Any diver who has been to Scapa Flow to visit the remains of the World War I German naval fleet will know the story of the 21st June 1919 when 74 ships were scuttled. Due to some heroic efforts only 52 ships actually hit the seabed. Initially, the British Admiralty were determined to leave the German fleet on the seabed and let them rust. But the wrecks were a considerable hazard to local vessels, with several being grounded on up-turned hulls. By 1922 the demand for scrap metal had increased and the Admiralty started selling off the wrecks for salvage, £250 for a destroyer and a mere £1000 for a whole battleship (of course 100 years ago that was the equivalent of £54,000 but that still seems cheap).
Over the next 8 years Ernest Cox developed some incredible techniques to lift huge battleships from the seabed within Scapa Flow. The wrecks were salvaged for fixtures and fittings with artefacts being recovered in good condition including bottles of wine, musical instruments, and the metal ships were broken up for scrap sales. By 1930, the price of scrap metal had crashed leaving the whole operation in danger of financial ruin and by 1933 Cox sold out to Metal Industries Group and they lifted the last of the battleships in 1939 as World War II loomed. Just 3 battleships and 4 cruisers remained. These are the wrecks that divers now visit, but they all bear the scars of the salvage work carried out by Nundy Ltd and then from 1970 by Dougall Campbell as Scapa Flow Salvage Company. Explosives were used to blow holes into engine rooms to get the non-ferrous metals and to open up the hulls to recover the valuable torpedo tubes. Campbell also realised that the armour belts of 14 inch thick steel with a high content of nickel and chrome were easy to recover and valuable enough to be worth the effort. [Dougall freely shared his amazing knowledge to a number of Scapa Flow projects in advance of the centenary, and sadly passed away on July 26th 2018].
Sensibilities have changed regarding wrecks and their salvage. HMS Vanguard is now considered a war grave after she was lost with 845 men following an explosion in her magazine in July 1917, but by the 1950s and then again in 1970s, she was salvaged for her propellers, condensers, torpedo tubes, armour plating and Weir pumps. It wasn’t until 2002 that the wreck became a Controlled Site and diving was restricted, but for 85 years she was stripped of any useful metals ie the ones that would command a good price on the scrap market.
Early salvage operations were driven by the demand for scrap metal. In post WWI industrial development was being held back by lack of metal. But post WWII there was a new driver for recovering steel produced before WWI, lack of background radiation in the metal itself. As the nuclear and space races took hold on the 1950s and medical advancements in 1960s, there was a growing demand for steel that had very low levels of background radiation. Atomic testing in the 1950s released Cobalt-60 into the atmosphere. Steel production involves pumping air (or oxygen) through molten pig iron, which reacts with impurities creating oxides that can be removed as slag. Atmospheric atomic tests released atmospheric radiation which peaked in 1963, so any air or oxygen used to produce steel since that time introduced low levels of background radiation into the metal.
Ordinarily, this isn’t an issue. You wouldn’t notice or be affected by a trace in your cutlery or the spice rack in your kitchen or the panels in your car. But it matters if you are trying to build sensitive instruments to detect radiation. Geiger counters, body scanners and space equipment can all be affected by the low level of radiation introduced during the manufacturing process. That makes the steel armour plating from the pre-atomic era significantly more valuable than would otherwise be the case. Our latter found sensibilities to protect the wrecks as war graves wasn’t apparent decades ago. In Scapa Flow the salvage has stopped, but internationally wrecks are disappearing in their entirety. Happily, the half-life of Co-60 is short, only 5.26 years. Since the moratorium on atmospheric testing in 1963, levels of atmospheric radiation have been rapidly dropping, with only occasional contributions from Chernobyl, Windscale, Three Mile Island. This means that production of low background radiation steel is now possible, combined with computerised correction for background levels. However a drop in the market value of pre-atomic steel is unlikely to save wrecks around the world, particularly in Asia where even the former pride of the British Navy HMS Prince of Wales and HMS Repulse have been targeted by metal scavengers.
Michelle has been scuba diving for nearly 30 years. Drawing on her science background she tackles some bits of marine science. and sometimes has a sideways glance at the people and events that she encounters in the diving world.