West Wight Potter Owners Home Port _______________________________________________________________________________________________ |
| Technical Information Swinging a Compass with a GPS by Dick Herman |
GPS's are wonderful things and I used mine to swing my compass.
I discovered that I could get a magnetic heading readout off my Garmin, so when I
was sailing on Lake Folsom, I turned to 090 on my compass and checked it
against the GPS.
The compass was reading 095, or five degrees high.
I then turned to 180 and did the same. This time it was pretty accurate.
When I turned to 270, the compass was reading 260 degrees, or ten degrees low.
I had to start the engine to make 360, and again, the compass was pretty accurate.
I made a mental note of the differences and apply them when I turn to a heading
in the eastern or western quadrant.
If my desired heading is between 045 and 135, I subtract five degrees.
If my desired heading is between 225 and 315, I add ten degrees.
Piece of cake!
Dick Herman
I discovered that I could get a magnetic heading readout off my Garmin, so when I
was sailing on Lake Folsom, I turned to 090 on my compass and checked it
against the GPS.
The compass was reading 095, or five degrees high.
I then turned to 180 and did the same. This time it was pretty accurate.
When I turned to 270, the compass was reading 260 degrees, or ten degrees low.
I had to start the engine to make 360, and again, the compass was pretty accurate.
I made a mental note of the differences and apply them when I turn to a heading
in the eastern or western quadrant.
If my desired heading is between 045 and 135, I subtract five degrees.
If my desired heading is between 225 and 315, I add ten degrees.
Piece of cake!
Dick Herman