This just popped up on one of the lists I subscribe to, http://www.sea-pack.com/ - it's claimed that "USCG has them on their aircraft in their ditch bags".

Looks like a "must have" if it works!

I wonder if you have to use the syrup, or if you can get drinkable plain ol' water without the syrup. I'll have to call them, and I'll report the answers I get.

Thanks for the link!

From their "What's New" page



So at most, you can produce 2.5 liters of water from a basic kit. You can purchase syrup for additional 2.5 liters at $38 a shot.

I can see this being used for small life rafts, but for larger sized rafts, a reverse osmosis pump is going to give you higher, essentially unlimited, output so you'll have more water for less dollars per liter.

It's still a pretty interesting product. Looks like that company sells a variety of water filter products.

Cheers,

Tom A.

I thought I heard once that a human could drink up to a liter/day of sea water without screwing up their biochemistry. Has anybody else heard that? I have not researched it.

It's a (unique) forward osmosis system, so you need the syrup. The dissolved solids in the syrup are what draw the freshwater through the membrane in the "forward" direction, "down" the osmotic gradient, without any additional work by the user. Otherwise, you would need a hand pump to force the freshwater through the membrane in the "reverse" direction, "up" the osmotic gradient, like in your typical reverse osmosis system.

Definitely affordable option, if you are going on known long term sailing then I would carry the KATADYN SURVIVOR 35 (sometimes you can get good deals off of E-bay) but definitely SeaPack would be great for the BOB than a heavy 10 lb KATADYN SURVIVOR 35. And Bear G won't be happy because if will allow you to filter and drink urine.

"I thought I heard once that a human could drink up to a liter/day of sea water without screwing up their biochemistry."

NO!

From Wikipedia: "... seawater should not be drunk because of its high salt content. In the long run, more water must be expended to eliminate the salt (through excretion in urine) than the amount of water that is gained from drinking the seawater itself.

"...The amount of sodium chloride in human blood and in urine is always kept within a very narrow range of 9 g per L (0.9% by weight). Drinking seawater (which contains about 3.5% ions of dissolved sodium chloride) temporarily increases the concentration of sodium chloride in the blood, so the only way to excrete the excess sodium chloride in the urine is by sacrificing internal water from cells. The cells eventually give so much water to try to dilute the salt that they die from dehydration, quickly followed by organs and eventually the organism."

Sue

http://www.caske2000.org/survival/survivesea.htm#Drinking%20sea%20water

This is one site saying that. For survival, not health. I'm not sure everyone agrees with it though.

It's the Alain Bombard French physician making the controversial claim.

The website talks about producing a "drink" not water. I assume the product of this system is a koolaid type liquid that is safe to drink.

Craig.

This may be off topic, but ...

I'm curious about the "sweet" aspect of this process.

It reminds me of a potentially (?) similar situation -- the chemistry of electrolyte replacement mixes.

The cure for electrolyte depletion, associated with dehydration, is simply "a handful of sugar and a pinch of salt" in clean water. Research found that the intestinal wall would not let salts through unless some sugars were present.

So, is this product simply a reverse of that process?

Going back to the basics of osmosis:

Water will move across a semi-permeable membrane from areas of higher concentration of salts and/or sugars to less concentrated areas. The “receiving” side of the semi-permeable membrane contains the highly concentrated sugar solution. Since this side of the membrane has a higher osmolarity then the side containing the salt water, the water (since the salt cannot cross the membrane) will pass through the membrane in an attempt to dilute the sugar solution.

Pete

Interesting! So, if I understand correctly, the sugar/salt ratio controls the direction of osmosis?

I've never looked at it from that angle, which is (I guess) a mimic of the biological process.

Rather, I've seen it from the angle of "controlled pressure applied to a membrane" that forces osmosis to the lower-mineral-concentration side. This is the most common industrial application -- from bottled water production to boiler feedwater for power generation stations.

Regarding the product itself, though, I doubt this process could produce a fraction of the drinking water that a pump/membrane system could provide.

Does anyone know the size of this kit packaged? It looks as though it might be a nice alternative to on-person carry for over water excursions where it is impractical to carry a reverse osmosis desalinator in your vest.

There are numerous different products that fit different requirements. Check out the product catalog: http://www.sea-pack.com/images/MantaVenturesProductCatalog.pdf It has conversion times and such.

The LifePack is designed and priced for people that wish to store them at home for disaster preparedness (hurricanes and earthquakes).

The SeaPack was developed for use in an abandonship bag or life raft canister. 9" x 13" x 2"

The X-Pack is the first product design and is used for disaster relief.

The Expedition is designed to produce drink while on the move. Try that with a hand held RO pump.

The HydroWell is made for supporting large groups of people, but it weighs enough that you would need a vehicle to transport it.

None of these products require electricity or pumping. They work by themselves while you are away taking care of something else or sleeping.

