Tidal curves

[vyv_cox]

My information is not current, last time I was there was something like 7 years ago. I bought my current boat from Pwllheli, berthed on the piles on the south side of the entrance channel. At that time the depth was a good deal greater on the port side on entering. Deep keeled boats anchored outside for a couple of hours on LW springs but many others entered regardless.

 

[david_e]

Re: free demo

errr - not that familiar with this process - have just downloaded - now how do I find it? And do I ignore any windows that say it might be unsafe? (you can see why I ordered the disk!)

 

[Rich_F]

Take a look at <A target="_blank" HREF=http://www.ukho.gov.uk/tideprediction.cfm>UKHO Tidal Predictions</A>; you can get predictions for Pwllheli for the next week, though the graph doesn't seem to be working properly this morning.

In my experience, these predictions are far more accurate than the tidal curves in the almanac. Recently, during springs at Beaulieu, there were low water and early high water stands shown on the prediction, with the stands being different in nature on consecutive tides. There was no sign of these complexities on the published tidal curves.

Watching the water showed the Admiralty predictions to be correct, and gave me a choice of three slack periods during the flood, during which I could leave my berth with no stress!

BTW, I have until recently been unhappy with the UKHO's policy of preventing unlicensed tidal prediction software for the UK. However, it seems as though they are now capable of much more accurate predictions (presumably based on recent research), so I can see why they might want to discourage people from using older, inferior methods.

 

[bigmart]

Re: free demo

When you downloaded the file it would have been saved to a directory on your computer. Just go to that directory & double click on the icon for the program. It should install itself & then, if you follow the instructions you will beable to see the data.

Martin

 

[johna]

For Tides on a Palm see www.neptune-navigation.com

Excellent back up and also do a planner plotter. No direct connection with Company but have used the product for past 8-9 years.

 

[DeeGee]

I can't see why one should be better or worse than the other. They use harmonic tidal predictions, ie the sum of 18 or is it 28 harmonics, due to sun, moon, planets etc etc etc. The predictions are correct to some silly accuracy, but the pressure and prevailing wind can cause major local variations on top of that - and ditto for a dredged channel.

 

[Rich_F]

The almanac method is not using harmonics as such - for a start, there is no correction on a tidal curve for differences due to time of day, much less for planets, etc.

I can't comment on the accuracy of the UKHO web predictions against all other computer methods. However, old versions of the freeware tidetool (which the UKHO has now prohibited from producing UK predictions) do use harmonic predictions, and are not even close to the detail shown in the web predictions.

Maybe the UKHO has recently developed a better way of modelling the effect of water movement in the Solent, and the rivers leading into it?

Rich

 

[david_e]

Re: channel depth

Checked this week-end, albeit a handrawn and coloured chart, the one in the marina office shows the whole of the channel as 0.56 below chart datum, will still be checking myself at another time.

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[mldpt]

Ive just downloaded it and paid for it. Great it of software for less than a tenner.
Thanks.
Mike www.pagetsladysailing.co.uk

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