ADMIRALTY Hydrographic Notes

Hydrographic Notes

​Hydrographic Notes allow you to inform us of any navigationally significant information. This information could include new or suspected dangers, changes to navigational aids, amendments to details included in publications and suspicious charts or publications that could be counterfeit.


These can be sent in paper format (as outlined below) or sent using the ADMIRALTY H-Note App.

For emergency information affecting safety of life at sea, forward to:

Alternatively, contact T:+44 (0)1823 353448 (direct line) or F: +44 (0)1823 322352.

What to include in Hydrographic Note submissions


The Hydrographic Note forms below contain information to help you complete any submission. These details are also included within Chapter 8 of the Mariner's Handbook (NP100). Please note that you should also contact the originating hydrographic office when navigating on IMO-approved, non-ADMIRALTY nautical charts.

Find out more about the Mariner's Handbook (NP100)

Please email your completed form to: For urgent information contact our Customer Services team: +44 (0) 1823 484444.

Once we’ve received and processed your data, we’ll acknowledge receipt of it by post or email.

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 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.

ADMIRALTY Hydrographic Notes

H-Note App

The ADMIRALTY H-Note App helps you to send the UKHO reports on suspected dangers to navigation or changes observed in aids to navigation using a mobile device. Free to download and easy to use, the application takes advantage of your mobile’s built-in camera and GPS to help gather important navigational information and to email it to the UKHO once your vessel is in a Wi-Fi or cellular coverage area.


When you submit an H-Note via the App, you will receive an acknowledgement. The information you send will be used by the UKHO to take immediate action or considered for use in the next appropriate revision of a chart or publication.

Download the H-Note App Legal Agreement

Download the H-Note App Privacy Notice

Downloading the H-Note App


The H-Note App is available for free for iOS devices (iPhone, iPad and iPod touch) and Android devices. It can be downloaded from the app store links below: 

Download the H-Note iOS App on the App Store

Download the H-Note Android App on the Google Play store