ON BOARD WATER
Water is an essential element of life, and constitutes more than 70% of the human body.
Its handling on board must be done with all possible care, as it is one of the most important aspects of a vessel's hygiene.
We use water mainly for direct consumption (drinking water and food preparation), cleaning food and the utensils used for cooking and eating. It is also used for toilets, laundry and cleaning accommodations, etc.
Water destined for human consumption must pass a series of requisites:
Water with these characteristics can be named «drinking water».
This water can be produced on board through distillation and filtering of seawater, but the more usual way (especially on small vessels) is to get it from a port where it will have been treated on land. If there is any doubt, it should be treated on board to ensure that it is drinkable. The supply and drainage systems should be scrupulously checked to prevent contamination.
The drinking water system includes the deposits, pumps and distribution system and must be absolutely independent of other plumbing systems on the vessel, especially those of residual water systems. It should be made of materials resistant to corrosion and toxins. It should have anti-return and filter systems in the deposits, that impede the entry of insects and rodents, as well as automatic level indicators that avoid the use of dipsticks.
The deposit should be able to drain itself completely, have a lateral inspection window and be cleaned periodically.
Refilling is especially important, there should be a covered refill pipe and connector to take the hose from the port. Hoses should be kept in a cupboard clearly marked "Drinking water hose", and should not be used for anything else. The hoses should be cleaned and disinfected periodically to ensure it remains in good condition.
When calculating the supply of drinking water, we should bear in mind that the minimum needs of crewmembers per day are 32 litres of water for drinking and cooking and 88 litres for washing. These quantities can be increased, to improve hygiene facilities, to 200 litres/crewmembers/day. Consumption will also depend on the type of vessels and navigation zone. Supplies should be increased for trips in hot climates.
If there are any doubts about the quality of the water or if contamination is suspected, proceed with the most simple, practical and secure purifying system of chlorination, which is carried out with commercial bleach and not detergent (see APPENDIX 8).
If the vessel has a distillation system, it should be checked and disinfected periodically and disconnected when navigating through highly contaminated waters (water less than 12 miles from the coast, drainage outlet areas and oil tanker cleaning areas, etc, are generally considered polluted).
Ice that is going to come into contact with food or drink must be made with drinking water and handled in hygienic conditions, with clean gloves, shoes and clothing, washed with drinkable water beforehand.
Dinghy and lifeboat drinking water
The traditional lifeboat drinking water tanks have been replaced by individual rations, vacuum-sealed in bags or cans that aid in the task of maintenance (you only need to check the expiry date and absence of leaks). If the dinghies have their water reserves in tanks, they should be renewed every month at the same time as the deposit inspection.