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Master (Yachts) < 3000GT Oral Prep > ECDIS & CHARTWORK > Flashcards

ECDIS & CHARTWORK Flashcards

1
Q

What are the carriage requirements for ECDIS?

A

SOLAS Chapter 5 Regulation 19.2. All ships irrespective of size, shall have nautical charts and nautical publications. An ECDIS is also accepted as meeting the chart carriage requirements.
SOLAS Chapter 5 Regulation 27. Nautical charts and nautical publications shall be adequate and up to date.
The implementation period for ECDIS is now over
Existing cargo vessels below 10,000 GT launched before July 2012 will not require ECDIS.
All new cargo ships over 3000GT require ECDIS.

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2
Q

What is an ECDIS? How is it equivalent to paper charts?

A

Electronic Chart Display and Information System
ECDIS must be equivalent to paper charts in regard to the following factors:
• Same database of information
• Same data source
• Same compilation scale
• Same ability to correct
• Same or known symbology

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3
Q

What are the 3 IMO Standards for ECDIS?

A

S-57 IHO Transfer standards for digital hydrographic data. It is the data format used for the transfer of digital hydrographic data between national hydrographic offices and for its distribution to manufacturers, mariners and other data users. Ensuring that all electronic charts contain all the chart information that is necessary for safe navigation.
S-52 IHO Specifications for chart content and display aspects of ECDIS. Determines how ENC data is displayed on an ECDIS screen through symbols, line styles, colours and other visual cues. Ensures that what the mariner sees on the screen is displayed in the same way across all approved makes and models of ECDIS.
S-63 IHO Data protection scheme. Covers piracy protection, selective access, and authentication. Ensures that data comes from an official source, reducing the risk of using inaccurate data and the risk of malware being introduced to a ship’s IT systems.

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4
Q

How is an ENC created?

A
  1. Surveying hydrographer produces hydrographic data. Hydrographic data is sent to National Hydrographic Office (UKHO). UKHO produces ENCs in accordance with S-57.
  2. National Hydrographic office sends ENCs to RENC, which ensures that ENC is compliant with standards.
  3. Once it is confirmed that the ENCs are complaint with the standards. The chart distributor distributes charts in accordance with the security standards of S-63
  4. ENCs are loaded into the ECDIS. ECDIS creates a SENC, ensuring data is displayed in accordance with S-52
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5
Q

How would you correct an ENC? How do you demonstrate an ENC is up to date?

A

Corrections are downloaded via a secure server using a chart and publication management software.
Corrections are loaded onto a clean and designated USB stick. The USB stick is transferred across to the ECDIS system
The corrections are cumulative.
Corrections do not automatically remove withdrawn ENC cells.
The readme file contained in the data download specifies which cells are withdrawn.
Ts & Ps are applied using Admiralty Information Overlay. Otherwise they must be manually entered.

To demonstrate ENCs are up to date, generate system report or interrogate individual cells.

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6
Q

What are the differences between Vector and Raster charts?

A

Vector charts. Digital representation of a database with greater functionality.
• Information can be interrogated
• Alarms are triggered automatically
• Display is seamless
• Displayed content can be customised
• Scale can be customised without causing distortion
• Compatible with other inputs and overlays
• Data files are much smaller
• Mariners are less familiar with the presentation
Raster chart. Scan of a paper chart presented in digital format with limited functionality.
• Information cannot be interrogated
• Alarms are not triggered automatically
• Display is not seamless
• Displayed content cannot be customised
• The chart must be viewed at it´s intended scale. There is no zoom function.
• Overlays can cause the display to become cluttered
• Data files are much larger
• Mariners are more familiar with the presentation
Raster charts are not considered to be equivalent to paper charts for the purpose of carriage requirements.
Tip. DIP ACIDS

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7
Q

What are the compulsory alarms and indications on an ECDIS?

A

Alarms. System announcing by audible means, or audible and visual means, a condition requiring attention.
• Crossing safety contour
• Deviation from route
• Approach to critical point

•	Position system failure
•	Different geodetic datum
Indications. Visual indication giving information about the condition of a system or equipment
•	Area with special conditions
•	Customised display
•	Default safety contour
  • Information over scale
  • Large scale ENC available
  • No ENC available
  • Route planning across safety contour
  • Route planning across specified area
  • Crossing a danger in route monitoring mode
  • Different reference system
  • System test failure
  • Malfunction of ECDIS
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8
Q

How do you know if an ECDIS system is approved?

