Ammunition bunker

The Department's description

Exterior description and setting

Building 1
One of 21 ammunition bunkers erected in Fincarn Glen by American military personnel in 1941-42.
Situated at the top of the slope above the glen, this single-storey, single-bay structure is aligned N-S along the western perimeter of the site, with its entrance is at S. It is of rectangular plan and semicircular cross-section.
All its components are of pre-formed galvanised steel. Its roof and sides are of overlapping curved corrugated sheeting, all completely covered with earth.
The two end walls are of flat steel panels held together with flanges bolted together up their outside faces. These walls have flat tops and sloping sides which extend beyond the roof and sides to retain their earth covering. The back wall (at N) was originally covered with earth as well, but this has been removed and some panels replaced with a doorway. Some of the remaining panels have since collapsed as well, but the vertical reinforcing struts survive.
There were originally two steel doors at its S end, but both are now missing along with part of the wall to the left of the doorway. Affixed to the wall to the left of doorway is an electricity junction box. On its cast aluminium cover is the legend: "100 amp 660 volt flameproof junction box/ Type Walsall" 9346BX/ Groups 2 & 3. PLP 2026/ Isolate supply elsewhere/ before removing covers/ Made in England". Below the top box are two smaller ones, the covers of which read: "This box must be/ entirely filled/ with sealing/ compound". The figure '3' is also painted on the left-hand wall. The wall to the right of the doorway has three metal brackets (for fire buckets), and also the figure '3' and a painted panel reading "Fire point no [?]/ Buckets 3/ Stirrup pump/ [?]". There is no obvious platform in front of the door (but it may be buried).
An earthen berm runs parallel with both sides of the bunker as a blast mitigation measure. It probably extended across its N end as well, but has since been dug away. The OS maps also show a berm a short distance beyond the front of the bunker, but no traces of it survive.
The structure is now disused and overgrown with bushes.

Setting:
All the ammo bunkers were widely spaced out along the glen to minimise collateral damage should one have exploded. The nearest ones to this one are 80m to NE (HB01/06/019E Building 3) and 95m to SE (HB01/06/019G Building 2 ); both are at the bottom of the glen.
This example sits at the top of a wooded slope rising up the west side of the glen. There is an area of scrub to its N and meadow to W and S. A post-and-wire fence marks the boundary of the former military base.

Building 2
One of 21 ammunition bunkers erected in Fincarn Glen by American military personnel in 1941-42.
Situated in the middle of the glen, this single-storey, single-bay structure is aligned E-W into the hillside with its entrance at E. It is of rectangular plan and semicircular cross-section.
All its components are of pre-formed galvanised steel. Its roof and sides are of overlapping curved corrugated sheeting, all completely covered with earth.
The two end walls are of flat steel panels held together with flanges bolted together up their outside faces. These walls have flat tops and sloping sides which extend beyond the roof and sides to retain their earth covering. The back wall (at W) is dug into the hillside and thus covered with earth as well.
There are two outward-opening steel doors at its E end, each with a vent at its bottom. One of the three panels over the door heads is now missing but the surviving two each have a square vent. In front of the doorway is a mass concrete loading platform. On the walls to the left and the right of the doorway are the painted figures '3'.
The bunker is now disused and partly overgrown with bushes. A short distance north are two large metal containers, the function of which is uncertain.

Setting:
All the ammo bunkers were widely spaced out along the glen to minimise collateral damage should one have exploded. The nearest to this one are 95m to NW (HB01/06/019G Building 1) and 100m to SSE (HB01/06/019G Building 4).
This example sits at the bottom of a grassy slope rising up the west side of the glen. The stream flowing northwards through the glen runs in front of its entrance, just beyond an unpaved track down the glen.

Building 3
This structure sits at the top of the slope up the W side of Fincarn Glen, towards its S end. Its original function is not obvious, but its current owner beleives it to have been the base of a water tower, long removed.
It comprises a low polygonal concrete wall cut into the gropund. Overall, it measures 4.9m long by 3.1m wide (16ft 0in a x10ft 0in). The middle section is of octagonal plan and has square extensions on its E and W cants. The octagonal section is open to its top, but the end sections have reinforced-concrete caps, only vestiges of which survive. No fixtures or fittings are now evident.

