SUBMISSION TO NI ON COLREGS SURVEY

WARNING: THIS SUBMISSION SHOULD NOT BE READ BY STUDENTS AS IT IS A STUDY OF WHAT PEOPLE DO; NOT WHAT THEY SHOULD DO.

Introduction

The Nautical Institute is to be congratulated on the number of papers appearing in its journal, Seaways, studying the behaviour of mariners in the application of the rules for the avoidance of collision at sea. In particular, Captain Roger Syms has made a masterly analysis of the NI Colregs Survey undertaken by the Institute as a first step in its major project to improve collision avoidance at sea under Captain Irvingís leadership.In approaching the rules from the behavioural aspect of mariners all concerned have a worthy predecessor, namely, Captain Philip Howard Colomb who flourished circa 1872. Vice-Admiral Colomb (as he later became) has already been referred to in the columns of Seaways, see the letter of Professor John Kemp in November 1996 and of John Wilde Crosbie in July 2003.

From his observations of the behaviour of mariners Colomb identified two axioms for the avoidance of collision at sea. He also called them natural laws as opposed to the artificial or positive laws contained in the enacted rules. To these two axioms I venture to add a third which I shall call Grayís axiom for reasons which will become obvious from its wording set out below which is based upon Thomas Grayís famous rhyme published in 1878:-

ďBoth in safety and in doubt,

I always keep a good lookout;

In danger, with no room to turn,

I ease her, stop her, go a-stern.Ē

The axioms are essentially intuitive or instinctive rules and it is my submission that deviance from the enacted rules is most likely to occur where there is a conflict between the axioms and the enacted rules. It is submitted that mariners will revert to the axioms in the agony of the moment at close quarters, or when they believe that the rules do not apply at long range, or when the traffic situation is so complex that the application of the enacted rules is impossible.The axioms may be said to be the actions which would be followed in the absence of enacted rules. They are statements about what people will do or tend to do; not about what they should do. In an ideal world the axioms and the enacted rules would be identical.

It would therefore seem to be a worthwhile exercise to examine the NI Colreg Survey with reference to the Colomb-Gray axioms. The three axioms may be stated as follows:

1.†††† Colombís First Axiom:The broader on the bow any ship appears to the other the less hasty will be the otherís action. Thus the former (which is, of course, the faster ship) will in all likelihood act first and relieve the other of the need to act. Stated more simply: where two vessels are on a collision course, the one which has the other bearing closest to her own heading will keep out of the way. Because of the geometry of the collision situation this means that the faster ship will keep out of the way.

2.†††† Colombís Second Axiom: The ship which seizes the initiative to keep out of the way will not cross the path of the other. Thus she will alter course so as to bring the other ship from its bearing on one bow to a bearing on the other bow-this action at night clearly signalling to the other ship that she has altered course by the change in colour of the sidelight she is presenting from red to green or from green to red.

3.†††† Grayís Axiom: Where there is doubt about the other vesselís intentions, the ship which is seizing the initiative to keep out of the way will achieve her objective of not crossing the path of the other by augmenting her alteration of course by stopping or reducing speed or by stopping or reducing speed alone.

The First Scenario

Applying these axioms to the first scenario of the NI Colregs survey (see Seaways August 2003 for a description of this scenario and Captain Roger Symsí analysis of it in relation to the enacted rules) we arrive at the following:

Own-ship has the target closer to the bow than the target has own-ship. Therefore by the application of Colombís First Axiom the target will be less hasty to take action and own-ship will seize the initiative and take the action to keep out of the way. Because own-ship has seized the initiative and has relieved the target of the need to act, the target will stand on.

By the application of Colombís Second Axiom, own-ship will alter course so as not to cross the path of the target. This means that she will alter to starboard, towards the target, thereby bringing her across the bow to her port side and signalling this action by changing the presentation of her sidelights to the target from green to red.

It follows therefore that the natural actions for this scenario are in the notation of the tick-box scale of the survey:2.1

Since the notion of standing-on in the context of crossing a separation scheme also comprehends an alteration to starboard by the target, we may also (applying Captain Symsí reasoning) tick 2.2 as following from Colombís axioms.

However, the presence of the separation scheme, buffer zone, and inshore zone, and the size and speed of the target, raise the possibility that she will alter course to port for navigational reasons notwithstanding that she has been relieved of altering for collision avoidance. She can justify this action under the enacted rules either by reasoning that for her the enacted rules have not yet taken hold or, following Captain Syms, by reasoning that she has the right as a stand-on vessel to make a scheduled change of course. Applying Greyís axiom to this doubt, own-ship will slow down or stop (rather than alter course) to achieve her objective of not crossing the path of the target by own-shipís own action.It follows therefore that, after the complete application of all three axioms, the natural actions for this scenario are in the notation of the tick-box scale of the survey:4.3The same doubt about the targetís intentions could, on a similar application of Grayís axiom, lead to 4.2

Grayís axiom is, of course, entirely compatible with the enacted rules and it is respectfully submitted that if Captain Syms were to adopt the latter reasoning he would also come to this latter conclusion.

