D&T
Well-Known Member
Has anyone been through this year? same co ordinates as last year. I guess its a bit early for a survey yet?
SW Sunk
- Thread starter D&T
- Start date
tillergirl
Well-Known Member
1. Not heard anyone yet this year;
2. Last time the SW Sunk swatch moved, it progressively closed up and the new one (the current one) opened up. I am expecting it to be fine given how 'open' it was up last year. The only movement in 2016 over 2015 was less than 100 yards - if that - movement towards the north-east. I cannot say, of course, but I am optimistic;
3. My plan is to get LW springs in that mid May set of springs. There is a nice window between 10th to 13th May for a nice Spring dawn - I hope. Just got to get TG ready to launch on 27th April.....
If anyone has been this year it would be handy for anyone to say.
2. Last time the SW Sunk swatch moved, it progressively closed up and the new one (the current one) opened up. I am expecting it to be fine given how 'open' it was up last year. The only movement in 2016 over 2015 was less than 100 yards - if that - movement towards the north-east. I cannot say, of course, but I am optimistic;
3. My plan is to get LW springs in that mid May set of springs. There is a nice window between 10th to 13th May for a nice Spring dawn - I hope. Just got to get TG ready to launch on 27th April.....
If anyone has been this year it would be handy for anyone to say.
tillergirl
Well-Known Member
A report last night by Graham and Lindsey, Yacht Caroline out of Tollesbury; SW swatchway used successfully. Their data using the same waypoints suggested ample depth at CD and that the swatch is viable at low water as last year. Of course, one swallow isn't a summer and so it is necessary to add a caution until I have tested widely across the swatch. But it suggests it is be a surprise if it was not much change.
I am greatful to Graham and Lindsey information and their care.
I am greatful to Graham and Lindsey information and their care.
Supine Being
Well-Known Member
Friends came over at the end of April and said it was absolutely fine on last year's track. I'll be going over on the weekend after next and will post if I find anything surprising.
tillergirl
Well-Known Member
That would be good. I am being asked to do some work somewhere else and I am wondering if I can delay this re-survey as it seems to be ok. Could I possible ask you to record some times and depths?
Supine Being
Well-Known Member
Sure - I'll scribble down what I can as we pass over and let you know
tillergirl
Well-Known Member
Excellent, well done.
Athene V30
Well-Known Member
See you in Calais!
Supine Being
Well-Known Member
Excellent! See you there.
Supine Being
Well-Known Member
Hi,
Here's what I found. It's a bit thin on the SE end of the SW Sunk and, on the return journey even more so as I was a bit too far south. When it suddenly dropped to 0.4 under the keel, it was a little clenching, I have to say. I've not had the chance to plot it against a chart yet, but here's the raw data:
Southbound 26/05/2017. Tide ~ 3.7m (at Whitaker)
Time Lat Long Total Depth Depth at CD
0234 51° 37' 987''N 001° 16' 506''E 11.4 7.7
0237 51° 37' 976''N 001° 16' 840''E 5.3 1.6
0238 51° 37' 971''N 001° 16' 926''E 8.4 4.7
0239 51° 37' 963''N 001° 17' 107''E 6.7 3.0
0239 51° 37' 962''N 001° 17' 123''E 6.6 2.9
0239 51° 37' 957''N 001° 17' 187''E 6.0 2.3
0240 51° 37' 949''N 001° 17' 277''E 5.5 1.8
0240 51° 37' 947''N 001° 17' 304''E 5.3 1.6
0241 51° 17' 376''N 001° 17' 376''E 5.0 1.3
0241 51° 37' 931''N 001° 17' 420''E 4.9 1.2
