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Kilroot Coastal Artillery Battery

A site visit and photographic report on the history and current condition of Kilroot Battery, a 1910 coastal artillery battery on the western coast of Belfast Lough. The fort was in use until 1956 when the coastal artillery units were disbanded, and during the Second World War, it saw expansion when a hunted infantry camp was constructed in the fields to the rear. With the exception of the gun positions, the majority of the fort buildings remain and most are in daily use by the current owners, Irish Salt Mining and Exploration Company Ltd. This report has been compiled following a visit to the site in December 2019, and I will attempt to visualise or compare features of Kilroot with those elsewhere as much as possible to give an impression of what the fort would have looked like.


Constructed as a sister fort to Grey Point (completed 1907) across Belfast Lough, the coastal artillery battery at Kilroot was completed in 1910. The recommendation for a second fort covering the Lough was made in 1905 in a report of the Committee of the Armaments of the Home Ports by Colonel J F Owen, and Kilroot was chosen as the location (Defending the North, Bill Clements, 2003). Kilroot was designated an inspection battery, tasked with carrying out inspections of shipping wishing to enter Belfast Lough. This may have been an arbitrary decision, or in part have been due to the Fort’s position as a field of view (and fire) out to and beyond the Bangor and the Copeland Isles. It may also have been due to the deep water anchorage available off the shore at Kilroot.

Maps & Plans

The fort at Kilroot was absent from contemporary mapping, as was common practice for security purposes, however the site is denoted by the presence of BS WD markers on the map – War Department Boundary Stones © Ordnance Survey Ireland.
A first world war era plan of Kilroot Battery (modified by the author for the web) from Military Archives Ireland (reference AD119287-003). The plan shows the above-ground structures of the 1910 battery in outline, but also has a hunted infantry camp to the rear. I believe this camp was a later addition following the declaration of emergency in 1914.


A plan of the fort from 1911, soon after competition. Plan from National Archives WO 78/4748.

From the 1911 plan, we know much more about the fort and the buildings that were constructed originally.

  • Two barbettes for 6-inch breech-loading coastal artillery guns
  • Two magazines and shell stores
  • Shelter
  • Royal Artillery (RA) store
  • Two 18-men blockhouses
  • Guardhouse or caretakers quarters
  • Cookhouse
  • Ablution room
  • Latrines
  • Workshop
  • Machine gun shed and stores
  • Oil and paint store

Representation of a fort similar in design to Kilroot with subterranean magazines and two gun positions mounted in barbettes. Tynemouth Castle Battery, Historic England reference IC103/006. Artist Nick Hardcastle.

Representation of a fort similar in design to Kilroot with subterranean magazines and two gun positions, mounted in barbettes.
Oil and paint store from the 1911 plan of the fort.
Latrines from the 1911 plan of the fort. Situated behind the main crew shelter. The perimeter wall to the front and side of the latrines is original to the fort’s construction.
Guardhouse from the 1911 plan of the fort, with original cast iron pillars.


You may think there is a notable omission in the original plan; barrack accommodation. While a hutted camp appears to have been constructed to the rear of the fort in 1914, in peacetime there may not have been barracks other than the above-ground shelter in the middle of the battery. The fort was manned by locally recruited soldiers from the Royal Garrison Artillery and the Antrim Royal Garrison Artillery (Special Reserve). With local barracks at Carrickfergus Castle, Victoria Barracks in Belfast or Palace Barracks in Holywood, or indeed local soldiers living at home, there was no requirement for permanent barracks. Nor would the fort have been manned permanently in peacetime; instead a resident caretaker (living in the guard house) would have maintained the fort, with soldiers arriving for training or in the event of mobilisation.

There were two shelters marked on the plans of Kilroot. These were rooms that the crew on watch would have rested in. One was above ground and one was opposite the magazines below ground. It is likely there was more comfort above ground, with facilities for recreation and eating, and below ground would have been used for high readiness. Neither of these shelters was entered during the visit.

The above-ground shelter is the building on the right of this image. The later addition on top serves as the mining company offices. To the left is the fort guardhouse.
The second shelter at the fort was below ground and was accessed by the door on the right.

Defensive Measures

With the political situation in Ireland becoming more volatile, protection against angry locals was just as critical as protection against invading foreign powers. To defend the fort from land attack, two defensive positions, or blockhouses, were constructed at the north and south; left and right on the plan above. These would have housed up to 18 men each, most likely infantry-trained soldiers, and provided protection against land attack. I haven’t seen examples of blockhouses of this nature in England, but below is an example from Lenan Head Fort on Lough Swilly that is likely to be similar to the ones at Kilroot.

