Secrets of Scape Flow

Opotiki News, Volume II, Issue 251, 27 October 1939, Page 1 (Supplement)

Secrets of Scape Flow

ITH storms converging on their depot ships from every point of the compass, there are men descending day after day into the troubled depths of the ocean at Scapa to continue the job of bringing to the surface the ships of the German Grand Fleet, scuttled in those waters at the end of the last war. They are calmly achieving the impossible, dhe slow and graceful movements of the divers as they work as deep as they can go are gradully removing the sunken monsters. • v Down there at d4O Teet-or so wa'e’s very little light, the prestretis terrific and you feel as - wereh your limbs were as leaden quietlr boots. The diver is the passenuer of the men -who will so cllown into the sunken wreck „outx he has paved the way. ".Imagine him, at that great kiepith, every breath a labour, qjlfhking about on the upturned ■ Itdll of a former warship. Down VcStries the huge air lock —25 tons |oWtt reaching 120 feet above him Uyr Vv :;

—through which entry will be gained to the ship. It is swaying. Twenty feet this way; twenty feet that. There is a gale above, for you can’t get a completely calm day in the Orkneys, and the enormous leverage of that long length of tube gives the wind full scope to wreck havoc with the work. But it must be stilled for it is to be fastened to the hull as securely as if it were part of it. Gradually it is stilled and the diver moves forward to drill the holes through the heavy plating of the hull which must correspond within a fraction of an inch , to those on the flange of the airlock. His mate beside him is following up the work and screwing in bolts where he has drilled the holes. Almost out of sight a few yards away the rest of the team are fixing guy ropes, like those of a flagpole, to sockets in the steel hull, so that not the strongest storm the Orkneys can produce will tear the lock from the wreck. If ever it did it would mean death to many. But the strength

How the Sunken German Fleet was Salvaged to Build the Queen Mary and many of Britain’s Latest Men-o-War.

that will oppose these vast natural forces is not there until the clivers have finished, and till then, if only a matter of a comparatively few minutes, there is a dramatic anxiety lest a slight rise in the wind will tear it away. Once it is fixed, though, it becomes a highway foi the men who work inside the wteck, as much as 150 feet down to piepaie it for being raised to the surface. When the Germans in 1918 sunk the half-million tons of their Grand Fleet, which was interned at Scapa, they thought they would never be seen again. 1 hey deliberately capsized all they could so that salvage would be impossible. Yet from 1924 till now about half*of that fleet has been raised and broken up for scrap —250,000 tons of it! And work is going so much like clockwork now that there seems no reason why the remainder should be raised in time. How the Airlock Works For six years after it was sunk, the German fleet lay at Scapa,

until a shipbreaker, Mr. E. F. Cox, looking around for more battleships to break up, decided to try to salvage it. If raised to the surface and brought to the breakers’ yard its value would teach a high figure, well above £1,000,000, "but the question of whether it could be raised-was seriously doubted by experts. Even if it could be raised the cost of doing so might still be too high to make it worth while. When in true pioneering spirit Mr. Cox’s company set out to attempt the mighty task, with tlmm as chief salvage officer, was .Mr. T. E. Mackenzie, who remained in that post after Metal Industries took over the work in 1933. To him must go most of the credit for the ingenuity that made the world’s greatest salvage job a success. To begin with, twenty-five of the destroyers were raised by conventional salvage methods, and a vain attempt costing £40,000 was made to float the Elindenburg, first of the large ships to be tackled.. The most interesting part of the work began with the use of compressed air for lifting these mighty vessels. Theoretically, this is very simple; in practice, there are complications an(d hazards. In the case of a ship lying at some depth, divers go down and seal up all holes in the wreck, making it airtight. A long airlock reaching from the wreck to some feet above the surface of the water is

lowered and fixed by divers to the hull. This airlock is merely a tube with airtight doors at top and bottom and ladders down the inside. Compressed air is pumped into the airlock and as the pressure of the air becomes equal to the pressure of the water, the latter is forced down. Since the pressure of the water increases as you go down, air has to he continually pumped in to increase the air pressure and so press the water down farther still. Gradually the water is pressed out of the airlock, and in time it is pressed right out of the hull of the wreck, leaving this filled with air, which is prevented from escaping by the double doors at the.top of the airlock. Workmen can now pass down into the wreck through 'these double doors and they proceed to seal off the ship into airtight sections and to strengthen bulkheads. Finally, when everything is ready the water is pushed -down, lightening the total weight of the wreck until it is buoyant enough to rush to the surface. The first ship to be raised in this way was the Moltke; Airlocks were fixed to the upturned hull, the water pushed down, and the ship sectioned off so that it would be possible to control the movement of the ship when it was rising. When the Moltke was ready for lifting many experiments

were made before the hull was brought to the “surface. The bow was lifted first and then dropped again by the "simple expedient of letting out air. Next step was to try the stern, but this refused to move. More experiments had to be made before it finally lifted and the ship could be balanced. As soon as it was raised, however, air gushed out from a hole somewhere and threatened to sink it again before the hole could be filled by divers working at breakneck speed.

