We are surrounded by an ocean of water but it’s not drinkable. How can we convert it to drinking water? We are 5 people on board Ingwe and need to drink 1 gallon per day for 21 days of this passage, In addition we need water to bathe, to cook and so on. Although we could in principle carry that much water we have a “water maker” that converts sea water to pure drinking water using a reversed osmosis system. How does it work? Surprisingly its quite simple and relies on three components: a source of
sea water, a semi permeable membrane that allows only water molecules to pass through and a pressure pump.

The first component is easy. We have lots of sea water. There are commercially available reverse osmosis membranes and one can rig a high pressure pump. The way this works is that on one side of the membrane is sea water which contains water
and salt. With pressure, molecules small enough to pass through the membrane are forced to do so. In this way water but not salt passes through to provide pure water, leaving salt behind. In this video we show you some of the components which include some filters to clean the water prior to delivery to the membrane in order that it not get clogged. This afternoon we made 35 gallons of fresh drinkable water and all powered by solar energy.