HE was an extraordinary man whose attention to detail helped protect sailors on their voyages for decades.

And almost three centuries after he was born in Charlbury, a blue plaque will be unveiled to honour Larcum Kendall.

Born in September 1721, the watchmaker was commissioned by the Board of Longitude in 1765 to copy a marine clock design pioneered by John Harrison and create a more cost effective version.

The result was one of world’s first working chronometers – very accurate clocks used by ships at sea for navigation.

The plaque will be put up in the spot closest to where the cottage he grew up in once stood.

Charlbury Society chairman Simon Walker said the town was proud of Mr Kendall.

He said: “It is a really good thing for us to get this plaque. Before the chronometer was taken around the world by Captain [James] Cook and [Vice Admiral William] Bligh, sailors did not have a way of determining where they were accurately.

“There were some awful tragedies because of it.

“Harrison can take credit for the design, but the level of safety was greatly moved on by Kendall.”

Mr Kendall created the K1 chronometer in 1769 and he was even praised by Mr Harrison’s son, William, who said the watch worked better than the original.

In 1772 it was sent for trials with the famous Captain James Cook, and worked so well he dubbed it his “trusty friend the watch”.

There would be two more versions of it, known as the K2 and K3, which eventually became more cost effective. The K1 originally sold for about £450, but the K3 would eventually sell for £100.

Oxfordshire Blue Plaque Board member Eda Forbes said the unveiling would be unusual because Mr Kendall’s home no longer exists.

And because it is going above an archway, next to the post office, it will not be unveiled by curtain.

She said: “It will go up there after the ceremony, so that is quite rare for us.

“Kendall was quite an extraordinary man, who grew up in a landlocked place like Charlbury but went on to produce something that would be used in great voyages.

“He was a significant figure with an exciting story.”

The blue plaque will be unveiled on Saturday, May 3, at 11.30am, in the garden of Charlbury Museum, in Market Street.

Jonathan Betts, senior curator in horology at the Royal Observatory Museum, Greenwich, and master of the Worshipful Company of Clockmakers, will speak at the ceremony.