RECORD SALVAGE WORK

Evening Post, Volume XCVI, Issue 41, 16 August 1918, Page 2

RECORD SALVAGE WORK

LIFTING SUNKEN SHIPS

THE NAVY'S NEWEST BRANCH

SOME REMARKABLE FEATS.

In the deep seas around the British | coasts for many a long day, a wonderful work has been performed by the newest arm of the Silent Service—the Admiralty Salvage Corps. Many fine salvage operations have these men carried out during the war, which in pre-war days would have been thought not only comercially impracticable but impossible. They have worked in 35 fathoms of water. They have raised ships with a cargo of 3500 tons, whereas ;oice upon a time 1500 was thought the summit of such an achievement. They have often worked in imminent dangar of death from enemy boats above and below water; and not a few have given their lives in the enterprise without even a posthumous honour. The Admiralty Salvage Corps performed some astonishing feats in raising sunken warships during 1914. But taking the subsequent two- years and confining the investigation tr> merchantmen, it is found that no fewer then 260 ships were salved during 1915-17, pnd most of them were over 1200 tons. In January of this year fourteen ships were salved: in February 41, in March 37, in April 36, in May 19, making a total of 407 ships salved, and valuable cargoes with them, in home waters alone. The work was first undertaken by the Liverpool Salvage Association; but the magnitude of the shipping losses, before the activities of the U-boats' were got under control, eventually put the scope' of the work beyond that of any private enterprise. And so for the first time in the history of the Navy, the Admiralty Salvage Corps came into existence. Today the department has the greatest quantity of plant and equipment that has ever been assembled in the world.

(( But .these facts and figures are not the "story" of the Admiralty Salvage Corps, although their result* have brought fortunes to shipowners, and, to the poor, cheaper food that they otherwise might have had. The glory of the corps is its personnel. The salvage operations performed by them are often conducted under^ very hazardous conditions. ft Long, patient, dangerous work, which it has taken divers and their surfaes-brothers days to carry out, is sometimes swept away by a single heavy sea. Not the le;ist of the troubles they have to contend with has been the accumulation of gas in the holds of vessels salved after long submersion, due to decomposed vegetable matter and rotting meat. In one instance of which there is a brief record four men were successively overcome by gas, and several have lost their lives.

LIFTING 2750 TONS.

An example of the actual lifting of a vessel from deep water by means of pontoons or lifting craft, is outlined by the Liverpool Salvage Association's Chief Surveyor.' Before the war, as already indicated, it was considered that a vessel sunk in deep water whose actual displacement or weight was more than about 1600 tons could be considered a total wreck. Apart from the financial considerations, which were then the principal determining feature in salvage work, it was thought that a sufficient number of wire ropes could not be placed under a vessel of a greater weight than 1500 tons to ensure each of them bearingsuch an equal and modified strain that they would not cut through the shell plating. Says Captain Young : A large Government collier, partially filled with coal, was sunk by collision, in twelve fathoms of water, partially blocking a most important channel and anchorage. Her removal became a matter of urgent necessity, but, owing to the strong tide and chances of bad weather, it was not practicable to use cofferdams or other methods of that description. There was no alternative but demolition by explosives or an attempted lift by means of pontoons. The destruction by explosives meant a long and costly operation, especially as each piece would have to be lifted and taken away to prevent spoiling the anchorage, which was used by the largest type of vessels. It was decided to attempt the lifting, the weight being calculated at 3500 tons, including the mud which had accumulated. It was proposed to reduce this weight by various methods to about 2800.

The vessel had sunk into the mud at the bottom past the turn of the bilge, and the prospects at first did not appear very encouraging, especially as another deep-drafted vessel coming up the channel had grounded on the upper works of the vessel, crushing down all deckhouses, etc., flush with the deck. Considerable difficulty wa-s experienced in getting the wire lifting ropes under the vessel on account of her being so far down in the mud and the necessity for the divers sending up all the debris_ of masts, funnels, etc., which were lying on the bottom alongside the ship. _ After a great deal of sweeping work with the salvage vessels, sixteen 9in wire' ropes (3in in diameter) were eventually placed in position under the bottom, and brought up to four Admiralty lifting craft placed over the wreck. 'Each of the 9in wire ropes had a guaranteed breaking strain of 250 tons. When everything had been prepared the water was emptied from the ballast tanks and forepeak by compressed air, and the first lift was successfully made. From the actual calculation of the displacement of the lifting vessels, it was found that they were carrying a load of 2,750 tons, and in this position the ship was carried" a distance of over one milo and moved inshore clear of the anchor^ age. Several other lifts were made arid the vessel gradually carried along until her decks were almost dry at low water. The divers were then able roughly to patch the hole, and a number of powerful pumps were started, the vessel was pumped out, and. floated. She was then placed high and dry on the beach and preparations made to replace and strengthen the patch over the fracture to enable the vessel to proceed to her repairing- port. The bottom being mud, the lower part of the fracture was not accessible. The mud was then dredged away, and a coffer-dam reaching alx>ve the high-water mark was constructed and fastened to the ship's side. When this was completed it enabled the mechanics to work inside and plate up the aperture. The vessel duly arrived at her repairing port and was repaired, after which she made many useful voyages until her ■career was ended by an enemy torpedo. Another daring instance of the kind of work carried out by tho corps was that of a large oil steamer which took fire. In order to put out the fire, then raging furiously, the corps put not less than forty shots into the vessel to sink her, prior to which several explosions occurred, which endangered the lives of the men working in small vessels around. The holes caused by the shots, and also by the fire, were then plugged, and tho ship was pumped out.

A CARGO WORTH THREE MILLIONS.

New types of salvage machinery have played an importaut part in the success of the work, and the development of these inventions lias, of course, been encouraged to a greater extent than would have been probable before tho war, when ships were not "goldl mines"

for their fortunate owners, and ■when shipping losses were normal. One of the greatest aids' to salvage work is the submersible electric motor-pumj.. The use of these pumps not long ago enabled a vessel of 14,000 tons, one of the latest type of cargo ships, to be salved, after having been submarined. . The vessel wan carrying a cargo of foodstuffs worth over three millions of money. Salvage tugs managed to prevent her sinking in deep water and to beach her, but at high tide sire was submerged save for the shelter deck. Ordinary pump? were useless, because they might have been washed away. The submersible electric motor pumps had to work in 57ft of water. Divers succeeded in penetrating the hull, and by the united efforts of the corps the submersible electric pumps were got to work, connected up with salvage ships by electric cables, and the_ holds of the ship were gradually drained off. These strenuous efforts proved successful, the big ship was floated, and the valuable cargo, including butter to eat a.nd wool for clothing, very largely salved. Not only was this done, but after being patched up with an Admiralty "standardised patch," the great provisioner will soon be ready for sea again.