In 1714 the British Parliament offered a prize of £20,000 (millions in today's money) to anyone who could find a practical solution to the very serious problem of determining longitude at sea. The Board of Longitude was set up to judge entries and award the prize.
The Board consisted of members of the Admiralty, the Astronomer Royal, top mathematics professors from Cambridge and Oxford (including Isaac Newton), and members of Parliament.
In 1735 John Harrison completed his first chronometer and received support from Astronomer Royal Edmond Halley to give it a sea trial. The machine did not perform flawlessly, but did provide a much better estimate of longitude than the ship's navigator. On the return leg to England, Harrison was able to determine the ship was some 150 km off its plotted course. Still, Harrison was not pleased with his machine and asked for and received money from the Board to build a better version.
Harrison did not approach the Board for another sea trial until 1761 when he developed a new chronometer in the shape of an oversized pocket watch, a vast improvement over his unwieldy 35 kg original. In the meantime, a new Astronomer Royal and the rest of the Board had become more interested in the lunar distance method of determining longitude. They were unwilling to give the full prize to him despite the fact that the new clock performed just as predicted, and within the parameters set by the Board before the trial. Instead, they gave him only a small reward and set up new requirements for Harrison to meet. Exasperated, Harrison petitioned King George III whose influence finally got Harrison the balance of the £20,000 reward in 1773.
The Board was eventually disbanded in 1828, by which time derivatives of Harrison's chronometers were in common use in the Royal Navy and the English merchant fleet.