1 INTRODUCTION

Since 2002, Electronic Chart Systems (ECS) have

gained legal status and became widely used on ships.

According to the requirements of SOLAS regulation

V/19-2.14, ECS could be used together with

navigational paper charts. The situation changed

significantly in 2009. Scientific and technological

progress is not standing still and at the IMO Maritime

Safety Committee meeting in May 2009, it was

decided to introduce ECDIS (Electronic Chart Display

and Information System), as a compulsory part of

navigation equipment, on all vessels of more than

10,000 GT. Risks associated with this early

implementation stage are outlined in [17], which

highlights the importance of system integrity

monitoring, operators’ training, and, generally,

spreading awareness of system limitations and errors

in order to reduce the potential of over-reliance.

The introduction of electronic charts was gradual,

from 2012 to 2018. During this period navigators had

to learn to work with new equipment and use ECDIS.

At the same time, paper charts were replaced by

electronic ones. ECDIS EHO [2] and further surveys

[4] allowed to extensively elaborate the end-user

feedback in transition and fully paperless periods

noticing the drastic change of paradigm between

conventional PNC (paper navigational chart) and

ENC (electronic navigational chart) navigation

experience. ECDIS EHO survey revealed that 60% of

respondents have problems of different nature when

operating the system (usability, access to information,

system software/hardware reliability, sensors, chart

handling, knowledge, and skill), and 19% of

respondents notify inconsistencies in system

operation.

The analysis of accidents in recent years keeps

revealing overreliance on ECDIS trait. The study of

causes of grounding accidents and analysis of possible

preventive measures [15] shows that “…obligation to

have Electronic Chart Display and Information

Systems (ECDIS) and compulsory ECDIS training for

Identification of Weak Links in the ECDIS - Operator

System Based on Simulator Training

O. Pipchenko, O. Burenkov, M. Tsymbal & V. Pernykoza

National University "Odessa Maritime Academy", Odessa, Ukraine

ABSTRACT: Statistics, based on grounding incident investigations, is not always sufficient for retrieving

objective information and designing comprehensive solutions for improving the ECDIS training process for

deck officers and development of methods aimed at reducing the grounding incident rate and improving the

effectiveness of navigation. The research studies statistics on deck officers` errors made during training on

bridge simulators equipped with ECDIS and provides an analysis of errors distribution among navigators of

different ranks. The study shows that in event of the EPFS (Electronic Position Fixing System) failure the

likelihood of grounding increases dramatically for all deck officers, irrespective of rank and experience, despite

having fully functional radar and ECDIS in dead reckoning mode.

http://www.transnav.eu

the International Journal

on Marine Navigation

and Safety of Sea Transportation

Volume 15

Number 1

March 2021

DOI: 10.12716/1001.15.01.07

watchkeeping officers” and “…improvement of

education and training” are the top alternatives

proposed to prevent grounding accidents involving

human errors. IMO has adopted the Guidance for

Good Practice for the use of ECDIS [8], which

emphasizes the importance of the operator's ability to

act in the event of failure, display data interpretation

and identification of possible errors. The trend of

ECDIS related groundings necessitates a more

detailed analysis of the accidents’ causes, as well as

further development of passage planning methods

adopted for paperless navigation.

Data obtained in the process of training and

assessment of deck officers on the mini-bridge

simulator equipped with ECDIS (Wartsilla Navi-

Sailor 4000) allowed to perform a more detailed

analysis of direct and indirect factors that increase the

probability of vessel grounding.

2 ECDIS SAFETY PARAMETERS AND DISPLAY

SETTINGS

The principal difference between ECDIS and paper

charts is that the operator can adjust the way the

system displays the nautical chart on the screen, as

well as the way the system notifies users of potential

hazards. This is done with a series of display settings

(filters) on one hand and safety parameters on the

other. Even as this feature can be very advantageous

in capable hands, misuse of display and safety settings

can lead to misjudgment and incorrect assessment of

the navigational situation.

For instance, the SCAMIN value of an object

determines the display scale below which the object is

no longer visible on ECDIS. The purpose of SCAMIN

is to reduce the amount of clutter displayed to the

ECDIS user. Depth soundings are usually the first to

disappear. In figure 1 you can see a comparison of the

same ENC with the current display scale slightly

smaller than the ENC compilation scale. What is

important, is that soundings, which are less than

Safety Depth disappear as well, when SCAMIN is ON.

Figure 1. Application of SCAMIN setting on ENC

Generally, a Guide to Safe Navigation issued by

Intertanko [5] as well as the work by Becker-Heins [1]

and ECDIS Procedures Guide by Witherby [17]

provide series of recommendations on proper display

and safety settings. As specified in ECDIS

performance standards by IMO [9], these settings are:

safety depth (Dsafe), safety contour (Csafe), deep contour

(Cdeep), shallow contour (Cshallow), cross-track distance

(XTD) and turn radius (Rad). It is important to

understand that these settings affect not only the

visual display, but also the behaviour of the alarm and

indication system, also known as anti-grounding

system.

It is important to define the safety depth from the

perspective of navigational risk assessment.

Lemma. The risk of grounding exists if the vessel

has a non-zero speed and is heading to an area where

the dynamic draft of the vessel may be equal to or

greater than the depth.

Hence, the safety depth is the depth above which,

considering measurement errors, inaccuracy of

cartographic information and dynamic factors (squat,

heaving and pitching, etc.), the vessel with a given

probability will pass without contact with the bottom.

The most detailed assessment of the safety depth

components is given in Harbour Approach Design

Guidelines by PIANC [6] shown in figure 2.

Figure 2. Safety depth components according to PIANC [6]

Basing on the analysis of the publications safety

depth and contours can be defined as:

safe static squat ZOC tide

D T UKC

  

= + +  +  +  +  +  − 

(1)

where: UKC – under keel clearance; Tstatic – ship static

draft;



squat – ship maximum squat;



ZOC – chart

accuracy (ZOC) correction;





- change of density

correction;





- correction for pitching and heaving;





- heel correction,



tide – tide level.

safe safe

deep static

shallow deep















(2)

Safety depth components can be generally defined

as:

( )

squat w

fU=

(3)

( )

ZOC

f ZOC h=

(4)

static





 = −





(5)

( )

max



=

(6)

( )

max max



=

(7)

( )

tide

ft=

(8)

where: S – set of parameters defining ship’s hull; C -

set of parameters defining the channel or shallow

bank configuration; Uw – ship speed through the

water; ρn – water density; φmax – maximum expected

heeling angle; wmax – maximum expected heave; θmax –

maximum expected pitching angle; G – set describing

a geographical location; t – time.

We will omit the detailed safety depth calculation

here, as it is a subject for a separate research and

analysis, however, components of equation (1) can be

estimated by methods suggested by Becker-Heins [1]

or PIANC [6].

On the basis of the analyses of industrial

recommendations and research publications,

particularly [1, 5, 11, 12], industry-recommended

limits and alarm settings are compiled in table 1.

Table 1. Summary of industry-recommended limits and

alarm settings

_______________________________________________

Parameter Setting

_______________________________________________

Display Standard + Custom layers

Ship as Contour

Turn radius To satisfy recommended RoT limit

(10-20°/min)

Safety Depth Draft + UKC Policy

Safety contour = Safety Depth

Deep contour = 2 × Draft

Shallow contour Next smaller than Safety Depth

Harbour Coastal Open

approach sailing Sea

Cross-track limit ≥Breadth – 0.1 nm – ≥Tactical

0.1 nm 1.0 nm Diam.– 2.0 nm

Safety frame 6 min | 12 min | 18 min |

XTL XTL XTL

Track time labels ≤6 min 12 - 30 min 30 – 60 min

_______________________________________________

Regardless of the ECDIS manufacturer ECDIS

performance standards by IMO [9] prescribe certain

layers of information to be available and adjustable in

any software model. Therefore, the generic approach

to display settings for planning and monitoring stages

was suggested in [11].

During the planning stage, when setting the track,

the user shall check that the present display is in the

best scale mode (coincides with the largest scale ENC

on the selected route leg), keeping the display in

custom mode, with certain layers being ON/OFF as

needed (table 2).

Table 2. ECDIS display setup for voyage planning

_______________________________________________

Parameter Setting

_______________________________________________

Display Standard

Custom layers ON

If there is too much clutter, temporarily:

Highlight Info OFF

Text OFF

Accuracy (ZOC) OFF

Full light lines OFF

_______________________________________________

On the monitoring stage Highlight Info, Accuracy

(ZOC) and Text layers can be kept OFF, if not needed

at the time. Additional information shall be brought

up, as shown in table 3.

Table 3. ECDIS display setup for monitoring

_______________________________________________

Parameter Setting

_______________________________________________

Display Standard

Custom layers ON

If there is too much clutter, temporarily:

Highlight Info OFF

Text OFF

Accuracy (ZOC) OFF

Full light lines OFF

Other parameters

Route mode Monitoring (Active)

Safety Frame ON (can be invisible)

Past Track ON

RADAR / AIS Propper filter settings and ALARMS

Primary + Secondary ON

source of position

Position Difference ON

alarm

_______________________________________________

3 ERROR STATISTICS – PASSAGE PLANNING

To find out the common traits in deck officers' errors

during the passage planning stage, statistics over the

2018-2020 period based on ECDIS proficiency

assessments of 875 deck officers of various ranks

(master, chief officer, 2nd officer, 3rd officer) in

different coastal navigation and harbour approach

areas was collected. All deck officers have previously

completed ECDIS generic training as required by

Table A-II/1 of the STCW Code between 2012 and

2020. Deck officers were required to create a short

route (5-6 legs) which included the following: route

assessment for hazards, safety depth calculation,

setup of ECDIS display and safety settings, and

plotting of “No-Go” areas (figures 3, 4 and 5).

Figure 3. Distribution of errors by type

Figure 4. Distribution of deck officers by rank

Figure 5. Distribution of errors by type and rank

Distribution by ranks (figure 5) shows that the least

number of errors are made by 2nd officers whose

direct responsibility is passage planning. 3rd Officers

are usually better than masters and chief officers in

using the software, however, they lack risk assessment

skills and often make mistakes, when it comes to route

safety assessment. At the same time, the contributing

factor to a lot of masters' and chief officers' mistakes is

the computer literacy and knowledge of specific

software.

The most common error is the misinterpretation of

ENC symbols observed among all ranks, regardless of

their work experience and, most alarmingly, the

misinterpretation of navigation hazard symbols.

Discussions with the trainees after the assessments

showed that often deck officers either do not see the

hazard or do not recognize it. The same result was

observed for the No-Go areas concept. Often No-Go

areas were simply repeating the safety contour or

were missed in necessary areas.

ECDIS anti-grounding alert and display

appearance are mainly dependent on the safety

contour value, correct calculation of which makes it

particularly important for safe navigation. As per

Intertanko [5] and other industry recommendations

the Safety contour is normally set equal to the Safety

depth. Therefore, incorrect Safety depth calculation

directly affects the Safety contour. Errors in the Safety

Depth calculation often occur as a result of incorrect

ZOC (Zone of Confidence – IHO [7]) application,

incorrect assessment of the minimum depths on the

route and incorrect calculation of tidal levels.

Improper track location (setting legs over the

hazard or shallow contour, incorrect assessment of

distance to the hazard or depth), which may lead to

grounding. Radius and XTD settings affect the route

safety check, as a safety corridor is built and checked

with regard to those parameters. Therefore, hazards

could often end up within the safety corridor, or XTD

and radius were too small for normal ship operations

in the specific area.

Also, insensitivity to alarms was observed quite

frequently. Audible alarms are often turned off too

fast without checking the actual cause or meaning of

the alarm.

The results obtained during error analysis correlate

with the results published in MAIB reports on marine

casualties related to improper use of ECDIS and [13],

and conclusions made by Lusic et al. [10], Turna et al.

[14]: lack of knowledge and understanding of safety

parameters, alarms, and especially Safety Frame and

XTD functions.

The analysis reveals an alarmingly low level of

knowledge and understanding of ECDIS capabilities,

which directly threatens the safety of navigation. The

results obtained indicate the need to make

appropriate changes to the training process and stress

the attention on the elements of knowledge where

deck officers show the worst results.

4 ERROR STATISTICS – EPFS FAULT

The STCW Code, Ch. VIII states: “… Fixes shall be

taken at frequent intervals, and shall be carried out by

more than one method whenever circumstances

allow. When using ECDIS, appropriate usage code

(scale) electronic navigational charts shall be used and

the ship’s position shall be checked by an independent

means of position fixing at appropriate intervals.”

The introduction of paperless navigation did not

cancel this requirement. However, the methods fixes

done on the chart changed substantially. The dead

reckoning and manual position fixing functionality

are compulsory for type-approved ECDIS software.

Although position-fixing (or verification)

requirements vary from company to company, mainly

it turned into a "paperwork exercise", where deck

officers plot positions on ECDIS display not to verify

where the ship is, but to fulfil the requirement.

