John Harrison Sea Clocks

Our range of Sea Clocks are inspired by the great John Harrison. In each clock we have embodied at least three of the basic principles from Harrison's first Sea Clocks.

Perhaps his most well-known invention is the unique escapement, which gives the clock its popular name, 'The Grasshopper'. The subtle and almost silent 'lock and release' action of the pallets permits them to work without oil (and consequently be free of the effects of changes in viscosity) and at the same time make it so enduringly fascinating to watch.

The Invar pendulum are linked at the back, which allow the clock to function ‘out of level’. Their gentle action gives each clock that restful quality which is typical of an earlier more tranquil age.

For the standard Sea Clock two styles are available, they are named 'His' and 'Hers'. As with all Sinclair Harding clocks a selection of finish and base materials can be specified to make your clock a very personal piece.

Moonphase Sea Clock

The Astronomer Royal, Edmund Halley (c1656-1742) was a proponent of the Lunar distance method for determining longitude. The observations and calculations required for this method took many hours and were prone to error. The hand painted Moonphase dial (each signed and numbered by the artist) on the Moonphase model symbolises this alternative method.

Our Moonphase Sea Clock provides in the Moonphase dial a representation of the competition (Lunar distance method) he faced for the solution to the Longitude problem back in the 18th Century. Each Moonphase dial is hand painted by our artist Keith Warrington, each with a hidden initial and date on each dial.

Almost every piece is made in the workshops of Sinclair Harding using a combination of modern technology, materials, and traditional finishing techniques. Every care is taken at each stage in the making and build to ensure that the final clock performs to a standard, which justifies the association with John Harrison.

HEIGHT: 45cm. WIDTH: 32cm. DEPTH: 21cm.

Moonphase Sea Clock finished in Rose Gold and Platinum combination on a Walnut Base.

Standard 'His' Sea Clock finished in Platinum on a Black Base.

Standard 'Hers' Sea Clock finished in Gold on a Walnut Base.


Chain Driven Fusee

Chain driven fusee, 8 day power reserve.

Seconds Hand

The unusual seconds hand deserves a special study. It sweeps through 240 degrees going from 0-60 seconds before vanishing, only to reappear instantly at zero again.

Moonphase Dial

Each Moonphase Dial is hand painted, each signed and date by our artist Keith Warrington.

Glass Shade

The clocks are protected by a bevelled glass shade with an opening door allowing the winding to be carried out without having to remove the shade.


All the parts on each clock are hand finished (even the ones you cannot see!). The Brass parts are protected with a thin layer of 23.5 carat Gold or Platinum. The finishes we offer are Gold, combination of Gold and Platinum or Platinum plated.

Our bases are French polished, this technique produces a high gloss surface. We also offer a range of granite bases. Each of our bases can be personalised with an engraved plaque.

Birds-eye Maple

Olive Ash

Tiger Oak Burr

Walnut Burr



Black Granite

Star Galaxy Granite.

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