Coastal Artillery


The Firth of Forth has been an important stretch of water since medieval times, when it was an important trading route between the prosperous royal capital and trading partners in Flanders and Holland. The military importance of the Forth in recent times increased dramatically with the construction of Rosyth Naval Base and Dockyard, completed in 1915. Its importance grew throughout the First World War, with the battlecruisers being stationed there. It also was used to repair many of the ships of the Grand Fleet following the Battle of Jutland in June 1916.

Even before the completion of Rosyth, the Forth was of considerable importance and the provision of defences had begun prior to the outbreak of war in 1914. These were organised into Outer, Middle and Inner lines of defence, with coast batteries on both north and south shores of the Forth, as well as on some of the islands within the estuary.

The importance of Rosyth and the Forth was apparent almost from the start of the Second World War, with the attack on ships in the Forth by the German Air Force on 16 October 1939. It was clear, just as it had been in the First World War, that defence of the naval base would need to be a priority, and many of the coast batteries which had been built during the First World War were reactivated in 1939. The orientation of the defence lines had, however, changed, moving down stream to extend the coverage, with the outer line of the First World War becoming the middle line of the Second World War. The inner line consisted of batteries on Inchgarvie, Inchmickery, Incholm, Cramond and Charles Hill; the middle line of batteries on Inchkeith, Leith, Pettycur and Kinghorn. An outer line was later added, comprising batteries built in 1939 and 1940 at Kincraig and Fidra. The name of the latter is actually rather misleading it was not, in fact, built on the island of Fidra, but on the coastline just north of Dirleton.

Fidra Coast Battery became operational in 1940, having been set up in a considerable hurry. Mr Tom Porteous, a forestry worker on Archerfield Estate, was given 24 hours notice by the Army to vacate his cottage, to allow the construction of the battery. Needless to say, he was not very pleased at being forced to move at such short notice! The battery when completed was equipped with two ex-navy 6 inch guns. These weapons had been removed from an obsolete warship and transferred for use by coast artillery. These large calibre guns, along with those at Kincraig and the others at the batteries of the middle line, were intended to fire against any large warships which attempted to enter the Firth of Forth, or to shell targets from off the estuary. The smaller, faster-firing, weapons of the inner line would have countered motor torpedo boats, or a similar such fast-moving threat, which had penetrated up the river towards the Forth Bridge.

Fidra was also equipped with coast artillery searchlights (CASL) which were intended to illuminate ships at night in order that they could be fired upon. Since Fidra was not equipped with radar, as were batteries elsewhere such as Kincraig, fire control could be carried out only by visual means. This required the use of a rangefinder which operated essentially like a pair of binoculars, where each lens was set not a couple of inches apart but several feet. This produced a stereo image from which the range to the target could be calculated. Of course, this process required that the target could be seen, hence the requirement for searchlights at night.

The threat of air attack meant that it was necessary for the gun positions to have overhead cover, something that had not been necessary during the First World War. Gun houses were constructed from brick, with steel girders used to provide support for concrete roofs. Similar methods were used to protect the searchlights. Further defence was provided by means of extensive camouflage measures carried out at Fidra, in an attempt to disguise its real function. False sloping roofs were provided, from which canvas curtains were hung, the effect of which was to turn the gun houses into apparently innocent domestic dwellings, and therefore of no interest to German photographic intelligence. Whether the Germans were aware of the existence of Fidra battery remains unclear, although bombs were dropped close by just before midnight on the night of 3 September 1940. However, these do not appear to be the result of a deliberate attack on the battery, but merely strays dumped by a German bomber.

For much of its short life Fidra had been manned by 309th Coast Battery which was part of the 505th Coast Regiment. However, in 1943 a reassessment took place of the requirement for the extensive coast defences in the Forth area. It was decided that in view of the decreased threat of attack a number of sites would be closed down, one of which was Fidra, which had been placed on care and maintenance by November 1943.

In addition to the Fidra coast battery, another form of coast artillery was provided by five ex-naval guns which were set up in temporary earthen emplacements at Spott. Little information is known about these guns, but it seems likely that they were an emergency emplacement set up in 1940 in response to the threat of invasion and prior to the construction of more permanent emplacements at places such as Fidra. Although the guns at Spott could cover the Firth of Forth, there is no record of them ever having been fired in anger.