A
  • Approved by Flag state
  • ECDIS must be listed on the Cargo ship safety construction certificate Form C
  • ECDIS must be listed on the Cargo ship safety equipment certificate Form E
  • Type approval certificate of the ECDIS system must be held
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9
Q

What are the back up requirements?

A

If using the ECDIS as a primary means of Navigation, there must be a completely standalone backup ECDIS system. Otherwise there must be a complete back up set of paper charts.
There must be 2 completely separate standalone ECDIS. Each ECDIS must have independent electronic position fixing system, power supply, UPS (45 seconds), ENC folio, software. A single gyro unit is considered to be acceptable. A backup electronic position fixing system is required.
There must be approval to sail paperless. Normally with a letter of utilization from the flag state.

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10
Q

What are the main limitations with ECDIS?

A
  • Input accuracy (Inaccurate satellite derived positions, Gyro)
  • Over-reliance on the electronic position fixing system. (Use other means of fixing position)
  • User settings. Safety contour and safety depths must be set accurately.
  • Anomalies. (SCAMIN, Datum, System lag). Operating ECDIS at the wrong scale.
  • Additional training. Generic and Type specific training.
  • Alarm apathy.
    Tip: IOU ATA
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11
Q

What must you ensure if you would like to sail paperless?

A

Appropriate back up requirements

Approval from Flag

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12
Q

What is SCAMIN?

A

Each element of data has a scale minimum value. As we zoom out, once the scale minimum value has been met, the ENC will not display the data. SCAMIN can be switched on or off, however when switched off, the chart may become overcluttered.

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13
Q

What is the difference between safety depth and safety contour? How do you calculate it?

A

Safety contour is used to designate a No-go area. Taking into account, Draught, Under keel clearance, Squat, Height of tide. The safety contour will be set at the next available contour up.
As safety depth is derived in the same way. The ECDIS will grey out all soundings deeper than the safety depth and bolds in depths that are at or less than the safety depth.

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14
Q

What training is required for ECDIS?

A

ECDIS Generic training. Required for all deck officers.
Type specific training. If ECDIS is the primary means of navigation, all deck officers must have type specific training for the type of ECDIS fitted onboard. (May be incorporated into the Safety Management System)

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15
Q

How would you monitor your progress along the route on an ECDIS?

A 
Safety parameters such as safety depth, safety contour, 
Radar overlay
Cross track distances
Manually plotting position
GNSS
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16
Q

Advantages and disadvantages between paper charts and ENCs?

A

Alarms
Seamless display
Disadvantages
Quality of coverage

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17
Q

The OOW calls you to say that you are off course, What are your actions?

A
  • Engage manual steering and manoeuvre back onto course

- Potential autopilot failure. Potential steering failure

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18
Q

Talk about a particular chart

A
  • Units of measurement
  • Publishers
  • Projection
  • Reference to other publications
  • Datum
  • Tidal information
  • Edition date and corrections
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19
Q

Explain the different chart projections

A

Mercator. The surface of the earth projected onto the inside of a vertically positioned cylinder (In line with Earths rotational axis)
- Used as navigational charts. Used in large and small scale.
- Lines of longitude are parallel to eachother. Latitude scale is distorted further towards the poles.
- A straight line cuts each prime meridian of longitude at the same angle. Known as a rhumb line.
- Bearings and courses can be plotted directly onto a Mercator chart.
Transverse Mercator. The surface of the earth projected onto the inside of a horizontally positioned cylinder.
- Used for large scale charts, harbour plans.
- Lines of latitude equally spaced. Distorted east or west of the centre of the chart
- Can be identified as they have their own distance scales printed on them
Gnomonic
- Used for ocean voyages to obtain a great circle.
- Lines of longitude converge at the poles. Lines of latitude are curved
- Great circles are represented as straight lines.
- A great circle is the shortest distance between 2 points on the earth´s surface.

To use a gnomonic chart. Plot a straight line on the gnomonic chart. Take the latitude at each 5 degrees of longitude. Plot the various points on a Mercator chart.

20
Q

What is the difference between great circle and rhumb line?

A

A great circle is used for ocean navigation. A straight line drawn between two points on a gnomonic chart. Great circles intersect the centre of the earth and therefore Indicate the shortest possible distance between those two points.
A rhumb line is used for normal navigation. It can is a straight line drawn on a Mercator projection chart. As it cuts each prime meridian of longitude at the same angle. Distances can be measured on the latitude scale of a Mercator chart.

