Re sighting of light in fog.
St. Catherine's Lighthouse (Isle of Wight) was originally constructed as a forty metre high tower, but subsequently reduced to twenty seven metres in 1875 because of difficulty sighting the light in fog. Is currently the third most powerful light maintained by Trinity.
Mariners use the following tables
Meteorological Optical Range Table
Code No.XXXWeatherXXXXXXXXXXXXXXDistance
0XXXXXXXXDense fogXXXXXXXXXXXXXLess than 50
1XXXXXXXXThick fogXXXXXXXXXXXXXf50 - 200 yards
2XXXXXXXXModerateXXXXXXXXXXXXf200 - 500 yards
3XXXXXXXXLight fogXXXXXXXXXXXXX500 - 1000 yards
4XXXXXXXXThin fog XXXXXXXXXXXXXX.5 - 1.0 nm
5XXXXXXXXHaze XXXXXXXXXXXXXXXX1.0 - 2.0 nm
6XXXXXXXXLight HazeXXXXXXXXXXXX2.0 - 5.5 nm
7XXXXXXXXClearXXXXXXXXXXXXXXXX5.5 - 11.0 nm
8XXXXXXXXVery ClearXXXXXXXXXXXX11.0 - 27.0 nm
9XXXXXXXXExceptionally ClearXXOver 27.0
Personally I don't see how they could have seen the light if you plot on the following chart.