After testing and final preparations, everything was ready for the lift on 11 May. At 11.30 hrs the bow began to lift and it continued to do so very slowly for over two hours, by which time it was 15 feet clear of the bottom. Then expanding air reached its full force and in less than 30 seconds the bow rushed to the surface with the usual spectacular effect. The most dangerous experience was that of the men on top of the airlocks who had been registering pressures, degree of list etc only a few feet above sea level and now found themselves clinging to precarious perches 120 feet in the air. Bertha hummed with activity as wires were paid out or hove in, pipe lines slackened and compressors switched to other compartments as required. So efficiently was everything organised that in less than a minute after the bow had broken surface, the ship was stable.
The bulkheads, however, had suffered badly from the quick alterations in pressure and the terrific expansion of air, while the slowness at which pressures were increased by the compressors disclosed a leakage of air which it took all the next day to make good. Then, at 13.00 hrs two days later, a slight movement was followed by the unexpected rush of the stern to the surface. Kaiserin then levelled out, and in two hours had 14 feet freeboard fore and aft, and was quite stable. Next day she was grounded in 12 fathoms, the superstructure, funnels and turrets were blasted away, and a few days later she was taken to Lyness to prepare her for her upside-down tow to Rosyth where she was docked beside the remains of König Albert.
Figure 6. Kaiserin – cross-section and subdivision.
Nine months’ hard work on Friedrich der Grosse began in June 1936. During the internment she had been the flagship of Vice-Admiral von Reuter who had taken exceptionally thorough measures before she was sunk. She was distinguishable from other ships of her class by a heavy foremast.
Her charted position was known and she was soon located on fairly soft bottom in 23 fathoms with a heavy port list of 16 degrees. The extent of the list and the fact that she was four degrees down by the stern presented many engineering difficulties, and it was immediately clear that the only practicable method of lifting her again was by the use of compressed air. The first of ten air-locks was in place at the beginning of July. Their construction was precisely the same as before, and the greater number enabled Metal Industries to divide the bunker sections into more compartments thereby providing better control over list and stability. The air-locks varied from 80 to 100 feet in length.
The acute list created problems in fixing the air-locks. Weather often delayed the work, and even in good weather divers had frequently to lash themselves in place to avoid being carried away by the strong tidal stream which flowed across the wreck. Despite all obstacles, all ten airlocks were secured just before the winter gales commenced.
Months of difficult work inside the ship were then spent in making bulkheads tight. Divers found every valve in the ship open, and in many cases valve spindles had been sawn off flush with packing glands so that they could not be closed. All too often, also, clips on watertight doors had been sawn off. Many doors were missing and never found, which indicated that they must have been removed and thrown overboard at the time of scuttling.
Davie Bell, one of the men working below, came up with a grisly story. He declared that he had found the dungeon where sailors had been left to die by their officers, and that the place was littered with human bones. Floating weeds had added to the eerie atmosphere and he had the uneasy feeling all the time he was working that the ship was haunted. A prompt examination soon revealed that the dungeon was the ship’s refrigeration room, and the bones were the remains of hams and legs of mutton.
By the third week in April 1937 the bulkheads were airtight and McKenzie was commenting on the cheerfulness with which divers had worked under circumstances of grave risk, while inside the ship men in wading dresses had again worked almost up to their necks in water. Many seemingly impossible tasks had been successfully completed at the second or third attempt, while some simple tasks which would not have occupied more than a few minutes on the surface had taken days to complete.
On 28 April at 05.00 hrs, the compressors were started and the lift began. It had all been seen several times before: the slow, inch-by-inch lifting of the bow for the first two feet, then the eruption at the water’s surface as the superstructure tore free of mud and silt, the cascading of water off the weed-covered bottom; the gigantic oily bubbles and the huge spouts of water, mud and oil; salvage ships rolling heavily in the turbulence, and Bertha’s deck awash for a few seconds; the quick subsidence of the turmoil, and the laughter and cheers of relief as five minutes later the bow lay quietly on the surface.
