The General Service groundsheet was introduced as early as 1897 and was to see service through both world wars. It was a tan sheet of rubberised fabric, 6ft 6in x 3ft and with 36 eyelets around its edges. This very versatile item could be used as a waterproof sheet on which to sleep to protect the user from the damp earth, could be used as a waterproof cape by wrapping it around a soldier’s shoulders or by joining two or more together using the eyelets and a piece of string small shelters could be constructed for a couple of men. Although supplemented by the MK VII design, which included a triangular portion and a collar to be a true cape, the original design remained in service and largely unchanged until after World War Two. At this point the colour of the groundsheet was updated from tan to dark green:The same colour change was implemented for the MK VII cape, however the groundsheet was approaching obsolescence and today although the cape remains very common, the green groundsheet is much harder to find. To be honest, until I came across this example I was not even aware that the groundsheet had been produced in green (even after more than ten years of collecting you are always learning new things!)
Other than the change in the colour, the design is unchanged and features eyelets all around the edges to allow a bivy to be constructed from multiple sheets:The groundsheet has a lovely clear maker’s stamp indicating it was produced by G Strauss & Sons in 1952:The official guidance for the making of the rubberised fabric dates back to 1917 and manufacturers were advised:
- Material and dye.- Each sheet is to be made of dyed cotton equal in quality and make to that of the sealed pattern; the dye must be similar in shade of colour to that of the sealed pattern, and must be equally fast with this to the action of atmospheric influences, weak acids and alkalis, detergents and bleaching agents.
- Proofing. – The proofing of the fabric, which is to be approximately of the same shade as that of the sealed pattern, and of smooth surface, must consist of:-
Mineral matter … not more than 52 per cent.
Sulphur … … not more than 3 per cent.
Rubber … … not less than 45 per cent, on the average (no single sheet to contain less than 43 per cent.)
The rubber is not to contain more than 10 per cent. organic matter extractable by acetone and not more than 10 per cent. organic matter extractable by alcoholic potash, after removal of acetone extract. No reclaimed, reworked, or de-resinified rubber is to be used.
The mineral matter, other than that used for colouring the proofing, is to consist of a mixture of zinc oxide and litharge.
Small additions of other ingredients, such as are generally recognised as having a beneficial influence on the composition or vulcanization, may be allowed (carbonates of magnesium excepted).
The nature and proportions of the various ingredients proposed as mineral matter, together with the nature and amount of colouring materials, must be declared at the time of tendering.
The method of conducting the analysis is that laid down in the General Appendix to Specification for Rubber Goods…
- Proofing.- The proofing must be free from grit and large sized particles of mineral matter, and must be uniformly spread over the surface of one side of the fabric; it must be of such thickness that a 3 inch square (9 square inches) of fabric shall have on its surface not less than 30 grains of proofing.
The proofing must be well vulcanized and adhere firmly to the fabric, and when detached from the fabric by a suitable solvent and dried, it must be elastic and not readily broken.
The sheets may be inspected as regards proofing during manufacture (and samples taken) by the Chief Inspector, (Inspection Department), Royal Arsenal, Woolwich, or his representative.’
This groundsheet was an excellent little find and as my collection of post war jungle kit has grown, new finds have become more infrequent making a new discovery all the nicer.