Capt Zakirul Bhuiyan MSc, PGCE, FNI, AFRIN

Senior Lecturer

Warsash Maritime Academy

Digital Hydrography on the Maritime Web - Embracing the challenges and opportunities

29-30 October 2013, Southampton

The need for effective ECDIS display management

WYSIWYG

What You See Is What You Get

The appearance and content of the chart

data displayed on ECDIS may change

significantly from different settings

Scanned Copy

of Paper Chart

BA2037

Base Display

Minimum set of information which must always be

displayed and cannot be removed

May be helpful for initial appraisal in the planning

stage and moving the chart display to allow a

faster re-generation of the display.

Base Display cannot be used for navigation

Display Settings on ENC

Standard Display

Information

contained in the

‘base display’ and

most of the detail

needed for safe

navigation

The sounding features are not given

It does not necessarily display all the chart objects which

are necessary for safe navigation under all circumstances

All Other Information

It is to be

displayed

individually

on demand

Need to understand the requirement of layer selection

‘Displaying everything, without seamanlike

consideration, should not be an option’

Compilation Scale

Under-scale and Over-scale

SCAMIN

Scale Minimum

Reduces clutter when zoomed out Safety critical information may be removed

Scamin attributes available

1:22 000

1:15 000

What is the difference?

Scamin Filter applied

Scamin Filter applied

So, Always check plans at Compilation Scale before

use

Safety Settings

Shallow Contour highlights the

gradient of the seabed

Deep Contour

indicates the

area where

own ship may

experience

Squat

Safety Contour marks the boundary between safe and unsafe water

Safety depth affects the display of soundings. Here 7m

or less appear in black

7

Dredged area less than safety contour value

Dredged to 9.5m

Dredged area less than safety contour

The depth contours may differ between electronic charts produced by different hydrographic offices.

10.9 m

5.4 m

18.2 m

Example: US Charts

Safety Contour 10m No apparent danger

Failure to manage display layers has resulted in grounding incidents in recent years

Pride of Canterbury

7.8

Isolated danger displayed when Safety Contour is changed to 5m

Pride of Canterbury

Pride of Canterbury

When ‘All Other Information’ Display is used

1.8 m

Accuracy & Reliability

Paper Charts – Source Diagram

Electronic Nav Charts – Catzoc

Catzoc (Zone of Confidence)

A1 area: Very high accuracy survey by British Govt

B area: medium accuracy survey by ABP

‘Pick Report’ is too complex and sometimes difficult to

find out the right information from a chart

‘Pick Report’ function

Mariners are warned that positions showed from Global navigation Satellite Systems, such as GPS,

may be more accurate than the charted detail, due to the age and quality of some of the source

Information. Mariners are therefore advised to exercise particular caution when navigating close

to the shore or in the vicinity of dangers.

Land Features

Fortified Structure Object name:

Horse Sand Fort

A

Virtual

AtoN,

making

Safe

Water

ENC Symbols

The same symbol is being used for the danger and non-danger !!

Magnetic Variation

Where is the Neap Rate?

Tidal

Diamond

Paper Chart

Time varying Objects

Special buoys are only

shown during March to

October

Hidden Picture File

An understanding of the basics, which may not appear on an ECDIS display monitor.

A navigator must cross the TSS on a heading at

right angles to the general direction of traffic flow and he

needs to appreciate the vessel will be set away from the ship’s heading and thus the predicted ground track needs to be on ECDIS, allowing

for set and drift

Ground Track 148 deg

Course to Steer 135 deg

Set: SW’ly Rate: 3.2 Kts

Integrity Monitoring Techniques

Cross check by all available means:

look out of the window as ‘human eyes are

the most valuable tool at a navigator’s

disposal’

manual position fixing (Visual/Radar) comparison of Radar/ARPA overlays observation of a parallel index on the radar monitoring the depth shown by echo sounder checking the track history change sensor if available

No Error

GPS Error

Gyro Error

The implication of getting ECDIS Display Settings wrong will certainly result in the loss of the navigator’s situational awareness and thus lead to more incidents (i.e. Collision, grounding etc.) and near misses.

ECDIS – Display Settings

e.g. CSL Thames, CFL Performer, Cosco Busan, Pride of Canterbury, LT Cortesia , Maersk Kendal,

THANK YOU

Any Questions ?