Page 103 - Collision Avoidance Rules Guide

It has been found that strict compliance with Rule 10 would make
it difficult, if not impossible, to effectively carry out essential opera-
tions such as hydrographic surveying and the servicing of cables. The
IMO General Assembly therefore adopted, in 1981, paragraphs (k)
and (1) which exempt a vessel engaged in an operation for the main-
tenance of safety of navigation, or in the laying, servicing or picking
up of a submarine cable, within a traffic separation scheme from
complying with Rule 10 to the extent necessary to carry out the
operation.
Vessels engaged in the operations referred to in paragraphs (k)
and (I), and which are exhibiting the lights or shapes prescribed in
Rule 27(b), may thus be exempted from compliance with Rule 10
and may even be justified in proceeding in a direction opposite to the
general direction of traffic flow in a traffic lane. However, they are
expected to comply with Rule 10 whenever possible.
The Government, or appropriate authority, must be notified of, and
must authorise, such operations. Information about vessels working
in a traffic separation scheme shall, so far as practicable, be promul-
gated beforehand by Notices to Mariners and by subsequent radio
warnings before, and at regular intervals during, the operations.
In the General Provisions on Ships’ Routeing it is specified that
such operations shall as far as possible be avoided in conditions of
restricted visibility.

Precautionary area
A precautionary area is defined in the IMO principles of ships’ route-
ing as a routeing measure comprising an area within definite limits
where ships must navigate with particular caution and within which
the directions of traffic flow may be recommended.

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