Page 50 - Collision Avoidance Rules Guide

The efficiency of the equipment for the purpose of detecting the
presence of other vessels and determining whether risk of collision
exists must also be related to the competence of those observing it
and the way it is being used. Occasional glances at the radar screen
would hardly constitute proper use of the equipment to justify a high
speed in restricted visibility.
Norefoss-Fina Canada

When reliance is placed on the radar, it cannot be too strongly emphasized that
a continuous radar watch should be kept by one person experienced in its use,
as this officer was. (Mr Justice Hewson, 1962)
Niceto de Larrinaga-Sitala
High speeds at collision cause much greater damage than low speeds. High
speeds before collision give less time to appreciate properly the develop-
ment of the situation. Therefore, if radar is relied upon it must be properly
used. If you rely upon the extended and accurate look-out which is provided
by radar to justify immoderate speed, you must be careful to see that you use
your radar properly and with seamanlike prudence upon the indications and
inferences which are given by it, or may be drawn from the data supplied by
it. (Mr Justice Hewson, 1963)
The radar should be properly set up, making such adjustments to the
controls as may be necessary to achieve maximum efficiency.
To check that this efficiency is being maintained the performance
monitor should be used at frequent intervals.
If any shadow sectors or blind arcs are suspected, or known, to be
present, the vessel should be swung off course for a short period at
regular intervals so that they may be examined. The us Coast Guard
investigation of the collision between the vessels Sparrows Point and
Manx Fisher found that the Manx Fisher had approached within the
shadow sector of the radar of the Sparrows Point.
Range scale

Constraints may be imposed by every range scale that can be used.
When using the longer range scales definition and discrimination are
reduced and small targets are less likely to be detected, whereas
shorter range scales do not permit early detection of targets and do
not enable the observer to obtain an overall assessment when several
vessels are in the vicinity. The range scale which is most suitable for

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