into my kayak cockpit in my back yard, but several hours of Minnesota sun produced nary a drop of distilled water. At the San Diego Kayak Club's annual picnic a couple of years ago, I saw a floating bagel-shaped solar still, but I don't know how well it worked. Maybe one of the San Diego Paddlewisers can tell us. Chuck Holst *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Myself and three others crossed the Sea of Cortez (Gulf of California) from San Francisquito, Baja to Bahia Kino, Sonora and back. Although we carried eighty pounds of water each we also brought two solar stills and one fire still. The solar stills were comprised of two clear spheres, one inside the other and floated in the relatively cool sea water with the upper hemisphere exposed to intense sunlight. Sea water within one sphere condensed as distilled water and ran down the surface of the other, collecting sphere. The fire still was constructed of a pressure cooker, surgical and copper tubing for use on land. It was not necessary to use either of the stills and I cannot report on the effectiveness of the solar model (though Ken tested it) or where one may be purchased. Sid Taylor would it be at all feasible to >create a small solar still *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
From: "Patrick Maun" <patrick_at_patrickmaun.com> > would it be at all feasible to > create a small solar still (ie evaporate saltwater into a collector) > to make a bit of fresh water. Absolutely. However, there are a few problems to work out. The solar stills that I'm familiar with are too large to put on a kayak. They tend to be on the order of a meter square. As well, they can't be jostled, because there's not much separating the fresh and brackish water and a typical wave will cause the brackish to splash into the fresh. Most of the designs must be oriented towards the sun to work efficiently. One simple design, for example, is a shallow box, tilted up so it faces the sun. The box is divided into two sections. The "uphill" portion is large and covered with a black surface to catch the heat. The smaller "downhill" section is for the captured fresh water. The box would be, say, a little over a meter long and a little less wide. The fresh water section would take up the lower 10 cm or so of the box. The wall between the fresh and salt would be about 8-9 cm high and the overall box about 10 cm thick. The whole assembly is covered with glass. A couple of tanks (bottles whatever) are used, one to contain the salt water at the top of the box and one to collect the excess salt water near the bottom. A third collects the fresh water from the bottom. The brackish water is trickled down the upper portion and the heat evaporates some of it. The evaporated water condenses on the inside of the glass and runs down the glass to collect in the fresh water collection area. That describes a version I saw working at McGill U. when I was a student there. A fancier version is at http://www.solardome.com/SolarDome84.html. This site states that "approximately 8 square feet (of glass cover) will distill around 1 gallon of water per day, over five hours of full sunlight." Size is a drawback. There are also designs for emergency water stills in survival books. I think I first saw one in The Complete Walker, but I may be confusing it with another book. These kinds of stills usually involve suspending a tarp or sheet of cloth or plastic over a pool of brackish water and using the tarp to collect the condensed fresh water. The fresh will dribble to the lowest point where it's collected. I spoke to a couple of doctors earlier this year while kayaking. We somehow got onto the topic of water purification (I think a result of my evangelizing for alternative housing and living arrangements to reduce pollution and energy consumption). I pointed to a pop bottle on the deck of his kayak which was clouded on top from the condensation of water from his cola. "That's a still" I said. He said he saw one that was not much bigger for water production. I haven't been able to track such a beast down, however. A couple of the biggest problems facing third world countries is desalination and/or purification of water (both large and small scale) and small scale refrigeration, all with little power. If you can solve any of these, you can be rich! Mike *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
At 02:42 PM 10/14/01 -0400, Michael Daly wrote: >A couple of the biggest problems facing third world countries is desalination and/or >purification of water (both large and small scale) and small scale refrigeration, all >with little power. If you can solve any of these, you can be rich! Fog harvesting is an interesting possible solution, depending on conditions. The writeup I just looked at claimed 3 liters of water per day from a 1 meter section of fog harvester. The fog harvester is basically a piece of landscaping fabric held between posts "blocking" any prevailing wind. The fog condenses on the fabric and drips off the bottom of the fabric into a trough. 30 seconds of research left me with 2 older but interesting articles. http://www.idrc.ca/reports/read_article_english.cfm?article_num=284 http://www.unep.or.jp/ietc/Publications/TechPublications/TechPub-8c/fog.asp I read something about fog harvesting in a recent periodical, I of course forget what magazine, which used a fine wire set up in a mesh similar to a large spider web, as the fog harvester. kirk *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
The use of a distillation system (still) is an economical and reasonable to make fresh / purified water from sea water on extended trips. I have used my small aluminum 2 liter pressure cooker with a 6 foot length of plastic tubing to make about .5 liters/hr. with no difficulty. I attach the tubing to the center vent on the lid of the pressure cooker and with my Peak 1 stove at a medium-medium low setting I can fill up a ½ liter bottle in about an hr. It certainly can also be done on a wood fire or any other source of heat sufficient to boil the water gently. It is not the fastest way but on a trip you have, time, an unlimited source of sea water, a stove, and a pot (pressure cooker for camping is about $26) and it is very easy to bring a piece of flexible plastic that will fit tightly on the center vent (I believe that it is about $.25/foot in your local hardware store. You can also drink the water with confidence since it has been boiled and condensed leaving most everything behind (salt, bacteria, microorganisms, silt, pollen etc.). Hal "Power your boat with carbohydrates not hydrocarbons." Wilton, NH *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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