Notices to Mariners Week 41

UKHO Permanent/Temporary/Preliminary and Trinity House

1. New Editions of ADMIRALTY Charts published 08 October 2020 – Chart 1606 – England – East Coast, Thames Estuary, Fisherman’s Gat to Princes Channel., Chart 1607- International Chart Series, England – East Coast, Thames Estuary, Southern Part., Chart 1609 – England – East Coast, Thames Estuary, Knock John Channel to Sea Reach. – Includes changes to depths from the latest British Government and Port of London Authority surveys. Note: On publication of these New Editions former Notice 1620(P)/20 is cancelled. – Ntm 1620(P) was issued in Week 13 this year. An extensive preliminary notice of 13 reduced depths and 10 new drying heights in the southern part of the Thames Estuary: 7 changes in and around the Long Sand and Tizard Bank, 11 changes on the Shingles and the Ridge Sand and Pan Sand (sound of the Princes Channel), and 5 changes on the Margate Sand. Some of the changes are dramatic but are generally not in the usual routes for leisure craft.

2. ENGLAND – East Coast – Buoy. – This notice is UKHO confirmation of local NtM about the location of the replaced Ray Sand special buoy. The Ray Sand has been moved so see the image either on my download or in the NtM page Notices to Mariners Note in the image includes the amended position of the Ray Sand Middle (changed earlier this year) and the location for one of the Patrac seabed monitoring equipment collecting data for the new Bradwell Nuclear Power Station.

3. BELGIUM – Lights. – The three MOW beacons; MOW1, MOW2 and MOW3 off Zeebrugge have been changed lights from yellow to white. Otherwise no other changes.

4. EAST COAST OF ENGLAND – APPROACHES TO LOWESTOFT – STANFORD CHANNEL – SOUTH HOLM LIGHTED BUOY – The South Holm cardinal buoy (South of Lowestoft) has been moved south – probably in consequence of NtM 772 earlier this year. See the image and notice for position. Worth noting if you go that way.


1. Port of London Authority – NEW STRUCTURE – HARBOUR MASTER’S TEAM – With more challenging times ahead, we have restructured the Harbour Master’s team to create a more flexible, efficient and resilient team covering the ‘whole river’ rather than the historic focus on upper and lower districts. The accompanying organisation chart shows the new structure which was put in place on the 1 September 2020. The upper, middle and lower districts will still exist for Vessel Traffic Services, Notice to Mariners, etc. There will continue to be a Harbour Master presence in Pinnacle House, our London office and several of the team will be based there, although there will be greater flexibility, with coverage along the river provided by all team members. Individuals’ telephone numbers and email addresses remain unchanged and the generic Upper District and Lower District email addresses remain in use.
The organisation chart provides the detail of the new structure and can be downloaded on the Temporary List in the above quote web page.

2. All COASTS OF ENGLAND AND WALES – DISCONTINUATION OF GENERAL LIGHTHOUSE AUTHORITIES DIFFERENTIAL GLOBAL POSITIONING SYSTEM (DGPS) TRANSMISSIONS. – Vessel owners, operators and masters are advised that, after careful consideration of the results of a comprehensive user consultation process, the General Lighthouse Authorities for the UK and Ireland have concluded that their Differential Global Positioning System (DGPS) is no longer required and have made the decision that the system will be discontinued from 31st March 2022. The (DGPS) Service for UK and Ireland was established at a time when the publicly available GPS signal was intentionally degraded, resulting in large position errors. Augmentation was necessary to correct for these errors and meet minimum requirements for maritime positioning and navigation. In the year 2000, the intentional error in GPS positioning was removed. Since then, system technology has
improved and the GPS constellation has been modernised. Observed positional accuracy for unaugmented GPS now consistently meets IMO requirements for accuracy around the coast of the UK and Ireland for marine navigation.
How will the discontinuation impact you?
For the vast majority of maritime users, the discontinuation of DGPS service for the UK and Ireland will not impact the accuracy of satellite positioning. DGPS receivers will no longer receive the DGPS signal in areas where it was previously available. This may generate a ‘lost signal’ alarm, but receivers will still provide a GPS derived position.
Alternate sources for high accuracy positioning
Other options are available for obtaining higher accuracy positioning in the UK and Ireland. Further Navigation Warnings will be issued when the above changes take place.

3. Paglesham Fairway No 1 Lighted Buoy, River Roach – NAVIGATION – Mariners are advised that Paglesham Fairway No 1 Lighted Buoy is back on station.

4. (Updated 23.09.2020) – Medway Approach Channel – No.1 Light Buoy Off Station – Notice is hereby given that: Medway Approach Channel No.1 buoy: a temporary buoy with the same light characteristics has been placed on station, A cancellation notice will be issued as soon as the original No.1 buoy is back on station.

5. (Updated 28.09.20) – RIVER MEDWAY – MEDWAY APPROACH CHANNEL – SS RICHARD MONTGOMERY WRECK SURVEY – NOTICE IS HEREBY GIVEN that due to delays caused by adverse weather conditions the survey of the Richard Montgomery wreck is now due to be complete on or around the 4th of October 2020.

You can see the full details of those two updates but scrolling down the Temporary List.

6. Port of Rochester – Rail Bridge Inspections – On the 11th of October 2020 between 0800 – 1800 there will be an inspection of the Rochester Rail Bridge structure which will cause some disruption to river traffic. The bridge investigation work will be carried out by rope access teams and will be completed in two stages. Span closures will be imposed whilst inspections are underway and two safety boats will be deployed beneath operational areas to police traffic, the safety craft will be monitoring VHF channel 74 at all times. Further information may be obtained from Medway VTS on VHF Channel 74, call sign “Medway VTS” or telephone 0151 949 6148. Image on the Temporary List.

7. RIVER MEDWAY – SALTPAN REACH – ISLE of GRAIN JETTIES 6 & 7 – Inspection Work – work to inspect the cathodic protection on Isle of Grain Jetties 6 and 7 is due to commence 5th October 2020. For approximately one week ‘CPCL’ will be working from a safety boat on the waterline around and underneath the jetty structures to complete the following:
Checks on the Transformer rectifier unit
Junction box monitoring
Recording of all Anode and Pile potentials survey
The safety craft will be monitoring VHF channels 74 & 16 at all times, vessels should pass Jetties 6 & 7 with caution, minimise their wash and maintain a listening watch on VHF Channel 74.

8. Port of Wells – Dredging – dreging – dredging……

9. London Array Wind Farm has issued a local NtM about Diving Operations but – as usual – getting the Notice is pretty impossible. I have put in the usual request……:censored:

Local NtMs compiled by and reproduced by kind permission of Roger Gaspar, author of Crossing the Thames Estuary