INSTRUCTIONS:
Mariners are requested to notify the Australian Hydrographic Office (AHO) when new or suspected
dangers to navigation are discovered, changes are observed in aids to navigation, port infrastructure,
or corrections to publications are seen to be necessary. The mariner can also report any ENC display
issues experienced. The Mariner's Handbook for Australian Waters (AHP20) and the Mariner’s
Handbook (NP 100) give general instructions. The provisions of international and national laws should
be complied with when forwarding such reports. The Hydrographic Note may be forwarded to:
Postal:
Hydrographer of Australia
Locked Bag 8801
Wollongong NSW 2500
E-mail:
datacentre@hydro.gov.au
W
hen submitting a report it may be worth noting:
• Reports which are incomplete or lacking detail should still be submitted - some information is
far better than no information, and may contribute to preventing a significant accident.
• Photographs of the observed feature in support of brief written notes are a most effective
means of providing detailed information quickly and simply.
Similarly, a screen capture or
photograph of the navigation screen may be equally effective if accompanied by an
explanation.
Simply attach an image to the email generated by the submit button.
•
Marked copies of charts and publications may also be a convenient way of passing information.
All still need to be supplemented by location and sender details. Any marked-up original paper
charts used for this purpose will be replaced upon request.
• If submitting an echo sounder trace, an output file from the echo sounder, or quoting an
observed depth measured by an echo sounder, the notes should include the date and time of
observation, and whether the echo sounder on the vessel is set to read from the keel or
waterline. If reading from the keel, the vessel’s draft is helpful in calculating the true depth. Dat
e
and time of observation are useful in adjusting the measured depth for tide, while the speed of
sound is also useful if known (a default value of 1500 metres/ sec is common) to refine the
measurement further.
Modern echo sounders frequently have the ability to record the passage to
hard disk. If the electronic data is available for submission, then the sounding files will typically have
each depth tagged with date, time and position (in any order). Typically these can be exported as an
ASCII (plain text) file and supplied via digital media or emailed with the report.
• I
t is possible that in deeper water an echo sounder can go ‘around-the-clock’ and show a
shallow false return, or receive strong returns from fish or abnormal water layers. If possible,
depths should continue to be recorded until general agreement with surrounding charted
depths is restored. If unsure, please send the information anyway.
•
Latitude and longitude should preferably only be quoted for the position of a feature if the position
was determined using a Global Navigational Satellite System (GPS, GLONAS). If the position was
determined by a combination of ranges and bearings (true or magnetic being specified) fro
m
obs
erved features please include the ranges, bearings and features as part of the notes.
• R
eports of uncharted shoal depths, as well as navigation aids out of order should, at the
mariner’s discretion, also be made by radio to the nearest coast radio station or the relevant
port authority. The draft of modern tankers and bulk cargo vessels is such any observed shoal
depths in general depths of 30 metres or less may be significant, particularly as the observed
depth may be at the edge of a much shallower feature.
Note: An acknowledgment of receipt will be published and the information then used to the best
advantage which may mean immediate action or inclusion in a revision in due course. When a Notice
to Mariners is issued the sender’s ship or name is quoted as the authority.
