Page 105 - Collision Avoidance Rules Guide

Vessels engaged in such activities as fishing or underwater opera-
tions and vessels not under command may be incapable of manceu-
vring effectively. A slow vessel being overtaken by a vessel of high
speed may not observe the overtaking vessel until it is too late to get
clear by her own action. Even in a crossing situation involving two
power-driven vessels, if both were to be required to keep out of the
way, the vessel expected to pass ahead of the other is likely to be less
capable of achieving a safe passing distance by her own action than
the vessel expected to cross astern of the other.
Rules 13 and 18 of Section I1 are based on the principle of allocating
prime responsibility to the vessel which will usually be more capable
of keeping out of the way. If no such distinction were made the vessel
with the greater ability to take effective avoiding action would be more
likely to wait for the other to keep out of the way.
It is, of course, not possible to allocate greater responsibility to the
vessel which is more capable of taking avoiding action when the
visibility is restricted and the vessels are not in visual sight of one
another as all vessels do not have an operational radar and a means
of identifying a hampered vessel by radar has not yet been estab-
lished. Fortunately, there are few areas of the world in which serious
restriction of visibility is likely to be frequently experienced.
The 1972 Conference did adopt some changes which resulted in
greater compatibility between the Rules for vessels in visual sight of
one another and the Rule for restricted visibility. The most important of
these is that a privileged vessel is now permitted to act at an earlier stage
when vessels are in sight of each other. In restricted visibility more
emphasis has been placed on the avoidance of an alteration of course to
port for a vessel detected forward of the beam, which is in accordance
with the principles established in Rules 14, 15 and 17(c) of Section II.

RULE 12
Sailing Vessels
(a) When two sailing vessels are approaching one another, so as
to involve risk of collision, one of them shall keep out of the
way of the other as follows:
(i) when each has the wind on a different side, the vessel
which has the wind on the port side shall keep out of the
way of the other;

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