Page 127 - Collision Avoidance Rules Guide

assumed that the give-way vessel is not taking appropriate action is
likely to be held mainly to blame if practically simultaneous action
by the give-way vessel causes a confused situation which results in
collision.
The stand-on vessel is required to keep her course and speed until
it becomes apparent that the give-way vessel is either failing to take
action in ample time or failing to take sufficient action to achieve a
safe passing distance. The obligations of the give-way vessel are
specified in Rules 8 and 16. Rule 16 requires every give-way vessel
to take early and substantial action and the provisions of Rule 8
include requirements to take action which will be readily apparent to
the other vessel and will result in passing at a safe distance.
Action should not be taken by the stand-on vessel without first
determining that risk of collision does in fact exist. Compass bear-
ings should be observed accurately and the radar should be used to
measure the range of the approaching vessel. The earliest moment
for permitted action will obviously be related to the range and the
rate of change of range.
In the open sea a give-way vessel which approaches to within a
distance of about two miles in a crossing situation involving two
merchant ships can usually be considered to have waited too long,
but smaller or greater distances may apply depending upon the size
and manceuvrability of the vessels and depending particularly upon
the rate of approach.

Action to be taken by the stand-on vessel
When vessels are in sight of one another any vessel which fails to
understand the intentions or actions of an approaching vessel, or is in
doubt whether the other is taking sufficient action to avoid collision, is
required by Rule 34(d) to immediately indicate such doubt by giving
at least five short and rapid blasts on the whistle. The sound signal may
be supplemented by a light signal of at least five short and rapid flashes
which may be more effective as a ‘wake-up’ signal, especially at
distances over 2 miles. If these signals bring no immediate response
further precautionary measures should be taken aboard the stand-on
vessel, depending upon the circumstances, such as calling the master,
changing to manual steering and putting the engines on stand-by.
A stand-on vessel which takes permitted action to avoid collision
by her manceuvre alone, when it becomes apparent that the give-way
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