0242 51° 37' 922''N 001° 17' 499''E 5.1 1.4
0242 51° 37' 914''N 001° 17' 567''E 5.8 2.1
0243 51° 37' 904''N 001° 17' 638''E 6.5 2.8
0243 51° 37' 895''N 001° 17' 691''E 6.9 3.2
Northbound 29/05/2017. Tide ~1.8m (at Whitaker)
Time Lat Long Depth Depth at CD
1037 51° 37' 828''N 001° 18' 248''E 5.8 4.0
1037 51° 37' 830''N 001° 18' 202''E 5.7 3.9
1039 51° 37' 858''N 001° 17' 876''E 5.7 3.9
1040 51° 37' 876''N 001° 17' 609''E 2.5 0.7
1041 51° 37' 885''N 001° 17' 562''E 2.1 0.3
1041 51° 37' 894''N 001° 17' 494''E 2.3 0.5
1042 51° 37' 903''N 001° 17' 406''E 2.4 0.6
1042 51° 37' 914''N 001° 17' 314''E 2.1 0.3
1043 51° 37' 928''N 001° 17' 204''E 2.5 0.7
1043 51° 37' 938''N 001° 17' 103''E 3.4 1.6
1044 51° 37' 950''N 001° 17' 004''E 4.5 2.7
1045 51° 37' 971''N 001° 16' 801''E 7.3 5.5
1046 51° 37' 991''N 001° 16' 602''E 8.7 6.9
1048 51° 38' 007''N 001° 16' 312''E 9.9 8.1
(apologies for the non-formatting - looks like all my nice neat tabs don't carry over to the final presentation)
Here's what I found. It's a bit thin on the SE end of the SW Sunk and, on the return journey even more so as I was a bit too far south. When it suddenly dropped to 0.4 under the keel, it was a little clenching, I have to say. I've not had the chance to plot it against a chart yet, but here's the raw data:
Southbound 26/05/2017. Tide ~ 3.7m (at Whitaker)
Time Lat Long Total Depth Depth at CD
0234 51° 37' 987''N 001° 16' 506''E 11.4 7.7
0237 51° 37' 976''N 001° 16' 840''E 5.3 1.6
0238 51° 37' 971''N 001° 16' 926''E 8.4 4.7
0239 51° 37' 963''N 001° 17' 107''E 6.7 3.0
0239 51° 37' 962''N 001° 17' 123''E 6.6 2.9
0239 51° 37' 957''N 001° 17' 187''E 6.0 2.3
0240 51° 37' 949''N 001° 17' 277''E 5.5 1.8
0240 51° 37' 947''N 001° 17' 304''E 5.3 1.6
0241 51° 17' 376''N 001° 17' 376''E 5.0 1.3
0241 51° 37' 931''N 001° 17' 420''E 4.9 1.2
0242 51° 37' 922''N 001° 17' 499''E 5.1 1.4
0242 51° 37' 914''N 001° 17' 567''E 5.8 2.1
0243 51° 37' 904''N 001° 17' 638''E 6.5 2.8
0243 51° 37' 895''N 001° 17' 691''E 6.9 3.2
Northbound 29/05/2017. Tide ~1.8m (at Whitaker)
Time Lat Long Depth Depth at CD
1037 51° 37' 828''N 001° 18' 248''E 5.8 4.0
1037 51° 37' 830''N 001° 18' 202''E 5.7 3.9
1039 51° 37' 858''N 001° 17' 876''E 5.7 3.9
1040 51° 37' 876''N 001° 17' 609''E 2.5 0.7
1041 51° 37' 885''N 001° 17' 562''E 2.1 0.3
1041 51° 37' 894''N 001° 17' 494''E 2.3 0.5
1042 51° 37' 903''N 001° 17' 406''E 2.4 0.6
1042 51° 37' 914''N 001° 17' 314''E 2.1 0.3
1043 51° 37' 928''N 001° 17' 204''E 2.5 0.7
1043 51° 37' 938''N 001° 17' 103''E 3.4 1.6
1044 51° 37' 950''N 001° 17' 004''E 4.5 2.7
1045 51° 37' 971''N 001° 16' 801''E 7.3 5.5
1046 51° 37' 991''N 001° 16' 602''E 8.7 6.9
1048 51° 38' 007''N 001° 16' 312''E 9.9 8.1
(apologies for the non-formatting - looks like all my nice neat tabs don't carry over to the final presentation)
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tillergirl
Well-Known Member
Just running through the positions.
Right, a quick plot Out and Return:
It will take me a little while to plot those positions against my chartlet - in fact I will leave that for the morning. My initial reaction is that the SW Sunk knoll has extend up from the SW. It is very steep-to. Has the swatch and moved up from the SW? I had been hoping to avoid doing a rerun this year based upon the comments early because there are several requests elsewhere and my schedule this year has been amok. But it looks like it needs a rerun. I am just wondering if it will be a nice calm week next week. The springs are not huge which is not that helpful as I want to have a look at the sands at low water but probably ok.
