H4 Longitude Timekeeper – The solution to the longitude problem

John Harrison (1693-1776) was a trained carpenter who taught himself the art of watchmaking. From 1727 he dealt with the so-called longitude problem and devoted the rest of his life to solving it. The term longitude problem denotes the difficult determination of the geographical longitude when determining the position, especially of ships, in the open sea. This regularly had fatal consequences when ships ran aground.

From 1728 Harrison worked on a timepiece that was supposed to have a inaccuracy of just a few seconds at sea. After many years of tireless work and some very promising but nonetheless unsuitable designs and prototypes (H1 – H3), he succeeded with his sea watch H4. For many years it had been considered technically impossible to creat such a small, but nonetheless accurate watch. His ship‘s chronometer was revolutionary with a diameter of 13 cm and a beat rate of 18,000 A / h (2.5 Hz) and, as a lifesaver at sea, is one of the most important clocks in the world.

The KronSegler automatic watch series H4 Longitude Timekeeper is optically based on Harrison’s chronometer, but with a diameter of 42.5 mm and a thickness of only 9.9 mm it is optimized for today’s wearing habits. The flat, fast-swinging movement on 24 rubies with 28,800 A/h (4 Hz) makes the steps of the seconds hand barely perceptible. A modified date display is inserted at the 6 o’clock position.

The case has many optical features. A new type of IPG-plating, which can be produced for the first time in the colors olivegold and copper, gives the watch an extraordinary, almost antique look. The crown resembles a model of the earth with degrees of longitude and latitude. The lugs on the housing have a curved, inwardly folded shape, similar to the bow waves of a ship. The case is brushed lengthways, the bezel and the waves of the lugs shimmer polished. Just like the original H4, the inner hour scale has Roman indexes and the outer minute scale has Arabic indexes. Instead of the hand shape used in the 18th century for the H4, which is rather impractical and difficult to recognize by today’s standards, the Kronsegler H4 Longitude Timekeeper has classically elegant hands whose tips are filled with fluorescent superluminova. The watch is available in 5 model colours with a steel, copper-colored or olivegold case and sandy-coloured, blue and green dials.

Equipment and scope of delivery:
The watch glass is a sapphire crystal with the highest possible scratch resistance. The leather straps in blue or brown are padded, alligator embossed and provided with a KRONSEGLER coat of arms button and a folding clasp with safety double push-button. The H4 is delivered in an exclusive box with certificate, detailed booklet and polishing cloth.

KS Automatic CAL K 029.024 CITIZEN Base, 24 Jewels, 28.800 A/h, 4 Hz, movement thickness with rotor 4.1 mm, power reserve 38 – 42 hours, decorated movement rotor, date modification 6 o’clock


Additional information


€690, 00



Uhrwerk / Movement

KS Automatik CAL K 029.024 CITIZEN Base, 24 Jewels, 28.800 A/h, 4 Hz, 38 – 42 h

Case diameter

42, 5 mm

Case thickness

9, 9 mm

Case material

stainless steel 316L

Dial color




Band material


Band width

20 mm

Clasp type

Butterfly folding clasp

Water resistance




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