During a forced sailing, water is much more valuable than food. After all, you almost don’t move and you are wasting little energy. Yet liquid is consumed constantly. Remember that you should not drink seawater.
Condensate. You’ll need a box, two containers, waterproof material, and weights. Take one container, and pour seawater inside. Place the other in a box next to it. Secure one piece of waterproof material (such as polyethylene) above both, and put a weight over the empty container. Soon the container will be filled with fresh water.
Rainwater. Try to ensure that you always have a couple of empty containers left for collecting rainwater.
Save yourself properly