X-Packs - 1 filter with 10- 2 oz syrup charges
Individual Weight- 2.75 pounds

X-Pack Resupply - 10- 2 oz syrup charges
Individual Weight- 2.75 pounds

LifePacks - 1 filter with 6-2 oz syrup charges
Individual Weight- 2.0 pounds

SeaPacks - 1 filter with 5-4 oz syrup charges
Individual Weight- 3.0 pounds

Expeditions - 1 filter in bladder with 10-120 mil syrup charges and cleaning kit
Individual Weight- 7 pounds

Expedition with backpack - 1 filter in bladder in a backpack with 10-120 mil syrup charges and cleaning kit
Individual Weight- 9 pounds

Expedition Resupply kit - 10-120 mil syrup charges and cleaning kit
Individual Weight- 5.5 pounds

Expedition Filter kit - 10-120 mil syrup charges and cleaning kit
Individual Weight- 6.25 pounds

Hydrowell Watercan 0- 1 Filter with 20-410 mil syrup charges and a syrup feed tray and 1 accessory kit.
Individual Weight- 37 pounds

Hydrowell Watercan 1-1 Filter in can with 20-410 mil syrup charges and a syrup feed tray and 1 accessory kit.
Individual Weight- 41 pounds

Hydrowell Watercan 2- 1 Filter in can with a clean water collection can and 20-410 mil syrup charges and a syrup feed tray and 1 accessory kit.
Individual Weight- 48 pounds

Hydrowell Watercan Resupply kit - 20-410 mil syrup charges and 1 accessory kit.
Individual Weight- 31 pounds

Hydrowell Watercan Filter kit - 1 Watercan Filter
Individual Weight- 3.25 pounds

You are correct in your statement that these systems can not produce as much as a hand held RO pump. (The HydroWell can produce as much.)

The beauty with these systems is that they do not require pumping, which is why the Coast Guard has them on their planes. The USCG found that most pilots are disabled during a crash and they can't operate a RO pump in that injured state.

People are purchasing the SeaPack and LifePacks because they are so much less expensive than RO pumps that can handle salt. They also do not require pumping or maintenance.

Rick Feineis
Managing Partner
Manta Ventures, LLC
www.sea-pack.com

Yes, it works well.

Please give me a call anytime.

866-314-4824

Rick Feineis
Managing Partner
Manta Ventures, LLC
http://www.sea-pack.com

I developed the SeaPack last year when sailing from the Bahamas to Norfolk, VA. Here we were on a $500,000 catamaran and the captain did not have a hand held RO pump. I asked him why and he said that they were too expensive. I came home and researched other people that cross oceans. 98% of them did not have portable RO systems because they are too expensive.

The SeaPack was developed off of the same concept as the other systems except that it can handle salt water. The other systems can't due to the filter and the level of sugar that is used.

Since there is no pressure to push the water through the filter, these systems can not clog due to turbid (muddy) water.

These have already saved lives over in the Middle East. A military squad was left in the desert longer than planned. They had the X-Packs along and converted their urine into the survival drink. Saved the lot of them.

Rick Feineis
Managing Partner
Manta Ventures, LLC
http://www.sea-pack.com

That's nice- does it work without the syrup? I'm asking because you didn't really answer Farmer's question, and in all honesty, it would be my first one. My second question would be is their a field expedient alternative to the proprietary goo?

http://www.straightdope.com/mailbag/msaltwater.html

http://www.seashellsandsuch.com/articles/canidrinkseawater.php

I'm not sure what the resource is on drinking a liter a day, but that would appear to make your body use more than a liter to dispose of the wastes in seawater. It may be that the liter a day presumes fresh water is freely available? Drinking only seawater at even a liter a day would appear from other online resources to mean you would deplete your stores of body fluids more quickly than not drinking at all.

The FAQ says the basic filtration speed at 95 degrees Fahrenheit is 0.5 liters in 3.6 hours. That's about how long it takes me to drink 2 to 3 liters at Burning Man at that temperature. Of course, I'm active during the day. I guess if I'm on a liferaft at see, I won't be going anywhere. :-> Still, I'm not sure I'd be happy with a half liter every 3 to 4 hours, assuming the water is 95 degrees.

I'm unable to determine what the specs mean for the Seapack:
"Volume: 1.8 liters"
Does this mean the bag will let me put in 1.8 liters, then filters it at the rate of a half liter every 3.6 hours at 95 degrees? And it comes with 5 syrup bags that produce 2.5 liters of 'survival drink"? One bag per half liter, it seems.

I note that a serving size of the drink is 8 fl. oz. :->

Their catalog says that the syrup is required to drive the osmosis process. I'm sure this particular bottle of this particular syrup is not required, but you'd have to find the right chemistry if you wanted to do it yourself.