Diagram 7. Friedrich der Grosse: plan showing arrangement of sections.
The forward air-locks which had previously shown only ten to 15 feet above water now towered 120 feet in the air.
The stern was lightened to prevent crushing, and at 21.00 hrs work was discontinued, except for maintaining pressures until 05.00 hrs the following day when pumping at full power began again. An hour after noon the stern rose to the surface in 40 seconds, creating the inevitable turbulence, but though the ships rolled and sheered, and the wires strained tight, nothing broke, and within an hour Friedrich der Grosse lay flat with 12 feet of freeboard. After divers had surveyed the underside of the wreck, she was towed to shallow water off Risa where her superstructure was blasted away. Ten days later she was towed to Lyness, and having been prepared for her bottom-up tow, proceeded in charge of three Dutch tugs and Metal Industries’ salvage tug, Metinda, to the breakers’ yard at Rosyth.
The departure from Lyness received full honours from the vessels which witnessed it and from the workshops at Lyness. Whistles and sirens blew. A Blue Funnel liner, salvage steamers, the Admiralty’s boom defence ships, and even the curious locomotives on Orkney’s only railway system combined to give the departing ship a worthy farewell. Everything that had steam blew, except Bertha, lying in Bring Deeps, and the famous pontoon which lay at anchor temporarily out of use. Friedrich der Grosse acknowledged the salute with a resonant note on her great bell, which had been hung on her keel for the occasion, and the Dutch tugs saluted with deep notes on their sirens.
The tugs were admired by all. The commodore of the small fleet was Captain B. Hart in Thames. Captain Thomas Vet was in Zwarte Zee, the most powerful tug in the world. She was 792 tons and built at Rotterdam in 1933. Captain A. van Dorp skippered Roode Zee. With them were Engineer Heer W. van Beelen, superintendent for L. Smit & Co of Rotterdam, the firm which had towed 80 floating docks to different parts of the world, and Heer J.P. Bruynzeel, a travelling student. Roode Zee and Thames were being used for the first time.
But no sooner had they left the islands than Friedrich der Grosse was caught by the ‘race’. Tugs lashed the sea with their propellers in an attempt to maintain speed, and the heavy towing chains were heaved out of the water. Zwarte Zee, which could develop 4,000 horsepower and a speed of 20 knots, was keeling over as the speed increased, but the tugs could not hold the enormous mass of metal which, pulled by the ebb tide, was drawn back, hauling the tugs with her. The sea swirled around, exposing the great hulk’s triple screws as she swung slowly round, edging her way broadside on to the rocks under John o’ Groats. For the next half hour she was swept to and fro. The intended direction was east, but until 13.30 hrs they were travelling west, the tugs groaning and straining in vain to hold her. At last the tide turned and the sea began to surge from the Atlantic, and almost abruptly Friedrich der Grosse gave up her wayward struggle and began moving towards the North Sea of her own accord without the aid of the tugs, so powerful was the tide. For a time the tugs had little more to do than keep her headed through the passage. After three days a stiff breeze blew across the North Sea, and heavy seas creamed over the heaving hulk. Air was lost out of her and the speed fell to three knots, but the holes inside were sealed and for the next 11 days she behaved perfectly, and the crew of 12 living aboard her in the bunkhouse strapped to her keel had little
to do but fool about. It took six hours for her to shoot the Firth of Forth; once she scraped the stonework but was pushed off by Zwarte Zee, and at last she was safely moored, on 5 August 1937.
After she was dry-docked, 200 men were employed in breaking her up. There had recently been increases in the prices of scrap-metal and the value of her hull was now assessed at more than £130,000.
So many ships had now been raised that when Grosser Kurfürst was refloated on 29 April 1938 by similar means, little publicity was given to the feat. (Incidentally, several steel plates used in the liner Queen Mary were forged from the scrap metal of Grosser Kurfürst.) The lift was perfect, by far the best of anything that had gone before, and there was nothing spectacular about it. Her superstructure lay embedded in the blue clay which forms the floor of Scapa Flow. One of her sections formed almost the whole bow and another the whole stern. Of her decks, the first, nearest the keel and working from keel to superstructure, was a double-bottom tank containing the trimming tanks; the second was the lower platform deck containing the pump-room, stores etc, the third, the upper platform deck, contained the magazines; the fourth was the armour or protective deck; the fifth, the mess deck; the sixth, the battery deck; finally there was an overdeck, or top deck, containing six-inch guns and casemate guns.
