Reply To: Tidal rates in World War 1
The British method of calculating tidal streams for the years 1914-18 changed most markedly for Heligoland during that period. The original data is that of C N J Börgen who collected data, mostly elevational, during the 1880s. He applied harmonic methods of analysis and prediction independent of Thomson/Darwin/Roberts.
Heinrich Rauschelbach succeeded him in his work in Germany on tides across the world in the early twentieth century. However the data collected by Börgen was also available in Britain to Edward Roberts, Harold Warburg and eventually Arthur Doodson. The German authorities also supplied them with modern prediction data up to the end of 1916.
Warburg was particularly interested in tidal streams and after winning the Thomas Gray Memorial Prize with Doodson, they went on to produce A. T. Doodson and H. D. Warburg, The Admiralty Tide Tables Part III containing Instructions for Predicting Tides and Tidal Streams and for Analysing Observations and Tables to assist Prediction and Analysis, (London, 1938). This is more appropriate than their 1941 manual.
Despite that Admiralty title, Doodson and Warburg undertook most of their work, particularly for the 1939-45 period, under the Liverpool Tidal Institute. The Proudman Oceanographic Laboratory now carries on their work, and the tide predicting machine made for Roberts, which Doodson and Warburg used for that most critical period, is also held in Liverpool.