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Trust Your Senses

Sounds, smells, and sights you shouldn't ignore.

Sunken Boat

A few years ago, the owner of a 30-foot sailboat thought he smelled a faint burning odor in his boat as he and his family sailed on Puget Sound in Washington state. At first, he dismissed it as his imagination but his wife and kids thought they smelled it too. He went down below and began using the only tool he had to locate the problem — his nose. The odor seemed to be coming from under a quarter berth and as he lifted the cover, the smell really hit him. He quickly located a positive wire that had been pinched against a battery ground post and was slowly melting. Had he not investigated, a fire could easily have started.

Most people would have a hard time ignoring a blaring alarm or flashing light, but those same people might not trust their own senses to tell them when something is wrong. While modern boats are equipped with all kinds of sensors, the best ones are likely on your face — your ears, eyes, and nose. When something doesn't smell, look, or sound right, trust your senses and investigate before it's too late.

The Sniff Test

Gasoline fumes are highly explosive and even a quick whiff of gasoline needs to be investigated immediately. Fuel tanks are a common leak area. Aluminum fuel tanks don't last forever and a tank that is over 10 years old should be the prime suspect if gas is smelled. Owners have often reported fuel tank leaks just after a particularly rough outing; corroded sections can open up after being severely jostled. Fuel hoses age and can begin to leak as well. Hose manufacturers say that fuel hoses are designed to last about 10 years (USCG-approved hoses are stamped with their manufacture date). Take a clean rag and run it along your fuel hoses. Put your nose to use: If the rag smells like gasoline, the hose is due for replacement. Or — using your eyes — look for cracks or bulges that indicate the fuel line is due (overdue) for replacement. Fuel line connections are another common source of leaks.

In one claim (#0303086), a large sailboat was destroyed in a dramatic explosion that blew the skipper into the water. The cause appeared to be gasoline from portable containers stored on deck that dribbled down the mast step. The owner reported smelling fumes when he arrived the day before and had opened the hatches, and even thought he may have also smelled gas just prior to the explosion. Unfortunately, he did not take the time to investigate the source of the fumes and eliminate the hazard. If you smell gas, don't discount it — trust your nose. If you can't locate the source of a fuel leak but still smell gas, call in a professional before using your boat.

Propane is another odor that humans can detect easily, thanks to the distinctive smell manufacturers add. Even the slightest odor of propane should be cause for alarm since it's under pressure and will continue leaking until the leak is found and eliminated. Propane is heavier than air and will sink to the lowest part of the bilge — the slightest spark can ignite it. If you smell propane, turn off the main valve, open hatches and get off the boat until the leak is found and repaired. The most common propane leaks are from old, cracked, or cut hoses and connections. Propane installation should follow ABYC standards and for that reason, any work should be performed by an ABYC-certified shop with a technician who is experienced in all phases of propane repair and installation.

The next time you board your boat, take a deep breath. Does it smell fresh or is it (phew) dank and musty? While mildew can't destroy your boat like a gas leak can, it can nonetheless be very expensive to eliminate. Smelling mildew (the fuzzy stuff that is produced by mold) means there is a lot of moisture down below. The moisture could be coming from a leaking portlight or hatch; on a sailboat, chain plates and stanchions are common areas for leaks. Clogged cockpit scuppers can spill water into the cabin. Leaks can cause rot in wooden bulkheads and deck cores, so smelling mildew means making a careful inspection of the inside of your boat to find the source of the water. Mildew is encouraged by poor air circulation and condensation, which can usually be remedied by adding traditional dorades or low-profile vents. An even better remedy would be to add solar-powered vents, which move a surprising amount of air and can even run at night using a small battery. Chemical dehumidifiers can be used in confined spaces. They're cheap and easy to use.

Listen Up

Some sounds are obviously trouble — a loud bang or crunch. Some noises are more subtle — a squeal or rumble. Any unusual noise, especially a noise that changes or gets louder, should be checked out.

Last year, the owner of a 32-foot powerboat and his girlfriend were nearly killed by carbon monoxide poisoning while they were sleeping at anchor with the generator running. The boat was well kept, with only 500 hours on the engines. The owner noted that he had been hearing an unfamiliar noise coming from the generator when it was operating, but had never investigated. The noise, it turned out, was a leak in the generator's exhaust system, which was the source of CO that was entering the cabin. Had the gas tank not run dry, it's likely that both people would have died. Here's another noise associated with CO that you should not ignore: the CO detector blaring. It sounds obvious to pay attention to an alarm, but many older detectors are prone to false alarms and owners either ignore them, or worse, unplug them. Newer detectors are far more accurate and when they sound, it's critical to get everyone out of the cabin and into fresh air until the source of the CO has been repaired. Note that this is one situation where you can't trust your senses; carbon monoxide is colorless and odorless.

