Airguide Compass Directions

Airguide Compass DirectionsWhen you install a compass into a boat, various metal parts---sometimes even the screws used to mount the compass---might cause it to deviate from the real magnetic readings. In an extreme example, your compass could read 90 or more degrees off---i.e., the compass could read north when your boat points east. Airguide Instrument Company marine compasses feature built-in adjustable compensators that correct variation created by magnetic fields. By correcting for magnetic variation, you'll know that your compass's heading points toward the actual magnetic heading.
 

Instructions

Difficulty: Moderate

Things You’ll Need:
  • Hand-held compass
  • Targets
 
Step 1
Use a hand-held compass to set up four targets at each of the cardinal directions. When adjusting your compass, your boat must be at the center of these targets, so make sure the points are far enough apart to handle the length of your boat. To visualize this, imagine a large "X" with your boat in the center. At the ends of each line---north, south, east and west---place a target.
Step 2
Move your boat into the center of the "X" and point the craft to the north. If the compass doesn't indicate north, find the north-south compensator shaft, which is labeled "N-S," and turn it until the compass indicates north.
Step 3
Turn your boat to point at the east target. Adjust the east-west compensator shaft, which is labeled "E-W," until the compass indicates east or 90 degrees.
Step 4
Point the boat at the south target, which is 180 degrees. Read the degrees the compass varies from south. Adjust the north-south compensator shaft to correct for one-half of the error. For example, if the compass reads 190 degrees, the error is 10 degrees. Correcting for one-half is a change of five degrees. Adjust the compass to read 185 degrees.
Step 5
Point the boat to the west target and check for any variation. If necessary, correct the variation just like you did for the south target.
 

Tips & Warnings

 
Although mounted compasses are accurate within several degrees, for more accuracy carry a hand-held sighting compass.
 
According to Airguide Instrument Compass, its compasses are designed to read to magnetic headings. The company states that the compass cannot be corrected for true headings by using the compensator shafts.

Article Written By Bryan Hansel

Bryan Hansel is a freelance photographer and kayaking guide who began writing in 1993. His outdoors articles appear on various websites. Hansel holds a Bachelor of Arts in English and religion from the University of Iowa.

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