STEP CHANGE FOR SAFETY GLOBAL SHARING DEC 2013 - SAFE NAVIGATION | Page 43

Authorised User (see Terms and Conditions): Member of North of England P&I Association

Rule 7: Risk of collision
(a) Every vessel shall use all available means appropriate to the prevailing circumstances and conditions to determine if risk of collision exists. If there is any doubt such
risk shall be deemed to exist.
(b) Proper use shall be made of radar equipment if fitted and operational, including long-range scanning to obtain early warning of risk of collision and radar plotting or
equivalent systematic observation of detected objects.
(c) Assumptions shall not be made on the basis of scanty information, especially scanty radar information.
(d) In determining if risk of collision exists the following considerations shall be among those taken into account:
(i) such risk shall be deemed to exist if the compass bearing of an approaching vessel does not appreciably change;
(ii) such risk may sometimes exist even when an appreciable bearing change is evident, particularly when approaching a very large vessel or a tow or when
approaching a vessel at close range.

IS THERE A RISK OF COLLISION?
• Use radar:
• With ARPA, use relative vectors to determine the risk of collision.
• Is the target passing ahead or astern or are you going to collide?
Remember the primary information you need to answer these
questions is relative information.
• Do not trust ARPA to give you an accurate CPA. Take 0.5 nautical mile
off each indication to be safe and, if the CPA is already 0.5 nautical
mile, then assume a risk of collision exists.
• Do not just rely on a change of bearing as an indicator of clearance.
As a target ship approaches, its change of bearing should accelerate
significantly. If the change of bearing does not accelerate then there is a
risk of collision.

Rule 5 on look-out and Rule 7 are also closely linked. Under Rule 5 you must
use all available means to collect information on the situation around you
(look-out) and under Rule 7 you must use that information continuously to
assess the risk of collision.
To assess the risk of collision you must continuously ask yourself:
• Is a collision possible, because of the action (or inaction) of any vessel in
the vicinity – including your own vessel?
• Is a collision probable? If so, the risk of collision is already here and you
need to act urgently.
This risk-assessment process is essential if you are to take appropriate
action – see Rule 8 action to avoid collision.
Risk-assessment techniques include:

Do not relax – keep monitoring the situation until the target ship is
passed and clear.

• Look and listen – as with keeping a look-out, you must use all the
information and equipment available to determine the risk of collision.
• Use the compass to check the bearing of approaching vessels, and do
this regularly. A steady bearing indicates the risk of collision but a risk of
collision may exist even with a bearing change, particularly at close range
and with large vessels.

SUMMARY
Always assess the risk of collision.

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