Spitway

[tillergirl]

Larry (aka Gladys) and I went down to the Spitway yesterday. We hoovered up 13853 soundings while down there and I have just finished doing the QA and first part of the post processing (aka making sense of the data). I shall top and tail a new chartlet midday tomorrow.

The chart reduction process always does need a bit of thought and yesterday there was just over a surge of 0.2m all through the flood. I have assumed the surge has been constant at the Spitway on the basis that there was a surge at Walton and at West Mersea. It would be a bit tricky not to have a surge in between. So the data suggests in line twixt the buoys have reduced down to 1.1/1.15m CD for a stretch about 40m and a long stretch at 1.2m CD as one approaches the Swin Spitway. The better water is still where I said in 2022 though it has also lost 0.1/0.2m of depth. But of course one can always add on the height of tide!

Lovely day, couldn't have be better conditions. Chartlet up tomorrow.

 

[Cantata]

Good stuff, Roger (and Larry).
I guess no commercial traffic at all these days to churn it up a bit since the coasters stopped running in and out of Wivenhoe.
I wonder if Trinity House might be persuaded to move the buoys?

 

[tillergirl]

I did wonder if I should send in the data to Trinity House (of course I will send in the data to the UKHO). I guess it might be an issue of 'significance'. e.g. few years back the difference between the buoys and the 'best' water was only 0.2m. Not worth moving them then? Now, arguably, it is 0.5m. But I think there was a professional survey last November/December.

 

[tillergirl]

Chartlet done and posted up. Goto: Downloads second item down. You can download the jpg by clicking on the image but it is a big file (5MB). The download button has the pdf which is more reasonable.

 

[NealB]

Chartlet done and posted up. Goto: Downloads second item down. You can download the jpg by clicking on the image but it is a big file (5MB). The download button has the pdf which is more reasonable.

Thank you!!

 

[Black Diamond]

Thanks Roger and Larry, looks like we could have curved even further east, but we had the luxury of a neap tide metre under the keel in a flat sea. Hopefully TH will pop the stripy buoys further east.

 

[tillergirl]

No sooner do we issue a new chartlet and the UKHO issue a new Notice to Mariners! As I think I said there had been a major Civil Hydrography Programme last winter and this had identified that the wreck marked at 4m was 'out of position'. I think that had been in that position for over 20 years but this is the first professional survey for ages and they found it on the north side of the Spitway with 3.7m of water over it.

I have redone the chartlet and V2 is available at: Downloads

I have been told by the UKHO that our survey will add to the data from the CHP. I intend to send in the data to Trinity House with the observation that it might be worth considering moving the SWBs and many leisure users would prefer that (please say now if you consider otherwise).

 

[Plum]

No sooner do we issue a new chartlet and the UKHO issue a new Notice to Mariners! As I think I said there had been a major Civil Hydrography Programme last winter and this had identified that the wreck marked at 4m was 'out of position'. I think that had been in that position for over 20 years but this is the first professional survey for ages and they found it on the north side of the Spitway with 3.7m of water over it.

I have redone the chartlet and V2 is available at: Downloads

I have been told by the UKHO that our survey will add to the data from the CHP. I intend to send in the data to Trinity House with the observation that it might be worth considering moving the SWBs and many leisure users would prefer that (please say now if you consider otherwise).

Many thanks for your chartlets. Although the spitway is mostly soft mud, the Buxey Sand, in particular the area west of, and getting closer to the current position of the Swin Spitway buoy, is hard sand (I touched bottom there a few months ago! and there was a helicopter evacuation from a yacht pounding near there last year) so I believe moving that buoy eastwards is important for safety.

Edit: the reason for the yacht in difficult was not due to the position of the Swin Spitway buoy, i only mention this to illustrate the danger of hard sand.

 

[DanTribe]

Off topic, but we just came into the Ore using the ECP chartlet.very reassuring and much appreciated.