Emergency Water Desalination - SailNet Community
Reply
 
LinkBack Thread Tools
post #1 of 26 Old 03-08-2010 Thread Starter
Junior Member
 
Join Date: Mar 2010
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Question Emergency Water Desalination

Hi there-
I'm on a team of junior level engineering students who, as a design project have been tasked with creating an emergency water desalinator. It is our understanding that very few smaller vessels carry any sort of device like this - largely because of cost. We have a conceptual design, however, none of us have any real experience sailing. From those willing, we would greatly appreciate some input.

Here's the basics:
1. Remove salt through evaporation instead of expensive RO filters or through FO filters that require a sugar-like solution.

2. Total weight 15-25lbs

3. APPROX Dimensions of: 2.5ft*1ft*1ft

4.Production of 1-2 gallons/day should be very easy

5.Total cost to produce >30USD

6.We are attempting to make this work only requiring hand-power($$), but may require electrical input (similar to that of car battery) to achieve 1-2 gal/day. (Evaporating water is very energy intensive)

Are there any thoughts given that much? Anything you would or would not like to see in this type of device? Do you realistically seeing something like this being included in your emergency supplies? How many consecutive days would you want to be able to count on this device providing water?

Any thoughts that you have would be very much appreciated and seriously considered.

Thanks much,
David
NeverSailed is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 26 Old 03-08-2010
Senior Member
 
hellosailor's Avatar
 
Join Date: Apr 2006
Posts: 11,335
Thanks: 4
Thanked 129 Times in 126 Posts
Rep Power: 11
   
"1. Remove salt through evaporation"
There's nothing new about that. Survival training has taught how to use a piece of plastic for solar evaporative desalination for ages. Replicating something so well documented would be pointless, unless you can add something new to it.
And it is no trick doing this on a small boat--except of course when the sea is not calm. If your setup can work, say, on the roof of a car while four big guys are jumping up and down rocking it on the shocks, now you've got conditions similar to what might be found on a sailboat.
hellosailor is offline  
Quote Quick Reply Share with Facebook
post #3 of 26 Old 03-08-2010 Thread Starter
Junior Member
 
Join Date: Mar 2010
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
The advantage we see in creating a machine, is that it would produce a much larger quanitity of water than using just solar energy - especially if there's no sun.
We are considering conditons in using this, we've wanted some insight on just how rough the sea is - particularly in a small boat.
NeverSailed is offline  
Quote Quick Reply Share with Facebook
post #4 of 26 Old 03-08-2010
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 14 Times in 12 Posts
Rep Power: 14
         
A solar still is not hard to create, and given sunlight in the tropics, quite effective. One way to improve on it is to use a Pelletier effect chiller to increase the rate of condensation.

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #5 of 26 Old 03-08-2010
Senior Member
 
tommays's Avatar
 
Join Date: Sep 2008
Posts: 4,296
Thanks: 1
Thanked 30 Times in 30 Posts
Rep Power: 7
 
If you out to sea (offshore) and there is any kind of wind the big issue would be a unit that would hold up to the normal waves/wind that beat up most anything on deck

Things get torn off sailboats all the time in bad weather

1970 Cal 29 Sea Fever

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

1981 J24 Tangent 2930
Tommays
Northport NY


If a dirty bottom slows you down what do you think it does to your boat
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
tommays is online now  
Quote Quick Reply Share with Facebook
post #6 of 26 Old 03-08-2010
Junior Member
 
Join Date: Mar 2010
Location: Huntington Beach, Ca
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Thoughts:

You're going to need quite a few BTU's in order to evaporate enough water to meet your goals. The first thing I can think of is using some sort of hand operated heat pump in order to accomplish the energy transfer...

Sea Roughness? Standing up while below is like trying to stand up inside a pickup camper while driving down a washed out forest road that throws you side to side and just happens to take you over 8-10 foot high rolling hills at the same time. Not impossible, but not that easy at first either, and you better have something to hold on to.
stolpsTDI is offline  
Quote Quick Reply Share with Facebook
post #7 of 26 Old 03-08-2010
Senior Member
 
Join Date: Dec 2009
Location: Long Beach CA
Posts: 235
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 6
 
If you could develop a device capable of a
gallon or two of fresh water a day, you would
definitely be on to something.
There are emergency hand pump
water makers that require a lot of hard labor
to yield a gallon of water. Solar stills require
a bit of manipulation to eek out a mere trickle of water.
I envision a device that could sit on deck and
passively, yet slowly, produce drinking water from
sea water all day long. You might consider
incorperating a solar powered fan to hasten
evaporation. Two gallons a day sounds optimistic,
but I hope you prove it is not impossible.

Islander 30 II 'COOL'
COOL is offline  
Quote Quick Reply Share with Facebook
post #8 of 26 Old 03-08-2010
Senior Member
 
Join Date: Sep 2007
Posts: 451
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
 
You should have 2 quarts per day per crew member as a minimum objective. I think some kind of piston pump (hand operated) and membrane is likely better than evaporation. If it's dark & stormy the hand pump should still be viable.
RXBOT is offline  
Quote Quick Reply Share with Facebook
post #9 of 26 Old 03-08-2010
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 14 Times in 12 Posts
Rep Power: 14
         
Hand powered RO watermakers, like the Survivor 35/40e series are well known. They're also high-maintenance and expensive.

Solar stills are low-maintenance, low cost, and low output. Hell, you can make one from a big ziploc bag, a bowl and a piece of black plexiglass.

I think the OP is looking to design something between the two.

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #10 of 26 Old 03-08-2010
Senior Member
 
Join Date: Nov 2002
Location: New York
Posts: 5,826
Thanks: 0
Thanked 18 Times in 17 Posts
Rep Power: 15
     
Quote:
Originally Posted by NeverSailed View Post
Hi there-
I'm on a team of junior level engineering students who, as a design project have been tasked with creating an emergency water desalinator. It is our understanding that very few smaller vessels carry any sort of device like this - largely because of cost. We have a conceptual design, however, none of us have any real experience sailing. From those willing, we would greatly appreciate some input.

Here's the basics:
1. Remove salt through evaporation instead of expensive RO filters or through FO filters that require a sugar-like solution.

2. Total weight 15-25lbs

3. APPROX Dimensions of: 2.5ft*1ft*1ft

4.Production of 1-2 gallons/day should be very easy

5.Total cost to produce >30USD

6.We are attempting to make this work only requiring hand-power($$), but may require electrical input (similar to that of car battery) to achieve 1-2 gal/day. (Evaporating water is very energy intensive)

Are there any thoughts given that much? Anything you would or would not like to see in this type of device? Do you realistically seeing something like this being included in your emergency supplies? How many consecutive days would you want to be able to count on this device providing water?

Any thoughts that you have would be very much appreciated and seriously considered.

Thanks much,
David
I don't get it! One would think if you are going to need a emergency water desalinator you are going to need it in a life raft and not on board the vessel.

I can't see packing a car battery in my ditch bag. How would a person recharge it so you make more water? The 4 x 8 foot solar panel or the gen-set in the ditch bag.

The cost of 30 dollars? You can't buy the car battery for that. There is a reason that there are hand pump water makers on the market.

I don't see the need or the practicality of it.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Never Forgotten

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
bubb2 is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Water, Water Everywhere Tania Aebi Cruising Articles 0 06-14-2004 08:00 PM
Beyond the Bucket Brigade Brian Hancock Seamanship Articles 0 01-01-2003 07:00 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome