Art. XLIX. —On the Raising of the S. S. “Taranaki.”

Transactions and Proceedings of the Royal Society of New Zealand, Volume 2, 1869, Page 203

Art. XLIX. —On the Raising of the S. S. “Taranaki.” By J. T. Stewart. (With Illustrations.) [Read before the Wellington Philosophical Society, November 13, 1869.] Although this subject has been already brought a good deal before the public, and the main facts stated, I have thought it advisable to lay a more detailed account of it before the society, at the risk of appearing to go over a good deal of the same ground that the public prints have already done. Taking a good deal of interest in this matter from its start, I have collected the following details, principally from information supplied to me by Messrs. Seagar and Thirkell; and I have made the accompanying sketches from that information, and from inspection of the gear used by them. The screw-steamer “Taranaki,” belonging to the New Zealand Steam Navigation Company, was wrecked and sunk in Bowden's Bay, Tory Channel, Queen Charlotte's Sound, on the 19th August, 1868. Her tonnage is 299 register, h. p. 100, length of keel 182 feet, beam 25 feet, and depth of hold 16 feet. She was a new boat, built on the river Clyde, in Scotland, a locality now taking the lead in British iron shipbuilding. Shortly after the wreck the company called for tenders for raising her. The Directors, however, declined undertaking the task of raising the wreck, and it was sold to a few residents in Wellington, in the beginning of March, 1869, who then took steps for raising her. Several schemes were proposed to them, but that submitted by Messrs. Seagar and Thirkell, of Wellington, was chosen, and the carrying out of the operations was entrusted to them; and the result shows the choice was judicious. I shall endeavour to give a short account of the scheme as proposed for raising her, and then give some notes of the successful carrying out of the operations. The wreck was supposed to be lying in about one hundred feet of water, and the weight to be raised was estimated at about 450 tons. 1st. There was the floating-power required as a base to work from, and to carry this weight in addition to the men and the plant or apparatus.

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 ½ 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 ¼ 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 ½ in. by ⅝ in. iron, with 1 ¼ 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 3 ¾ in. by 1 in. iron, and thickened where it took hold of the port-hole to 2 ½ 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 ½ in. by ½ 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 ⅝ in., and pierced with 1 ½ 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 ⅜ inches diameter iron, and screwed for 2 feet 3 ½ inches in length, and had four threads to an inch. Each screw was turned by a spanner, or lever, 5 feet long, of 1 ½ 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

To accompany Paper by J. T. Stewart on raising S.S.Taranaki

the pontoons themselves affected by currents and winds, must involve a certain amount of swinging motion, horizontally or laterally; besides the tops of the rods were not all vertically over the hooks in the port-holes. To allow for this the upper washer of wrought-iron was rounded in the bottom, and rested and titted in a hollow recess in the cast-iron washer or plate, which hollow was turned so as to fit accurately to the bottom of the upper washer. This then allowed to the upper washer, the screw, the nut, and top of rod, a certain amount of oscillation, to suit which the aperture in the cast-iron washer, or plate, was beveled out somewhat towards the lower edge. (See sketch). A set of counter-balance weights had also to be provided to carry the weight of the rods, when adjusting or fleeting the screws. These weights were carried by ropes attached to the upper part of the rods, and passing over sheaves placed in the cross logs which rested on the pontoons. The weight was made sufficient to balance the weight of rod, and this arrangement allowed the pontoons to rise and fall with the tide. The four pontoons were placed two on each side of the sunken vessel, so that a space was left between them over the wreck, about one foot more than the breadth of the “Taranaki.” Twenty-two sets of cross beams, each carrying two lifting rods, rested on the pontoons, and passed across over the wreck. These beams were double, consisting each of two pieces, each piece 18 in. by 9 in., placed five inches apart, and bolted together in three places by three-quarter inch bolts. The length of the beams was from 48 feet to 53 feet, according to position. They were of Kahikatea, or N. Z. white pine. They proved strong enough for the strain, but with nothing to spare, deflecting a foot in the middle when the strain came on them. Two of them sprung in the early part of the work, but they were of lighter scantling, and were strengthened and used afterwards. On each of these beams, and over the inner side of the pontoons so as to plumb the sunken vessel's sides, were placed two blocks of hard wood (Rata), each 15 in. by 5 in., and 2 feet long, with a hole 5 inches square for the lifting rod to pass through, and on this block was placed the plate, or washer, already described, carrying the upper washer and nut of the lifting screw. (See sketch.) On an average, fifty-four men were employed. The mode of screwing up a lift was, first to screw up all the screws on one side for one foot, or half the length of lift, then proceed to the other side and screw up two feet, or the full length of the lift, and then go back to the first side, and screw up the remaining half of the lift for this side. The mode of fleeting the screws was, to begin to fleet simultaneously the foremost screw on each of the two pontoons upon one side, and the after-most screw on each of the two pontoons on the other side; and then, when these had been adjusted and were being tightened up, the screws next but one to the four already fleeted were slacked off, and so on, till all the screws were gone through and got ready for a fresh lift. Thus no one log had the strain taken off both of its ends at one time. In this operation eight sets of lifting rods were relieved of the weight at one time, and the weight of the wreck was then borne safely by the remaining thirty-six rods. They could fleet and screw up twice in one day, taking about an hour to fleet, and three hours to heave up a lift. Two divers were employed, who had the arduous task of fixing the hooks under such a depth of water, opening the ports, cutting away the woodwork, and other jobs, such as sending up the anchors and chains, etc. Their labour was much facilitated by the use of a box, or cage, 6 feet by