Setting:
This structure sits on the edge of the scarp down to the glen, between two ammunition bunkers to its NW and SW (HB01/06/019G Building 1 and /019H Building 1). An unsurfaced track runs along its E side and the post-and-wire boundary fence around the military premises lies a short distance W.

Building 4
One of 21 ammunition bunkers erected in Fincarn Glen by American military personnel in 1941-42.
Situated towards the south end of the glen, this single-storey, single-bay structure is aligned E-W into the hillside with its entrance at E. It is of rectangular plan and semicircular cross-section.
All its components are of pre-formed galvanised steel. Its roof and sides are of overlapping curved corrugated sheeting, all completely covered with earth.
The two end walls are of flat steel panels held together with flanges bolted together up their outside faces. These walls have flat tops and sloping sides which extend beyond the roof and sides to retain their earth covering. The back wall (at W) is dug into the hillside and thus covered with earth as well.
There are two outward-opening steel doors at its E end, each with a vent at its bottom; there are also three vents over the door head. In front of the doorway is a mass concrete loading platform. On the walls to the left and the right of the doorway are the painted figures '3'. Also to the right of the doorway is a painted panel bearing the words 'buckets' and 'stirrup'.
The bunker is now disused and grassed over.

Setting:
All the ammo bunkers were widely spaced out along the glen to minimise collateral damage should one have exploded. The nearest to this one are 100m to NNW (HB01/06/019G Building 2) and 105m to S (HB01/06/019I Building 2).
This example sits at the bottom of a grassy slope rising up the west side of the glen. The stream flowing northwards through the glen runs in front of its entrance, just beyond an unpaved track down the glen.

Historical information

The Fincarn Ammunition Depot was constructed by American military personnel with the assistance of local labour. It was completed by May 1942 and used for the temporary storage of munitions shipped into Lisahally Port on Lough Foyle, 6km to the north. From Fincarn, the ammo was transferred to military bases such as the nearby Maydown and Eglinton airfields.
The steelwork on many of the ammo bunkers bear the legend "Armco Ingot Iron Manufactured by the American Rolling Mill Co Middletown, Ohio 2oz coating". 'Armco' is the acronym of the American Roller Mill Corporation of Middletown Ohio, founded in 1899 and a pioneer of continuous rolled sheet steel production. The name is still used generically to this day to denote cylindrical corrugated metal culverts under roads etc.
This bunker is essentially a standard Armco hut, the size of which was 50ft x 20ft x 10ft radius. Its heavy-duty galvanised steel sheeting and arched cross-section made it capable of being buried under several metres of earth. It is not unlike a Quonset hut, the American equivalent of the British Nissen hut, but without any internal framework and by a different maker.
C Company of the 1st Provisional Marine Battalion, an infantry brigade of the US Marine Corps, was based nearby at Beech Hill and performed guard duty here for a time. The bunkers may also have been used for as a chemical storage depot (known as C-910) between November 1943 and August 1944.
Although erected in the early 1940s, no buildings or structures are depicted in Fincarn Glen on the 1948-49 OS map, presumably for security reasons. All the features are, however, shown on the 1963 OS map under the caption "Disused Camp Site".

References - Primary Sources:
1. PRONI OS/6/5/14/5. OS 1:2500 map, Co Londonderry sheet 14-05 (1948-49).
2. PRONI OS/11/37/5/1. OS Irish Grid map sheet 37-05 (1966-67).
3. PRONI OS/11/37/9/1. OS Irish Grid map sheet 37-05 (1968).

Secondary Sources
1. A. Glenfield, Second World War in Northern Ireland, .
2. ARMCO history: ,, and .
3. Quonset huts: J. Decker & C. Chiei (eds), Quonset: Metal Living for a Modern Age (Princetown: Princetown Architectural Press, 2005), and .
4. Chemical storage, .