At a Depth of 140 Feet

The job was not ended with lifting the ship. The hull had to be brought to Rosyth on the Forth to be broken up, and throughout the period it was being made ready for this journey and during the journey itself, the ship was kept afloat only by constantly pumping more air into her. For this purpose compressors and living quarters for the men tending them were erected on the upturned hull. That was an adventurous journey. The Moltke got out of control in the Pentland Firth and floated westwards with the tide.

She had a last fling as she neared the graveyard of ships at Rosyth, just beyond the Forth bridge. The tide caught her, and it looked as though she would foul the pier. Hurriedly hawsers from the leading tugs were cast off.

Mackenzie, in charge on her hull, gave orders to the two tugs at her sides, and they did what they could to twist her around, one at full speed astern, and the other at full speed ahead. By scarcely a hair’s breadth she cleared the pier and floated through the middle arch broadside on.

Venturing gradually into greater depths, other vessels were salved, the Von der Tann, for instance, and the Prinz Regent Luitpold, the latter being raised from 105 feet, which was at the time a world’s record depth. With increasing depths, the difficulties and dangers grew in proportion. At about this time

Metal Industries took over. The new firm completely refitted the depot at Lyness on Hoy, and provided a new depot ship. They retained Mackenzie and it was liis vastly improved organisation I saw at work, raising the Friedrich 1 der Grosse from the terrific depth of 140 feet when I flew to the island on the mail service operating up there. That flight showed what conditions can be like. On the day I intended, to fly north, the air service was cancelled because of an 80-mile-an-hour gale blowing in the Orkneys ! The following day, on which the flight was made, the air was as bumpy as one could imagine.

Lyness on Hoy, the base of operations, is a sort of reserve naval base, and there is complete camp equipment to house the men, who run their own messes —divers’ mess, staff mess, and so on.

The firm has its own quay and an engineering shop where plant is prepared for use on the wreck, and such things as airlocks built as required. They are so far away from the engineering world that they have to be almost completely self-supporting. Working at high pressure has its dangers which, if proper precautions are not taken, may have serious consequences for the divers. No one is allowed to go down unless he is in perfect health, and lungs and heart must be sound. Divers must come out from the pressure very gradually or there is-serious danger of onset of compressed air illness, resulting from the formation of nitrogen bubbles in the blood. The only cure is to be put back under pressure which is gradually reduced to normal again.

There are other dangers, too; gas, for instance, is often found in the wrecks, and this may become ignited by oxy-acteylene cutting tools and cause an explosion. On one occasion Mackenzie nearly cut short his career in salvage. He was fpund floating unconscious on the surface after an explosion, and only came round in* hospital. Every effort is made to counter such danger by a chemist whose sole duty it is to test the air in each section of the wreck. These labours reach a climax when all is ready to bring the wreck to the surface. Everything

will be calculated b Finally, the long air the compressors on ship to the airlocks a to allow for the locks hundred feet into the ai

The salvage boats n a safe distance, and pressors set to work p into the various sectior ment will be seen. P ship will rise a foot o then suddenly it will i surface, the air within panding as the press water outside is reduo

On the top of ea when the ship is abou a workman who must pressure gauges. The perience the sensatio 10 feet above the sea and 150 feet above it v ton battleship floatii them less than ten se One of them said aft such experience: “Ne When that excitir has passed, the rest < becomes routine in Tlie wreck, still kef pumping in air, is tc base at Lyness, and ready for the journey pressors, with a comf generating set and ' ters for the men, are the upturned hull. As I left Hoy : above Scapa Flow i plane to Kirkwall c island, I caught a gli scene of the wreck kenzie and his crew The eight huge airloc from the sea markir of the Friedrichder (

Beside them lay tl a tug and a drifter, small, and stretchin me was the Flow o\ fleet was once seal not a sigh remains locks projecting fr< great ship and tin flotilla. The ships are all too deep to V Though I could nc that just about the 1 over, men would be of the wreck thro locks. These men have finished, will over 400,000 tons o the bed of Scap weight of five Que< ships—and where '

get so much shippi spot again ?