piloting tips and techniques 81
convert a bearing to true or magnetic or even use a protractor. Just draw a line
on the chart through the two objects, extend the line over the water, and you’re
somewhere on that LOP. No error, no slipped parallel rulers, no fuss, and no
doubt about it. Cross that LOP with a bearing to an object off the beam, and
you’ve got a solid fi x. Here are some ways to use ranges:
Track drift : Keep in a channel by choosing two objects that are in line
and dead ahead of your course. But check dead astern, too. Over-the-shoulder
ranges give the quickest warning that your boat is drift ing off track. (See below
for corrective actions when you drift off -range.)
Track advance: The elapsed time between successive ranges along the
side of a trackline will enable you to calculate your boat’s speed over ground,
or advance, along the trackline.
Track turns: Use a natural range to tell you when to turn onto a new
trackline. Plot this range onto the trackline ahead of time. Label the line TB
for turn bearing.
Fast and easy line of position (LOP): When two charted objects line up,
write down your time and draw the LOP over your trackline. Th is gives you an
instant estimated position (EP). Upgrade it to a fi x by taking and plotting a bearing
to a charted object 60 to 120 degrees off the range.
HOW TO REGAIN A RANGE AFTER DRIFTING
Range ahead: If you start drift ing off a range dead ahead, follow the direction
of the closer object. If the closer object is to the left of the more distant object,
turn left ; if it is to the right, turn right.
Range astern (over-the-shoulder): If you start to drift while using an over-
the-shoulder range, follow the direction of the farther object. If the more distant
object is to the left , turn left ; if to the right, turn right.
A Simple Solution to Running-Fix Confusion
If you’re like me, one of the harder concepts to grasp is the running fi x. To
make a running fi x you need three things:
- A charted object located between your bow and beam
- A trackline
- A good estimate of your boatspeed
Let’s suppose you have a lighthouse off your bow. You take a bearing to the
lighthouse of 350 degrees magnetic. You plot this bearing on your chart and
make sure that the bearing line crosses your trackline. Label the time you took
the bearing as 1000. Now you steer down your trackline at a speed of 4 knots.
At 1100 you take a second bearing to the lighthouse. This time it bears
300 degrees magnetic. You plot this second line onto the chart and make sure