Notices to Mariners - Week 20

[tillergirl]

UKHO Permanent/Temporary/Preliminary Notices

1. ENGLAND - East Coast - Depths. - 4 reduction of depth off the jetties of the West Tilbury Power Station and Sewage Works. Unlikely to be a place we would go!
2. NETHERLANDS - Legend. Note. - A new ‘changeable depths’ warning in the Siljkgat (off the Goeree, Dutch coast) and accompanied note i.e Depths likely to change!
3. ENGLAND - East Coast - Depth. - One reduction of depth right in the middle of the entrance to the Tilbury Lock.
4. NETHERLANDS - Buoy. - A temporary new south cardinal buoy established in the Oostgat channel (off the Zouteland, Dutch coast).
5. ENGLAND - East Coast - Works. - The Kingsnorth Power Station on the banks of the Medway has been demolished.

Local

1. Burnham Fairway No 2 Lighted Buoy - NAVIGATION - Following consultation between the Crouch Harbour Authority and Trinity House Mariners are advised that the Burnham Fairway (Red) No 2 Lighted Buoy in approximate position: 51° 37.264’N, 000° 48.862’E has been permanently withdrawn.
2. Dredging Operations - Medway Approach Channel & Chatham Lock Approaches - dredging operations are due to take place in the Medway Approach Channel and Chatham Lock Approaches. Work will commence on 8th May 2021 with completion expected on or around 10th May 2021. Dredging operations will be carried out by the water injection dredger ‘Maas’ who will display the required signals for respective operations by day and night, all vessels are requested to pass with caution and minimise their wash. Dredging in the Medway approach channel will be conducted over 3 tides and will be concentrated in the area to the south of the channel between No.4 and No.8 buoys. Dredging in the approaches to Chatham locks will be conducted over 2 tides. Admiralty Chart No’s. 3683 & 1835 refer. Further information may be obtained from Medway VTS on VHF Channel 74, call sign “Medway VTS” or telephone 0151 949 6148.
3. Port of Wells dredging
4. London Array Wind Farm - Works this week include: Safe distances within the Offshore Wind farm:
• A 50m radius advisory caution zone is established around each wind turbine and offshore sub-station platform (Permanent)
• A 100m exclusion zone will be in place during rope access operations.
• A 150m exclusion zone will be in place when dive support vessel moorings are deployed at WTG’s
• A 500m exclusion zone will be in place during dive operations.
The locations are NOT specified. There are 4 mooring buoys temporarily laid marked with a yellow buoy and Orange 5s light. There are two adjacent to Fisherman's Gat (out of the way) - see the chartlet showing the position in the Local List on: Notices to Mariners

That's it.

 

[PeterWright]

Hi Roger,

Thank you again for your diligent contribution to the safety of us all.

I must say the frequency of additional restrictions to the normal in the London Array makes me question yet again how they were allowed to build so many turbines right next to Foulger's Gat. The dog leg they have built into the marked route through their forest is bad enough but the enhanced exclusion zones arising from entirely foreseeable maintenance requirements will make passage through there in poor visibility next to impossible if the exclusion zones are around any of the turbines next to the Gat.

Peter.

 

[tillergirl]

I suppose the 'planner' (whoever they were) were balancing the needs of 'clean' energy against a few hundred leisure users a year. I cannot understand why a dogleg was created. Moving one turbine would have created a free bottom opening to Foulger's Gat. But there it is.

I find it frustrating that once the Farm got into normal regular operation, information from them has been less helpful. During the build I was on an email notification list for all of their NtMs - which was very helpful, and there was also a weekly update on progress. Now, the notification list has stopped... or at least I have been deleted and cannot get reinstated. There is an on-line weekly Notices of Operations where I got the above but there have been two actual NtMs that are not published. There is a button on the website for the NtMs but that takes one straight back to the Notice of Weekly Operations. I assume the NtMs would actually provide the locations of the maintenance if only it was publicly published.

I note this week extended the divers exclusion zone from 250m to 500m. In theory one exclusion zone in the Gat would still leave it open, two opposite would close it.

 

[PeterWright]

Hi Roger,

I share your view on the dogleg. I have heard that it was created to move the S end of the gat further east to prevent craft using Fisherman's get being confused by the Foulger's buoy. If that's true, it would be unfair to blame the wind farm folk and seems to be a case of seeking perfection making things worse. There was, I understand a lengthy consultation which included PLA and the RYA before the layout was finalised.

In my mind, closing off half the gat is bad enough for a sailing vessel in poor visibility, the wind may be such that you can only just lay the course, or you may even need the odd tack, If they don't make public which turbines they are working on, how are we to know where the exclusion zones lie?

Peter.

p.s. Much of the above is negated by the Wind Farmers giving Roger a very helpful reply reported under Roger's thread on Foulger's Gat Maintenance. P.

 

[tillergirl]

As to the question of where the exclusion zone(s) lie, the only answer is listen to any Ch 16 warning and to call up any LA vessel. Which then brings up the issue of how often is the warning broadcast to be broadcast? And will they broadcast warnings about any turbine or just those bordering the Gat and dogleg?
So do we know all the turbine numbers either side of the Gat and dogleg. If someone wants to note down the relevant turbines, they are:

Affecting the diving and requiring a 500m exclusion zone: A13, B13, B15, C17, D17 & D19
Affecting 'roping' requiring a 100m exclusion zone: A10, A13, B10, B11, B13, C15, D17, E19 & E20.. Frankly we would all stay away more than 100m from any turbine wouldn't we?

 

[tillergirl]

And now this afternoon the 'Mooring deployment and exclusion zone radius' was updated to 250m from WTG. The link in the above quoted page has been updated.

 

[PeterWright]

I note that they use positions of their turbines plotted on a chart with the old Foulger's Gat buoys on their NtMs. Can't they afford to by a new chart and plot them on that, so we can see the relative positions of the turbines and the buoys? Perhaps I'm just getting to be a Grumpy Old Man.

Peter.

 

[tillergirl]

A tad grumpy ... but nuffin wrong with that. In fairness the peeps probably don't have the easy graphic tools. Does this help:

London Array for Divers work by Roger Gaspar, on Flickr

Turbines affected by the Diving 500m exclusion zone now in 'magenta'. (the 4 temporary mooring buoys now added - I will ignore the 'roping' works.)

That can now be downloaded on the Local Authority List on Notices to Mariners

Is it clear enough? The image is getting a little 'busy' so show differences without making a mess.

 

[PeterWright]

Hi Roger,

That's just brilliant. I had already noted that your chartlet plots the turbines and the current buoyage, which is the level of precision I have come to associate with your very professional volutary work. Is it too much to expect those who are making considerable sums of money from operating these turbines to work to a similar standard? If they don't have the tools, they could easiiy enough buy them! Perhaps there's a business opportunity for you there to offer London Array to prepare their NtMs properly.

I'm sorry if my question caused you extra work to recolour the turbines they plan to work on, that was not my intention.

Peter.

 

[tillergirl]

No, no extra work. Given the works will last for 6 months 'aka the season', I planned to do an update to my readers on the Update list and the official notice image was clearly 'hopeless' and needed something better. Changing the colour was a matter of a few minutes.