Before electronics, two means of navigation helped mariners find
their way. Offshore, they relied on celestial navigation, through
which they could fix their position through sightings of the sun,
moon, or stars.
Coastal navigation, on the other hand, is a set of techniquesfor
plotting a fix through sightings of terrestrial objects. These can
be natural or man-made, such as church spires, water towers,
hilltops, or radio antennae. Using a hand bearing compass, the
mariner takes bearings to two such objects, extends these bearing
lines on a nautical chart, and thereby fixes his or her
position.
A quicker and more accurate substitute for one measured bearing
is a “transit” (also called a “range”.) This is a line through two
visible, charted objects. Taking a measured bearing on one object
while passing across a transit produces a fix.
The classroom portion of this cache is now complete. It is time
for the practical lesson.
- Park in the restaurant lot identified by the IP.
- Walk southeast (toward Albany) along the sidewalk of Central
Ave. Don't cross the street
- As you walk, look for the tall radio antennae to your right, or
as we sailors say, on your starboard beam. You should see at
least two of the three. They will be nearly aligned and come closer
into alignment as you proceed.
- Continue walking until they are perfectly aligned. You'll
see the top of the second tower through the structure of the
first. You have now reached the transit.
- Wait, if necessary, until your GPSr has its most accurate
reading.
- Project a waypoint to a distance of 289' at a heading of 345.7°
True.
- There will be the cache. Please sign (you'll need your own pen)
and then replace it carefully.