MakeShift Challenge: Survive a Deserted Island: Most Plausible Entry

John Hannan’s Most Plausible Winning Entry
by Lee D. Zlotoff
March 30, 2007

Heidi Klum, Anna Kournikova, Scarlett Johansson, and I are stranded on an island in the South Pacific and are in need of potable water. As we’d like a lot of water for drinking, cooking, and showering, we decide on a system that will collect water from 3 separate processes:

1. evaporation/condensation
2. settling, and
3. cooling/condensation.

We plan to use the nylon sailcloth as our main method of capturing the potable water, and the nylon waterproof windbreaker to be our bucket to store the final product. The system will be operating 24 hours a day with different processes in the morning and evening hours.

Process 1 (Evaporation/Cooling)
will operate during the day when the sun is out and we can take advantage of evaporation/condensation. First thing in the morning Scarlett and I will do, or OK maybe second thing in the morning we’ll do, is take the sailcloth down to the ocean, dunk it under the waves, and scoop out a big load of seawater. Next we’ll carefully drag that up the beach to our staging area. The staging area will look out and have a good view of the sun throughout the day and we’ll have a series of rock piles or dirt piles that we can tie the ends of the sailcloth into. We’ll tie the sailcloth in such a way that there will be a pool of water on the ground with the pool formed by the base of the triangular shaped cloth. The tip of the triangular sail is pulled up over the pool of water and comes out to a point (see Figure 1 and Figure 2). During the heat of the day, water from the pool evaporates, rises into the air where it hits the top of the sailcloth, and then condenses. The water starts to roll down the cloth till it reaches the drip point where we can collect the water in the nylon jacket. When the salt water evaporates, the salt is left behind and only the fresh water is released into the air. Thus, any of the water we collect from condensation will be good to drink. To collect water in the jacket we simply tie a knot up above the arms and now have essentially a big garbage bag.

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Fig. 1: Process 1 front view.

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Fig. 2: Process 1 side view.

Process 2 (Settling) All day long the salt water in the pool will be lying stagnant, and given enough time the heavier salt will settle to the bottom of the pool. Thus in the evening enough salt will have settled that we can skim some fresh water off the top. Maybe this water won’t be fully salt-free but it should be good enough for showering or cooking purposes. We can cut the hood off the nylon jacket to use as a cup to scoop the water up.

Process 3 (Cooling/Condensation) In the evening before heading off to sleep, we’ll dump out all the unused water and set the sail up as a tarp again using the rock piles we’ve created. This time we’ll put the base of the triangle high up and the tip of the triangle down low (see Figure 3). As the evening air cools and reaches the condensation point, fresh water will be collected at the underside of the tarp. Since there’s a slant to the tarp, again the water starts to roll down the tarp due to gravity till it reaches the drip point where again our nylon collection bucket will be waiting. Further, Scarlett and I will be sleeping under the tarp and additional water vapor from our heavy breathing will be released into the air and collected by the tarp.

Fig. 3: Process 3 side view.

Let’s see, I think that covers everything … any ropes that we need to secure the sailcloth can be made from my T-shirt or the sleeves of the rain jacket, or we can use some of those viney plants that are hanging around the camp.

Bonus points: no matches used!

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