The argument about being able to drink a certain amount of sea water per day may stem from the fact that, normally, people consume (more than) a recommended 3 grams of salt per day with their food. Your body should be able to cope with this amount of salt because it needs it as nutrition. If you are floating around in a life raft, you probably won’t be consuming this level of salt (unless you pack some food along with you, but then you should have packed water, too ). So, maybe your body is able to cope with a certain amount of sea water by simply using the salt as nutrition instead of just getting rid of it through urination.

Of course, that whole spiel was purely half-educated guesswork and could be totally full of crap. Enjoy!

Obviously it works and provides a drinkable liquid, my concerns/questions are:

What is the osmolarity of the processed liquid if the input side is fully loaded?

If an insufficient amount of input material i.e. urine is used, is the processed solution of such a high osmolarity, that by drinking the solution could one become dehydrated?

Is there a minimal amount of input solution listed on the device to prevent the osmolarity of the processed solution being too concentrated?

What is the caloric content of the syrup?

Pete

Just some educated guesses from me. I think it's safe to assume that the proccessed liquid will have an osmolarity higher than seawater to initiate and maintain forward osmosis as the output volume increases and dilutes the syrup. Depending on what reference you consult, seawater's osmolarity can vary from roughly 1,000-2,500 mOsm/L so the processed liquid's osmolarity probably falls roughly into this range, too. Just for reference, the body's normal osmolarity is roughly 300 mOsm/L.


In the FAQ for this product, it already advises users to sip the processed liquid, and to space out the sips, so even when fully loaded, the manufacturer already knows the processed liquid is concentrated enough to potentially cause dehydration, so I think it's safe to assume (there I go assuming again) that the answer to your question is "yes". At least, unlike sipping seawater and getting all that extra salt, the high osmolarity of the processed liquid is primarily from sugar and not salt, so at least your body can do something useful with the sugar.


The website lists 480 calories.

Thanks Arney for the info, I should have looked a little closer at the site.

I was hoping in part, to use the questions as a mechanism to encourage some dialog amongst the members and especially with Rick regarding some potential pitfalls/issues (in addition to those noted at the product site) with the product line.

In the past we have discussed the benefits and risks of various sport/rehydration drinks and thought that we might look at the processed liquid in similar manner.

Pete

I know what you mean. I held off answering yesterday to give Rick a chance to answer instead of just throwing out my educated guesses. I'm still hoping that he can clarify some of the points.

You do raise valid questions, Pete, and I'm glad you thought of them. We're not creating "Kool-Aid" here, it's something much more concentrated than that and not something to just chug down when you're thirsty and stuck somewhere.

There's definitely a place for a product like this, though, as long as buyers are aware of the pros and cons. I'll keep an eye out for real world testimonials in the future.

I was especially thinking of the use of urine. The site states that the product was not designed for use with urine, but then goes on to say urine has been used successfully. I would think that the amount of urine produced by a group of people might be sufficient to ensure the processed liquid was not too concentrated, but if only one or two individuals were contributing, the resultant processed liquid would be extremely hypertonic.

From what I can tell from the web site the two smaller units require 1.8L to achieve whatever final hypertonic dilution the syrup is designed to process. As noted, consumption of even this diluted liquid should be carefully controlled. This would pretty easy with seawater being the source of input, but 1.8L of urine is quite a lot of urine. Even one-half or 0.9L/900ml of urine is a fair amount and would result in the processed liquid having twice hypertonicity of the regular 1.8L input.

I was just wondering if there is a warning to tell consumers not to use less then X amount of input, otherwise the resulting processed liquid would be dangerous to consume, due to the acceleration of dehydration.

Pete

Sounds like it stuck in life rafts to me.

I was really hoping this would be able to be more useful for dry land applications, particularly with chemically contaminated water, but without a field expedient option for the syrup and minimum volume requirements, it sounds like it really isn't suited for that mission.

I would think that if you had a ‘starter” amount of clean water and regular sugar, you could improvise the syrup. With this combo and large amounts of contaminated water, I think use of the product on land would be feasible. I would just be cautious about drinking large quantities of the processed liquid, especially if under diluted.

Pete

Hi guys,

Sorry about the 2 month delay in getting back to you on this. I almost forgot about this board until I was checking up on what I needed to respond to.

Please visit the Expedition site. Based on your questions about output amounts I have updated the information on the site to provide more detailed information on what the Expedition can produce.

specifications...

Volume: 3 liters of drink - 2.5 liters of dirty water - Produces 25 liters of drink from syrup provided with system
Filter life: 30 - 90 days
Filter output: 1 liter an hours at 20 C
User effort: seconds to fill, no work required for filtering

I also have new videos for you to watch. http://www.sea-pack.com/video.html

Yes, you could produce the syrup yourself as it is made from dextrose. I suppose with enough effort an money we all could produce almost anything ourselves, but why take the risk?

Please let me know your thoughts.

Rick