Expedition Navigation Software 
1 - Boj
- Expert
Offline - From: Netherlands
- Registered: 10/02/2016
- Posts: 38
Timing of tidetech current GRIBs vs Winning Tides
I've recently started to import the tidetech current GRIB files into expedition. After I found out how to make a custom file, I've managed to get the current data I want to use for the Middle Sea Race.
While preparing, I noticed that the currents predicted in the Solent UK model in tidetech are about one hour 'behind' the currents predicted in Winningtides. For comparison reasons I've uploaded them both into expedition.
The question now is; is this hour difference just because the models are different, or is there a structural issue, for example that the Winning Tides Solent module uses the UTC installed as BST?
I run this Toughbook wit UTC set as timezone and have Expedition with 'Settings/System; 'Local Time' switched off. In Settings/Tides; Offset is 0.
- Ernie M
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- Registered: 11/05/2015
- Posts: 399
Re: Timing of tidetech current GRIBs vs Winning Tides
Boj,
I can't answer your question but you could try downloading the NOAA/GFS 0.25 data (which is available for the RMSR) in Exp. Might give you a clue as to which of the 2 you have is the outlier.
Cheers,
Ernie
- Ernie M
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Re: Timing of tidetech current GRIBs vs Winning Tides
oops You were talking about tidal currents not current time...sorry
Mea culpa
E
- Nick
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- Posts: 2,740
Re: Timing of tidetech current GRIBs vs Winning Tides
How do they compare with the Admiralty tide book?
Maybe check with Tidetech. They had a recent issue in San Francisco where their tides were an hour out.
Also, have a look at the Messina tidal currents in Exp. These have been added recently added, so I don't know how good they are.
- Boj
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- From: Netherlands
- Registered: 10/02/2016
- Posts: 38
Re: Timing of tidetech current GRIBs vs Winning Tides
Dear Ernie and Nick,
I've compared the tidetech Solent Uk file to the WinningTides Booklet and they are very similar. However the WinningTides Solent model selected and displayed in Expedition seems to be one hour ahead of both the booklet and the tidetech file.
I assume the raw data in the WinningTides booklet and in the WinningTides Solent model are the same, so I guess there is something wrong with the time offset in Expedition, could it be reading UTC for BST?
I'll have a look at the WinningTides Messina model over the next couple of days.
Boj
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Thread Starter- Nick
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Re: Timing of tidetech current GRIBs vs Winning Tides
There doesn't seem to be much difference between Tidetech and WT Solent when I look at it.
You can choose UTC or local time in Exp. Maybe mail me some screen shots?
- Ernie M
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Re: Timing of tidetech current GRIBs vs Winning Tides
Kind of a reach but could the computer internal time & savings time switch be set incorrectly?
- Boj
- Expert
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- From: Netherlands
- Registered: 10/02/2016
- Posts: 38
Re: Timing of tidetech current GRIBs vs Winning Tides
I don't know what did the trick, but I've reset the date and time settings again to UTC and switched 'Local time' on and off and reset the whole system.
Both the data from tidetech seem to match with the WinningTides book and the WinningTides Solent model. So it must have been a settings problem.
Thank you both for thinking this through with me.
Thanx!
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Thread Starter- Nick
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Re: Timing of tidetech current GRIBs vs Winning Tides
- Boj
- Expert
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- From: Netherlands
- Registered: 10/02/2016
- Posts: 38
Re: Timing of tidetech current GRIBs vs Winning Tides
Thank you for the clarification Nick, the admiralty PDF, explains to me (now), why not to rely on Hw times to much in the future and try to configure the tidal offset in Expedition.
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