Ecdis

Question 1

What is ECDIS

Answer 1

Electronic chart display information system

It Is an aid to navigation which uses electronic navigational charts to display chart, passage and vessel information on a computer display

Question 2

Requirements for ECDIS to be primary form of navigation
(x8)

Answer 2

• Type approved
• official up to date ENC’s
• must be maintained to comply with latest IHO requirements
• operators need to have generic and type approval training certificates
• Must be include in the Safety Equipment Certificate’s - Form E
• must have approved, independent, up to date backup system
• risk assessment needs to be completed
• onboard familiarisation training

Question 3

What is a vector chart or enc

Answer 3

• Digital chart that is made up of different layers of digital information which can be displayed as a seamless chart
• Chart Information is contained in a database and can be displayed and removed as required.
• Developed with information supplied by approved hydrographic offices
• vector charts can be zoomed and will not pixelate.

Question 4

What is a raster chart

Answer 4

• Rastor chart is a picture of a paper
• if zoomed in it will pixelate
• information can not be selected or deselected
• what you see is what you get
• very space consuming

Question 5

What is a SENC

Answer 5

• A SENC is made up of information provided in the vector/enc chart so as to be displayed in the Brand/make of Ecdis system
• The SENC is specific to the make of Ecdis system.

Question 6

Ecdis alarms
(x7)

Answer 6

• crossing safety contour
• XTE/deviation from route
• Approaching a critical point
• Area special conditions
• Malfunction of Ecdis system
• Position system failure
• different geodetic system

Question 7

Ecdis indications

Answer 7

• larger scale ENC available
• Information over scale
• No ENC available
• Default Safety contour
• route planning across SAFTEY contour
• Route planning across specified area (prohibited area)
• Crossing a danger in route monitoring
• different reference system (i.e. Ft or meter)
• System test failure
• Customised display

Question 8

What is IHO S52

Answer 8

International standard for enc Presentation library for chart symbols, objects, colors

Question 9

What is IHO S57

Answer 9

Sets the standard format for Data transfer between the IHO, hydrographic offices, manufactures, software developers and end users of ECIDS.

Question 10

Types of display

Answer 10

Base display
Standard display
All layers
Custom

Question 11

What is contained in the base display

Answer 11

• Safety contour
• Coast line
• Isolated dangers that lie with in the safe area of the safety contour
• Iso dangers that lie in safe zone like bridges or overhead cables or bouys
• Traffic routing
• Scale range, orientation, display mode
• Units of depth

Question 12

What is in standard/ default display

Answer 12

• all base info
• drying line
• AIDS to navigation (lights and bouys)
• boundaries of fairways and channels
• warning indications
• prohibited areas
• indication of cautionary notes
• visual and radar conspicuous features
• chart scale boundaries

Question 13

What are the CATZOCS

Answer 13

Category zones of confidence

A1. +- 5m, extremely accurate, (6)

A2. +- 20m, Very accurate not as accurate as a1 (5)
All lower CATZOCS require additional safety margins

B. +-50mm, NAV Hazards not expected but may exist (4)

C. +- 500m low accuracy, depth anomalies may exist (3)

D. poor accuracy, severe depth anomalies may exist (2)

U. unsurveyed (1)

Question 14

How to update ECDIS

Answer 14

Weekly update provide by the UKHO or a RENCS via a disk disk/USB or a direct download via Internet on to a separate computer and transferred to Ecdis system on a clean virus free sub drive

The weekly updates contain latest editions of charts and permanent corrections

Updates are made to the SENC and cannot be edited. The ECDIS system will log and record all updates that are made to the ENC.

Question 15

How must NAVTEX and NAV warnings be entered into an ecdis

Answer 15

When NAV warnings are released via navtex or Inmarsat SAFTEY net they must be manually entered onto the chart sytem. They Ecdis system will indicate that they are manual corrections and may be deleted.

Question 16

What is safety depth

Answer 16

A User set depth which is generally set as the same depth as the safety contour. Ecdis will display all soundings shallower than this depth as black/bold and all soundings deeper than this as grey.

