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    Re: Historical tides
    From: Stephen N.G. Davies
    Date: 2019 Feb 17, 06:46 +0800
    There used to be a British publication, NP159, which was the Admiralty’s graphical method of tidal prediction for secondary ports for which full tables were not given. At the back of each volume of the Admiralty Tide Tables was a long list of secondary ports with their most important harmonic constants. One used these to complete a prepared table in NP159, then plotted the results on a diagram (two as I recall - it’s 20 years since I used it) to yield the tidal curves for, I think, 24 hrs. The system was described, in a couple of papers available online by a couple of Royal Navy officers, NC Glen and AG Merriman, in 1977 and 1981 respectively, just after the NP159 method began what seems to have been its short life. Just tap ‘Admiralty graphical method of tidal prediction NP159’ into Google.
    Stephen D

    Sent from my iPhone

    On 16 Feb 2019, at 9:46 PM, Alexandre Eremenko <NoReply_Eremenko@fer3.com> wrote:

    Thanks for the interesting reference.
    (I knew more or less the scientific part of the story. My question was purely practical:
    what available sources I can use for a specific "prediction".)
    Perhaps there exists an online tide calculator?
    Enter location and date, and obtain the result.

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