21
Q

What are the Datums used on charts?

A

WGS84. (Word Geodetic System 1984)

ETRS89. (European Terrestrial Reference System 1989)

22
Q

What are compass roses on a chart?

A

Indicate the magnetic variation. Used to transfer bearings

23
Q

What are routeing charts?

A

Each charted area contains 12 separate charts for each calendar month
Contains the following information
• Wind Roses. Statistical wind data
• Ocean Currents. Predominant direction & Average rate
• Ice Limits. Average limit of pack ice & Mean Iceberg limit
• Load lines. Limits of load line zones
• Shipping Routes. Distance between ports or End of Great Circle routes

• Chartlets for: Tropical storm tracks, Frequency of winds F7 and greater, Dew point temperature, Mean sea temperature, Mean air pressure, Mean air temperature, Fog, Low visibility

24
Q

What is nominal range of lights on a chart?

A

Nominal range. The range of the light in 10 NM of meteorological visibility.

25
Q

What are tidal diamonds? How would you use them?

A

Tidal diamonds are an accurate way of estimating the tidal set and rate at a given position. We first calculate our ETA at the position of the diamond. We then consult the tide tables for the primary port for each diamond table on the chart. Primary ports are given in block capitals. Noting the time of high water closest to our ETA, we can then use the tidal diamond table to pick off the set and rate for spring and neaps depending on the time of our ETA compared to the time of the nearest high water, +or- from high water. This information can be used to calculate courses to steer and to identify hazards at the appraisal stage.

26
Q

What is Dead reckoning and EP?

A

Dead reckoning. Estimation of where the vessel would be at a particular time if it were not affected by any external forces such as wind, current or tidal stream. It is found using only course steered and speed through the water.
Estimated Position. Estimation of the vessel’s position by the inclusion of tidal stream and leeway to the DR position.

27
Q

What are the Principles of Position fixing?

A
  • Regular intervals. The interval between should never be greater than half the time
  • Multiple methods. Do not rely on a single source
  • Be aware of limitations of electronic methods
  • Make use of transit
  • Use 3 position lines for visual bearings
  • Use the echo sounder
  • Use conspicuous fixed objects. Don’t use buoys.
28
Q

List the methods of position fixing

A
  • Dead reckoning and Estimated position
  • 3-point fix
  • Running fix
  • Vertical sextant angles
  • Horizontal sextant angles
  • Dipping distance
  • Radar range and visual bearing
  • Radar ranges
  • Parallel index
  • Echo sounder
  • Celestial
  • GPS
29
Q

How would you do a 3-point fix?

A
  • Identify 3 conspicuous points suitable for position fixing on the chart.
  • Take visual bearings of the conspicuous points using an azimuth mirror.
  • Convert bearings to True if necessary
  • Plot position lines on chart
  • The position is where the position lines intersect
  • If they do not all intersect at the same position, fix the position closest to the danger
30
Q

How would you carry out a range and bearing?

A
  • Identify a conspicuous point suitable for visual bearing and radar ranging
  • Take visual bearings of the conspicuous points using an azimuth mirror.
  • Convert bearings to True if necessary and plot position lines on chart
  • Take a radar range of the conspicuous point using the x-band radar.
  • Plot the range position line on the chart. Where the position lines intersect is the position.
31
Q

How would you carry out a running fix?

A
  • A running fix is used when there are limited conspicuous points available on the chart
  • Take first bearing of the conspicuous object and plot on the chart
  • Note the time, CTW and STW.
  • Take a second bearing of the same conspicuous object and plot on the chart
  • Chose any position in safe water on the initial position line
  • Plot the estimated position taking into account the effects of tide
  • Transfer the initial position line parallel through the estimated position
  • Where the second position line and the transferred position line intersect is the position fix.
32
Q

How would you derive a position fix using a vertical sextant angle?

A
  1. Identify a suitably charter landmark with significant height.
  2. Measure the vertical angular distance between the top of the object and the waterline
  3. Taking into account the height of eye of the observer, calculate the range from norries tables
  4. The range combined with the bearing gives a position fix.
33
Q

How would you derive a position fix using a Horizontal sextant angles?

