OPERATIONS ON THE AUSTRAL.

Lyttelton Times, Volume LIX, Issue 6868, 5 March 1883, Page 5

OPERATIONS ON THE AUSTRAL.

The following it a description of the process which was used to raise the Austral, which appears in the Melbourne Ag« 41 The steamship lies iu about 32ft of water at the deepest part. No part of the deck reaches the surface. The forepart is only ISia under w»ter at low tide, but in she afterpart there is. in one corner, 26|ft of water washing over the upper deck. The coffer-dam oommeuers at the upper deck, and will, when finished, roach above the surface, the full length of the vessel. It is bsing made of planks of kauri pine, strongly fitted together, and forming a wall lOin la thickness. It is made in sections 16ft in length. Each section, when completed, is lowered and strongly secured in its place by divers. Already.the forepart of the ship has been treated in this way, but the heaviest work has yet to bo performed in the after-part, where there ia from 20 to 26 feet of water to contend with, Tho fixing of this coffer-dam or wall is, however, by no means the most difficult part of tho work. While tho ship, is full of water, the outer pressure against tins wall is at present neutralised by tho resistance of the water on the inner side, but when tho pumps are put in operation this resistance will of course bo removed, and tho wail will have to withstand tho enormous lateral pressure of 91b to the square inch. In order, therefore, to prevent a collapse tho two wall* which will extend along tho ship from stem to stern will have to bo shored up cm the inn.-r sides. In the fore part of the ship this has already been done. Cfot only aro there great strong beams extending horizontally from side to side, but there are numerous powerful support* extending across the vessel diagonally, This seme thing will be done tho full iongto or the ship, tha wall or coffer-dam ben-g also sauroi against the masts wherever practicable, so that it will bo for all practicable purposes, as strong as tho permanent sides of a ship. When this w&IHog is completed it will, instead of being caulked, which would be & work involving great delay, be made water-tight by means of an outer covering of canvas. For this par* pose £6,000 square feet of canvas will be required. Tumping machinery has been obtained from Melbourne, and it will be capable of pumping 230 tons per minute.'*