More than two miles of two-inch salvage piping were in use, and in the wreck were 383 yards of air piping and a similar length of three-quarter-foot air piping. Connected to the airlocks were four miles of wires. One worker said that down below on a sunny day he could read small print 20 fathoms below by the daylight filtering down through her portholes.
The craft in attendance were the tugs Bertha, Metinda and Monarch, also Mary Cowie, the motor cabin cruiser Doris and the pontoon ship Never Die. Never Die was ugly but reliable, a vessel without bow or stern. She was moored off the bow of the wreck, connected to her by a hawser. A big derrick on her pointed skywards, and she sat slightly on her heel, for water had been pumped into the stern tanks to augment the pontoon’s bow resistance to the wreck. Hawsers were made fast between the raised bow of the wreck, the pontoon and Bertha, to prevent the hulk when it rose from moving further from, or nearer to, Bertha, for to have done so would have snapped the air-lines. The blow of escaping air when the stern rose tended to push Bertha away, and both bow and stern hawsers had to be light enough for men to be able to operate them within seconds of receiving orders, yet strong enough to keep the air-lines from parting and depriving the wreck of its means of buoyancy. Bertha pumped in free air at the rate of 2,350 cubic feet per minute and Metinda at 1,000 cubic feet per minute.
The bow lifted gently when she came up, and to inform the depot of their success, a kite was flown from the diving boat where Cowan, the chemist, stood by.
Every man had his eye on a watch when the lift was made, for there was a raffle on the time she would surface, which was exactly 12.54½ hrs. There was remarkably little seaweed or other marine growths on her as she had lain in a strong tideway.
At the banquet and dance to celebrate the success of the lift, an event instituted by Metal Industries Ltd, a parody composed by Max Wilkinson, a senior executive, was greatly appreciated by those whose working lives depended upon air pressure:
Ol’ man Pressure, dat ol’ man Pressure,
He must know sumpin’, but don’t say nothin’,
He keeps wreck raisin’,
He keeps on pressin’ along.
He don’t plant taters, lie don’t grow cotton,
But all that meet him do feel rotten,
Body all achin’ and mighty tender.
Just a little twinge and you lands in chamber.
Ol’ man Pressure, dat ol’ man Pressure,
He may bust sumpin’, but don’t say nothin’
He keeps wreck raisin’,
He keeps on pressin’ along.
Salvage operations ended just before World War II with the raising of Derfflinger, described by McKenzie as the most difficult and interesting case of all those lifted. She had taken part in the bombardment of Scarborough. At Jutland she had been badly punished and had lost more than 150 men. She lay, too, the deepest of all to the north-west of Cava, upside-down and listing 20 degrees, with 90 feet of water over her at high tide on one side and 110 feet on the other. This was twice the depth from which Moltke had been raised. Her nine air-locks had therefore to be positioned deeper than any others which had been made, and the longest was 130 feet, weighing 30 tons, complete with fittings, ladders, guys etc. After 20 years on the bottom Derfflinger was deep in mud. Work began in July 1938. In the early stages the list was so steep that men had literally to slide to work on her. Scaling and patching occupied eight months. On McKenzie’s advice she was partitioned into 11 sealed sections. Men inside the hull had to work at a pressure of 64 pounds to the square inch and they needed one and a half hours of decompression after each hourly shift, a time to which they were limited each day.