Question 17

What is a safety contour

Answer 17

User defined contour which indicate the boundary between safe and unsafe water. It is made up of the draught of the vessel + squat + a safety margin(minimum UKC)- height of tide.
If there is not a contour for the set depth the ECDIS unit will select the next deepest contour as the safety contour. If the vessel crosses the safety contour an alarm will sound. If the safety contour is crossed during route planning and indication will be displayed.

Question 18

How do you determine the safety depth and safety contour depth.

Answer 18

Vessel safety = vessel draft + squat + safety margin (min UKC)

Static draft: the draft of the vessel when fully loaded and not making way.

Squat: the amount of squat that the vessel will experience at the maximum speed for that particular area

Safety margin: the minimum under keel clearance that is required by the vessels SMS

Question 19

What is a shallow contour and how is it calculated

Answer 19

Shallow contour is the depth shallower the safety contour entered in by the user. It indicates the depth at which the vessel will ground. The area shallower than this will be Shaded dark blue.

It is calculated as the draft + squat

Question 20

What is np133C

Answer 20

It is the admiralty ENC AND ECDIS MAINTENANCE RECORD

It provides a reference guide and record for use of Ecdis
It is used to record all enc software updates, annual performance checks, ,maintenance records
It assists with port state control inspections to ensure the vessels Ecdis system complies with SOLAS chapter 5

Question 21

What are the differences between RASTER and VECTOR charts

Answer 21

• raster cannot be interrogated.
• raster must be displayed at scale of chart
• cannot zoom
• horizontal datum may be different to the Gnss datum
• raster will not trigger any auto alarms, may trigger user set alarms i.e. Clearing lines, isolated dangers, danger areas
• features on chart cannot be removed
• look ahead may not be as useful as depending on the scale of the raster chart you can only look so far
• changing orientation of the chart may effect readability of symbols and notes
• cannot display ships safety contour or safety depth

Question 22

When can you use a RNC chart

Answer 22

When there is no enc available for that area. It must be backed up by either a risk assessment or an up to date paper chart

Question 23

What is SCAMIN and SCAMAX

Answer 23

Scale minimum and scale maximum

SCAMIN is the levels of under zoom at which the Ecdis unit starts to remove certain features. Helps reduce screen clutter.

SCAMAX Ecdis starts to remove items when to far zoomed in

Question 24

How are t and p notices displayed on the Ecdis display

Answer 24

They will have a red or green shaded area around them..

Question 25

What is the Safety Frame function

Answer 25

Is either a vector(rectangle)or arc (cone) that lies ahead of the vessel and provides earlier warning of an approaching danger.

Question 26

What MGN’s discus ECDIS.

Answer 26

MGN 285 MGN 360 MGN 379 use of electronic navigation aids

Question 27

Whats is the deep contour.

Answer 27

It is the deepest depth at which the vessel will begin to experience squat. Usually about 2 x draft.

Question 28

Limitations of ECDIS

Answer 28

- Over reliance - Alarm Deafness - Tendency fo operator to focus more on the ECDIS than out the window - Incorrect Scale usage - SCAMIN, Wrong scale ECDis will auto remove objects - CATZOCS, not as obvious - ECDIS programs differ in their functionality and operation - ECDIS not updated correctly then may not be able to display symbols correctly - Only as reliable as the info inputted. Bad Gps = Bad position, - Screen clutter - Users ability to remove information

Question 29

How to know if ECDIS is up to date.

Answer 29

ECSIS Chart 1. (DPPC) Data Presentation and Performance Check Individual cell used to display a charts symbol key. If ECDIS does not have the latest software and S-52 library installed symbols will not be displayed. Records of updates to be entered into ECDIS and ENC Maintenace record

Question 30

What is S-63

Answer 30

Data Security. Piracy prevention: Prevent unauthorised use. Selective access: Restrict access to cells that have been licensed Authentication: To provide assurance that the information has come from an approved source.