Page 86 - Collision Avoidance Rules Guide

and furthermore to reduce speed in order to decrease the period of
running closely parallel to each other.
A vessel about to be overtaken must take account of the signals of
intent made by the vessel wishing to overtake. If it is not considered
safe for the other vessel to pass the signal of at least five short rapid
blasts could be made on the whistle. This signal indicates doubt
about the intentions or actions of the other vessel and implies that the
vessel ahead does not consider it safe for the vessel astern to attempt
to pass. In such circumstances the whistle signals should, if possible,
be supplemented by the use of VHF radio communication to clarify
the situation. The radiotelephone may also be used to advantage
when it is considered safe to pass, in order to reach a clear under-
standing of the procedure to be followed.
Although Rule 9 is in Section 1 of Part B which relates to conduct
in all conditions of visibility, the signals prescribed in Rule 34(c) are
only to be made by vessels in sight of one another. As Rules 9(e) and
34(c) are complementary it is implied that Rule 9(e) applies only to
vessels in visual sight of each other.

If) Bends in a channel
This paragraph is based on Rule 25(b) of the 1960 Regulations.
However, it now applies to all vessels, not just to power-driven ves-
sels, and is extended to cover areas of a narrow channel or fairway
where other vessels may be obscured by an intervening obstruction.
On approaching a bend, or section of the channel where other
vessels may be obscured, a vessel must sound one prolonged blast as
prescribed in Rule 34(e). If, a few minutes later, a signal is heard
from another vessel which is approaching the bend, this must be
answered by a further signal of one prolonged blast.
The bend must be rounded with alertness and caution regardless of
whether an approaching vessel is heard. A power-driven vessel must not
‘cut the corner’ and get on to the wrong side of the fairway. When two
power-driven vessels approaching from opposite directions hear each
other’s signals it may be a precaution demanded by good seamanship
for the vessel stemming the tide to wait until the other has passed clear.

Trevethick-Talabot
In the River Thames there is a well recognised and positive Rule (No. 23) of
the Thames Conservancy to the effect that, when vessels are approaching
each other, at bends such as I have described, it is the duty of the one having

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