International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 3
Number 3
September 2009
1.1 Casualty Investigation Code
The global harmonisation of marine casualty
investigation was taken a step further last year with
the approval by the International Maritime Organi-
zation of the new Code of the International Stand-
ards and Recommended Practices for a Safety Inves-
tigation into a Marine Casualty or Marine Incident
(Casualty Investigation Code). The Maritime Safety
Committee adopted the Casualty Investigation Code
by resolution MSC.255(84). And a new regulation 6
in chapter XI-1 of the SOLAS Convention was also
adopted (resolution MSC.257(84)), giving mandato-
ry status to the Code, which takes effect on 1 Janu-
ary 2010. However, the IMO has invited Govern-
ments to start implementing the new Code on a
voluntary basis prior to the effective date of the
Code [1].
1.2 Common approach of 1997
This most recent Code incorporates and builds on
the best practices in marine casualty investigation
that were established by the IMO’s Code for the In-
vestigation of Marine Casualties and Incidents,
adopted in November 1997. That Code sought to
promote co-operation and a common approach to
marine casualty and marine incident investigations
between States. While the new Code specifies some
mandatory requirements, it does recognize the varia-
tions in national laws in relation to the investigation
of marine casualties and incidents. But the broad aim
is to facilitate and promote objective marine safety
investigations for the benefit of flag States, coastal
States, and the shipping industry in general.
1.3 Objectives and purpose
The objectives and purpose are well stated in the
Code’s opening chapter:
“1.1 The objective of this Code is to provide a
common approach for States to adopt in the con-
duct of marine safety investigations into marine
casualties and marine incidents. Marine safety in-
vestigations do not seek to apportion blame or de-
termine liability. Instead a marine safety investi-
gation, as defined in this Code, is an investigation
Reconstructing a Marine Casualty: The
Effectiveness of the Full-Mission Simulator as a
Casualty Analysis Tool
E. Doyle
Cork, Ireland
ABSTRACT: The primary purpose of a marine casualty investigation is to seek to establish the causal factors
of the casualty with a view to learning the hard lessons and avoiding a repetition.
The broad questions of an investigation: "who?, what?, when?, where?, why?, and how?", all help to uncover
the facts. The investigation sequence will cover a diverse range of fact-finding activities, amongst which, as
often the case, may be a requirement for “conducting specialised studies”. Following the fact-finding stage
the typical investigation progresses to analysis of the facts, reaches conclusions and makes recommendations.
Keeping an open mind, to avoid premature conclusions, requires the separation of the fact-finding and
analysis phases. But the analysis may well help to identify missing pieces of evidence, or different lines of
enquiry that may otherwise have gone undetected. As an effective reconstruction tool, a full-mission bridge
simulator offers an opportunity to examine a broad spectrum of environmental condition
s and vessel
characteristics, as well as equipment failures, human factors and operating procedures. A casualty incident
can be reconstructed in a real-time simulated environment, to aid more detailed analysis.
Within the usual confines of the legal process, comprehension of nautical ‘black magic’ is greatly simplified
for non-mariners, by seeing the simulated casualty incident unfold, in real-time or in selected short-time seg-
conducted with the objective of preventing ma-
rine casualties and marine incidents in the future.
The Code envisages that this aim will be achieved
through States:
.1 applying consistent methodology and ap-
proach, to enable and encourage a broad rang-
ing investigation, where necessary, in the in-
terests of uncovering the causal factors and
other safety risks; and
.2 providing reports to the Organization to
enable a wide dissemination of information to
assist the international marine industry to ad-
dress safety issues.”
1.4 Causal factors rather than blame or fault
As we can see, the primary purpose of a casualty
investigation is to seek to establish the causal factors
of the casualty with a view to learning the hard
lessons and avoiding a repetition. And while it is
not, and never should be, the role of a marine safety
investigation team to attribute blame or fault, that is
not to say the investigating authority should refrain
from fully reporting the causes because fault or lia-
bility might be inferred from its findings.
2.1 Uncovering the facts
The investigation must attempt to uncover all the
facts, by seeking answers to such fundamental
questions as: "who?, what?, when?, where?, why?,
and how?" In this regard, the fact-finding sequence
of the investigation is likely to include such
activities as:
inspecting the location;
gathering or recording physical evidence;
interviewing witnesses;
reviewing of documents, procedure and records;
conducting specialised studies (as required);
identifying conflicts in evidence;
identifying missing information; and
recording additional factors and possible
underlying causes.
2.2 Progression to analysis
Following the fact-finding stage a typical marine
casualty or incident investigation includes: analyses
of the facts; conclusions; and recommendations.
2.3 Fact-finding and analysis
Investigators need to keep an open mind and avoid
reaching conclusions too early. It may appear self-
evident that the fact-finding stage of the process
should be separate from the analysis. But it must
always be borne in mind that the analysis may well
help to identify missing pieces of evidence, or
different lines of enquiry that may otherwise have
gone undetected.
