Boating and Sailing.pdf - Moja ladja

Chapter 13: Tools and Tricks of Navigation
So, if you have a true course written on a chart and want to know what compass course to
steer, you add or subtract the variation, which gives you the magnetic course, and then
add or subtract the deviation, which gives you the compass course:
C + D = M + V = T
In this case, the rule is to add easterly errors and subtract westerly errors. If you know the
compass course to a landmark ahead and want to know the true bearing, you work the
equation the other way: Add or subtract the deviation to get magnetic course, and then
add or subtract the variation to get true course, useful in plotting your exact position on a
chart:
T + V = M + D = C
In this equation, you subtract easterly errors and add westerly errors.
Electronic Navigation
Now that you’ve seen this much about compass navigation, you probably want to forget
all about it.
Fortunately, you can, most of the time. Modern electronic navigation gear takes care of all
the calculations for you and puts you exactly where you want to be every time—as long as
it doesn’t break.
Although electronic navigation is as good as it gets, it’s always wise to have a backup if
your primary set goes down and a compass in case all else fails.
LORAN Waves Good-Bye
187
Long Range Navigation Systems (LORAN) are on their way out, but you’ll still see a few
used by older offshore anglers.
The reason is that all these folks have their bottom fishing spots located with LORAN
numbers, and LORAN has proven itself strong in the “repeatability” department—that is,
it returns your boat to almost the same exact position time after time for a given set of
numbers, unlike Global Positioning Systems or GPS, which tends to wander a bit from
day to day.
However, LORAN towers are being phased out by the government, and as the LORAN
boxes die, most won’t be repaired but rather replaced by the less-expensive GPS units.