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
Irving’s 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 Gray’s axiom for reasons which will become obvious from its
wording set out below which is based upon Thomas Gray’s famous rhyme published
in 1878:-
“Both 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.”
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.
Colomb’s First Axiom: The broader on the bow any ship appears to
the other the less hasty will be the other’s 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.
Colomb’s 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.
Gray’s Axiom: Where there is
doubt about the other vessel’s 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 Syms’ 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 Colomb’s 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 Colomb’s 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 Syms’ reasoning) tick 2.2 as following from Colomb’s 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 Grey’s 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-ship’s 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: 4.3 The same doubt about the target’s
intentions could, on a similar application of Gray’s axiom, lead to 4.2
Gray’s 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 Colomb’s first and second
axioms to the first scenario I arrived at tick-box answers 2.1 and 2.2 There was therefore no conflict between the
axioms and the rules so my conjecture remained untested. Applying the third axiom
(my so-called Gray’s axiom) to the first scenario yielded answers 4.2 and 4.3 This explained the cluster of 4.2 and 4.3 (and also perhaps 4.1)
answers in Captain Syms’ analysis of the survey returns and appeared to support
my conjecture. However, the reasoning which led me to answers 4.2 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-Syms’ Axiom after the
architects of the survey which has revealed it) which axiom may, perhaps, be
expressed thus:
4.
Baillod-Syms’ 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.
In the second scenario, own-ship again has
the target closer to the bow than the target has own-ship. Therefore, by
Colomb’s 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 Colomb’s 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 Grays’ 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.
Moving on to the third scenario, the target
ship has own-ship bearing closer to the bow. By Colomb’s First Axiom the target
is most likely to act thereby relieving own-ship of the need to act. By
Colomb’s 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 Gray’s 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.
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,