ADMIRALTY TIDAL PUBLICATION

1.GENERAL ARRANGEMENT:-

• PART 1:-Part 1 is that these tables give daily predictions of the times and heights of high and low waters at a selected number of standard ports.

This list of standard ports is given inside the front cover included with each set of prediction for standard ports (with exception of venezia) is a diagram to facilitate the calculation of heights at times other than high and low water .

 

• An explanation of the use of the diagram is given in the instruction for the use of tables(page xii).

• The introduction of part 1 deals with a number of subjects of general interest, particularly the effect of meteorological condition on tidal heights.

• PART 2:-It gives data for prediction at a large number of secondary ports ,this is in the form of time and height differences referred to one of the standard ports of part 1.

• PART 3:-it gives data of the harmonic constant for use with the simplified harmonic method of tidal prediction NP.159.

• In those cases where harmonic constants are given, two alternative methods of predictions are available.

2.SOURCE OF TIDAL PREDICTIONS:-

• Predictions for some standard ports in the British isles and elsewhere are computed on behalf of the harbour authorities by the oceanographic laboratory ,bidston,others are prepared by the hydrographers of the navy.

• predictions for the remaining standard ports are received from the appropriate authorities in Denmark , France ,Germany ,Netherlands,and Norway.

• Data in part2 for places outside the British isles are ,in general, extracted from the tide tables published by the appropriate national authority.

• A list of authorities responsible for the observations , analyses and predictions at standard ports is given in table v (page xxxvii).

3.SPECIAL PREDICTIONS FOR SECONDARY PORTS.

• The hydrographic office can supply daily predictions for secondary ports,either as times and heights of high and low waters or S hourly heights, upon request.

4.TIMES USED FOR PREDICTIONS IN VOL1.

• All the times of predictions in part 1 are given in the standard time kept at the place. In the British isles the time used is universal time (GMT).

5.HEIGHTS OF PREDICTIONS.

• All predicted heights in part 1 are given in meters above chart datum.The height difference in part3 are also given in meters