Ammunition bunker

The Department's description

Exterior description and setting

Building 1 (B1)
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 NW-SE into the hillside with its entrance at NW. 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 SE) 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; the left-hand one is now off its hinges. In front of the doorway is a mass concrete loading platform. On the wall to the left of doorway are two metal brackets (for fire buckets), the painted figure '3', and lettering reading "Fire point no [?]/ Buckets 3/ Stirrup pump". On the wall to the right of the doorway is a green painted panel reading "Fire alarm ...".
The bunker is now disused and overgrown with trees and shrubs.

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 175m to N (HB01/06/019D Building 2) and 105m to SW (HB01/06/019F).
This example sits at the bottom of a wooded slope rising up the east side of the glen. The stream flowing northwards through the glen runs in front of its entrance, just beyond a grassed-over trackway down the glen.

Building 2 (Record only)
This structure is located in the middle of Fincarn Glen, immediately SE of the stream of the same name which runs northwards through the glen. It is cut into the base of a steep vegetated slope and comprises a cast-in-situ mass concrete cube open along its NW side. This side formerly had a hinged metal door which now lies loose to one side. Apart from the doorway, no external features are visible.

Setting:
The shelter sits just SE of the Fincarn Glen stream, with a concrete track running along the side of the watercourse. On the opposite side of the stream is an ammunition bunker (HB01/06/019F), and to its NE and S are two further bunkers (HB01/06/019E Building 1 and /019E Building 3 resp).

Building 3 (B1)
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 W. 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 E) is dug into the hillside and thus covered with earth as well.
There are two outward-opening steel doors at its W end, each with a vent at its bottom; the left-hand one is now off its hinges. There are also three vents in the panelling over the door head. In front of the doorway is a mass concrete loading platform. On the wall to the left of doorway is the painted figure '3'. There is an identical figure on the right-hand wall along with a painted panel with instructions in the event of a fire.
The bunker is now disused and partly overgrown with trees and shrubs.

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 NW (HB01/06/019F) and 80m to SW (HB01/06/019G Building 1 ).
This example sits at the bottom of a wooded slope rising up the east side of the glen. The stream flowing northwards through the glen runs in front of its entrance, just beyond a grassed-over trackway 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 well preserved 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 remarkably well preserved.
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 stare. 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
Presumed to have been a store, this 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 3
A corrugated steel ammunition bunker built by the US military authorities in 1941-42 for the temporary storage of ammunition.
This well preserved 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 remarkably 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 - 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. Virtually all its original fabric survives in an unaltered stare. 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.