2.4 Simulator as effective reconstruction tool
In the course of very many marine safety
investigations, the availability of a full-mission
bridge simulator is likely to offer a powerful and
productive analytical tool. Such a tool affords the
opportunity to examine a broad spectrum of
environmental conditions and vessel characteristics,
as well as equipment failures, human factors and
operating procedures. A marine casualty may be
reconstructed in a real-time simulated environment,
to allow detailed analysis of the incident. Mariners
who have had the benefit of full-mission simulator
training will readily appreciate the merits of the
debriefing/playback feature, allowing detailed
examination of the exercise or simulated incident, as
the replay unfolds in real-time or short-time
2.5 Investigation and legal proceedings enhanced
Such simulation can be replayed at will, with very
obvious benefits for expediting the work of the ma-
rine safety investigation team. In another forum,
such as the civil judicial process, it has the added
benefit for non-mariners of aiding the comprehen-
sion of nautical terminology with the consequent po-
tential to expedite settlement.
3.1 Investigation and litigation
A practical example of the potential beneficial anal-
ysis that a simulated examination might generate is
given from the following marine casualty case study.
It centers on a collision off the southeast coast of
Ireland, in June 2000. The collision was investigated
by the newly established Marine Casualty Investiga-
tion Board (MCIB) [2], who did not have access to
adequate simulation facilities at that time. The case
also generated High Court proceedings which, in the
event, were settled shortly before the scheduled
3.2 Summary of the incident
On the morning of 13 June 2000, the beam trawler
mfv STELIMAR (LOA 19m, 200t) was on passage
from her home port of Dunmore East, heading to-
wards her usual fishing grounds. She was steering a
course of about 145˚, and making about 8.5 knots.
The weather was fair: Wind SW’ly F 3/4, with good
At the same time, the tanker mv ALMANAMA
(LOA 249m, 97,000 dwt) was making a course of
256˚, speed 13.8 knots, bound for Cork Harbour.
The vessel had cleared the traffic separation scheme
at Tuskar Rock and was now on a course that would
take her across the path of STELIMAR. In fact, the
two vessels were on converging courses, in circum-
stances where the bearing between them was not
changing significantly a collision seemed inevi-
table unless avoiding action was taken by one or
both vessels.
This was a classic "crossing situation" for which
there is clear provision in the COLREGS. Rule 15
obliged ALMANAMA, as the give-way vessel, to
keep out of the way and thus avoid collision, while
Rule 17 required STELIMAR, the stand-on vessel,
to maintain her course and speed in the early
stage of the encounter, at any rate.
In the event, a collision did occur, at a position
about 14 miles SSE of Hook Head. STELIMAR sus-
tained substantial damage, which necessitated her
being towed back to Dunmore East. Given the
enormous disparity in the size and tonnage of the
two vessels it was nothing less than incredible good
fortune that STELIMAR did not capsize and found-
In addition to her Rule 15 obligation, ALMA-
NAMA was also required by Rule 16, to "…take
early and substantial action to keep well clear." In
discharging her obligations, ALMANAMA could
have made a large alteration of course to starboard
so as to make her intentions very clear to the stand-
on vessel, or she could have made a substantial re-
duction to her speed but this action would not have
been so readily apparent to the stand-on vessel. Ac-
cepting that speed reductions are rarely used by
give-way vessels when taking avoiding action in
open sea situations, ALMANAMA could reasonably
have been expected to make a substantial alteration
of course to starboard. Further, she should have
done so at an early stage in the encounter so as to
avoid putting STELIMAR in the unnecessary and
difficult position of having to take avoiding action
under Rule 17(a)(ii).
3.3 ‘Factual’ conflict
The MCIB investigation report noted the “Factual
Report of the Collision…” from STELIMAR’s per-
spective, and a similar Factual Report…” from
ALMANAMA. There should be no surprise that the-
se ‘factual reports’ were in conflict. The real surprise
was that the MCIB analysis failed to resolve the con-
flict adequately.
3.4 STELIMAR’s perspective
STELIMAR'S skipper first noticed a large merchant
vessel visually, broad on his port bow at a distance
of 6 or 7 miles, on a general W'ly heading, shaping
to cross his path she would need closer attention
as the range closed.
When the radar image of this large ship, soon to
be identified as ALMANAMA, first appeared at the
extremity of his 3-mile radar display, the skipper be-
gan to pay continuous attention to her progress. He
believed that she was making 14 or 15 knots, and his
concern was heightened by the developing situation,
as presented in Fig. 1: he was in a crossing situation
with a large vessel, whose bearing appeared to re-
main the same or nearly so.
Figure 1. A reconstruction of the crossing encounter
3.5 Imminent collision
When the vessels were about 1.5 miles apart, and
ALMANAMA had still not altered course,
STELIMAR came to the conclusion that he would
have to take avoiding action.
