161-RR-1
Page 1 of 1
©
Copyright Lapware 2002
USCG 161 Book 1
STEPS
You are on a vessel heading due south and see the lights shown one point on the
port bow. This vessel could be heading __________.
Possible heading is determined in the following manner:
See illustration: DIAGRAM 51
HEADING 180° - 11.25 ° = S x E (168.75°)
Green Side Light bearing S x E (168.75°)
Compute the reciprocal of the observed bearing
and then move 10 points (112.5°) to the LEFT
or in a counter-clockwise direction.
Step No. 1 - Reverse the bearing
S x E (168.75°) ± 180° = N x W (348.75°)
Step No. 2 - Move 10 points to the left
348.75°
N x W
- 112.50°
-10 points left
236.25°
SW x W
Possible headings are:
SW x W (236.25°) to N x W (348.75°)
(A) NW
Northwest (315°) = ANSWER
(B) SW
(C) NE
(D) SE
RULES OF THE ROAD
VESSEL HEADING
Green
Sector
Visible
E
W
N
GREEN
Side
Light
RED
Side
Light
NxW
SxE
SWxW
NW
S