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The Encyclopedia of Horology

Complication · Calendar & astronomy

Tide Indication

Partially verified

A display of the state of the tide at a reference location.

Definition

A display of the state of the tide at a reference location.

Historical origin

Tide indication is a traditional feature of coastal clocks, since tides follow the lunar day closely enough for a geared approximation.

How it works

A wheel geared to the lunar rather than solar day drives an indicator through the tidal cycle.

Because real tides depend on local geography, the indication is an approximation for one location.

Pocket watch context

Found on some marine and coastal pocket instruments.

Wristwatch context

An occasional feature of modern sailing watches.

Clock context

Coastal longcase clocks frequently carried tide dials for a named port.

Identification

  • A tidal scale, often combined with a moonphase

Servicing notes

This is specialist work. Levers, springs and cam profiles in complicated work are calibre-specific, and incorrect reassembly commonly damages parts that cannot be bought. Refer the movement to a watchmaker experienced with this mechanism.

General guidance only. Complicated mechanisms should be assessed and serviced by a qualified watchmaker or clockmaker specialist, not adjusted at home.

Diagram

date ring, thirty-one positionsdate aperturedriving wheel and jumper
Schematic: calendar work under the dial. An outline schematic drawn to show the arrangement of the parts discussed here. It is not a dimensioned working drawing and does not depict a particular maker's calibre.

Sources & references

  1. de Carle, D., Watch and Clock Encyclopedia
  2. Britten, F. J., Old Clocks and Watches and Their Makers
  3. Horological Journal (British Horological Institute), technical articles

Where sources disagree, the disagreement is stated rather than resolved silently.