16 C O N T E X T 1 3 7 : N O V E M B E R 2 0 1 4 the Cromarty Firth, Captain Donald John Munro was commanded by the Admiralty to install booms on the ‘Cromarty model’ around Scapa Flow. Placed where they could be covered from the landward by coast batteries, these booms consisted of sections of steel wire-mesh curtains suspended from hawsers which were anchored to the shore by chain cables.They were held in place by a series of buoys and by drifters which operated ‘gates’ for authorised access. Designed also to be used against fast surface craft, boom defence was developed on a massive scale through both world wars.Although tangible evidence is now generally confined to trailing chains and anchor points on the foreshores below the batteries, substantial heaps of dredged booms in Calf Sound off Flotta probably constitute the biggest collection of boom nets to be found anywhere in Britain. Laid in front of the booms were lines of electromagnetic indicator loops, acoustic sensing hydrophones and controlled minefields, all of which were directed from hutted stations onshore. Hoxa Sound was the scene of the one successful combined use of such techniques when, on 28 October 1918, UB-116 was detected trying to breach the boom defences and was blown up in the minefield. Another method of denying enemy access was the deployment of blockships, redundant vessels that were ballasted and sunk in position. Between September 1914 and October 1915 no fewer than 23 vessels were sunk in this way across five channels, four of them on the vulnerable eastern flank of Scapa Flow. Of the first world war blockships, the most recognisable survivor is the stern section of the Reginald, an 1878 motor schooner which lies in East Weddel Sound. Distorted remnants of a remarkable and possibly unique mile-long, fixed barrier built of bolted steel rails, laid in 1917 across the main northern channel, remain at the bottom of Clestrain Sound. Aircraft were used mainly for submarine reconnaissance purposes. Some vestiges survive of the airship station, kite balloon station and five seaplane bases that were established around Scapa Flow.The field that served as a naval aviation practice strip at Smoogro on the northern shore of the Flow is also identifiable. It was from here in August 1917 that Commander Dunning took off to make a historic, first-ever deck landing on to a moving ship.The creation of air defences was prompted by the threat posed by Zeppelins and ship-borne, torpedo-carrying aircraft. Structural remains of two anti-aircraft batteries established in Orkney in 1917-18 are now rare wartime survivals.The one on Burray Ness is the most complete in Scotland. First located at Scapa, in late 1914 the shore base of the Admiral Commanding Orkney and Shetland (ACOS) moved to Longhope Hotel on South Walls, Hoy. For much of the war, however, essential support for the fleet – coaling, oiling, arming, repairing, refitting, administering, accommodating – was carried out afloat, not ashore. It was not until September 1916 that plans were agreed and funding granted for a major stores, fuel and ordnance depot to be built at Lyness on Hoy. Beginning with the construction of a large wharf, the programme included four oil storage tanks, petrol tanks, a power house, paravane and torpedo depots, storage sheds, workers’ camps and two reservoirs. Much of this construction work continued after the Armistice, but by late 1920 the anchorage had been closed and the naval headquarters transferred to Invergordon. One of the four original oil tanks and the big sheds that began life as paravane and torpedo depots have survived second world war developments and the subsequent closure (in 1957) of the Lyness base. In a complete reversal of its wartime role, from late November 1918 Scapa Flow became the internment anchorage for 74 vessels of the German High Seas Fleet, which, on the concealed orders of Admiral von Reuter, were dramatically scuttled on 21 June 1919. Sunk in the deepest water beyond economic salvage, three battleships and four cruisers still survive as wrecks, and digital three-dimensional virtual models of them can be viewed at www.scapamap.org. A former paravane and torpedo depot, Lyness, Hoy, converted to a NAAFI and cinema in the second world war, and now the largest surviving first world war structure in Orkney. A view from the north east, taken in 2014. (Photo: Michael Taylor) The Royal Hotel, Longhope, SouthWalls, Hoy, the first world war shore base of the Admiral Commanding, Orkneys and Shetlands. A view from the west, taken in 2011. (Photo:The Orcadian) The former head of architecture at RCAHMS, Geoffrey Stell is a parttime tutor in building analysis at Edinburgh College of Art, University of Edinburgh. His publications include Orkney atWar: defending Scapa Flow,Volume 1,World War 1 (Kirkwall, 2011).
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