HOW IS SHE HEADING?	231
Diagram 4 represents a steamship heading North with the wind
from North, right ahead, and a sailing vessel ahead showing both her
side-lights, or her green light, or her red light. "We wish to discuss
between what points she may be heading, how she is carrying the
wind, and what action the steamship should tajke if there were risk
of collision*
1.	When the wind is North the prohibited courses for a sailing
vessel lie between E.N.E. and W.N.W.
When she is showing both side-lights she is heading South with the
wind right aft.
When showing her green light only she is heading somewhere between
E.N.E. and South. She is either free with the wind on her port quarter,
or close-hauled to port.
When showing her red light only she is heading somewhere between
W.N.W. and South, and is either free with the wind on her starboard
side, or close-hauled to starboard.
 2.	Her red light 4 points on my starboard bow would indicate
that she is heading between S.W. and W.N.W., close-hauled to starboard,
or she may have the wind a little abaft her starboard beam.
 3.	Her red light on my starboard beam would indicate she is heading
between West and W.N.W., close-hauled to port.
 4.	Her green light 4 points on the port bow indicates she is heading
between S.E. and E.N.E. so that she is either close-hauled to port,
or running with the wind free a little abaft her port beam.
 5.	Her green light on my port beam indicates she is heading between
East and E,N.E,, close-hauled to port.
When a light keeps on the same bearing there is risk of collision, and
should this be imminent I would alter course to starboard for a red
light on my starboard bow and give 1 blast. Alter course to port for
a green light on my port bow and give 2 blasts.