Everybody has heard the bilge pump come on a time or two. The skipper of a 34-foot sailboat, for example, heard his bilge pump running occasionally but thought nothing of it. Boats leak a little … the bilge pump should be able to handle it. But that's exactly the wrong thinking. Bilge pumps are designed to handle nuisance leaks until they can be repaired. Over time, even a small chronic leak can sink a boat if the bilge pump were to fail. Small leaks can also become large leaks and overwhelm the pump. In the case of the 34-foot sailboat, the owner told the investigator that he'd meant to get to the bottom of the frequently running bilge pump when he had a chance. Unfortunately, that never came. The boat sank at the slip when a rusting stuffing box clamp finally let go, flooding the boat so quickly that the bilge pump couldn't keep up (Claim #0987635).

Another claim involved a 26-foot powerboat whose engine squealed whenever it was started. Since the sound went away after the engine warmed up, the owner ignored it. The squeal turned out to be a drive belt that ran the boat's cooling water pump. The pump was worn, which caused it to bind up, which in turn caused the belt to squeal as it slipped. During a family outing, the engine overheated enough to cause a lot of scary-looking smoke from the engine compartment. The boat had to be towed in and the repairs were far more expensive than a new pump.

A loud thud on the hull is certainly a cause for alarm, but unfortunately some skippers just cross their fingers and hope it was nothing, which is asking for trouble. Running into a log or other floating debris can knock a hole in the hull, tear out a transducer, or rip off an outdrive, all of which can trigger a leak. Even small leaks can eventually sink a boat. If you strike something in the water, stop the boat and thoroughly explore the bilge. Note, however, that a leak may not be immediately obvious and it is a good idea to check again later. The skipper of a 32-foot sailboat heard a loud bang on the hull while sailing fast on Lake Pontchartrain in Louisiana. After glancing below and not finding any rising water, he eventually sailed back to his marina and docked his boat. The next day, the marina called, telling him his boat had sunk. An investigator found the “bang” damaged the stuffing box, causing it to leak slowly. As the boat filled and lowered in the water, the cockpit scuppers were forced under, adding to the inflow. The boat sank (Claim #0987364).

Some sounds are harder to place than a squeal or a bang. A grumbling noise while underway could be a worn cutlass bearing, an engine out of alignment, or a transmission in need of maintenance before it catastrophically fails. Try to have a listener pinpoint the area while the boat is underway. That way, back at the dock, you or your mechanic will have a much better idea of where to start looking.

Open Your Eyes

Muskrats Chewed Through the Inside of the Engine's Exhaust Hose

A muskrat chewed through the inside of the engine's exhaust hose and set up housekeeping in this 34-foot powerboat. The aroma from the critter's frequent buffet dinners, which should have alerted the owner that something was amiss, was ignored and the boat eventually sank. If something smells "fishy" in your boat, don't assume it will go away. Trust your nose and find the source before it's too late.

For the most part, problems you might see on your boat are obvious — smoke billowing from the engine compartment, a crack in the hull, and so on. But there are some more subtle clues you might see that you shouldn't discount. For example, black smoke coming from your diesel exhaust could be a sign of a clogged air filter; lots of steam could be a failing water pump impeller. See a little corrosion on your outdrive? Don't ignore it, as it may be an early (and preventable) sign of stray current corrosion. In another case, the owner of a 36-foot sailboat was looking up his mast when he noticed that it appeared slightly crooked. He had it inspected by a rigger, who found that a tang on the mast had cracked and was forcing the mast out of alignment, something that could have brought the whole rig down if not addressed.

Trust Your Feelings

Everyone knows when they aren't feeling well — a little dizzy or wobbly — it's time to see a doctor. Trust those same senses on your boat. If it seems like it's handling a little sluggish, don't ignore it. Several years ago, a man noted that he got an indication of a problem when his boat began to feel sluggish — it was hard to steer and seemed to be slowing down. Thinking it was his imagination, he continued on for a few more valuable minutes until it began to roll erratically. By then it was too late; the boat had been taking on water (through a broken stuffing box) and the boat had begun sinking.

Another thing you shouldn't ignore is stiff steering. Many boats use cables to steer the boat and the cables can corrode internally over time. When that happens, the cable is living on borrowed time. Replace any cables that are excessively sticky or have cracks or bulges.

Finally, pay attention to what your feet are telling you. If you feel a new vibration from the cockpit, it could be an out-of-alignment engine (which can damage the transmission over time) or a bent prop, which can also cause transmission or engine damage.

If you trust your senses and react quickly, you can save yourself and your boat a lot of grief later.

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BoatUS Editors

Contributor, BoatUS Magazine

Award-winning BoatUS Magazine is the official publication of Boat Owners Association of The United States. The magazine provides boating skills, DIY maintenance, safety, news and more from top experts.