Criteria for listing: architectural interest

Not listed

Criteria for listing: historic interest

Not listed

Evaluation

This record has now been protected by scheduling under LDY014:014 and can be viewed on the NISMR database:

Building 1
A corrugated steel ammunition bunker built by the US military authorities in 1941-42 for the temporary storage of ammunition.
This ammo bunker is of architectural interest as a good example of a Second World War ammunition store. Its superstructure is of lightweight pre-fabricated components so that it could be transported easily (across the Atlantic in this case) and quickly erected using unskilled local labour. Its semicircular arch design did away with the need for an internal frame and no foundations were required as it was self-supporting. Pre-fabrication was extensively used during the war for military buildings and structures. Once fabricated, earth dug from its vicinity was used to give the store added protection against blast damage and also camouflaged it. The berm around it gave added protection in the event of an explosion.
The bunker's setting is of special note - adjacent to a narrow glen which could be easily defended at both ends. The spacing between it and its neighbours - 80+ metres - also minimised any damage should one have exploded. It also has considerable group value in being one of 21 ammo stores and one of 24 surviving military structures in Fincarn Glen.
Historically, this bunker had a rare and unusual function. Its original fabric survives unaltered, albeit partly missing and in poor condition. It is a tangible reminder of the large American presence in and around Londonderry during the Second World War. The Fincarn ammo stores are probably the largest surviving concentration of their type anywhere in the Province.
Because of their specialist function, American connection and survival as a group, they are not only of local interest, but of provincial significance as well.

Building 2
A corrugated steel ammunition bunker built by the US military authorities in 1941-42 for the temporary storage of ammunition.
This ammo bunker is of architectural interest as a good example of a Second World War ammunition store. Its superstructure is of lightweight pre-fabricated components so that it could be transported easily (across the Atlantic in this case) and quickly erected using unskilled local labour. Its semicircular arch design did away with the need for an internal frame and no foundations were required as it was self-supporting. Pre-fabrication was extensively used during the war for military buildings and structures. Once fabricated, earth dug from its vicinity was used to give the store added protection against blast damage and also camouflaged it. The interior is reasonably well preserved, and its historical significance greatly enhanced by the stencilled and handwritten inscriptions. Its character is diminished somewhat by the animal pens, but these could be removed easily.
The bunker's setting is of special note - in a narrow glen which could be easily defended at both ends. The spacing between it and its neighbours - 95+ metres - also minimised any damage should one have exploded. It also has considerable group value in being one of 21 ammo stores and one of 24 surviving military structures in Fincarn Glen.
Historically, this bunker had a rare and unusual function. Virtually all its original fabric survives in an unaltered state. It is a tangible reminder of the large American presence in and around Londonderry during the Second World War. The Fincarn ammo stores are probably the largest surviving concentration of their type anywhere in the Province.
Because of their specialist function, American connection and survival as a group, they are not only of local interest, but of provincial significance as well.

Building 3
Presumed to have been the base of a water tower,, this relatively small concrete structure was built by the US military authorities in 1941-42 in connection with the Fincarn ammunition depot. However, it is of no special architectural or historical merit.

Building 4
A corrugated steel ammunition bunker built by the US military authorities in 1941-42 for the temporary storage of ammunition.
This ammo bunker is of architectural interest as a good example of a Second World War ammunition store. Its superstructure is of lightweight pre-fabricated components so that it could be transported easily (across the Atlantic in this case) and quickly erected using unskilled local labour. Its semicircular arch design did away with the need for an internal frame and no foundations were required as it was self-supporting. Pre-fabrication was extensively used during the war for military buildings and structures. Once fabricated, earth dug from its vicinity was used to give the store added protection against blast damage and also camouflaged it. The interior is reasonably well preserved, and its historical significance greatly enhanced by the stencilled and handwritten inscriptions.
The bunker's setting is of special note - in a narrow glen which could be easily defended at both ends. The spacing between it and its neighbours - 100+ metres - also minimised any damage should one have exploded. It also has considerable group value in being one of 21 ammo stores and one of 24 surviving military structures in Fincarn Glen.
Historically, this bunker had a rare and unusual function. Virtually all its original fabric survives in an unaltered state. It is a tangible reminder of the large American presence in and around Londonderry during the Second World War. The Fincarn ammo stores are probably the largest surviving concentration of their type anywhere in the Province.
Because of their specialist function, American connection and survival as a group, they are not only of local interest, but of provincial significance as well.