How To Read the Clinometer on a Silva Compass

How To Read the Clinometer on a Silva Compass
Being aware of altitude change when navigating with a map, especially in untrailed back country, can be critical to knowing your position and destination. The Silva Ranger 515 CL, CLQ and Explorer Pro compasses have a small arrow dangling from the instrument's center of rotation and a percent scale on the edge of the compass dial that can be used to estimate a slope's angle of inclination, which may indicate its safety (particularly in snow) and from which changes in elevation may be calculated. These compasses sell for less than $100.

Instructions

Difficulty: Moderately Easy

Things You’ll Need:
  • Silva Ranger 515 CL, CLQ or Explorer Pro compass
  • Silva Ranger 515 CL, CLQ or Explorer Pro compass
Step 1
Open the compass to its limit, creating a single plane from the mirror and compass face.
Step 2
Rotate the compass dial to a point where either "W" or "E" is set on the direction arrow on the compass hinge. This sets the percent-scale so that the red compass clinometer needle hangs at zero percent when the compass is held on its edge, horizontal to the ground.
Step 3
With compass held in fully extended arm, move it up or down until its edge matches the slope of terrain as you measure the angle of inclination.
Step 4
Holding the compass steady, read the percent slope measurement indicated by the hanging needle on the percent scale. Repeat the process to check accuracy and verify your results holding the extended compass close to your eye and sighting the slope.
Step 5
If needed, do appropriate calculations to determine height of an object or altitude change.

Tips & Warnings

 
Be sure to learn the correct method of determining heights of objects before attempting these calculations. This might be useful in finding the relative heights of two potential routes or in figuring whether a tree will hit a structure if felled.
 
The hanging needle will occasionally get caught on the compass housing. Tap lightly to free it. This method of slope measurement is not as accurate as using a real clinometer.
 
The hanging needle will occasionally get caught on the compass housing. Tap lightly to free it.
 
This method of slope measurement is not as accurate as using a real clinometer.

Article Written By Barry Truman

Barry Truman has published many outdoor activity articles in the past five years with International Real Travel Adventures, the Everett Herald and Seattle Post Intelligencer newspapers, Backpacking Light Magazine and Trails.com. He has a forestry degree from the University of Washington.

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