Attachment_3_-_Precautions_in_using_navigational_charts_in_Greenland_waters.pdf

INTERNATIONAL MARITIME ORGANIZATION

IMO

E

SUB-COMMITTEE ON SAFETY OF

NAVIGATION

55th session Agenda item 20

NAV 55/INF.6

21 May 2009

ENGLISH ONLY

ANY OTHER BUSINESS

Precautions in using navigational charts in Greenland waters

Submitted by Denmark

SUMMARY

Executive summary: This document provides information regarding precautions in use of navigational charts in Greenland waters in terms of inaccuracies in paper charts due to incorrect positioning of the coastline, geographical datum and hydrographic survey. Further, this document informs of precautions regarding the use of electronic navigation in Greenland coastal waters.

Strategic direction: 5.2

High-level action: 5.2.4

Planned output: ‐

Action to be taken: Paragraph 35

Related documents: MSC 86/3; SN.1/Circ.276, SN.1/Circ.255, SN/Circ.213, SN.1/Circ.207/Rev.1 and MSC/Circ.1056

Introduction 1 At its eighty-sixth session, the Maritime Safety Committee is expected to adopt a carriage requirement for an Electronic Chart Display and Information System (ECDIS) for SOLAS vessels with an implementation period from 2012 to 2018. In this context, Denmark has found it essential to provide guidance on navigation in Greenland waters in the light of the still limited coverage of Electronic Navigational Charts (ENC) in these waters in 2012 and ahead.

2 Greenland covers a large Arctic area (2,127,600 km2) and is navigationally considered a remote area. The distances between the settlements in Greenland are large, and the consequences of an accident may be greater in Greenland compared to more densely navigated waters, where search and rescue facilities are seldom far away. In addition to this, an accident could have a serious impact on the vulnerable Arctic environment.

For reasons of economy, this document is printed in a limited number. Delegates are kindly asked to bring their copies to meetings and not to request additional copies.

3 Navigation in Greenland waters differs significantly from navigation in other (non-Arctic) waters. In general, it is difficult for mariners who are not familiar with the conditions to navigate around Greenland. It is, to a high degree, due to the climate and the influence of the weather.

Furthermore, instruments such as magnetic compasses may be unusable and gyrocompasses may be unreliable.

4 In waters with more frequent maritime traffic, markings and other navigational systems have normally been established to assist mariners. Due to the remote Arctic location and the historically low density of maritime traffic, the assistance offered to mariners in the form of charts within the scope of relevant IHO standards and other facilities has not reached the same level in Greenland. Furthermore, floating markings are not an option due to ice conditions and great depths.

5 In addition, systematic and completely covering hydrographic surveys have not been carried out in many areas along the coasts of Greenland due to the wide extent of the sea area and the Greenland archipelago. In other words, depth conditions will be unknown or depth data will be of poor quality in large areas. For mariners it is essential to understand the limitations in the source material providing the basis for the production of paper charts and, consequently, the information given in the paper charts must be interpreted with caution.

6 Modern navigation is based on Global Navigational Satellite Systems (GNSS) as, e.g., GPS. The continuous marking of the ship.s position on an ENC in the ECDIS system is made by means of GNSS. Positions obtained from satellite navigation systems refer to World Geodetic System 1984 (WGS 84) datum.

7 The use of ECDIS in Greenland waters requires the availability of ENCs which refer to WGS 84 datum and are produced with a correct positioning of topography, including coastline, and hydrography in the geographic net. At present, ENCs are not available for Greenland coastal navigation, except for a very few exceptions.

8 In Greenland coastal waters, the inaccuracies in the present paper charts could endanger safety of navigation if the navigator relies on satellite based electronic navigation instead of the use of terrestrial navigation.

Navigation in Greenland waters in terms of inaccuracies in paper charts

9 At present, the paper charts available for Greenland waters are not compatible with GNSS navigation, as, e.g., GPS, for several reasons.

