The production capacity of fresh water by the machine is given by the manufacturer and expressed in liters per hour. The production you require will depend on the needs of the boat and the estimated consumption in liters per day. The different uses must be taken into account: cooking, drinking, bathing, cleaning, etc. The best way to determine this quantity is to calculate the daily consumption for the number of people onboard on a shorter trip before purchasing a watermaker.
It is important to determine the lean production capacity. Overestimating the requirement risks over-dimensioning the system and therefore infrequent use. Bacteria are then likely to develop and affect the proper functioning of the watermaker. The choice of production capacity will also depend on the number of hours that the watermaker will be running daily.
However, more often than not for larger ships, underestimating how much water it will take to navigate comfortably is more common. It’s important to calculate the amount of water you’ll need for your crew to be comfortable and not only the minimal amount of water it will take them to stay alive. Underestimating can lead to crew tensions.
Marine watermakers can produce from a few dozen liters up to several thousand liters per hour. Your choice will depend on the type of navigation you’ll be doing.
Use simple math to determine the gallons per hour you’ll need the machine to produce during your navigation: Divide the total gallons of water required per day by the number of hours the watermaker will be used.