The northern Scottish islands of the Orkney Islands were positioned perfectly for the Grand Fleet based at a large safe inlet of Scapa Flow. It's strategic importance meant that it's perfect position meant the Grand Fleet could be deployed in to the northern entrance to the North Sea and the Atlantic.

For aerial protection it was decided that a RNAS airship base would need to be set up. The challenges of this was that on the Orkney Islands, there are few trees, which would mean very little in the way of protection from the prevailing winds which would sweep over the landscape from the North Atlantic. Most airship sites were selected having natural sheltered positions from the wind.

It was mid way through the First World War, in April 1916 that Commander Roland Hunt was sent to select a location for an airship base. Earlier Col. Harris who was Commander of the Orkney Defenses, had scouted out a number of locations on the island in the vicinity of Scapa Flow. Harris had reported back that only two locations would be suitable.

Of the two, a small hollow situated some two and a half miles west of Kirkwall, provided protection from the prevailing winds. With the exception of some low barbed wire fences to keep the sheep in local fields by the farmers on the islands, the surrounding countryside was clear of any obstacles for a considerable distance, and thus proving suitable for airship operations.

There was suitable dry level ground for the foundations of an airship shed. Other than the exposure to the prevailing wind, one of the other drawbacks about Orkney was that, surprisingly for Scotland, was the lack of a water supply during the summer months. It was noted that the water was almost non existent, the only source of water being a stream used by a local whisky distillery nearer the shore.

The onset of the winter months proved troublesome as had been expected for the RNAS Caldale. It was reported to the Admiralty in November 1918, that very high winds and heave rain had been experienced, and these were sweeping through the shed. Doors had not been fitted in time and it was not possible to re-inflate the ships as at the wind was sweeping through the shed. The rain was also soaking the aeroplanes which had also been stored in the shed, despite efforts to protect them with deck cloths. Some work had begun on the Coastal Patrol shed, but this had been destroyed by wind and needed to be cleared away before progress could be started again. The hydrogen main and electrical circuits had been delayed due to the non delivery of material. One other thing which hampered the construction process was that as the site was so far north, in the winter months with the clocks changing back in October, it meant that it was noted that it was barely daylight by 8:00am in the morning and dark again by 4:30pm, thus cutting down the productive working hours.

Due to this delay on the Coastal shed, and the winter weather, it was decided to suspend any airship flying operations, and the RNAS base was now put on a "care and maintenance" basis only for the winter months.

The situation improved in the spring of 1917, and operations resumed in the April. A submarine bomb target had been laid out on the ground to offer target practice to the airship crews. The Submarine Scout shed was nearing completion and material had arrived at the docks for the erecting of the second shed. Like with some of the other RNAS stations, as they were often sited in remote coastal areas, getting the materials from a railway station or from a nearby dock, the last few miles always proved troublesome. The motor lorry allocated to do the job, kept on breaking down, and thus hampered the deliver of the materials. A light railway assembled so that the last half mile could be delivered from the dock without too many issues. In August, the onset of fog, and also high winds limited th number of patrols which could be flown by the Submarine Scout ships which were based there.

Construction of the new airship shed was assisted by 100 men from the Grand Fleet, which was moored in Scapa Flow. The second Coastal shed was finally completed in the end of 1917, and the windbreaks were still being worked upon. Unusually for an airship station there were six which had been erected to provide as much shelter as possible.

Unfortunalty in the latter part of 1917, firstly 26th November 1917, the S.S.P.2 left Caldale on patrol, however the wind strengthened, and after an hour the pilot decided to return to base. Shortly on this turn for home, the ship signaled that it's engine had failed and it was going to make a forced landing. A station lookout later reported that he had seen the S.S.P.2 come down in the sea, and explode off the Island of Westray HMS Leopard, which had been in the vicinity could not trace the wreckage or survivors. It's crew of 3 men, Flt Lt S. Deveraux, AM1 A.E. Scott, and L.M. J Wilson (Wireless Operator) were all lost.

In December another incident occurred. The S.S.P.4 left the base on a night flight on the evening of 21st December 1917. After an hour, it reported that it was snowing heavily and it was attempting to return to the base. Over the next few hours the airship reported that it could not make any headway due to the wind. The crew requested that ships with searchlights be sent to the area so they could determine their position. After this last message, no further messages were received. The remains of the S.S.P.4 were found on the Island of Westray the next day. There were no signs of the crew consisting of Flt. Cdr W. Horner, L.M Anthony and AM9 R.Behn.

The winter weather caused the local roads to the base to become blocked, and the lorry was unable to make deliveries. The essential supplies were delivered to the base on sledges pulled by ratings. By the end of 1917 only one Submarine Scout ship remained, S.S.41. It had been deflated in the shed for maintenance.

Perhaps it was a consequence of the loss of the two airships in the winter months, the Admiralty decided that the base be closed on 22nd January 1918. This was not the end of the story for RNAS Caldale. A short time later, the base was reopened as a kite balloon station, which were manned balloons which were towed behind warships to direct the gunfire of the fleet.

After the Armistice, in November of 1918, the station again was closed down as the use for either airships, or kite balloons, were no longer required. By 1920, the base had fallen in to disrepair and was derelict. During the World War II, the what was left of the buildings on the base was used house a vehicle repair yard, and to store barrage balloons. Many of the building were brought back to good order to make the watertight, and also make way for other buildings needed for the Royal Naval Base at Scapa Flow.

Since both wars, the buildings have been demolished.

For more information on the base, and some excellent pictures, please visit the excellent historical research site Crashsite Orkneys