Font Size

100% 150% 200%

Background Colour

Default Contrast
Close Reset

Clyde Defences, Portkil Battery Land Defences, Toman Dubh, No 3 Position

Blockhouse(S) (First World War), Trench(S) (First World War)

Site Name Clyde Defences, Portkil Battery Land Defences, Toman Dubh, No 3 Position

Classification Blockhouse(S) (First World War), Trench(S) (First World War)

Canmore ID 133244

Site Number NS28SW 30

NGR NS 2439 8134

Datum OSGB36 - NGR


Ordnance Survey licence number 100057073. All rights reserved.
Canmore Disclaimer. © Copyright and database right 2022.

Toggle Aerial | View on large map

Digital Images

Administrative Areas

  • Council Argyll And Bute
  • Parish Rosneath
  • Former Region Strathclyde
  • Former District Dumbarton
  • Former County Dunbartonshire

World War One Audit of Surviving Remains (15 July 2013)

The enclosure (NS 2439 8134) noted in the local SMR coincides with a defensive structure marked on a War Office map dated 1916 (The National Archives WO 78/4396), of the outer landward defences of Portkil Battery. . It is one of two 'Blockhouses' and two (possibly three) trench systems forming 'No. 3 Position'. The blockhouses are shown as being surrounded by horse-shoe-shaped banks. The other pillbox was at NS 24293 81502, and the maps show that this was connected by telephone to the battery. The two trench systems were at NS 24205 81550 and NS 24383 81743, which is noted on the local SMR as a Shieling hut. What may be a third cresent shaped trench not depicted on the War Office map lies at NS 24534 81608.

Information from HS/RCAHMS World War One Audit Project (GJB) 15 July 2013.

Archaeology Notes

NS28SW 30 2439 8134

NS 2439 8134 Enclosure.

Strathclyde Regional Council SMR 1995.


Project (March 2013 - September 2013)

A project to characterise the quantity and quality of the Scottish resource of known surviving remains of the First World War. Carried out in partnership between Historic Scotland and RCAHMS.

Field Visit (26 September 2016)

The First World War defences on Toman Dubh form part (No. 3 Position) of a larger infrastructure designed to protect the Portkil Coastal Battery (NS28SE 39) from its landward side (see also NS28SW 5, and NS28SE 39.15-17). Toman Dubh is a low rise in boggy moorland partly occupied by a mature conifer plantation, and the defences on it comprise two blockhouses (No. 5 and No. 6) and four firing trenches, some of these elements being depicted on a military plan (National Archives: WO78/4396). Blockhouse No. 5 (NS 24277 81486) is situated on the highest part of the hill, close to the crest of the steepish west flank which runs down to Lindowan Reservoir. Unfortunately, whilst its location was identified with some degree of certainty on the date of visit, forestry ploughing and the subsequent growth of the trees has rendered the positive identification of specific elements of the blockhouse very difficult. Similarly with the trenches (NS 2419 8156) depicted on the plan lying downhill and NW of the blockhouse, a short distance inside the edge of the modern plantation. Blockhouse No. 6 (NS 24389 81334) is situated on the SE shoulder of the hill in rough pasture. Subcircular on plan, it measures approximately 9m in diameter within a grass-grown bank about 1.5m in thickness and 0.4m in external height with an entrance on the SW. An external ditch, which probably served both as a drain and a source of material for the bank, measures up to 2.9m in breadth on the WSW by 0.2m in depth. Three firing-trenches are situated on the north and north-east flanks of the hill, all comprising a comparatively shallow ditch 1m to 1.2m in breadth and from 0.7m to 1m in depth, fronted by a low upcast mound. The most westerly ditch (NS 24380 81749) is a NW-facing arc at least 25m in length. The second trench lies about 25m uphill to the SE (NS 24410 81718) and comprised a straight length of waterlogged ditch some 13.5m long and facing NNE. The third trench (NS 24533 81606) is a NE-facing arc measuring about 27m in length.

Visited by HES, Survey and Recording (JRS, AK, AM) 26 September 2016.


MyCanmore Image Contributions

Contribute an Image

MyCanmore Text Contributions