Editing Scapa Flow (section)

===Salvage operation===

Although many of the larger ships turned turtle and came to rest upside down or on their sides in relatively deep water (25–45 m), some—including the battlecruiser {{SMS|Moltke||2}}—were left with parts of their superstructure or upturned bows still protruding from the water or just below the surface.

These ships posed a severe hazard to navigation; small boats, trawlers, and drifters regularly became snagged on them with the rise and fall of the tides. The Admiralty initially declared that there would be no attempt at salvage, that the sunken hulks would remain where they were, to 'rest and rust.' In the first few years after the war, there was abundant scrap metal as a result of the huge quantities of leftover tanks, artillery and ordnance. By the early 1920s, the situation had changed.

In 1922, the Admiralty invited tenders from interested parties for the salvage of the sunken ships, although at the time few believed that it would be possible to raise the deeper wrecks.<ref name=george/> The contract went to a wealthy engineer and scrap metal merchant, [[Ernest Cox]], who created a new company, a division of Cox & Danks Ltd, for the venture, and so began what is often called the greatest maritime salvage operation of all time.<ref name=george/>

During the next eight years, Cox and his workforce of divers, engineers, and labourers engaged in the complex task of raising the sunken fleet. First the relatively small destroyers were winched to the surface using pontoons and floating docks to be sold for scrap to help finance the operation, then the bigger battleships and battlecruisers were lifted, by sealing the multiple holes in the wrecks, and welding to the hulls long steel tubes which protruded above the water, for use as airlocks. In this fashion the submerged hulls were made into air-tight chambers and raised with compressed air, still inverted, back to the surface.

Cox endured bad luck and frequent fierce storms which often ruined his work, swamping and re-sinking ships which had just been raised. At one stage, during the [[General Strike of 1926]], the salvage operation was about to grind to a halt due to a lack of coal to feed the many boilers for the water pumps and generators. Cox ordered that the abundant fuel bunkers of the sunken (but only partly submerged) battlecruiser {{SMS|Seydlitz||2}} be broken into to extract the coal with mechanical grabs, allowing work to continue.

Although he ultimately lost money on the contract, Cox kept going, employing new technology and methods as conditions dictated. By 1939, Cox and Metal Industries Ltd. (the company that he had sold out to in 1932) had successfully raised 45 of the 52 scuttled ships. The last, the massive {{SMS|Derfflinger||2}}, was raised from a record depth of 45 metres just before work was suspended with the start of the Second World War, before being towed to Rosyth where it was broken up in 1946.

A [[Morse key]] recovered from the battleship [[SMS Grosser Kurfürst (1913)|''Grosser Kurfürst'']] during the salvage is displayed at a Fife museum.<ref>Museum of Communication, 131 High Street, Burntisland.</ref>