Longitude Time

Although determining longitude is quite easy today with GPS and other modern navigation tools, there were some difficulties in the past.

Before the 1700s, it was very difficult for ships to determine their exact longitude because clocks could not remain stable at sea due to the rocking motion. The first requirement for calculating longitude using time was knowing the time at two different locations. Due to the inability to determine longitude, long sea voyages took longer, and sailors died from various diseases because they could not eat properly, not to mention the economic losses.

Gemma Frisius proposed the idea of using a mechanical clock to determine longitude in 1530. However, it was not until 200 years later that this idea was realized by John Harrison, a clockmaker with a genius beyond his time.

John Harrison, an English clockmaker who lived in the 18th century, specialized in accurately measuring time and making the machine that measured it portable, almost single-handedly solving the long-standing problem of longitude in navigation and becoming a legend.

In 1735, after five years of effort, Harrison developed his first clock, which he named H-1. H-1 bore no resemblance to the clocks made before it, and its unusual appearance also set it apart from the clocks produced after it. H-1 successfully passed its first sea voyage test.

Harrison sought support from the Board of Longitude to create a better clock, and two years later, he developed the H-2. This revolutionary timepiece passed all the rigorous tests.

Harrison, who was 48 years old when he began its construction, spent 19 years creating the H-3. The innovations on the H-3, which consists of 753 parts, are still used today in thermostats and temperature control devices.

However, Harrison had decided to create a marine chronometer the size of a pocket watch, so four years after the H-3, he further developed the design and created the H-4. Harrison’s most famous invention was the H4 marine chronometer, which was the first to feature a design unaffected by swaying motions. Though it was very large for a pocket watch (with a diameter of 12.5 cm) and very small for a marine chronometer, this watch symbolized the beginning of a new era with its revolutionary features. The H4, along with Harrison’s other marine chronometers, significantly improved navigation during sea voyages and enabled more accurate results in longitude calculations.