204 



2nd. There was the apparatus required to lift the vessel from this floating 

 base. 



For the first purpose four pontoons were planned with the following 

 dimensions : two of them were 95 feet long on top, 91 feet long at bottom, 14 

 feet wide at top, 12| feet wide at bottom, and 8 feet deep. The other two were 

 85 feet long on top, and 81 feet long at bottom, and of the same breadth and 

 depth as the first two ; strongly framed, decked, planked, and caulked, and 

 with three watertight bulkheads in each. 



The pontoons were built by contract, at Picton, of N. Z. white pine. 



These four pontoons, if sunk to a depth of 6 feet, would represent a 

 displacement of 775 tons nearly, and if totally submerged, of some 1050 tons ; 

 thus allowing an ample margin for the weight of the sunken vessel, and also 

 for that of the necessary men, tools, and gear, besides their own weight. 



In working, it was found that when the weight came on, they had a 

 displacement of 5 feet in depth, and it was calculated that out of this about 

 400 tons was due to the weight of the wreck under water, and the remainder 

 to that of the pontoons themselves, with the workmen and gear. 



The iron work for the lifting apparatus was designed and made by Mr. 

 Seagar, at his works in Wellington. 



The lifting apparatus may be described, generally, as consisting of forty- 

 four long iron rods, with hooks at bottom to catch in the circular openings, or 

 ports, in the sides of the vessel — twenty-two upon each side. (See plate XII.) 

 The upper ends of these rods led up to the pontoons, and were attached to 

 screws on the top of each rod for raising the weight. 



More particularly, — each of these rods was of 1^ inch diameter round iron. 

 This was equal to take a strain of sixteen tons each, or in all 700 tons. The 

 rods were divided into links twelve feet long, with oval eyes, connected by 

 short double links, 9 inches long, of 3^ in. by fin. iron, with l^in. pins. In 

 working it was observed that it would have been an improvement to have had 

 the rods in shorter links, say of four feet each. 



The hook at bottom was made of 3f in. by 1 in. iron, and thickened where 

 it took hold of the port-hole to 2^ inches, and an ingenious slide or stop took 

 hold of the lower side of the port-hole, and supported the hook after it was 

 fixed, thus preventing it slipping out when the upward strain was relaxed, and 

 this was found effectually to keep the hook in position. This stop was of 2 J in. 

 by ^in. iron, with a slot in it, to enable it to move along two pinching screws 

 through the side of the hook. (See sketch.) This stop was fastened by the 

 diver as soon as he got the hook in its place. When working, a short length 

 of chain, 3 feet to 4 feet long, was attached between the hook and the lower end 

 of the suspending rod. 



The upper end of each suspending rod had two shorter links of 4 feet 

 each, and above these, and forming the upper length of suspension bars, was 

 the fleeting link, which was double and of flat iron, each piece being 3 feet 

 5 in. long by 4 in. by § in. , and pierced with 1 J in. holes, four and a half inches 

 apart, so as to admit of adjustment of the length of the bars, when fleeting the 

 screws to take a fresh lift. These fleeting links were attached at the top to 

 the bottom of the lifting screw. 



The lifting screws were of 2§ inches diameter iron, and screwed for 

 2 feet 3 1 inches in length, and had four threads to an inch. Each screw was 

 turned by a spanner, or lever, 5 feet long, of 1|- inch round iron, moved by 

 two, or sometimes three, men, and with an eye fitting over the nut. The nut 

 worked upon double washers or plates, bearing on a wooden block which 

 rested on the cross logs of the pontoons, as will presently be described. These 

 washers were adapted to the special nature of the work to be done. 



The lifting of a movable body at such a depth, acted on by currents, and 