What we have demonstrated is that under the first scenario the natural axioms and the enacted rules lead to the same result and there is no conflict which would explain the deviation of the survey results from that expected under the enacted rules.

However, the exercise has served to introduce the three natural axioms of collision avoidance and the methodology suggested for applying them to a study of the scenarios of the NI Colreg survey.

The First Scenario (continued)

This is a continuation of my submission in which I introduced the three natural axioms of collision avoidance and suggested a methodology for applying them to a study of the scenarios of the NI Colreg survey. I conjectured that, since the axioms are instinctive laws of nature, deviance from the enacted rules is most likely to occur where there is a conflict between the axioms and the rules.

In applying Colombís first and second axioms to the first scenario I arrived at tick-box answers 2.1 and 2.2There was therefore no conflict between the axioms and the rules so my conjecture remained untested. Applying the third axiom (my so-called Grayís axiom) to the first scenario yielded answers4.2 and 4.3†† This explained the cluster of4.2 and 4.3 (and also perhaps 4.1) answers in Captain Symsí analysis of the survey returns and appeared to support my conjecture. However, the reasoning which led me to answers4.2 and 4.3 would, in my opinion, have led to the same result under the enacted rules and, if this was correct, my conjecture remained untested since the axioms and the rules were still leading to the same result.

The cluster of 27 answers comprised in 4.2 and 4.3 were arrived at by interpreting both the axioms and the rules so as to maintain the separation scheme. There were a further cluster of 60 answers comprised in 1.2, 1.3, 1.4 and 1.5 where the enacted rules were ignored and the natural axioms disobeyed ostensibly for the purpose of maintaining the traffic separation scheme.These clusters together amounted to 87 answers given to maintain the traffic separation scheme. This was over 20% of the total survey.

This suggests that there is a fourth axiom (which I shall take the liberty of calling the Baillod-Symsí Axiom after the architects of the survey which has revealed it) which axiom may, perhaps, be expressed thus:

4.††† Baillod-Symsí Axiom (of natural collision avoidance): Notwithstanding any other natural axiom or enacted law to the contrary, a ship taking action to avoid collision in or near a separation scheme will endeavour to act in a manner which maintains the traffic scheme.

If there really is such a fourth axiom, then, it appears to explain 20% of the answers whereas correct answers under the enacted rules only comprised 63%†† This leaves 17% of answers unexpected and unexplained under either the axioms or the enacted rules.††

It remains to apply the axioms to the second and third scenarios.

The Second Scenario

In the second scenario, own-ship again has the target closer to the bow than the target has own-ship. Therefore, by Colombís First Axiom, it may be expected that own ship will seize the initiative and keep out of the way thereby relieving the target of the need to act. By Colombís Second Axiom own ship will alter to starboard allowing the target to stand on. This results in answer 2.1

However, the limitations of the channel invoke Graysí Axiom and own-ship will augment her alteration of course by slowing down or will rely on slowing down alone. This results in answer 4.1

The axioms therefore give rise to answers 2.1 and 4.1 and in the survey returns these amount to 39 and 134, respectively. A total of 173 (or over 41%) answers explained by the axioms.

The correct answers under the enacted rules are 4.2, 4.3, 4.4 and 4.5 which together comprise 63 answers or 15% of the survey returns.

In this scenario, therefore, it seems that the natural law predominates over enacted law and the conflict between them gives rise to substantial deviance from the enacted rules. However, a further 183 wrong answers (comprising 44% of the survey returns) remained unexplained by this hypothesis.

The Third Scenario

Moving on to the third scenario, the target ship has own-ship bearing closer to the bow. By Colombís First Axiom the target is most likely to act thereby relieving own-ship of the need to act. By Colombís Second Axiom the target will alter to starboard. Therefore, the answer which follows from the axioms is 1.2 augmented by 1.3 and 1.4 if we apply Grayís axiom because of the fog. These comprise 134, 5 and 4 survey returns, respectively. A total of 143 or 34%.

The correct answer under the enacted rules is 2.2 of which there were 98 such answers or only 23.5% of the survey returns.

Again, in this scenario mariners seem to be predominantly following the natural axioms rather than the enacted rules. Though, again the other 42.5% of the survey which comprised wrong answers remains unexplained by this hypothesis.

Conclusion

It is concluded that there are powerful instinctive forces which operate to undermine any positive or enacted law which requires mariners to act contrary to the natural axioms of collision avoidance.The axioms identified in this submission are not necessarily accurate or complete and, indeed, the NI Colregs Survey appears to have revealed a fourth axiom relating to traffic separation schemes. What seems clear is that such natural laws exist and should be identified and harnessed. At the very least a strong case can be made that enacted laws should be simplified to allow the natural laws to operate freely.The alternative is to educate and train mariners to act contrary to their intuition. To this latter extent the NI Colregs Survey has served an immediate and very useful purpose in alerting lecturers in nautical science to the underlying tendencies which they have to overcome, not just by education but by training.†††††

John Wilde Crosbie, FNI, Dublin, Ireland.

10th August, 2003.