Evaporator. This is sometimes also called a “fresh water generator”. Modern vessels are fitted with a fresh water distilling plant.
This installation is particularly useful on long voyages as it results in considerable savings on the quantity of fresh water carried, therefore increasing the deadweight capacity for cargo correspondingly. Moreover, time is saved at ports of call where fresh water is ordinarily replenished. Against the advantages, however, should be set the initial cost of distilling plant and distillation of fresh water per ton. The evaporator is also considered when the crew accommodation and fresh water supplies are assessed before a vessel is registered. Under the British system, the shipowner must ensure that there is tank capacity for 90 liters of fresh water per man per day between replenishment of fresh water. This can be reduced to tank capacity of two days’ supply if an approved fresh water generator is carried.