That second plot on the out run looks a little odd. By the way, ignore the two Fouls. The PLA don't regard them as still being there and anyway they were at 8 or 9m deep.
Right, a quick plot Out and Return:
It will take me a little while to plot those positions against my chartlet - in fact I will leave that for the morning. My initial reaction is that the SW Sunk knoll has extend up from the SW. It is very steep-to. Has the swatch and moved up from the SW? I had been hoping to avoid doing a rerun this year based upon the comments early because there are several requests elsewhere and my schedule this year has been amok. But it looks like it needs a rerun. I am just wondering if it will be a nice calm week next week. The springs are not huge which is not that helpful as I want to have a look at the sands at low water but probably ok.
That second plot on the out run looks a little odd. By the way, ignore the two Fouls. The PLA don't regard them as still being there and anyway they were at 8 or 9m deep.
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tillergirl
Well-Known Member
'Supine'
Very valuable data. Thanks. Dare I suggest things are better than I thought at first 'plot' last night. I have just quickly overlaid some of your data over my 2016 chartlet. Always assuming our GPSs are of sufficiency and equal accuracy (not a negative critical comment, indeed I am thinking there is good correlation) would suggest that you skirted, even flirted with the SW Knoll!
Have a look:
Red, your outer run, Yellow, your return. The figures overlap and indeed overlap the original data - and I omitted some of your data because they would overlap. I will have to magnify the scale which will take me a little while (the drawing software can easily expand the drawing but can distort the process) and so I'll have a go tonight.
I am thinking that once again has extended very slightly from the SW. In 2016 over 2015 my view was the SW Knoll had migrated very slightly, perhaps 150m to the NE, perhaps it has gone again. The change in 2016 over 2015 matched a retreat from the Middle Sunk knoll - perhaps that has happened again. Of course the yellow 0.7 is valuable information and shows a significant change. Well done.
More later tonight.
Very valuable data. Thanks. Dare I suggest things are better than I thought at first 'plot' last night. I have just quickly overlaid some of your data over my 2016 chartlet. Always assuming our GPSs are of sufficiency and equal accuracy (not a negative critical comment, indeed I am thinking there is good correlation) would suggest that you skirted, even flirted with the SW Knoll!
Have a look:
Red, your outer run, Yellow, your return. The figures overlap and indeed overlap the original data - and I omitted some of your data because they would overlap. I will have to magnify the scale which will take me a little while (the drawing software can easily expand the drawing but can distort the process) and so I'll have a go tonight.
I am thinking that once again has extended very slightly from the SW. In 2016 over 2015 my view was the SW Knoll had migrated very slightly, perhaps 150m to the NE, perhaps it has gone again. The change in 2016 over 2015 matched a retreat from the Middle Sunk knoll - perhaps that has happened again. Of course the yellow 0.7 is valuable information and shows a significant change. Well done.
More later tonight.
Supine Being
Well-Known Member
Brilliant, thanks for that. You're dead right on the second number outbound, I had a little finger trouble typing in. The depths should have been 9.3m total depth and 5.6m CD. Thanks, as always, for your help.
tillergirl
Well-Known Member
Good oh.
Now scaled up:
Black soundings = me in 2016
Red soundings = Supine Being outward
Magenta soundings = Supine Being coming back.
So I would venue that with the exception of the building of the 'hook' to the east perhaps there hasn't been a lot of movement of the SW Knoll on the basis of this and earlier data.
Now scaled up:
Black soundings = me in 2016
Red soundings = Supine Being outward
Magenta soundings = Supine Being coming back.
So I would venue that with the exception of the building of the 'hook' to the east perhaps there hasn't been a lot of movement of the SW Knoll on the basis of this and earlier data.
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Supine Being
Well-Known Member
That's really clear, thanks. Tell you what, I'm going to check my waypoints the next time I'm on the boat as I really was cutting it very fine, even on last year's chartlet. Still, I guess the data at the edges is interesting for these purposes. Gave me a couple of interesting moments too.
tillergirl
Well-Known Member
Oh the edges were really interesting. I would have never suggested you try as close as you did (inadvertently) but it is very good to add to the sum of the whole. Whilst I couldn't claim the swatch is perfect, all the evidence so far from you and the others is suggesting it is going to be fine.