Cornelia Battery Engine Room, (Building T199)
Click to view large map
|See more photographs|
The Cornelia Battery Engine Room (today also known as a Generator Room or Power House) supplied power to the Cornelia Battery on the northwest side of Robben Island. The Cornelia Battery included the No.1 and the No.2 6" Gun Emplacements, the Battery Observation Post (BOP), the Command Post, the Workshop and two Searchlights.
The Engine Room was designed to protect and camouflage the Generator installation. The Engine Room is situated a short distance to the south of the Cornelia Battery, to the southwest of No. 1 Searchlight Emplacement Building (Cornelia Battery) and to the southwest of No. 2 Searchlight Emplacement Building (Cornelia Battery).
The Engine Room is large rectangular, single-storey, reinforced concrete structure with a flat roof. The internal and external faces of the concrete walls and underside of the flat concrete roof bear clear 'witness marks' of the timber planks that were used for temporary shuttering during construction. The short span of the flat concrete roof was supported by substantial concrete down-stand beams. The steel reinforcing bars within the concrete walls have rusted in places and have caused localised spalling of the concrete on the exterior facades.
The door and window openings all have a projecting horizontal concrete hood mould directly above the opening to 'shed' any rainwater running down the facade and to minimise the impact of this water on the window or door opening. A similarly shaped concrete window cill is provided to all the window openings.
The 'memory' of a rectangular painted sign exists above the entrance door with the Building Number 'T199' (painted by the military) still just visible. A more recent building number 'A2' has been painted in white paint on a small black rectangular background on the right hand side of the door. Remnants of painted camouflage patterns exist on the external face of the concrete walls.
Entry into the building is through a double outward opening door (on the northeast side) made of steel plates, rivetted to a heavy welded angle iron frame. Each door leaf was hung on heavy duty metal pintle hinges. A rotating bar and staple was used externally to secure the doors in a closed position.
The Engine Room was provided with inward-opening steel cottage pane casement windows with heavy outward-opening steel plate shutters. The doors and the window shutters are badly affected by rust due to the exposed position of the building.
Fresh cool air was drawn over each of the Engine radiators through low-level rectangular openings on the west wall. These openings were provided with double sided fixed louvres made of heavy steel plate to direct and control the air flow.
Groups of four small simple rectangular openings were provided on the internal face of the concrete wall at high level to allow the warm air to exit the building. Similar groups of five small rectangular ventilation openings were provided on the external face of the concrete wall but these were not aligned with the internal openings and therefore did not permit a direct line of sight into the building. This arrangement was presumably designed to minimise light exiting the building at night under emergency conditions. Each of the rectangular openings was provided with a woven mesh screen - close to the external face - to prevent the ingress of birds.
The Engine exhaust pipes exited the building though low level openings on the west wall and rose vertically up the external face of the wall. The flat concrete roof was cantilevered an additional distance on the western side. Four circular penetrations were provided through this cantilevered edge - at positions matching the exhaust pipes. These apertures permitted the external wall-mounted vertical exhaust pipes to pass through the edge of the roof slab and discharge above roof level.
The electrical Generators and other equipment were presumably removed when the military ceased to have a presence on the Island in 1960. Clear 'witness marks' visible on the interior walls of the building provide interesting evidence of the original layout of the four generator control panels, conduiting, pipework, fuel lines, electrical switchgear and signage. These items - if not stripped out by the military - have all been removed in the intervening years - presumably as memorabilia or by scrap metal collectors.
What appears to be the original internal wall paint survives internally with a 'battle-ship' grey dado, a darker green dado line and a light khaki (now over painted with a cream) for the balance of the walls and ceiling.
The generating equipment installed in the Engine Room comprised three large diesel driven DC generators; presumably one for each searchlight and the third to power the balance of the Battery. A fourth, smaller generator was also provided for auxiliary services when the large generators were shut down.
In order to start the diesel engines it was apparently standard practise to lift all the valves to the cylinders in order to decompress the engine. The engine was then 'swung' using a manual crank handle; a single cylinder's valves were closed to start on one cylinder after which the others would be progressively brought in.
It has not been determined where the main diesel tank for the the fuel supply to the generators was originally accommodated. However witness marks (paint shadows) are visible on the internal face of the wall at high level above each generator providing clear evidence of the size and position of a small daily, or ready use, fuel tank. These diesel tanks were mounted on the wall through which the air intakes and exhausts passed.
Each of the four generator units was mounted as a single unit on a steel frame on a low linear concrete plinth to permit secure mounting and levelling of the electrical generator and in-line engine. Each generator unit comprised of a diesel engine linked to an electrical generator and each unit was carefully 'shimmed' to ensure it was perfectly level. The units could obviously be split and dismantled to replace defective or damaged major components if required.
The Engine Room's heritage value lies in its historical associations with World War II, as a good example of a building designed for a particular purpose and function and as an architectural landmark on the coastline of Robben Island.
STATEMENT OF SIGNIFICANCE
The Engine Room is closely associated with the defence of Table Bay (and Cape Town) during World War II (1939-45), and during the immediate post-war period when the Island was used as a military Training Base. The building accommodated, protected and camouflaged the generators which enabled the daily operation of the Cornelia Battery and more importantly the nighttime operation of the two Cornelia Battery searchlights.
The Engine Room is a good example of specialised coastal defence architecture. The scale and volume of the machine room, the cantilevered roof overhang, the in-situ off-shutter cast concrete finish and the heavy louvred steel shutters all create a distinctive visual impact.
The Engine Room reinforces the character of the historically important WWII layer present on Robben Island. The choice of construction materials and the robust detailing relate closely to the other concrete structures built for the military on Robben Island.
CHARACTER DEFINING ELEMENTS
The heritage character of the Engine Room resides in the following character-defining elements: Its small scale one-storey, concrete construction, the witness marks of interior fittings (now removed), the heavy duty steel window shutters, the louvred fresh air intakes on the east side of the building, the memory of the exhaust pipes on the external facade, the memory of the engine coolant pipelines and ready tanks, the low linear concrete plinths for secure mounting and levelling of the Electrical Generators and in-line Engines, the recessed floor ducts for the reticulation of the electrical cables and the steel plate doors.
Text compiled by William Martinson with invaluable input and advise from Chris Dooner; October 2019.