An Admiralty Notice to Mariners (NM) is an update or alteration to a marine chart to ensure that the best information is available for the safe and effective planning and navigation of voyages.
Every year the United Kingdom Hydrographic Office (UKHO) issues over 5,000 NMs which allow mariners to update their charts with the latest safety-critical information.
Each NM is compiled using the same highly reliable data as that used to produce the regular Admiralty nautical charts, and mariners are kept up to date via the weekly online Leisure Notices to Mariners service on the UKHO website: www.ukho.gov.uk/leisure
Many leisure mariners, in believing that “rocks don’t move,” tend to overlook the importance of chart updates. However, changes in buoyage and lights, new wrecks, temporary obstructions or changes in depth to rivers and estuaries are all examples of updates to charts that are critical for safe navigation.
Updating is easy and there is advice on how to do this on the UKHO website, from using pens direct onto the paper charts to the pasting and imposition of colour blocks. The updating of Memory-Map marine charts is just as simple.
First, if you’ve not done so already set the co-ordinates in Memory-Map to display as Lat/Long using the Mode > Position Format > Lat, Long > Deg, Min setting.
Then use the Mark button to place a mark on the screen and drag or edit the properties to put it in the right place. The properties box also allows you to change the name, symbol and add notes.
Finally, we recommend ticking the ‘Locked’ box to lock the mark in position so you don’t then accidentally drag it to the wrong place some time in the future!
Before updating you should determine if the NM is applicable to your chart and vessel. You may decide that it isn’t relevant; for example, changes to a very deep sounding or a new cable in very deep water are not necessarily of interest to the leisure mariner. You should also be aware that NMs are applicable only to current editions and charts, and not past editions.
Be safe on the water this summer with up-to-date nautical charts. The intuitive and easy to use software with Memory-Map digital marine charts can be used on your PC, iPhone, iPad or Android device. The complete folio of over 850 high quality raster charts covering all of the UK, Ireland and the Channel Islands is sourced from data obtained from the UKHO and look identical to the paper charts you use on board.