Patent GB-140841-A (GB)
Title: Improvements in and relating to apparatus for raising sunken vessels
IPC: B63C7/24
Filed: 1918-11-20
Abstract: 140,841. Dawson, C. B. Nov. 20, 1918. Salvage vessels.-In apparatus for effecting the salvage of sunken vessels, a rotary toothed cutter is employed to break up the ground near the vessel, the excavated material being removed by suction apparatus. The rotation of the cutter is effected by a cable which is reciprocated by motor boats on the surface of the water, the cable afterwards being released from the cutter and dragged under the vessel, the ends being attached to winches carried on pairs of pontoons connected by cross-beams. When the requisite number of cables are in position, the vessel may be raised thereby and towed into shallow water. The baseplate of the cutter 41, Fig. 1, is hinged to the underside of a bracket 36 mounted on the lower end of the suction pipe 18. In its operative position, the base plate 38 is secured to the bracket by lugs 38<1> and cottars 40. The cable c<1>, which is dragged forwards and backwards by motor boats to rotate the cutter, is guided to the rim of the cutter by shackles 45, Figs. 3 and 8, hinged to the bracket 36, and held in operative position by cottars 46. The cottars 40, 46 are connected by ropes 48 secured at one end to the bracket and passing under pulleys 49<1> to the surface of the water. When the ground has been sufficiently excavated, the ropes 48 are pulled, the cottars being thereby withdrawn, and the cutter swings down into the position shown in Fig. 5, the actuating cable c<1> being thereby released so that it may be dragged by motor boats under the sunken vessel. Scrapers c<x> may be attached to the cable c<1> to facilitate its passage under the vessel, these scrapers being removed before lifting commences. The suction pipe 18, which partly supported by a cable 20 operated by a winch 22 on the salvage lighter 17, is adjusted vertically by a rack which gears with a pinion 34 on a platform 33<1> which is itself adjusted by bevel gearing 32 which actuates a nut on the screwed upper end of a rod 30, the lower end of which carries a disk 30 serving as a bearing in or upon the sea bed. The pipe 18 is partly supported by a counterweight 35, and is held centrally in the well of the lighter 17 by a square framework 26 having folding doors embracing the pipe. The framework 26 is held in position by spring-controlled rods 26' connected one to each corner of the framework and mounted on a staging 25. The bracket 36, which carries the cutter, has a notch 36<3> which straddles the bow of the sunken ship, and has also a depending curtain 36<5> which directs the excavated material to the mouth of the suction pipe. The pairs of pontoons P', by which the raising of the vessel is effected, are preferably connected by cross girders 56, Fig. 11, having near their ends saddles 57 seated upon stub shafts 58 pivoted in chairs 58<1> seated on bolsters 59 fixed to the decks of the pontoons, so that the latter are free to rock without straining the girders. To facilitate the locatiag and regulating of the wheel 41, pipe 18, and other parts, an attendant may be lowered into proximity with the vessels by means of a receptacle 50, Fig. 1, provided with glazed apertures 53, and an aperture 53<1> provided with a lens through which rays from a lamp may be thrown on to the work. The receptacle is supplied with air by a tube 54 connected with an air pump 55, and is fitted with a telephone connexion 56.