He could have altered course to starboard but the
skipper felt this would have prolonged the period of
uncertainty. In the event, he chose to de-clutch the
main engine and allow STELIMAR'S speed to
quickly run down. He estimated he did this when
the vessels were about 0.75 to 0.5 miles apart or
about 2 to 2.5 minutes before impact.
In taking the speed off his vessel the skipper an-
ticipated that ALMANAMA would pass safely
ahead of him. However, very shortly afterwards
(perhaps when 0.5 to 0.25 miles apart) he was
alarmed to see a man on ALMANAMA'S starboard
bridge wing running into the bridge in an agitated
state. He was deeply concerned at this and, believing
that he now had a full emergency on hand, he put his
engine to "Full astern". He estimates the two vessels
were about 0.25 miles apart at this point and that he
was at "Full astern" for 30 to 40 seconds until the
collision. He believed that ALMANAMA was turn-
ing slowly to starboard, towards STELIMAR as she
gained stern-way.
3.6 ALMANAMA’s perspective
Meanwhile, the Factual Report…” from the other
vessel has the OOW on the bridge of ALMANAMA,
plotting a fix for 1115 and altering course to 256°.
The vessel’s speed was about 13.8 knots.
At 1120 he observed a small target (STELIMAR)
some 40˚ to 50˚ on the starboard bow at a distance of
5 or 6 miles. He claims he acquired and plotted this
target on the ARPA, which predicted a CPA of 1 to
1.5 miles with the target crossing ahead. He also
took a series of visual bearings, which indicated that
the vessel was passing ahead, but did acknowledge
that the bearings were changing very slowly. He es-
timated that the fishing vessel was heading on a
course of about 150° at about 10 or 11 Knots.
When the fishing vessel was between 2.5 and 3.5
miles off and about 1.5 to 2.5 points on the starboard
bow, the OOW tried to call it on VHF Channel 16,
but there was no reply from STELIMAR.
3.7 Belated course alteration
He now altered course to starboard, to 268°, though
the fishing vessel was still fine to starboard and
about 1 mile off. He claimed that STELIMAR al-
tered course to port to about 120° and possibly re-
duced speed also. ALMANAMA then applied hard-
to-port helm in a final, and ultimately vain, attempt
at trying to avoid collision.
4.1 Course recorder trace
ALMANAMA’s course recorder trace confirmed her
course alteration from 230˚ to 256˚at 1115. It also
showed that her next course alteration, to 268˚, was
made just about two minutes prior to the collision,
and that the hard-to-port manoeuvre had practically
no effect before impact.
4.2 Hard lesson on failure to “take early and
substantial action”
Deconstruction of the final phase of this collision
encounter was clear to all; STELIMAR took emer-
gency "full astern" action when it seemed clear to
her that collision could not otherwise be avoided, but
the action was unsuccessful because the beneficial
effect of her stern-way motion was nullified by the
very belated turn to starboard by ALMANAMA,
culminating in the collision.
4.3 Making relative velocity simple
The most glaring and unresolved conflict between
the two parties was ALMANAMA’s contention that
STELIMAR was expected to cross ahead at a CPA
of 1 to 1.5 miles, this information allegedly predict-
ed from ARPA. Such contention is readily refuted
by means of a standard relative velocity plot, though
not so readily understood by non-mariners. Howev-
er, the use of a bridge simulator easily overcomes
those difficulties.
4.4 Construction of RelVel triangle
The veracity of the relative velocity information is
dependant on the vector accuracy for each ship. In
the case of ALMANAMA, her course and speed
were established from log records and instrumenta-
tion, while STELIMAR’s course and speed were
consistent with her recent departure (about 2 hours)
from her home port. Reversing the vectors from the
collision point allows construction of the basic rela-
tive velocity triangle, as given in Fig. 2. Because of
uncertainty in the precise timing of each vessel’s
movements in the final moments of the encounter
the plot may contain an inherent error, but nothing
of any significant consequence. This was confirmed
by rerunning the incident as a test exercise on the
NMCI bridge simulators.
Figure 2. The Relative velocity triangle, from ALMANAMA’s
4.5 Critical relative bearings
Given the geometry of this encounter, as outlined at
Fig. 1, it will be seen that STELIMAR was bearing
280˚ from ALMANAMA, or 50˚ on her starboard
bow before she altered course at 1115. The conten-
tion that STELIMAR was observed at 1120, about
40˚/50˚ x 5/6 miles on ALMANAMA’s starboard
bow, conflicts with the Fig. 1 plot which shows that
the vessels were no more than 4.4 miles apart then.
It is certainly the case that STELIMAR could not
have been seen 50˚ on the bow at any time after
ALMANAMA altered course at 1115 if it were
so, a collision could not possibly have happened.
The only rational conclusion is that STELIMAR was