The Care And Feeding Of Your Boat's Water Systems

Seawater Washing (1) — Seawater systems such as anchor washdown and dishwashing with a seawater foot pump (if you're in clean water and rinse well with potable water) can conserve water. Frequently bathing in saltwater causes skin problems in many people; a freshwater rinse helps. Washdown water pump should be a short distance from the thru-hull but above the waterline.

Drinking Water Purity (2, 6) — When in question, can be improved by adding a small amount of bleach. Some authorities recommend adding approximately 1 teaspoon of household bleach with no perfumes, dyes, or other additives per 10 gallons of water. If possible, agitate the water after adding bleach and then let it sit for an hour. Chlorine odor will dissipate after a day. Bleach may initially make the water to which it's added unclear because it's killed the “bugs.” The water clears as these settle to the bottom. Ultimately they should be flushed out. It's preferable and safer to add product manufactured for the purpose; camping stores are good sources. If you have questionable water purity and no way to remedy it, boil water before drinking. Drinking-water filters such as GE's FXUVC under-the-sink cartridge remove many impurities and greatly improve taste. A water system UV light, such as those used in some reverse-osmosis systems, can kill viruses.

Air Conditioning & Refrigeration (3) — Condensation drain trays should occasionally be inspected to clear any blockage in drain hoses, which should preferably drain overboard rather than into the bilge. If trays don't drain fully, they'll develop a musty odor that will be circulated by the air handler.

Icemakers (4) — Should be left open and off when not being used for a few days or longer to avoid odor and mold. Often the incoming water line is behind the unit in an area warmed by the unit. This facilitates stagnation and odor, particularly in the filter that may be in that area. When in use, the ice bin should be dumped at least every few days to keep water flowing. Good ventilation helps.

Bilge Water (5) — Oil-absorbent pads in bilges under the engine and whenever there's oil-spill potential are critical. They must not interfere with the operation of a bilge-pump float switch. Always clean loose fuel and oils out of the bilge with an oil-absorbent pad, and discard appropriately. Proper bilge-pump installation is critical and will vary with different boats. The hose interior should be smooth, the water column in the hose should be no more than needed, and great care must be taken to avoid backflooding from the sea. Visual and audible alarms at the helm are crucial.

Bilge pump hose should exit well above water line at maximum heel within the parameters of ABYC standards. Pumps should be in sections where water can pool more than minimally.

Sumps (7) — Those used for showers should be cleaned and flushed through regularly, even if the shower isn't often used. Shower sumps should discharge well above the water line at maximum heel within the parameters of ABYC standards.

Thru-Hulls (8) — Should be checked for obstruction every time you haul the boat and/or dive the bottom. Inspect them with a strong light, such as Streamlight's Stylus Pro 360, while hauled. While in the water, you may need to carefully (to avoid damaging hose and valve) work an old table knife or similar tool around inside the hole to clear it of barnacles and other obstructions. A carrot peeler makes a good tool for small holes. If the hole is covered by an external filter, this should be removed, when hauled, for painting inside, inspection, and cleaning.

Seacock with emergency plug.

Water Passages (8, 6) from thru-hull openings — Sinks, heads, engines, air conditioners, refrigeration, bilge pumps, and other components use thru-hull openings and hoses. Regularly inspect and operate all thru-hull valves. Some valves periodically require disassembly and lubrication or cleaning while the boat is hauled. You may need to close one quickly when a breach occurs in a water passage inside the boat.

Regularly inspect all hoses and connections. Old or suspect hoses will deteriorate over time and should be replaced. Eventually, wire inserts will rust and harm inner and/or outer hose walls. Preferred hose clamps are AWAB brand or similar. Double the clamps (unless doing so would cut into the hose, in which event a longer hose barb is indicated) and regularly inspect.

All components should be 316 grade stainless or better. Cheap hose clamps tend to rust and break. Use hose appropriate for the job, such as marine-sanitation hoses for heads. ABYC standards should be followed in these and all other aspects.

Holding Tank (9, 10, 11) — Some chemicals added to holding tanks can harm the environment if spilled, either from the boat or from pumpout-disposal systems and system failures. Various companies market what they claim to be environmentally friendly holding-tank additives with varying degrees of effectiveness. Some boaters install a Raritan ElectroScan MSD plumbed to treat and discharge overboard where it's legal, and treat and discharge into the holding tank at other times.

Head Water (10) — Regular addition of products such as Star brite Instant Fresh Toilet Treatment and Raritan CP help keep head water odorless and improve operation of the head. Petroleum-based products can harm valves, seals, and gaskets. Check manufacturer's recommendations. Regularly pouring white vinegar into the head and flushing will help diminish calcium buildup on inside walls of head plumbing. Raritan's CH is stated to be environmentally harmless and is specially formulated to remove heavy calcium buildup as well as prevent buildup if used regularly.

Head discharge hoses should be specified for MSD use. Other types of hoses are usually more likely to develop calcium buildup, deposits, blockages, and odor permeation. Plumbing the head to flush with fresh water can reduce odor. The head intake hose is positioned as it is in the illustration for clarity, but should be far enough from the head discharge to avoid sucking up waste.

Water Heater (12) — Should be standing upright with a backflow valve between the incoming cold water and the heater. Requires periodic flushing by squirting in clean dock water with a water hose under moderate pressure through a discharge port at top, squirting around inside as much as practical, and draining through open intake port at bottom. Some water heaters have an anode for cathodic protection that should be checked yearly.

Vented loop.

Anti-Siphon Loops and Valves (13) — Are needed in some hoses that exit underwater to prevent water from siphoning into the boat. Whether anti-siphon valves and loops are used depends in part on the location of relevant components in the boat and whether they're below the waterline or could end up below the waterline. These components may include heads, sinks, and engines and their raw-water intake and exhaust systems. As a precaution, when you're away from your boat, close the underwater seacocks.

Potable Water Tank (14, 15, 16) — Should be treated periodically with a product such as Star brite AQUA Water Treatment & Freshener to remove odors, scale, and bad taste. Also, thoroughly flush tank with clean water and pressure nozzle. Drain from bottom if possible; if not, pump it out. Follow manufacturer directions when applying anything to drinking water.

Follow instructions and warnings for cleaning additives, particularly with aluminum tanks. New tanks, especially fiberglass or plastic, may smell of the material of which they're made. Often, adding baking soda to the water will help, as well as with other odors later. The amount depends on the severity of the problem and volume of the tank.

Clarity of water may vary with source, such as from wells, cisterns, public water works, and reverse osmosis. The latter source, if coupled with a UV light and maintained well, probably produces the best water.

Drains and Scuppers (17) — Cockpits, side decks, and other areas of a boat normally have drains to rid the boat of rain and boarding seas. Test these regularly with a hose to be sure they're draining adequately. Leaves, plant material, dirt, and other debris can quickly obstruct them. Boats can sink if drains aren't kept clear. Clear them with a high-pressure hose nozzle or plunger.