The air-locks were secured in the same way as with previous ships with relays of six or eight divers who took from four to six hours to secure each air-lock. Water inside the ship was expelled by compressed air. When the ship’s bottom was dry, access to the double-bottom tank was obtained through a manhole drilled and cut in the bottom plating. The bottom of the air-lock shaft and the ship’s plating were then immediately sealed. If the tank lid of the double bottom was open, increasing pressure of air would cause the water in the tank to recede slowly but, if the tank was sealed, the pressure in the air-lock began to build up, something which had to be watched carefully as the Germans had arranged for the ships to capsize when scuttled by pumping and scaling many of the double-bottom tanks. When, therefore, the tank lid was found to be sealed, water in the tank was expelled through specially fitted valves until the lid could be located and opened.
Nine shafts were fitted, giving access to different sections of the ship. This division of the ship into sections gave the water in her different compartments a stepping effect, and provided better control over list and trim when the wreck was buoyant.
The method of work adopted was as follows: the first shift went down and completed its shift of one hour, whereupon it was relieved by the second shift. The first shift then entered the top chamber of the air-lock and began decompression. The lower chamber was then free for the second shift on completion of their working time. When the first shift completed decompression, it left the top chamber of the lock which was now free for the third shift to enter. Pressures in the top and lower chambers were then equalised so that the third shift could pass down, and the second shift move up to the top chamber. When men of the second shift had completed decompression, they left the air-lock, so that two chambers were now available as required for the third shift.
After the bow was raised pressures were adjusted in the various sections to control any list. Divers then went down to check whether the turrets had lifted with the ship or were still on the bottom. Had they fallen out, as was the case with Bayern, the weight would have been reduced by some 2,500 tons, thus raising the centre of gravity by about two feet four inches, which under certain conditions could have made the ship unstable. The divers’ reports were satisfactory, so compressed air was pumped into the stern at the rate of 4,000 to 5,000 cubic feet per minute. Then pressure in the after sections was slowly increased until positive buoyancy was obtained. The volume of air in the stern and its resultant expansion was lower than in the bow, but it was sufficient to drive down the bow to a dangerously low level owing to rapid compression forward as the ship levelled out on the surface. To counteract this, all the available compressing power was switched to the bow section when the first upward movement of the stern was seen. Thereafter it was comparatively easy to control both list and trim, as all bulkheads had successfully withstood heavy pressures caused by rapid alterations in pressure as the ship lifted. The foredeck, however, which was the weakest part, especially under internal pressure, was blown completely out by expanding air. At first she rose
only two feet a minute and then, as pressure decreased, the rusty hull rose 150 feet into the air creating the semblance of a sub-marine volcanic eruption. That many bulkheads withstood pressures and strains for which they were never designed was a tribute to German naval construction. Pressures were then balanced and divers went down to blast away all loose parts of the superstructure dragging on the bottom. When clear, she was towed inshore and grounded in 60 feet of water, and moored there with eight seven and a half-ton anchors, two off each bow and two off each quarter. Several weeks of reclamation work followed. Bulkheads were sealed down to still lower levels, casements were sealed up, and every aperture on the ship’s side from keel to battery deck was effectively sealed to gain buoyancy and raise the ship to maximum level. Then gauges were passed under the superstructure to check the draught at the lowest points. Forty feet three inches was recorded at the forward super (A) turret, 40 feet four inches at the conning tower and 39 feet nine inches at the after super turret. War being imminent, the Admiralty required Rosyth dry dock for more important work, so Derfflinger was towed behind Risa Island and moored there with ten seven and a half-ton anchors.
Between 1924 and 1939, 38 ships had been raised and 327,000 tons of steel recovered and broken up.
In the early days of the war, when Derfflinger lay moored alongside Iron Duke, at that time a training ship, three German aircraft appeared. At first they were not fired upon so as not to disclose the strength of the defences. But Iron Duke was holed and water flooded her compartments. McKenzie immediately went out to her, and it was his prompt advice and assistance which prevented her from sinking. Meanwhile, anti-aircraft guns had opened fire. One aircraft was brought down, all that was found of its pilot being a foot in a boot and an arm in a sleeve.
From Jutland to Junkyard: The raising of the scuttled German High Seas Fleet from Scapa Flow - the greatest salvage operation of all time Page 14