Notices to Mariners Week 46 plus a warning regarding the SW Sunk Swatchway

[tillergirl]

Permanent

A block amendment to UKHO Chart 2052 (Orford Ness to the Naze) showing the relevant new changes to buoyage at the Inner Sunk (as already notified in the CTTE download).
A 'foul' 10nm ESE off Southwold Harbour in 20m so unlikely to hinder leisure craft.

Temporary

Withdrawal of the Harwich Harbour and environs seasonal marks.

From Me

I have been notified by a Burnham based yachtsman that on 14th October while following the recommended track across the SW Sunk that they touched several times around the centre part of the sands. As they draw 1.5m and it was half tide, this suggests that the 2m depth I found there in early June has changed to drying 0 or 0.1m! I am laying up this week (and anyway the winds are too strong to poke around down there at the moment) so a re-survey will have to wait until the earliest moment I can do it next Spring. We somply do not know if the swatch has migrated to the north-east or filled.

 

[NUTMEG]

Thanks for posting mate.

I wonder what could cause the Sunk to fill? Weather, wind farm sediment disturbance or a Kraken?

 

[sailorman]

Thanks for posting mate.

I wonder what could cause the Sunk to fill? Weather, wind farm sediment disturbance or a Kraken?

All that sand displaced by the volume of those windmill bases planted in our sea

 

[tillergirl]

It has been gradually moving up from the south-west for the last couple of years and this is a very very unstable area. We know that the debris from the dredging of the Princes Channel was dumped in and around the North Edinburgh Channel a few years back but that was probably too long ago to have an impact (but who knows). I think that the Wind Farm view is that whilst there is significant scouring around the bases - up to 2m - the material gets dumped very locally. But given the extent of cabling that has been buried, that whole area has been farmed (sorry) extensively. Would it cross the Black Deep - probably not but they have of course just finished dredging a deep water channel in the Black Deep. I am not sure where that material has been deposited. I'll have a poke around the interweb and see what I can find. There must have been a public licence issued. But I do think we have to accept that that areas just changes. Bear in mind what I call Mystique's Knoll which is a very substantial area of drying sand (see the images on my SW Sunk download) was once 3.7m deep at CD. And that was certainly within the last ten years. Autumn has been pretty blowy.

I suspect there is a substantial route the other side of Mystique's Knoll - that is further to the north-east - but I ran out of time back in June to try it. I hope to launch very early May and get down there almost immediately (with my nicely cleaned fuel tank and sparkly new sails [don't tell SWMBO]. But in the meantime if anyone has any experiences, it would be useful to share them.

 

[tillergirl]

Reading up on the Gateway Plans, the intention was to use the spoil to backfill the jetties at the Gateway. However, the proposal did talk about the need to monitor the impact of the debris displaced during the dredging which gets carried away by the tide. They were doing some light dredging just SW of the SW Sunk swatchway so maybe.......

Thinking about it, there is a bit of environmental re-modelling going on this year:

1. The Gateway jetties have extended into the north side of the Thames;
2. The Wallesea island project with the backfill from the Crossrail project;
3. The London Array has stirred up a massive area
4. The Gateway project has created a deep water route of not less than 14.5m at CD from the Sunk Gyratory to the Gateway.

At the very least all that must have an impact. Bearing in mind that when they opened the seawall at Abbotts Farm at the top of Salcott Creek one of their arguments was that it was returning natural wetlands that eased flood pressures, presumably 1 and 2 will have the opposite effect. And as the Dutch Delta scheme closed off those wetlands to the flood tide back in the 50's does that mean that we are being increasingly exposed should a 53 coincidence happen again?