GovWire

Hydrographic notes

Please notify us if you discover or suspect any of the following by submitting the appropriate Hydrographic note.

• New dangers to navigation
• Changes in aids to navigation
• Errors in any navigational publication.

The Mariners Handbook (NP 100) Chapter 8 contains details of the information youll need to send. If practicable you should also contact the originating hydrographic office when navigating on IMO-approved non-UKHO nautical charts. Please also comply with national and international law when forwarding such reports.

If giving the information on paper please use either the version below or that included in NP100. NP100 will be updated with these later versions at the next edition.

H-note forms

Supporting information

Chart images and photographs - sent either with the hard copy or as attachments to the electronic copy - will help us to clarify your report.

Any format is acceptable. Those most commonly used are Word, Excel, JPEG, TIF, and AutoCAD. File sizes of the hydrographic notes range from approximately 61Kb to 70Kb; however the size of a returned email would depend on any additional attachments that have been made.

Email your completed form to sdr@ukho.gov.uk or fax it to: +44 (0)1823 352561. For urgent information fax to +44 (0)1823 322352 or send by email.

Once weve received and processed your data, well acknowledge receipt of it by post or email.

How to propose a hydrographic survey

Survey areas are prioritised using a risk analysis methodology but the Maritime and Coastguard Agency (MCA) also welcomes recommendations for areas needing assessment. Send your suggestions to navigationsafety@mcga.gov.uk

Typical indications of an area requiring a new survey

• Old underlying survey data (check using the source data diagram on the latest chart)
• A change in traffic patterns (eg, increases in cruise ship visits)
• An accident occurring due to inaccurate or incomplete survey data
• Changes to the seabed due to sand-wave movement / channel migration

Use of third party data on a nautical chart

If you are involved in producing or commissioning hydrographic surveys, then the UKHO would like to use them in the compilation of a new nautical chart which will help improve the safety of mariners.

You dont need to carry out your survey to full charting standards for it to be of use. Even without a full search for dangers, a modern survey can increase our knowledge of the seabed.

Our Bathymetric team is always happy to give help and advice on the requirements for gathering hydrographic data. You can contact them via BathyQueries@UKHO.gov.uk.

Share your bathymetric data

If you have bathymetric surveys you wish to share to the UKHO, this can be done via our UKHO Data Upload service.

Through this service, you can easily upload bathymetric data, provide supporting information and view previously submitted surveys.

Visit https://ukhodataupload.admiralty.co.uk/ to start using the service.

The minimum information required

• A copy of your final survey drawing and / or final digital dataset. The digital data may be in a simple ASCII xyz (latitude, longitude, depth OR grid E, grid N, depth) format. The drawing can be in hard copy, but we would prefer a digital file if possible (.tif, .pdf or CAD)
• If the data has been passed through a gridding or binning process to produce the final drawing or dataset, then a copy of the pre-gridding dataset would be beneficial. Gridding and some binning techniques may cause the shoal depths to be lost
• A note of the horizontal datum to which the positions are referred (or the grid, if appropriate)
• A note of the tidal datum to which the depths have been reduced
• The soundings should preferably be reduced using observed tides (not predicted tides from tide tables)

This basic level of information will enable us to accurately position the data and adjust the depths as necessary to chart datum. We can render surveys to this standard from scientific, environmental, engineering and similar projects without adding significantly to the cost of the work.

A metadata form listing the required and preferred information can be downloaded and rendered with data to ensure that we have all the necessary information.