Submarine Wrecking Vessel.

New Zealand Graphic, Volume XLIII, Issue 7, 18 August 1909, Page 44

Submarine Wrecking Vessel.

THE illustration represents a new type of wrecking vessel, which has been built at Wyvenhoe, Eng., for the recovery of certain ■unken bullion and specie, whose value is over £1,000,000. On the night of October 9, 1799, the British man-of-war “Lutine” sank off the entrance to the Zuyder Zee, while she was transporting some £1,178,000 worth of bullion and specie to Hamburg for the purpose of relieving the financial panic which existed there at that time. John Mavors Still, Lloyds’ Amsterdam agent, found the insurance effected to be £900.000 sterling at Lloyds and ■£loo.ooo e’erling at Hamburg. England was at war with Erance; and Holland, under French influence, claimed the wreck as spoils of war. The ship became sanded, however, as she lay at the entrance to ths Zuyder Zee. and the wreckers were forced to abandon her. Peace being declared, the King of Holland. in 1823, ceded to the King of England his rights to the treasure, and the King of England eeded the right back

to Lloyds. The sand being cut away from over the vessel by storms from time to time, diving operations were commenced under the supervision of Lloyds to recover the treasure. With the crude apparatus at hand, the company have succeeded in recovering in five attempts, during over a century, a total of 198 gold and silver bars and some 12.090 coins. The aand, however, continually drifted in on the wreck, and ultimately forced them to suspend operations. The engineer for the company having the contract with Lloyds requested Mr. lake to design a submarine recovery apparatus for the salving of this treasure. Xhe engineering problem is to remove

about 40.000 tons of sand that has accumulated above and around the wreck, and to clear out the sand from the interior of the vessel, first removing her decks if they still remain. For this purpose a plant has been designed consisting of a large light-draft surface vessel, provided with a well running partially through the centre of the vessel, for the purpose of housing the submarine bottom working apparatus. Two 12in sand pumps work in connection with the submarine tube. Their suetion ends are controlled from within the working compartment, and are to be used in the final cleaning out of the vessel, and to keep the sand away from the operators ■when they are working on the bottom. The capacity of the sand-pumping plant ie over 40,000 tons per day of 24 hours. Owing to the exposed nature of the location, and the faet that the sand drifts in so rapidly during the time of storm, the plant is made powerful

enough to complete the whole job in a few days’ time during the comparative cahn of the summer. The most interesting part of the plant is the submarine tube and working chamber. The former, built of steel plating, is hinged within the hull of the surface vessel. It is sft in diameter and 95ft long. Water ballast compartments are provided on either side; and there is a passageway down which the operators may walk when the working compartment is on the bottom. The working department, also built of steel plating, is constructed on the same prfnciple as the diving compartment in tlie Lake type of submarine boats, which principle has been successfully tested in

numerous submarine boats constructed here and abroad. It is about Bft. across, with large doors opening out from its bottom, and with provision for the admission of compressed air. The bottom door may lie opened, and the compartment may be hauled to any desired position by the use of anchor lines. The working chamber Is fitted with observation ports, for investigation of the bottom of the sea, which latter is lighted up by searchlights carried within the chamber. In working on a stationary wreck the chamber and tube would be moved, preferably by anchor lines; but when a search for a wreck or other object is being made, the chamber will either be suspended clear of the bottom, and the surface hull with its submarine tube and chamber towed by a tug; or the chamber will be lowered to the bottom, and the whole plant, surface and submerger, moved by means of a heavy mechanically-driven tractor wheel, pro-

jecting through the chamber and resting upon the bottom. To achieve this sufficient water ballast » admitted to causa the working chamber to rest on the bottom, embed the teeth of the tractor wheel, and so afford sufficient tractive adhesion. The traction wheel is driven by a motor within the compartment, and may he turned in any direction, like a unicyele. The compartment may thus be navigated in the most devious course, nrouud rocks or other kinds of obstructions. This last will be the method of progression adopted when the system is used in pearl fisheries, for which the plant is particularly well adapted. The small sketch shows the compartment fitted with

two large, mechanically-operated rakes, hinged, one on each side, at the axis of the chamber. This type of machine would be used on bottoms that are fairly dear of rocks, and the method of cleaning up oyster ground may be likened to that of a reaper cleaning up a wheat field. The working compartment is wheeled back and forth over the oyster beds in parallel lines. When the rakes become filled, the submarine compartment is stopped, the rakes are rotated and elevated by machinery within the submarine working chamber, and the oysters are dumped into a car which runs on rails on the top and sides of the tube, as shown in the sketch. The car being filled, it is hauled to the surface and dumped of its load. On prolific oyster bottom free from rode, and in the clear waters of Ceylon, sueh an apparatus would probably catch more oysters per day than several hundred native diver* operating in the usual manner. ,