The error of 2 degrees is *statistically insignificant* when using a
compass for marine purposes. Most sigtings will be less than 2 miles.
2 degrees error will be sin 2 = 3.5%. Thats 350 ft error in 2 miles
or 10-15 boat lengths!!! .... then add error for the boat while
pitching, rolling, yawing, set/drift, leeway, compass error, local
magnetic 'anomalies', etc. For short courses, 5-10% error is within
'normal limits' ............. then use your 'head' and your
**depthsounder** to keep a DR track.
;-)


In article , Chris
Doubleday wrote:

I am new to the world of compasses and sailing. My wife recently
purchased a sighting compass as a gift for me when sailing/cruising.
It is a traditional sighting compass with needle and mirror (Suunto
MC-2G-Global). I am more accustomed to using a compass with a compass
card and view finder. I suspect it will be difficult to get an
accurate bearing with the MC-2G-Global on a moving boat due to having
to adjust the bezel while sighting the landmark. Is this the reason
for the different design (card and finder) of the KB-20? The
MC-2G-Global does have a global needle which I underatdnw should help
with some of the pitching and rolling that will occur on a boat, but
it still seems like an error prone process, especially when trying to
get multiple simultaeous fixes as when dead recconing. The accuracy
is noted as 2 degrees, which I imagine is only attainable in the best
of conditions. Any opinions / experience with this sort of compass in
a cruising environment?