I have a sensitive nose, so much so that at any boat show, I can readily determine the age and condition of a boat with a few good sniffs. During the many years I have spent living aboard boats, one of my more obsessive traits has been wanting the interior to smell nice. This is an ongoing battle on a fishing boat and charter yacht.

Tracking down the source of interior stink is best done the moment the odor becomes obvious. Diesel boats can be especially challenging if fuel oil finds its way into the bilge during filter changes or repairs.

A common, though ineffective, solution is to pour soap into the bilge and spray water to build up mounds of suds that eventually get pumped overboard. The problem with this program is twofold. First, the suds will transport remnants of fuel oil around the bilge, helping it to seep beneath floorboards and reach behind stringers. Second, the fuel oil will separate from the mixture when it goes overboard, exposing the boat owner to a costly federal fine for pollution.

A better approach is to evacuate the suds and oil with a wet vacuum and dispose of the contents on land, in an approved receptacle. The best strategy is to trap and collect any oil in disposable diapers (oil mats), instead of using water and soap.

A dry bilge and lazerette go a long way toward keeping odors in check. Inspect the undersides of hatches for clues that moisture is seeping below. Black mildew or water droplets are sure signs of moisture penetration, and can be the result of clogged drains in the hatch rim that can fill with leaves, fish scales, dirt or mop threads. When you rinse out the cockpit, lift any hatches, and wipe the undersides and rims to remove residual water and grime. If I am at the dock on a nice day, I leave a few hatches open to introduce fresh air belowdecks and into the engine room.

Similarly, open any side lockers or similar compartments in the cockpit or on the flybridge, and air out the contents. Try not to stow equipment such as dive gear in these wells unless it has been rinsed with fresh water and air-dried. Salt breeds moisture. Saltwater-covered items will never fully dry, and will instead grow into a mildew convention, with a rank odor to match.

The anchor rode locker is another breeding ground for mildew that will stain nylon anchor line and cover the compartment’s walls with black patchwork. If your boat has a forward deck hatch to the rode locker, leave it open on windy days to air-dry while at the dock or on the hook. A couple times during the season, remove all the rode and let it dry in the sun after rinsing it with fresh water.

If the only access to the rode locker is from a hatch in the forward bulkhead in the cabin, then each time you open it, you are introducing musty air into the boat’s interior. That musty air will latch onto the bunk spreads and other porous materials. However, if the boat is equipped with a chain and rode deck pipe, leave the cap off so air can circulate into the locker. Just remember to secure the cap before you leave the dock, and to schedule regular inspections and air-outs to help stem the production of mildew and reduce nose-twitching smells.

Perhaps the most obvious and obnoxious smells originate from the head. Marine sanitation devices that flush with fresh water are less prone to cause issues. When the device flushes with seawater, live organisms that die inside the intake hose can raise rank odors. If your head is set up with such a system, flush seawater through it before using the toilet, to fill the bowl with new water.

Head odors also can permeate intake and discharge hoses as they age. The best way to check for this is to drape a clean cotton cloth over the hose and leave it in place for an hour. Then, remove the cloth and give it a sniff. You will know right away if those hoses should be replaced.

Salt air and humidity contribute plenty of residual scents throughout the season. Encourage your guests to dry off before coming into the salon, and to avoid sitting on fabric-topped cushions or lounges. A carpet runner is a good idea to collect wet footprints, but runners or covers need to be laundered regularly, particularly when kept in place between trips. On my fishing trips, I cover my settee cushions and the L-shape lounge with clean bedsheets. This eliminates suntan-lotion stains, as well as fish blood. Durable fabrics such as Sunbrella are great choices for covering pillows, lounges and bunks, but they, too, need regular cleanings.

Smoking diesels are prime offenders in the scent department. The best way to keep those fumes at bay is to close the salon door or aft curtain underway. An open foredeck hatch or opening windshield will help maintain a steady flow of air to dispel exhaust fumes. Don’t be surprised if you discover a fine coating of diesel dust on horizontal surfaces throughout the interior. A clean cloth and a squirt of Simple Green or Orpine soap will remove the residue with a fast wipe. Similar scented cleaning supplies should be used regularly to prevent a buildup of grime.

Although my boat has a sole of varnished teak and holly (rather than carpet), I still keep a vacuum stick aboard to prevent the day’s collection of dust and dirt from grinding into the sole. I also encourage my guests to rinse the bottoms of their boat shoes before boarding. Daily cleanups rarely take much time, and the boat does not require heavy cleaning sessions.

Another little trick that helps the interior’s smell is to leave scented dryer sheets in hanging lockers and cabinets where there is little air movement. Hanging moisture-absorbing products in closets also does a good job of keeping clothes dry.

Perhaps the fastest way to get the interior of your boat smelling spring fresh is to spray a blast from a can of air freshener into the return grill of the air conditioning system. A minute or two later, the whole boat will smell great.

This article was originally published in the July/August 2022 issue.