By Biff Matthews, Pamlico Sail & Power Squadron

Along with PFD, personal flotation device, and hand held radio another safety item on your boat is the compass. Why? Safety! With no visual reference point, using your compass you will at least know which direction or heading you need to go or are going.

Imagine wanting to head home in a thick fog up the Pamlico River from Pamlico Sound without GPS or radar. An experienced boater is always aware of their approximate position. With that knowledge they know to head about east along with slightly north or south to reach land. From there they can pick their way home.

So, to keep you safe and heading the correct direction, let’s make sure your compass is in good condition as well as accurate. I know I’m talking old school but stuff happens, folks, and electronics fail always at the worst time. Old school is a backup plan.

1. When possible, cover or shield your compass from direct sunlight to prevent fading as well as to reduce its temperature. They seal special oil in a compass to dampen the card’s movement. Over time heat and sunlight will deteriorate the seal allowing the oil to evaporate. Covering it just extends its life, saving you money.

2. When you see an air bubble in the compass top, take it to a certified compass technician. He or she will check the seal, replacing it as needed plus top off the oil. While at the technician, have them check the compass for accuracy and adjust it if necessary.

3. Hose off your compass occasionally to remove salt and dirt. Be very careful when wiping with a rag, as salt and dirt will act like sandpaper on the rag, scratching the compass face.

4. Do not use harsh chemicals to clean the compass lens. Good old soap and water work well or use a good lens cleaner to remove tough dirt. Use a cleaner recommended for glasses, sunglasses or Plexiglas.

5. Do not place large metal objects, magnets, (speakers) near a compass. Also don’t mount electronic devices like radio, depth sounder and GPS near a compass since each generates its own magnetic field.

A friend sailing down the East coast went far off course when the first mate went below to fix lunch. To heat the soup she turned on the microwave oven.

So, how does a microwave oven take a boat off course? Read No. 5 again. Turning on the microwave oven created a magnetic field. Then because it was ceiling mounted under the helm station, that temporary magnetic field drew the compass off the intended course. Seeing that he was supposedly off course, the captain changed course in error.

6. Have only a certified compass technician service your compass. When calculating a compass heading, remember there are two magnetic fields to consider in the calculation.

A. Variation — degrees of variation in the earth’s magnetic field for that specific location that you will find on your chart’s compass rose.

B. Deviation — the plus or minus compensation of a boat’s field. Iron, magnets and magnetic fields (from electronic equipment), influence the Earth’s magnetic field around the boat causing deviation. Each boat has a unique magnetic field signature or deviation.

Next month I’ll explain how to make a deviation chart for your boat by swinging your compass. No, not swinging it over your head, though the idea of swinging the compass off my boat often temps me.

For local information on boating safety and education we invite you to go to our website www.pamlicosailandpoersquadron.org or email to tomgraham@suddenlink.net.