"Eeww! What’s that smell?" If you are a weekend sailor familiar with these words when you or your mate slide the companionway open, you’re also familiar with what follows. The odor consumes everything, ensuring that what was to be a daysail ends up becoming an effort to eliminate the smells. Who wants to sail in a foul smelling vessel?
This is not to say that liveaboards don’t have that problem too—they’re just able to stay on top of it easier. Hatches and companionways are opened to capture fresh air and ventilate below-decks more often than the boat that is closed up waiting for its weekend owner to show up. If an odor becomes noticeable, the liveaboard is right on top of it—after all, who wants to live in a foul smelling boat?
Ventilation is one of the key elements in keeping odors at bay, especially since many nasty smells are a direct result of the growth of molds and mildews. For the non-liveaboard, a good ventilation system is essential and requires both intake of fresh outside air into the boat and the exhaust of stale cabin air to the outside. The selection can vary from an active solar/battery ventilator to the passive system like cowl vents. Ventilators that are solar driven and charge a battery allow the ventilator to run at night and on cloudy or rainy days while keeping the weather out. Cowl vents move less air but keep some air moving through. A mix of active and passive ventilation works well on most boats.
Mold and mildew are living organisms whose spores are everywhere, just looking for a damp environment with little airflow in which to grow and flourish. Again, prevention is the best course. If the boat is being left for a period of time, turn all the cushions up on end to promote ventilation underneath and be sure all ports and hatches are securely latched so that there is no water dripping onto them. Damp-rid helps remove moisture from the air. If mold and mildew do get a foothold in the boat, the good news is that they are easy to kill with mild solutions of bleach or fungicides—the bad news is that they often leave their odor and stains behind in permeable surfaces such as fabrics, paints, and headliners.
Mold and mildew stains are difficult to remove. Some fabrics may be hand-washed in a light bleach solution and others may have to be dry-cleaned. Always check the fabric’s cleaning instructions prior to cleaning. Some interiors are lined with carpet-like fabrics that can be cleaned and deodorized with powdered carpet cleaners found on the grocery shelf. A few new products on the market, like Febreeze, are great for removing odors from fabrics that can’t be stripped off the boat and carried to the washer or the dry cleaners. These products are also good for foam cushions and mattresses. Headliners, usually made of a vinyl fabric, can be cleaned simply by wiping them down with white vinegar. Commercial products like Lysol (a fungicide) can be used on most permeable surfaces to kill mold and mildew and may remove some of the stains. Most often, the best way to remove the mold and mildew odor is simply a good "sunning" if the item can be carried out of the cabin. Mild abrasives, such as a paste made of baking or toothpaste, remove some stains from some surfaces.
Odors originate not only from mold and mildew, but from water sitting in hoses, wet bilges, and leaking sanitation systems. Most bilge pumps leave some water in the bilge and after it sits for a while things start to grow—and when algae grow, odors abound.
Several systems on the boat help create bilge odors: a packing gland drip, shower and icebox drains plumbed into the bilge, sanitation system, fuel system, oil, or other engine fluid leaks. Bilge odors can also be clues to potential problems; leaks in the sanitation system, a leaking thru-hull fitting (salt water starts showing up in the bilge), a fuel system, engine fluids, or hydraulic system leak will leave clues that you should not ignore. In these cases, just masking the odor will never solve the actual problem.
A few simple fixes can go a long way to prevent bilge odors. Sailors need to live with a packing gland drip, but by dry mopping during engine maintenance, the accumulation in the bilge will be minimized. One major fault with many boats is that gray water, with its collection of hair, soap, and bacteria, is allowed to drain into the bilge. Re-plumbing the shower into a separate gray water tank with a float switch that automatically pumps the contents overboard solves this problem permanently. Drips from the icebox often carry spilled milk and bits of food to the bilge, so when you install the gray water tank, lead the icebox drain to it too. Vent this tank properly and clean it often.
