RAISING SUNKEN VESSELS.

Globe, Volume XXI, Issue 1660, 16 June 1879, Page 3

RAISING SUNKEN VESSELS.

At the last meeting of the Royal United Service Institution, Admiral Phillimore in the chair, a paper was read by Mr Druitt Halpin, of London, on an economical means of raising ironclads sunk in deep water. The paper (says the London “Times”) had especial

reference to the raising of Her Majesty's ship Vanguard by moans of Mr Halpin’s system of recovering sunken vessels, for which he has sent in proposals to the Admiralty. This system was described in the “ Times” of the 25th of July last year, and has been considerably improved in detail since that date. Mr Hal pin first pointed out the importance of the subject dealt with in his paper, which he considered a necessary branch of modern naval science. He thought some systematic provision should be made for the recovery of our costly ironclads in the event of their sinking either accidentally or in an engagement, and attributed the indifference with which the subject was received to the impracticable nature of many of the methods proposed, and the great outlaynecessary for the construction of the plant, which if successfulcould only be used again for a similar purpose, and the expense of which would bo an entire loss in the event of failure. Mr Halpin then proceeded to describe his method in detail, demonstrating very clearly his mode of operation by means of working models and diagrams. The apparatus is designed in such a manner that the assistance of divers is entirely dispensed with, the labor usually performed by those men being accomplished by machinery. The plan consists of two distinct parts—first, a wrought-iron tower which is used for examining the wreck, boring holes in her, and making attachments ; and, secondly, a filiating dock, which supplies the necessary floating power, and to which the attachments are made fast. When not in use for wreck raising, the floating) dock may bo used as a first-class dry dock for ships, and is capable of being transported to any required station without the assistance of tugs. The tower, which has been much improved since Mi Halpin’s plans were first described in the “ Times,” is a wrought iron tube about 4ft. in diameter and of a length suitable to the depth of water in which the submerged vessel lies. The lower end is closed and ballasted in order to lower the centre of gravity of the structure, the top being fitted with a manhole door. At both top and bottom of the tube is an annular chamber capable of being filled or emptied at pleasure. By means of these chambers the tower may bo floated horizontally, and in that position turned round in the water for repairs. Towards the bottom of the tower is the working chamber, which is provided with strong windows through which the work can be seen by the aid of an electric lamp. From this chamber the whole of the operations of cleaning the ship's plates, boring the holes, and shipping the wire-rope attachments, are controlled by a man stationed inside, who is only subject to ordinary atmospheric pressure. The tower is anchored in position, and a tug stationed alongside supplies the motive power for driving the machinery inside the tower which actuates the cleaning and boring tools and which is under the control of the man in the working chamber. The floating dock consists of two vessels, each provided with screw propellers and engines, which latter are also used for pumping purposes. The two vessels are connected together by girders boxed in to form a hollow deck, which is provided with airchambers at the sides to control the dock when dry docking a ship. The deck is pierced by hawse-pipes, through which the wire rope attachments are passed up to winches on the upper deck, which are driven by the screw engines. In practice the tower is floated out to the wreck, lowered in position, and anchored, A space is cleared, a hole bored, and the attachment made, the wire rope being buoyed to a floating boom above. The tower is then shifted to a second position, and so on until all the attachments have been made along one side of the wreck and the ends of the ropes made fast to the boom. The tower is then shifted to the other side of the vessel, which is similarly operated upon, and the ropes attached to a second boom lashed to the first one. The floating dock is next brought into position, the booms separated, the ends of the wire ropes passed up through the hawse-holes and made fast to the winches on the deck. As the tide falls the ropes are tightened and the dock is partially sunk. At low water pumping is commenced, and as soon as the wreck lifts with the tide the dock steams inshore, holding the wreck suspended. This operation is continued until the shallowness of the water puts an end to the use of the dock in this capacity. During the receding tide the leaks in the wreck are stopped and the vessel pumped out and floated. The dock then comes into operation as an ordinary dry dock, the vessel being docked for repairs. The dock carries its own coal for consumption during these operations. Mr Halpin also described a floating breakwater which he proposes to employ for the protection of the dock in exposed stations where it might otherwise be impracticable to work it. The reading of the paper was followed by a discussion in which Mr Longridge, C.E., Captain Oolomb, R.N., Mr Gorman, 0.E., Admiral Solwyn, and Mr Morley, C.E., successively took part. Opinions strongly in favor of the apparatus were expressed, while on the other hand objections to the system as applied to the raising of the Vanguard, which wtre of a purely technical nature, were raised, but were fully mot by Mr Halpin in his reply. In proposing a vote of thanks to Mr Halpin, Admiral Phillimore gave that gentleman great credit for having successfully raised the Edith in Holyhead harbor, after others had failed in their attempts, and observed that, although opinions might differ as to the practicability of raising the Vanguard, all must be agreed as to the ingenious and practical character of the apparatus by which Mr Halpin proposed to attempt that operation.