AMSA gives sound navigational practices In accordance with SOLAS Chapter V
AMSA has issued notice to draw attention to navigational practices that should be followed by masters and officers in charge of a navigational watch on ships operating in Australian waters.
Australia’s official nautical charts and nautical publications are issued by the Australian Hydrographic Service (AHS) on authority of the Australian Government.
Using appropriate charts
An appropriate nautical chart is one of a suitable scale for the navigational task at hand, noting that the scale determines the level of detail that is provided.
Smaller scale charts are used to depict large areas. They are suitable for overall voyage planning and ocean transit purposes. Small scale charts have reduced levels of detail on aids to navigation, dangers, coastal features and infrastructure (particularly where larger scale charts exist). Significant depth detail is omitted. This makes small scale charts unsuitable for navigation in areas less than 30 metres depth, adjacent to the coast or near charted hazards. Small scale charts show the limits and identity of larger scale charts. Whether in paper or electronic format, small scale charts are neither intended nor suitable for coastal navigation.
Large scale charts should be used when navigating closer to the coast, reefs and other offshore hazards. These charts cover smaller areas and provide more detail on depth, dangers, aids to navigation and coastal features. Generally, Australian charts provide continuous coverage at a scale of 1:150,000 or larger when navigating within 24 nautical miles of land or major offshore features (except in particularly remote areas).
For coastal navigation, including when navigating near charted hazards, the largest scale charts produced should be used.
When using Electronic Chart Display and Information Systems (ECDIS) with Electronic Navigational Charts (ENC), officers in charge of a navigational watch should be familiar with the use and operation of ECDIS and electronic charts.
Australian nautical charts
Australian (AUS series) paper charts are available from chart agents world-wide. The series is also partially reproduced by the UK Hydrographic Office (UKHO) and covers major Australian shipping routes and commercial ports. Mariners should refer to AUS charts 5000 and 5001 or the online Australian chart index at:www.hydro.gov.au for details of available AUS series charts. Mariners should not assume that chart coverage does not exist simply because it is not indicated in the British Admiralty chart catalogue or if the UKHO has not reproduced an AUS series chart.
The Australian (AU) series of ENC replicates the content of paper charts on a grid-based scheme of 1, 10 and 30 degree squares; additionally, there are separate ENCs for each port. These are available in Australia through the AusENC service, internationally through the UKHO’s Admiralty Vector Chart Service, as well as other services affiliated with the International Centre for ENC (IC-ENC). Details of available Australian ENC are provided at:www.hydro.gov.au
Full ENC coverage of the Australian charting area is now available, along with services to distribute and update these charts. The Australian Raster Navigation Chart service (which was established in 1997 as an interim solution) has been withdrawn since July 2014.
Chart accuracy and reliability
The accuracy and reliability of a nautical chart depends on the quality of hydrographic and topographic surveys and other relevant information, noting that charts are made up from diverse sources of supplied information of potentially widely differing quality.
Whilst all larger scale AUS paper charts carry a Zone of Confidence (ZOC) diagram, Australian ENC have a selectable layer containing Categories of Zones of Confidence (CATZOC). The ZOC diagram or CATZOC layer enables mariners to assess the limitation of the hydrographic data from which the chart was compiled and the resulting degree of risk associated with navigating in a particular area. A more detailed explanation can be found in Seafarers Handbook for Australian Waters (AHP 20).
Source:AMSA