Nautical Studies

about Marine Navigation & Technology

Head on Situation

leave a comment »

An argument on using sidelights in defining head-on situation was put forwarded in court. It was argued that both sidelights of a target involved in the risk of collision must be seen to effect a head-on situation. The argument was later supported by an oversea maritime expert. Another renowned author also seems to express similar argument in his book about COLREG as follows:

“… Rule 14 is apparently not intended to apply to cases in which, from a vessel which is ahead or nearly ahead, one sidelight can be seen, but the other is obscured. (Cockcroft & Lameijer 1996, p99)”

It could be confusing. It could be difficult to understand if one will look into the text of the rule as well as its application at sea.

Rule 14(a) stated the actions required when ships “meeting on reciprocal or nearly courses” and involved in a risk of collision. Rule 14(b) follows with examples that a head-on “situation shall be deemed to exist”. Rule 14(a) defines head-on situations by the meeting courses and the risk of collision. The text of Rule 14(b) described certain “shall be ” situations but does not seem to exclude any other encounters meeting on reciprocal or nearly courses and involved in a risk of collision. The rule has not exclude any other possible situation such as those have only one sidelight or even none could be seen.

The argument went on and suggest that Rule 14(c) will not apply at all as there will not be any doubt about a situation if only one sidelight can be seen. Thus, it will never be a heading-on situation if not both sidelights were seen at night. It can only be a crossing, Rule 15, situation if it is the case.

As shown in the radar picture on the left with true motion trails displayed, a south bound ship detected three approaching targets on her port side. These approaching targets were met on reciprocal or nearly reciprocal courses.

The north bound targets were going to pass the south bound ship with a distance ranging from less than half a cable to about two cables, about 90 metres to 350 metres. To most mariners, these targets were involved in a head-on situation with the south bound vessel if risk of collision between them was considered.

The second picture shows the visual scene when the radar picture was captured. Actually, the first radar screen is an enlarged portion of the radar screen in the second picture.

It can be seen that none of the three approaching targets was showing both sidelights. Should these approaching targets be considered as ships involved in a head-on situation? Could they be crossing targets if there was risk of collision?

Each of the vessels “shall alter her course to starboard so that each shall pass on the port side of the other” if it is a head-on situation (COLREG Rule 14). Otherwise, “the vessel which has the other on her own starboard side shall keep out of the way” as stipulated in Rule 15 if it is a crossing situation. The problem is that there is nobody with the other on her own starboard side. There is no stand-on vessel either as there was not any vessel required to keep out of the way as stated in Rule 17(a)i.

Apparently, these encounters might not be simple. Is the rule in collision avoidance at sea so complicated? There might be the problem of the rules. Perhaps, it is the problem in reading or interpreting the rules.


Written by Bruce Chun

June 24, 2010 at 01:58

Posted in COLREG

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: