Watermakers and Water
For long passages your tanks may not hold enough water without you severely rationing it. Why not make it from the sea around you? Since you need water to live you should also consider water from other sources such as rain catchment and the spigot at the marina. In both of these cases you should consider some kind of filtering system before you drink it. Usually a catchment system will have as a minimum a course strainer for leaves etc. With respect to marina water there are two concerns, the drinability of the water considering its source and the condition of the marina's pipes and hoses and the chlorine in the water. You should also be concerened with your water storage tanks and their maintenance.
Links - there are others but these seem to be the best of the bunch
- Water Makers! Building Vs Buying - Cruising As A Lifestyle Pt. 12
- Cruise RO Water and Power - series
- Building A Water Maker - Making Cruising Affordable
- Dock-side water filter system
- Marine Watermaker desalination by SeaWaterPro
- AquaMaax Marine R O Desalinating Water Maker by ElectroMaax
- How to make a 30 gallon per hour watermaker using off the shelf parts.
- Life on a Boat - How We Get Fresh Water on our Sailboat || Off Grid Sailing