tag:blogger.com,1999:blog-30609206.post4723380532222495026..comments2024-01-13T16:26:11.682-05:00Comments on Daily Boater Boating News: Which Way is North?Editorhttp://www.blogger.com/profile/00849004483204745351noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-30609206.post-67798225875054966942011-03-29T11:42:13.675-04:002011-03-29T11:42:13.675-04:00The use of GPS Course Over Ground (COG) is a highl...The use of GPS Course Over Ground (COG) is a highly inaccurate method of determining deviation. COG is the vector sum of course being steered, wind and tide or ocean current. A better method is to choose a distant visible landmark, set it in as a temporary waypoint in the GPS and point the bow at the land mark. Note the difference between compass and GPS. This is deviation. Do this with enough points and you can construct a reasonable deviation table. Better yet, hire a compass adjuster to do the work for you and adjust out the deviation in the process. In a wood, fiberglass or aluminum boat, a competent adjuster can get all deviations below 2 degrees. For practical purposes this is nill with a typical 5 degree graduation compass dial.Bill Haimeshttp://www.islandmarineinst.comnoreply@blogger.com