The number of men working in a lighthouse in the UK was increased from 2 to 3 following an 1801 incident where one half of a duo died, the other placed him outside and was then driven mad by the wind causing his dead colleagues arm to appear to beckon him.

Smalls Lighthouse

Smalls Lighthouse stands on the largest of a group of wave-washed basalt and dolerite rocks[3][4] known as The Smalls approximately 20 miles (32 km) west of Marloes Peninsula in Pembrokeshire, Wales, and 8 miles (13 km) west of Grassholm. It was erected in 1861 by engineer James Douglass to replace a previous lighthouse which had been erected in 1776[5] on the same rock. It is the most remote lighthouse operated by Trinity House.[6]

Previous lighthouse[edit]

A model of the original lighthouse, on view at the Science Museum in London

The original Smalls Lighthouse was erected between 1775 and 1776, to the plans of Liverpool musical instrument maker Henry Whiteside.[5] It stood on nine oak pillars, allowing the sea to pass through…
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Source: https://en.wikipedia.org/wiki/Smalls_Lighthouse#Previous_lighthouse