Ships acquire potable water through external supply or by producing it onboard using specialized systems.
Ships require a constant supply of potable (safe for drinking) water for crew, passengers, and various onboard operations. There are two primary ways this water is acquired:
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Obtaining Potable Water from External Sources:
- Ships can directly receive potable water when in port. According to the reference, freshwater may be obtained from shore mains supply or water barge. This water is typically already treated and certified as potable.
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Producing Potable Water Onboard:
- For longer voyages or when external supply is not available, ships must convert non-potable water, usually seawater, into potable water. The reference states that alternatively, the majority of ships employ an evaporator system that uses distillation, or a pressurised filtering system which uses reverse osmosis to convert seawater into potable water. These systems are vital for self-sufficiency at sea.
Let's look closer at the onboard production methods:
- Evaporator System (Distillation): This traditional method involves heating seawater to create vapor, leaving the salts and impurities behind. The vapor is then condensed back into pure, fresh water.
- Pressurised Filtering System (Reverse Osmosis): This more modern technique forces seawater under high pressure through a semi-permeable membrane. The membrane allows water molecules to pass through but blocks most dissolved salts, minerals, and contaminants, resulting in potable water.
These onboard production methods ensure that ships can maintain a supply of fresh, safe drinking water even when far from shore.