10 Incorrect positioning of topography and hydrography in the geographic net. A major difficulty with the paper charts available for Greenland waters is the incorrect positioning of the coastline in the geographic net in the charts. At the northern and eastern coastlines where the uncertainty is most distinct, the coastline may be positioned several nautical miles incorrect. In other parts of Greenland, the uncertainty may be less, but still at a substantive level when comparing with the accurate position achievable from a GNSS receiver. In general, charts of the northern and eastern Greenland coastlines are misplaced by 0-5,000 metres, and in some areas of the extreme northeast Greenland even more. Charts of the west Greenland coastlines are misplaced by 0-1,000 metres.

11 Due to this fact a note has been inserted in the paper charts covering the Greenland west coast, stating, e.g., Due to age, quality and some of the source material, it must be expected that positions obtained from satellite navigation system are more accurate than those on this chart.

12 In the paper charts covering the Greenland east coast, the following note is found: The difference between satellite-derived positions and positions on this chart cannot be determined;

mariners are warned that these differences MAY BE SIGNIFICANT TO NAVIGATION and are therefore advised to use alternative sources of positional information, particularly when closing the shore or navigating in the vicinity of dangers.

13 Conclusion: In the paper charts available for Greenland waters, the positioning of the information in the charts (i.e. topography, including coastline, and hydrography, etc.) is inaccurate, which means that ships cannot navigate safely by means of satellite navigation on the basis of the present paper charts.

14 It is important to emphasize that, despite the inaccuracies of the paper charts; it is possible for ships to navigate in coastal areas if they use their radar equipment as the primary positioning instrument and rely on terrestrial navigation methods when navigating in Greenland waters.

15 Chart datum. The paper charts available for west Greenland waters are produced in the geographical datum .Qornoq 1927.. On each paper chart a note has been inserted giving the correction to be used if positions are obtained from a satellite navigation system, such as GPS, which refers to WGS 84 datum. This could state, e.g., Positions obtained from satellite navigation systems refer to WGS 84 datum; they should be moved 0.08. northward and 0.25 westward to agree with the chart.

16 For paper charts covering northern and eastern Greenland waters, the source material for chart datum may be unknown.

17 It is important to notice that the correction may vary from one chart to another and the correction is only to be used if the GNSS receiver has not been pre-selected to the .Qornoq 1927.

datum.

18 The use of the geodetic datum .Qornoq 1927. instead of the WGS 84 may have the following effect for Automatic Identification System (AIS) which relays the ship.s position signal from a GNSS receiver. It can get this information in two ways: From an external or a built-in receiver. AIS with an internal receiver transmits the ship.s position in WGS 84 coordinates. AIS with an external receiver can transmit the ship.s position in WGS 84 or in Qornoq 1927. This can give rise to misunderstandings and misinterpretations when AIS is used for anti-collision purposes.

19 Conclusion: GNSS should be used only as a secondary positioning instrument, and if used as such, mariners must be aware of the necessary correction between the reference chart datum in the paper charts and the information received from GNSS.

20 Hydrographic survey. IHO Special Publication No. 55 Third Edition (2004) on status of hydrographic surveying and nautical charting worldwide, latest update of 8 May 2009, states the following for Greenland: .The coastline of Greenland is very complex and the total sea area of the EEZ is ca. 2,000,000 square kilometres. Due to permanent ice cover, the limit for navigable waters has been set to 75 degrees northern latitude. The east coast is sparsely populated and only surveyed near populated areas. A prioritised programme is in force to resurvey navigable routes to and between populated areas on the west coast of Greenland, to modern standards..

21 The lack of survey data or its poor quality is reflected in the charts by, e.g., waters where depths are given only by passages of reconnaissance lines or even as white unsurveyed areas in the chart. Attention is also drawn to the fact that source diagrams are lacking in many of the paper charts available for Greenland waters. The basic lack of IHO compatible survey data for chart production should make ships keep an additional safety distance when passing underwater rocks and obstructions.

22 Unfortunately, it will be many years before all areas have been surveyed or re-surveyed and all paper charts revised accordingly. Until then, mariners should remain cautious to the dangers mentioned in this document.

