Tide Prediction Machines

Philip L. WoodworthNational Oceanography Centre, Liverpool

SLOC Meeting 21 June 2013

Doodson-Légé Machine

William Thomson, 1st Baron Kelvin

‘Father’ of TidePrediction (TP) Machines

First (official) tidePrediction machine bySir WilliamThomson (Lord Kelvin)1872, now in Science Museum.

10 constituents.

Edward Roberts

Another father ofTide Prediction machines

India Office Machine1877 made by A. Légé & Co., London to design of Edward Roberts. 20 (later 24) constants.

Tide Prediction Machines

• Only 25 Tide Prediction (TP) machines were ever built (plus models and prototypes no doubt)

• Three machines were associated with Bidston: the ‘Kelvin’, ‘Roberts’ and ‘Doodson-Légé’ machines

• The DL machine with 42 constituents was one of the last and largest although not the largest ever (see below).

Kelvin Machine

• The Liverpool Tidal Institute was funded in 1925 by Charles Booth (Booth Shipping Lines) to buy a new 25-28 constituent prediction machine (the Kelvin machine) for its sole use.

• Doodson took a lead in its construction and operation and used the machine to start an important business in tide table production.

• The Kelvin and Roberts machines were used for D-day predictions etc.

• The Kelvin machine was given (or sold) to SHOM after WW2 and used up until 1966. (Moved to Brest in 1970).

• An explanation how it worked in Joyce Scoffield’s book.

BidstonKelvinMachine

Bidston Kelvin machine now in lobby of SHOM at Brest

Roberts Machine

• When HWT Roberts (son of Edward) died in 1929, the LTI (Doodson) took over the Roberts business.

• That brought the ‘Roberts’ TP Machine of 1906 to Bidston, which was larger than the LTI machine (it had 40 constituents) but in need of an overhaul which Doodson oversaw.

• Beware it is called the ‘Légé machine’ in Doodson publications

• The Roberts machine now in the Liverpool Museum.

Roberts“Universal Tide Predicter” of 1906, winner of the “Grand Prix” of the Franco-British Exhibition of 1908

Doodson Machine

• Doodson’s final involvement with machines was the DL installed in 1950.

• 42 constants

Doodson-Légé Machine

A Couple of Other Machines

Valued by their Owners

Now in lobby of Norwegian Hydrographic Office Stavanger

One Other Machine

Not Valued by its Owner

Roberts machine

Most of the others we know where they are or what happened to them e.g.

- India machine now at Dehra Dun- Philippines machine

Others we don’t - but must be easy to find if we had the time e.g. Spanish and Argentina machines

Plan now is for Julie Ledder to get either the Roberts machine or Doodson-Lege machine back on loan from NML for display in the JPB atrium when building work is finished – watch this space.