Anybody got a Sheerness Tide Table handy please?

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tillergirl

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I need to know the predicted height of tide at Sheerness for Friday, 29th August please - both of the LW and both of the HW predictions please. Curiously I know the actuals but I need to compare against the predictions. So if anyone has one handy please. Next year I'll get a set for the boat, the office, the car and the bedroom!
 
Sheerness

Friday, 29 August 2008

05:51 1.1m
12:07 5.5m
18:19 0.5m

Saturday, 30 August 2008

00:40 5.7m
06:44 0.8m
12:58 5.8m
19:09 0.2m

Sunday, 31 August 2008

01:28 6.0m
07:30 0.6m
13:44 6.1m
19:54 0.0m

Taken From Belfield Tide Plotter Software
 
I suppose it depends where you look:-

29 August 2008 at Chatham ( deduct 9 minutes for Sheerness)
HW 00.03 5.6
LW 07.20 0.8
HW 13.17 5.9
LW 19.06 0.4

Tidal predictions by Proudman oceanographic Lab.

No comment on height of tide differentials, but times seem out for one or other of them
 
Ah yes, it does. First I needed the prediction for Sheerness because I was comparing the actual with the prediction. I had a prediction for the Ray Sand and I am reducing the sounding there to a datum. But you can't get an actual for the Ray Sand so I wanted to compare the actual at Sheerness and Harwich. If they were both on prediction, then its reasonable to assume that it was on prediction at the Ray Sand. Well so I reckon. I can then work away using the prediction height of tide to apply a timed height of tide reduction to soundings.

Actually HW on this day at Sheerness was 1230 and the height of tide was 5.424m. Belfield does seem to be early but the height of tide predicted matches what I expected from other data.

I should be able to publish a pdf of the Ray Sand next week. I've done it but I need to recheck the figures. Frankly I'd like another couple of passes further east. Could go Monday/Tuesday I suppose.

Thanks for the data
 
Tide Plotter uses UK Hydrographic Office data on which all royalties are paid. The simplified harmonic method of prediction NP159 is used to make calculations.

Method of Prediction

Tide Plotter uses the Admiralty Simplified Harmonic Method of Tidal Prediction. While this method is not as accurate as the method used for producing yearly tables it normally produces times within twenty minutes and 0.2m of the actual values. The advantage of this method is that it allows simple predictions for secondary ports where normal predictions are not made.
 
Yes, got that, but nothing retrospective on predictions. To get real detail on past actual heights at 15 minute intervals (anorak stuff this), log into data availability and you can download a month's worth.
 
Sorry - read the original post too quickly. Must stop doing that. I was looking for the wrong month!

Don't know about th actual data, but the graphs of predicted against actual are still available - although it doesn't look easy getting the numbers off the graph. Maybe can do it if printed with a good old fashioned ruler (particularly with the help of the raw actual data that you found). Don't know if this will come out as it is a search on custom dates.

2 days <span style="color:red"> </span> <span style="color:red"> </span> <span style="color:red"> </span>
 
No, you don't need to mess with graphs. Log into 'data availability' at Proudman which links through to the Ocean thingy people and after registering you can download (for selected stations) the past month of data showing the height of tide for each 15 minutes. It's in raw form but easily read. There is some interesting stuff - on 15th August for instance the tide was half a meter higher than predicted. Obviously if I am trying to reduce a sounding to some sort of datum, half a metre difference in the height of tide is significant.
 
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