Caution to be taken before navigating in Greenland coastal waters

23 In summary, at present caution must be taken in consideration that:

- official ENCs are not available for coastal navigation;

- only paper charts are available for coastal navigation, but these are not compatible with GNSS navigation;

- paper charts have incorrect positioning of coastlines in the geographic net;

- chart datum .Qornoq 1927. is used for some areas, mostly at west Greenland, instead of WGS 84 datum;

- for other areas, mostly north and east Greenland, the source material for chart datum may be unknown and the accuracy may be affected by the age and quality; and

- hydrographic surveys may be sporadic and areas may be considered as unexplored. In some areas, depths are only given by sounding tracks from passages of a reconnaissance nature.

24 Since official ENCs are not available for coastal navigation, voyages conducted primarily by means of GNSS navigation should not be chosen as a solution at present.

25 Furthermore, it must be noted that digital raster navigational charts (RNC-charts) used in an approved ECDIS or an Electronic Chart System (ECS) are not considered an acceptable method for safe navigation. In the case of Greenland waters, raster charts will have been produced by means of digitalization of paper charts and will, consequently, have inherited the topographic and hydrographic inaccuracies of paper charts.

26 Even if a position obtained from a GNSS receiver is corrected to the datum of the paper chart, where available, the navigator cannot trust the inserted GNSS-position in the paper chart due to the inaccurate positioning of the coastline in the geographic net.

27 It is important to be aware that terrestrial navigation, including the use of radar navigation, gyro, log, echo sounder and visual input, is the best method for conducting safe navigation when satellite navigation becomes uncertain. Paper charts and nautical publications become primary sources when planning and conducting a safe voyage. Terrestrial navigation will be relative to the surrounding coastline when using radar and visual observation methods.

Present status and future developments of nautical charts for Greenland waters

28 Guidance to mariners on navigation in Greenland is generally given by publishing official nautical charts, nautical publications and Notices to Mariners.

29 The nautical charts available for Greenland waters include paper charts, port plans and, in very few cases, electronic navigation charts (ENC). Today, Greenland waters are covered by 94 paper charts of various scales, while only 4 ENCs have been produced by early 2009.

ENC coverage is, consequently, a long-term process, which has only just begun.

30 In 2006, the Danish Hydrographic Office launched a project with the purpose of producing improved paper charts in terms of the geometric precision of the paper charts (i.e. topography, including coastline, and hydrography, etc.). In addition to this improvement, the paper charts will also be transformed into WGS 84 datum. In the improved paper charts, the coastline will be provided with a degree of precision that makes the use of satellite navigation sound and secure.

31 It is expected that ENCs corresponding to the improved paper charts will be produced and published as an ongoing process ahead. Among the ENCs published, ENCs in usage band overview (corresponding to scale 1:3500000 for sea passage) are expected to be published before 2012. Navigational and hydrographic information will be much simplified or completely left out in areas close to land. Consequently, it will only be possible to use these ENCs in usage band overview for navigation in open waters.

32 Conclusion: At present ENCs are not available for Greenland coastal navigation, except for a very few exceptions. It is expected that the ENC coverage will be continuously improved, but complete ENC coverage in coastal areas cannot be expected in 2012. In coastal areas, ships will therefore as a general rule have to use paper charts for navigation.

Recommendations on charts, ECDIS and voyage planning

33 Before planning a voyage to Greenland, the following IMO guidelines and resolutions should be consulted further in addition to the ordinary use of paper charts and nautical information:

• SN.1/Circ.207/Rev.1 on Differences between RCDS and ECDIS;

• SN/Circ.213 on Guidance on chart datums and the accuracy of positions on charts;

• SN.1/Circ.255 on Additional guidance on chart datums and the accuracy of positions on charts;

• SN.1/Circ.276 on Transitioning from paper chart to ECDIS navigation;

• Resolution A.893(21) on Guidelines for voyage planning;

• Resolution A.999(25) on Guidelines on voyage planning for passenger ships operating in remote areas; and

• MSC/Circ.1056 on Guidelines for ships operating in Arctic ice-covered waters.

These guidelines and resolutions and other IMO guidance material can be downloaded from the IMO website, www.imo.org.

Planned Safety of Navigation (SN) circular

34 Denmark will, before the implementation date of the new carriage requirement for ECDIS, forward a Safety of Navigation circular to the Organization providing the latest information on chart availability and quality for Greenland waters.

Action requested of the Sub-Committee

35 The Sub-Committee is invited to note the information provided.