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Friday, February 5, 2010

Water Strategy and Needs, Jerrycans, and Sailboat Voyaging

There are 3 basic survival needs: shelter, food, and water; water provides the largest challenge in our upcoming lifestyle.

As the official Water Buffalo, Water Master, and Water Transporter for our family, all watering needs and ensuring we are adequately stocked is my responsibility. As such, I've broken down the water concerns into 2: quantity and quality.

On the quantity front, our Gemini 3200 is equipped with two 30 gallon holding tanks making for a total of 60 gallons. These are plumbed into the boat such that we have water from the tap on the sinks (kitchen and bathroom) and a shower head.

Based on our usage patterns from the summer, it looks we are averaging about 12 gallons of water per day (coming out to 3 gallons of water per person per day). This is an all inclusive number to include water ingested, used for cooking, and washing things like dishes as well as our bodies.

This rate of consumption implies that the holding tanks give us a total of 5 days before replenishing is required. As the water master, that isn't a comfortable number for me. I want at least 8 days of water for the entire family. With 8 days of water, I feel comfortable that we would be able to find a suitable water source for refilling. Consequently, we plan on adding supplemental stores for water, and we will do so in the form of water Jerrycans.

There are 2 reasons for taking the Jerrycan approach, as opposed to installing more, or larger, plumbed in holding tanks. First, water acquisition will be easier. Second, cross contamination will be less likely.

At 8.3 lbs per gallon of water, identifying the right size and easy to carry Jerrycan will be important (remember, I'm the water transporter). The current working plan is to acquire six 5 gallon Jerrycans. Fully topped off, this implies 250 lbs of water, plus the weight of the container itself. This is a figure that must be carefully considered with respect to our load capacity.

Our plan is to use Jerrycans as our source for daily drinking water. That is, a Jerrycan will be out and easily accessible so that anyone can tap into it throughout the day to get some water for drinking. If we allocate Jerrycans as the daily drinking source, and we are completely topped off, at 1 gallon of water per day per person for drinking, we can make our 8 days. Clearly, if we suspect that we are running low on water, and the odds of finding any are low, we can also use water out of our main holding tanks for drinking. If we used all water sources (holding tanks plus Jerrycans) exclusively for drinking, we could make 22 days.

In addition to the static mode of being topped off with water from public sources along our journey, we plan on leveraging 2 other sources for refilling: rain and seawater.

We plan on taking advantage of what falls from the sky whenever we can. We will be adjusting our Bimini such that it is optimal for catching rain water. It will be fitted with an elephant trunk so that the rain water pooled on the Bimini can be routed to our holding tanks. It will be KJ's job to make this connection once it starts to rain.

We will also have a mechanical (as opposed to electric) water maker that will desalinate and purify sea water. Since it is mechanical in nature, it doesn't create mass volumes of water without tremendous effort so its usage will be mainly for generating drinking water.

The last commentary to offer on water quantity is that we plan on acquiring a water bladder for the dingy. This is basically a large balloon that can be pumped full of water. The idea is that we can bring the dingy laden bladder to a water source, fill it up, then dingy back to the boat and pump out from the bladder into the boat.

When obtaining water from untried sources, especially in third world countries, one must be very careful. We will be using the Clorox Bleach method of water purification. In general, you use 8 drops of Clorox per gallon of water, or 1/2 a teaspoon per 5 gallons of water. There are some other particulars about this, and if your interested I encourage you to do some research.

The mechanical water maker we will be using on the boat will have both a 10 micron filter and a 5 micron filter. These filters provide filtration capabilities on par, or better than, most water treatment plants in the USA.

As you can probably tell, we are giving water a lot of thought. It is back to the basic needs: shelter, food, and water. If we can keep these 3 covered, we can go indefinitely. Water appears to be the most tricky of the group.


  1. If you're planning to take jerry cans with you, look into flexible collapsible water jugs. They're still plastic, hold just as much water, but MUCH easier to store when empty (fold flat), are very durable, cost is cheap, and are VERY tough! Our family has had ours for nearly 10 years and they're still holding strong, plus I know lots of boy scout troops that use them on their scouting trips. Just google 'collapsible water jug'.

  2. @Anonymous - Thanks for the suggestion. We will definitely out the collapsible Jerry cans.

  3. If only the rest of the world would think 'back to the basics.' We need to learn from the boaters... water is the trickiest all over the world. Hubby AND Son work in the Water Purification field.

  4. Great blog thanks for sharing your thoughts. One question: Where did you find a mechanical water maker?

  5. Check out these water containers:


    They were recommended in one of the Pardey's books (I think) and we ordered 5 or 6 last year, for the same purpose you have described. As you may already know the black colour makes them less susceptible to UV degradation (so I have read).

  6. @Anonymous: The mechanical ones that we could find for sale were the emergency ones that cost around $800. However, we did find plans for DC powered ones, and I intend to replace the DC powered engine with a mechanical armature. The volume of water that can be produced, based on my rudimentary math, is quite small, but can produce enough for us if needed for a day. I plan on posting a blog on this item specifically.

    @Mike: Thanks for the link Mike! We will check them out. That is interesting on the UV degradation. We've been talking about acquiring at least one black container in hopes of heating water by placing the Jerry can on deck. I had also read of a technique regarding purification of water that leverages the UV radiation from the Sun. This "survival" mode technique suggests putting water in clear containers and leaving them in the sun for a few days. I'm not sure how much would be left after evaporation, but supposedly the harmful impurities (viruses, etc.) would be killed off.

  7. Just found your blog, we are preparing for our own family cruising adventure next year. I've been thinking about water as well.
    During some shorter trips we have taken we sometimes found that we needed to carry water a bit of a distance to the dingy. Our five gallon jugs were very difficult for me to carry. I'm not sure if it is practical, but I ran across these rolling water carriers, and they might be worth a second thought. http://www.hipporoller.org/ or http://boatbits.blogspot.com/2010/02/neat-wheelie-dealie.html

  8. Blogs are so informative where we get lots of information on any topic. Nice job keep it up!!

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