Blockhouse at Lenan Head Fort

We have become accustomed to invasion by shore landing following the successes of D-Day, but in the early stages of the 20th Century when Kilroot was constructed, an invading force needed a deep anchorage or port from which to mount their invasion. In what was to become Northern Ireland, Belfast was the leading industrial shipping port, had a large rope works, shipyard and so its protection was of utmost importance. Further afield the deep water of Lough Swilly, Lough Foyle, as well as Berehaven, Dublin and Cork ports were strategically important for protecting Ireland against invasion and had been similarly defended since the mid-19th Century.

Ammunition Storage

As was the convention of the time for large calibre guns, ammunition was stored in component parts; high explosive shells, propellant or powder in cartridge form, as well as fuzes for the shells. Stored in bulk, and susceptible to catastrophic damage in the event of enemy action, the deep core of most batteries was the magazine; or ammunition store. The magazines at Kilroot are remarkably preserved with some fascinating details.

My plan of what I believe the magazines looked like and their allocated use. Each gun had a separate cartridge and shell store. From my brief visit, I could not ascertain if there were shell lifts to the surface, but the two ‘gun level’ rooms at each end of the cartridge store may have allowed access from the store to the rear of the ready-use lockers.

Ready Use Lockers

What I haven’t seen in other forts of similar construction are lockers that appear to have been accessed from inside the magazine that would also have been at the gun level. Ordinarily, ammunition was raised to the surface by means of a shell lift directly from the magazine to a hatch by each gun. At Kilroot, these small annex rooms are at a split level joining the magazines to the gun level above. It’s possible that ammunition was passed through an issue hatch to this level, before being placed into the lockers for access by the gun crew.


The battery was equipped with twin 6-inch Breech Loading (BL) Mark VII guns in barbettes. Capable of firing a 45 kg high explosive shell up to a distance of up to over 14 km, these two guns could provide an impressive 16 rounds a minute between them. Neither, however, were ever fired in anger, but the crew would most likely have undertaken regular practices.

6 inch Breech Loading (BL) Mark VII guns on a typical coast mounting and in a barbette at Newhaven Fort, on the south coast of England. The guns at Kilroot would have been to this specification © Author.

A fascinating British WW2 training video is online courtesy of the Australian War Memorial. This 20-minute video gives us a great insight into the operation preparation and workings of a 6-inch coastal artillery battery.

The two gun positions at Kilroot have since been removed, as have the two flanking infantry blockhouses, and the earth banks to the front have also been dug away, exposing the front of the fort structure and helpfully giving an insight into construction. It appears that all the ancillary fort buildings remain and are still in daily use, and a large proportion of the original internal boundary wall exists. Kilroot shares a number of features with Grey Point fort but does not appear to have seen the further developments that Grey Point saw.

The front of the gun positions at Kilroot. Much of the earth bank has been removed, as have the barbettes and gun positions. What remains are the two buttresses at either end representing the ground level the barbettes would have been at, and the block in between is the buried magazine and shell store that would also have been covered with earth.

Records also tell us that the fort was equipped with three Maxim .303 machine guns (reduced to two in 1912). The Maxim was a formidable weapon of the early 20th Century, really being the first portable machine gun of the time, mounted on a wheeled carriage, and firing up to 650 rounds a minute from a continuous belt of ammunition. These Maxim guns, used for protection from land-based attack, would have been housed in the machine gun shed, below:

Inter-War Modifications

Searchlight emplacements, also known as Coast(al) Artillery Search Light (CASL), were installed in 1936 at Kilroot and Grey Point. The designs of the two are similar but not identical, Kilroot being constructed on two levels, and accessed by a side door via external steel stairs, the Grey Point CASL emplacements had rear entry doors.

What is unusual about the Kilroot CASL emplacements is that they are on two levels. This may be in part to their proximity to the water level and they required extra elevation, or that a generating set was installed below each CASL. Inside the emplacement on the lower level is evidence of wooden battening on the walls, perhaps to dampen the sound, and also a hole in the ceiling between each floor, perhaps to pass power cables to run the light. Without an examination of the floor (which was covered in detritus) to reveal any mounting bolts, I won’t know for sure.

Detached from the main fort, the ground floor of the emplacements had steel shuttered loopholes facing to the rear and sides. Perhaps this also acted as a defensible position in the event of a land attack?

Since publishing this article, I have discovered a simple line in the war diary of D.C.E. (Defences) from 3 February 19411The National Archives, WO 166/1139 accessed November 2022. The entry reads “Got C.F.D. to agree to a standard D.E.L.2Defence Electric Light, a type of searchlight associated with coastal artillery batteries. emplacement for No. 2 D.E.L. but with pillbox in base”. The text is ambiguous, talking about the batteries at Larne and Kilroot, but in principle a double height design of D.E.L. is likely to have been constructed at more than one battery.

Kilroot Fort Searchlight Emplacements

Fort Visit, January 2020

Below is my album of images from a permission visit in January 2020 to the site of Kilroot Battery.

Kilroot Fort

  • 1
    The National Archives, WO 166/1139 accessed November 2022
  • 2
    Defence Electric Light, a type of searchlight associated with coastal artillery batteries.