NavList:

The Harmonic Constants that Frank posted, were meant to be generic for the Normandy Coast rather than for any specific location.

So I wondered how would they compare to a modern day tide prediction at locations near to the D_Day battle - that took place 75 years ago.

In the following table, the first entry is the tide using the data that Frank posted (that was created 76 years ago), and the next 3 lines are from the Official French Website that distributes Tide information.

The times below are all UTC+0 Hrs, and the height is all metric - to allow easy comparison.

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 YEAR MO DA        TIME   HT.      TIME   HT.     TIME   HT.    TIME   HT.
 2019/06/06 TH       HHMM  M.      HHMM  M.     HHMM  M.     HHMM  M.
 "Position Z"            0543  0.99     1059  7.40     1806  1.34     2314  7.45
    Bessin                0553  1.08     1051  6.94     1810  1.37     2305  7.10
    Bains                  0556  1.05     1053  7.02     1814  1.31     2305  7.14 
    CSM                   0604  1.21     1105  7.13     1822  1.48     2309  7.26
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The current tide data for the following 3 ports in the Bay of Seine, can be found here
(as well as for many other ports around the World).

Bessin = Port-en-Bessin (France)
Coordinates : 049° 21' 00.0'' N, 000° 45' 00.0'' W

Bains = Arromanches-les-Bains (France)
Coordinates : 049° 21' 19.8'' N, 000° 37' 12.0'' W

CSM =  Courseulles-sur-Mer (France)
Coordinates : 049° 24' 37.8'' N, 000° 28' 35.4'' W
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I think it is most impressive how accurate the "Position Z" tide prediction still is - compared to modern day predictions.

The 1943 "Harmonic Constants" were clearly a well chosen data set !

Regards, Geoff Hitchcox, Christchurch, New Zealand.