Anti-invasion defences – background

 
The defence of the coast of the ‘German Sea’, as the North Sea was known until 1914, was the responsibility of the Navy and the Army in their respective maritime and terrestrial spheres.  In general, there was almost no coordination of their wider roles but coast defence was one of the few areas in which the War Office and the Admiralty had to work together; coordinated planning was achieved between 1890 and 1903 by the Joint Naval and Military Committee on Defence and, in 1903–4, by a series of joint conferences to discuss the nature and scale of defence required, mainly at naval and commercial ports

The Army built and manned the coast artillery batteries while the Navy managed the maritime defences – booms, patrol vessels, the Examination Service and, later, anti-submarine and anti- torpedo nets.

The oddity was Submarine Mining, which was an army responsibility until 1905 and then, when revived in the First World War, a naval one. Submarine Mining was a defensive weapon developed in the mid-19th century and implemented in the UK from the 1870s until 1905, by a Volunteer branch of the Royal Engineers. When an attack was believed to be imminent the local mining company would arm its mines and lay them in a pre-arranged site. An operator on shore, keeping the minefield under observation, could set off a group of mines if an enemy vessel was detected in the minefield.

Here is the full story of The Submarine Mining Station at Port Laing

The strength of the coast defences in the Forth between 1902 and 1918 is summarised in this table.