Common wisdom is that humans have 5 senses: sight, sound, smell, taste, and touch. Some research ascribes up to 33 senses to humans, including: equilibrioception (sense of balance), interoception (internal body senses such as thirst and hunger), hygroception (sense of humidity), thermoception (sense of temperature), and more.
Good sailors use all of their senses on a continuous basis:
Sight
This one is obvious. We look at navigation instruments. We look at the water for obstructions and sea state (waves, current). You can even tell wind strength from the visual texture of the water’s surface. We look around for traffic. We look to the sky for signs of changing weather. And, we look at our sails to make sure they are properly trimmed.
Sound
We listen for ship bells, buoys, fog horns, communications on the VHF radio, and engines from other vessels. We also listen to our own vessel of telltale noises, such as changes in engine regime, or anything unusual that might suggest a problem. In a prior post, I described a regular knocking sound that started on a wavy sea, causing Fregata to roll from port to starboard. It turned out it was nothing more than a shower door whose latch had become loose allowing the door to open and close with the rolling motion.
Smell
We detect changes in smell. Engine exhaust odor variation can indicate certain mechanical problems. Ozone smell can suggest an electrical problem. Even environmental smells are useful indications of potential problems. When I was younger, I attended Les Glénans sailing school in France. At one point when we were practicing nighttime navigation, we started detecting a fishy smell. We shined a flashlight toward shore to starboard and realized we’d “navigated” ourselves very close to an oyster farm and were running parallel to a row of oyster fences! The logical thing to do would have been to turn to port to move away from the farm. Fortunately, we shined the light to port before doing so. There were oyster fences there too! In pitch black darkness, we managed to get ourselves into a narrow corridor between rows of oyster fences. The wind was blowing 25 knots from astern, so there was no way to stop, or to lower the sails, which would have required making a 180º turn into the wind. There was no maneuvering space to do so. The only option was to hold a straight course through the farm. Eventually we emerged downwind, and turned to the safety of deep water without any further disasters! It was the sense of smell that saved us from a potentially serious accident.
Touch
Although modern cruising boats have electronic instruments that indicate wind speed and direction, you can also feel it with your sense of touch… you know, the old trick of wetting a finger and sticking up it in the air. Be careful which finger you use so as not to offend nearby crew members. The sense of touch is also useful for detecting changes in vibrations. Engines, generators, and other mechanical equipment usually have a fairly stable and recognizable vibration. Should that change, it’s often an indication of a problem. Just yesterday, we were using our bow thruster to line up to a mooring in very windy / wavy conditions. It vibrated differently than normal so we immediately stopped using it. We examined it underwater and tested it today. Fortunately, it seems fine. There was probably piece of loose rope, or a heavy piece of kelp lodged in the propellers. Continuing to try to use it under those conditions could have led to serious damage, but the sense of touch helped us detect the anomaly. And, in case you were wondering, we did manage to pick up the mooring without it… after the third try!
In other situations, smell can be used to diagnose a leak from an engine or a generator. Diesel fuel, oil, antifreeze, transmission fluid and other fluids that are critical mechanical systems have distinct smells. With practice, you can usually tell which is which. Here, combining sight with smell is helpful as liquids often have distinct colors.
Finally, after a long day at the helm, if you’re not on galley duty, the sense of smell helps you know what’s being cooked for dinner!
Taste
Two major rules of are sailing: (1) keep the water out of the boat and (2) keep the people in the boat. Whenever water appears in the boat, such as in a bilge, the first question (does not apply to lake sailors) is whether it’s fresh water or salt water. One of the best methods is to touch a very little dab of the liquid to the tip of your tongue. Salt water is most concerning of course as it may indicate sea water ingress. Fresh water usually is a leak in onboard plumbing. In either case, I strongly recommend not to swallow the suspect fluid (yuck)!
Even when people aren’t sailing, they naturally use many of our senses in concert subconsciously. When sailing, the 5 (or 33) senses are invaluable tools for keeping safe, troubleshooting problems, and predicting changing conditions.