Refrigeration and icebox odors result from decaying foods (bacteria) and standing water. An icebox should have a drain hole in the bottom but many refrigerated boxes do not. To eliminate odors in an icebox, remove all the contents, making sure to wipe spills off the cans and bottles, and run a cup of white vinegar down the drain. Mop up all excess water in the bottom and remove any moisture from the sides and lid. Wipe all surfaces down with white vinegar before refilling the box with food. If the boat sits unattended for any length of time, leave the lid off and place an opened box of baking soda in the icebox.
To remove odors from a refrigeration box, turn the system off, empty it, and allow it to defrost. Dispose of any food or dairy that may be suspect. Mop up all moisture in the box, damp-mop the insides and the lid (including the gaskets) with white vinegar until the odors are gone. Unless it’s really bad, once is usually enough. Thoroughly dry the interior and the lid, turn the system back on, and replenish it with fresh food. Place an opened box of baking soda on a shelf to absorb light odors. Replace the baking soda at least once a month. Again, If the boat sits unattended for long periods, leave the lid open and don’t turn the refrigeration system on.
Sink drains with gray water sitting in them, particularly the galley sink where food particles may not be completely flushed, will create an odor like no other. I used to think the smell of rotten eggs was bad but this smell will literally drive me off the boat. Always flush sink hoses with white vinegar or Joy dish soap at the end of each day. Close the seacock, allowing the white vinegar or dish soap to do its thing overnight. Once this "rotten egg" odor starts, eliminating it takes time and perseverance. Close the seacock and allow the white vinegar to sit in the hose for a few hours, then flush with hot freshwater. Repeat again—and again. If the odor is not entirely removed, close the seacock and add a very weak bleach solution (three tablespoons per gallon of water) to kill any bacterial growth. Allow this solution to sit in the hose for a couple of hours before re-opening the seacock, flushing and rinsing a few more times to be sure all traces of bleach are gone.
Head intake hoses and others that stand full of uncirculated salt water for long periods of time often become a breeding ground for marine life. If you get a nasty odor every time you flush the head, this is probably the cause, especially if the hose is the clear or opaque type that allows light through aiding the organism’s growth. In some cases, the problem is so severe that the only solution is to replace the hose, using a good quality hose made for the purpose.
Eliminating holding tank odors can be tricky, since you need to be at a pumpout station or three miles offshore in order to flush the tank legally. There is a variety of products on the market that claim to eliminate holding tank odor without the need to flush the tank by using chemicals, electronics, enzymes, and molecular recomposition. Some are "green" and others aren’t—check the labels. White vinegar is nontoxic and environmentally friendly and, with several flushings, freshens the holding tank. Again, it can only be used when offshore.
Oil and engine fluid leaks in the bilge occur mostly when the engine is being serviced. To minimize this and the potential environmental hazards, always change oil, transmission fluids, and coolant with the bilge pump off and either bilge pads or disposable diapers available to absorb any spills. If oil or fuel gets into the bilge, activating the bilge pump can result in stiff fines! Add a little water to the bilge and let these fluids float to the surface, then use disposable diapers or bilge pads to soak them up. Add a little water and a tiny amount of Joy dish soap to break up the oil or fuel further before mopping again with disposable diapers or bilge pads. If the boat is sitting at a slip or mooring, bilge pads under the hose connections leading into the fuel tank(s), fuel filters, engine, and under the hydraulic ram if the boat has hydraulic steering not only prevent leaks entering the bilge but also alert the sailor to any leakage.
Sewage in the bilge will be immediately apparent, but saltwater bacterial growth will take a little longer to become apparent. Bacterial odors from these two sources are enough to bring down the most odor-resistant nose. It’s important to repair any thru-hull and sanitation system leaks or there will always be an odor in the boat. Sometimes the sanitation hoses need to be replaced because of odor permeation into the rubber, and if this is the case, use the newer odor-resistant white vinyl hoses.
Remember, when cleaning or fighting odors to be kind to your surroundings. Choose environmentally friendly commercial products to eliminate odors. Flushing the bilge requires great quantities of freshwater pumped overboard. The sailor’s most ecologically friendly odor eliminators are also the most inexpensive—white vinegar, Joy dish soap (no phosphates), and baking soda.
With a little prevention, smells can be minimized and even eliminated. Next weekend let’s go sailing.