What is Emergency Water Supply?
Emergency water supply systems ensure access to drinking water if normal water systems fail or if you abandon ship.
Answered by Marine Keeper — the boat maintenance platform trusted by boat owners and charter operators to track, schedule, and understand every system on the water.
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What it is
Emergency water supply systems ensure access to drinking water if normal water systems fail or if you abandon ship. This can include sealed emergency water rations designed for long-term storage, manual watermakers (reverse osmosis desalinators operated by hand pump) that can produce fresh water from seawater without electrical power, or solar stills that can distill seawater to freshwater.
What it does
Emergency water rations provide immediately drinkable water in containers. Manual watermakers use hand-pumped pressure to force seawater through reverse osmosis membranes, removing salt and producing fresh drinking water. A solar still is a simple but highly effective device that uses sunlight to convert saltwater (or contaminated water) into freshwater through distillation. Its design uses the process of evaporation, condensation and collection to produce potable water without fuel or mechanical parts. These systems ensure you have access to water even if your boat's water tanks are contaminated, damaged, or inaccessible or if you've had to abandon ship.
Why it matters
Humans can survive only a few days days without water, and survival time decreases rapidly in hot conditions, with sun exposure, or after exertion. Loss of fresh water supply is a life-threatening emergency. Water tanks can become contaminated, lines can break, or you may need to abandon ship. Emergency water supplies and manual watermakers ensure you can survive extended periods without access to shore or rescue. This is particularly critical for offshore passages or cruising in remote areas where assistance may be days away.
General Maintenance
Check expiration dates on emergency water rations at the beginning of each sailing season and before any long voyage and replace before expiration (typically 5-year shelf life). For manual watermakers, follow manufacturer guidelines for long-term storage and maintenance of products; regular maintenance may involve cleaning or replacing filters, rinsing equipment, flushing in preparation for long-term storage, and more. Check that all components are present (pump handle, pre-filters, etc.). Ensure the unit is stored where it can be accessed in emergency and added to a grab bag if abandoning ship. Practice using the watermaker so you understand the physical effort required and technique needed. Since solar stills are often packed inside life rafts for years at a time, it is essential to inspect them during scheduled life-raft servicing. Check for cracks, cloudy domes, or damage to valves and hoses. Ensure collection bags, tubing, and accessories are included and intact, and confirm the manufacturer’s expiration date, as materials can degrade over time.
Common Issues
- Emergency water rations exceeding expiration dates without replacement
- Manual watermaker membranes drying out from lack of use
- Hoses and fittings deteriorating and developing leaks
- Pre-filter elements clogging or degrading
- Crew unaware of physical effort required to operate manual watermaker
- Components or instructions missing making operation difficult
- Unit stored in location that would be inaccessible in emergency
- Watermaker intake or discharge fittings corroding
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