About your Boat: The Compass

Despite advancements in technology and all the luxurious gadgets available out there, one of the most valuable and indispensable things on a boat remains to be the compass.

Generally determined by the sighting of landmarks, geographical positioning was quite limiting prior to the invention of the compass. Though there are early references to directional devices throughout history, it is not clear. An early method was the use of cordierite or a birefringent crystal on cloudy days permitting the Vikings to determine the sun’s direction and elevation from the polarization from daylight.

Invented in China, the compass was not adapted for navigation until the 11th century by the Song Dynasty. The most popular is the magnetic compass which uses the Earth’s magnetic field to ‘exert a torque on the needle,’ reaving Earth’s ‘true North.’ Another common compass seen aboard are liquid compasses. Invented in 1690, the device and needle are submerged in a liquid, preventing excessive wobbling and enabling easier reading.

Most modern compasses have continued to submerge the needle in a liquid (some liquids commonly used are lamp oil, mineral oil, white spirits, or ethyl alcohol.) One could argue why learn to use one if nowadays it’s common enough to find a compass app on your cell phone? But the truth remains that knowing the basics of a compass and how its used are basic skills of orientation that may unexpectedly help you get out of a pickle. We can’t always count on technology, can’t we? Batteries do die.

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