A
  1. Identify 3 suitably charter landmarks
  2. Measure the horizontal angular distance between points A and B, and then immediately afterwards, between points B and C
  3. A line is drawn between A and B. Then from point A and B draw a line which is 90 degrees minus the HSA, to the line between A and B. Draw these lines to seaward. The lines will intersect at D.
  4. Draw a circle with its centre on point D and a radius of D to B or D to A.
  5. Follow the same procedure for points B and C to obtain point E and draw another circle.
  6. Where the 2 position circles intersect is the position fix.
    A station pointer can also be used for this purpose.
34
Q

How do you obtain a range using a dipping distance or Horizon ranges?

A
  1. Identify a suitable landmark with significant height.
  2. Note the height of the landmark above MHWS. Note the height of the observer.
  3. Calculate the distance to the horizon from Norries nautical tables
  4. Add both distances together to get a range from the landmark.
  5. This range positon line can be combined with a bearing to give the position.
35
Q

How can you use the echo sounder to obtain a position?

A

TBD

36
Q

Explain a clearing bearing and a transit

A

Clearing bearings are drawn leading clear from a conspicuous object. A ship on this bearing will pass clear of the danger
Transits. When two conspicuous can be seen on the same line they can be used as a leading line to indicate safe water.

37
Q

Explain how you would use Parallel indexes

A

Parallel indexing is a technique used as a measure to monitor the progress of a vessel on the track and to minimise the cross-track distance and to keep vessel at a safe distance from the shoreline or rock. An index line is drawn parallel to the planned ground track at a range equal to the desired perpendicular passing distance of a fixed radar conspicuous object. As the vessel proceeds along it´s course, the radar conspicuous object will pass along the index line. If any misalignment is evident between the radar conspicuous object and the index line this will indicate cross track deviation from the initial planned course.

38
Q

Describe the procedure for checking a chart is up to date on paper

A
  1. Check the bottom left hand corner of the chart and note the edition date and the latest corrections which have been applied
  2. Check the latest cumulative list of notices to mariners. And check the corrections which have been applied under the relevant cart number.
  3. Cross check the corrections between those noted on the chart and those listed in the cumulative list.
  4. Check the most recent weekly notices to mariner.
  5. Check section I for new editions which have been published since the last cumulative list
  6. Check section II for a list of small corrections going by the list of charts affected.
39
Q

Describe the procedure for checking a chart is up to date online:

A
  1. Check weekly cumulative list of notices to mariners.
  2. Search for the Ts and Ps separately.
    Cumulative list only includes the previous 2 years of corrections
40
Q

What would you action be if you find multiple charts not up to date?

A

Speak to the second officer

Generate a non-conformity

41
Q

Describe the procedure for applying a chart correction

A
  1. Find the correction to be applied
  2. Confirm the chart affected
  3. Verify previous update applied
  4. Apply correction to the chart
  5. Write the correction number on the chart
  6. Update chart correction log
42
Q

What are Temporary and Preliminary notices? How should they be applied?

A

Temporary notice. A change of a temporary nature. It will not result in a permanent change to the chart.
Advance notice of a change which will result in a permanent change to the chart.
They can be found in the following publications:
• Weekly notices to Mariners section 2
• Weekly notices to Mariners section 1 every month (full list of current notices in force)
• Annual summary of notices to Mariners supplement – reprint of all T’s and P’s in force on 1st January of that year.
Applied as follows:
1. Written on the outside of the chart in pencil
2. Plotted o the chart in pencil if necessary.
3. Filed in a separate folder

43
Q

What is contained in an admiralty notice to mariners?

A
  1. Explanatory notes. Publications list
  2. Updates to standard nautical charts
  3. Reprints of NAVAREA navigational warnings
  4. Updates to sailing directions
  5. Updates to list of lights and fog signals
  6. Updates to list of radio signals
  7. Updates to miscellaneous nautical publications
  8. Updates to digital products and services
44
Q

What is a cumulative list of notices to mariners?

A

Produced 6 monthly (January and July. Contains the following:
• Date of issue of the current edition of each navigational chart
• Subsequent relevant Notices to Mariners issued over the last 2 years
• List of current editions of all hydrographic publications

45
Q

Symbols and abbreviations

A

See NP5011

46
Q

Vertical chart datums

A

See diagram

47
Q

How would you update a UKHO publication?

A

TBD

Master (Yachts) < 3000GT Oral Prep (15 decks)

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