Due to modern bridge design, radar is the only

equipment that can serve as the independent source of

LoP’s (Line of Position). With dominating satellite

positioning system reliability modern deck officers’

radar navigation skills started to degrade. A group of

instructors at NU "Odesa Maritime Academy"

recorded the results of 105 deck officers’ assessments

performed on Wartsilla Navi-Trainer 5000 mini-

bridges. As in the previous experiment all deck

officers have previously completed ECDIS generic

training as required by Table A-II/1 of the STCW Code

between 2012 and 2020.

Task description: car carrier (length - 236 m, max

draft – 9.2 m) is on the eastbound transit via

Singapore strait (daytime; visibility – 10 nm; wind –

NW/5 Bft; current SSE – 1 knot). Within several

minutes after the exercise has begun both available

EPFS sensors are set out of order without a warning,

i.e., no data is displayed on ship’s position, course

over ground (COG) and speed over ground (SOG).

During the task, 5 active vessels are moving along the

strait, leaving and entering the port of Singapore.

Other vessels are at anchor and do not interfere with

the passage (figure 6).

Figure 6. Vessel drift-off and consequential grounding as a

result of EPFS failure

Near-miss was defined as an approach to

navigational hazard or vessel closer than distance

given by equation:

( ) ( )

sin cos

min

SF L SF B

CPA



  +  

(9)

where CPAmin – minimum allowed closest point of

approach; L – ship length; B – ship breadth; α –

approach angle, °; SFL – longitudinal safety factor; SFB

– transverse safety factor.

The choice of variable CPA is based on the fact that

when approaching in narrow waters on opposite or

following courses it is quite difficult and due to the

limitations of the navigational nature not always

possible to maintain a large distance between vessels.

On the other hand, if the sea room allows vessels to

approach at angles close to perpendicular, the

navigators shall maintain a certain margin over the

distance to leave room for manoeuvre.

An example of the variable CPA calculated using

the mentioned method is shown in Fig. 7.

Figure 7. Minimum CPA as a function of ship dimensions

and approach angle

The experiment summary is given in table 4. The

deck officers, in their majority (88%), until the very

last moment did not pay attention to the fact that the

GPS did not work and continued to proceed unless

the ship ran aground or passed too close (near-miss)

to Batu Berhanti after 15 minutes (Fig. 7).

Table 4. Statistics on exercise with EPFS malfunction

_______________________________________________

Attempt 1st 2nd 3rd

_______________________________________________

Situation

1 Collision with a vessel 1 2

2 Grounding 3

3 Near-miss with ship or hazard 89 10 2

4 Safe passage (<70% of past track 12 46 10

within XTD)

5 Excellent passage (>70% of past track 35

within XTD)

Cause

6 Hazard was not detected 21 5

7 Hazard was not realized 71 6

8 Improper risk assessment 1 19

9 Ignoring speed manoeuvre 1

10 Wrong manoeuvre 36

11 Lack of planning 1

_______________________________________________

Figure 8. Distribution of deck officers by CoC (certificate of

competence)

A small portion of deck officers did not pass the

task (2%). They could not use ECDIS without

operational EPFS and failed all 3 attempts. Some deck

officers were confused when the vessel symbol did

not move on the ECDIS display and did not notice

other vessels, which led to collision (3%). In total, only

11% of mariners successfully completed the task on

the first attempt. They correctly assessed the situation,

determined the vessels’ position and managed to

follow the route.

It is important to notice that the participants for the

most part had considerable experience at sea (on

average 21.8 years total and 8.4 years in rank) as

shown in figure 8.

Figure 9. Distribution of experience among participants

Also, there is a wide fleet representation as shown

in figure 10, with mainly officers from container and

bulk fleet, who took the assessment.

Figure 10. Vessel types the participants work on

5 CONCLUSIONS

Modern ECDIS equipment is a critical navigational

instrument that in capable hands can help to

significantly increase the safety of navigation. This can

be achieved when the safety parameters are

determined correctly and appropriately set up in the

system.

Since ECDIS almost entirely replaced paper charts

in 2018, the risk of overreliance on this equipment and

related sensors increased dramatically. Seemingly, the

comfort of using ECDIS results in the degradation of

radar and visual navigation skills.

Inappropriate passage planning caused by the

erroneous determination of such parameters as safety

depth, safety contour, cross-track distance and turn

radius leads to the inability to recognize navigational

hazards. The latter in combination with the lack of

computer literacy and overreliance on ECDIS in the

unlikely event of EPFS failure creates a serious chance

for a high-potential incident.

Therefore, the implementation of proper passage

planning routines together with simulator training in

equipment failures related to the ECDIS system

(EPFS, gyro, log failures) is crucial for the safety of

modern-day navigation.

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