3 feet, formed of iron bars placed openly, and having a wooden floor. This was slung from the pontoons, and let down where the divers were to work, and in it they stood when at work. After hooking on the lifting hook to the port, the diver fixed the stop, or slide, to prevent the hook falling out, and also made fast the rod to the ship's rail above, to steady it. It was at first intended to make use of the lifting power of the tide, and assist it by filling the pontoons with water, and pumping them out as the tide rose. For this purpose valves were put in the bottom of the pontoons, and pumps provided. This plan was put in operation for some time, until, as the vessel was hauled ahead, it was found that the bank was so steep that she was liable to slip back when allowed to rest on the bottom. At one place the stern was observed to have thirty feet more water over it than the bows had, so sudden was the incline, and for a short distance near the top of the bank, the inclination was nearly 1 to 1. It was found necessary after this to keep her always suspended or carried from the pontoons, and to trust to the lifting power afforded by working the screws. This steep bank added much to the difficulties to be overcome, and the vessel was brought gradually side on to it, so as to bring her more to a level. This was done by lifting at each lift the stern more than the bows, and hauling it round at same time up the slope of the bank. As the vessel was lifted she was hauled ahead by being made fast by a chain cable from her bow to the “Ladybird,” which steamer was hauled ahead from time to time, as required, to moorings placed in shore. The position of the wreck may be briefly described. She lay on a comparatively level bottom of soft clay and shells, with a rise of six feet in the length of the vessel towards the bows, and the stern was sunk about seven feet in the mud; a great weight of mud was piled upon the poop deck, probably thrown over the stern when she went down. At the stern the depth of water was 17 ½ fathoms, or 105 feet, at high-water. This nearly level bottom extended ahead for about sixty feet, when the foot of a bank was reached. This bank rose at a rate of thirty feet in two hundred feet, or in about the length of the vessel, for a distance ahead of some five hundred feet, when the inclination increased to a rise of twenty-seven feet in thirty feet, for a short distance up to the top of the bank, over which there was a depth of twenty-one feet at high-water. On getting over this bank the depth increased to twenty-four feet for some distance, and then gradually shoaled in shore for a length of six hundred feet, or thereabouts, farther. The rise of tide at springs was 4 feet 6 inches, and at neaps 1 foot 6 inches, and there was a current on the ebb which greatly interfered with the operations of the divers for two-thirds of the ebb. The position, however, was landlocked and sheltered from any waves or swell of consequence. A notice of some of the damages sustained by the vessel may be interesting. First, the damage sustained when she struck on the rock before sinking, as found after she was raised:— The extent of the damage lay within three frames, or a length of 4 feet, in the engine room compartment, on the port side, close behind the donkey engine. There was a crack or rent in one of the plates; the top of the crack was about 4 feet under the load water-line; the crack was alongside one of the angle iron ship's frames. It was 3 feet long, and of an average width open of 1 inch. The frame was bulged in about 8 inches. There was also a hole about 2 feet aft of the crack and on the same level;

this hole was about 3 inches diameter, and had a sharp pointed bit of hard rock sticking in it. The “Taranaki” was divided into three compartments, by watertight bulkheads. The damage took place in the centre one, but the aft compartment seems gradually to have filled. The fore compartment evidently remained unfilled, as will be noticed afterwards. The vessel kept afloat for seven hours after she struck, and then went down stern first, burying the stern in the mud, scooping up twenty or thirty tons of soil on to the poop, knocking away the poop rail and stanchions round the stern, leaving the steering gear uninjured, but twisting round and breaking the rudder. The screw propeller had been knocked off on the rock shortly after she struck. The boiler was injured when she sunk, and was found to be very seriously damaged, having collapsed from the outside pressure of the water as the vessel suddenly sunk to the depth of 17 ½ fathoms, assisted probably by a partial vacuum formed by condensation of the steam. (See sketch of boiler.) The top of the shell, although arched and strengthened by angle iron ribs round the top, with 1 ¾ inch stays from the angle irons to the bottom of the boiler, was forced in 18 inches, crushing and bending these stays, and also the gusset stays 1 foot wide by 1 inch, at the angle formed by the top and back of boiler. The 1 ¾ inch stays, from top of boiler to top of combustion chamber, also were broken and bent. In collapsing, the top of the boiler had dragged back the uptake for 18 inches on top, taking the steam chest with it, and also dragged the back of the boiler in towards the combustion chamber, leaving the stays sticking through the back. The combustion chamber, the tubes, tube plates, and the bottom and front of the boiler were found uninjured and not moved. In the fore deck, over the forward compartment, which seems to have remained free of water till after she sank, ten deck beams were bent down 8 inches by the pressure of the water from outside, bending the 3 inch iron stanchions supporting them from the lower deck, and the hatches were found forced inwards. The forward watertight bulkhead was bulged in forward about 1 foot. Second, the effects accruing from her long retention under water:— She sunk on the 19th of August, 1868, and was pumped out, on raising her, on the 26th of September, 1869, —a period of over thirteen months. Her hull was completely coated with shelly encrustation, except the bottom, which the marine paint had kept tolerably clean. Her small spars and upper decks were completely worm eaten and gone; any Teak wood was found sound; the cabin fittings, where painted, were in general sound. The engines were found in working order, all the journals and bearings bright and clean. The wrought-iron starting gear tarnished but not damaged, and the cast-iron work uninjured. One of the cylinders was free of water, the other was full. Having thus attempted to give a description of the plan of operations, the position of the wreck, and mentioned the principal damages she sustained, I shall give some notes of the operation of raising the “Taranaki,” interspersed with a few extracts from a journal kept by Mr. Thirkell; and thus give some idea of the nature of the work. On the morning of June 23, 1869, a start was made by the adventurers from Wellington, in the steamer “Ladybird,” hired as a tender during the operations, and they got to Picton the same afternoon, and next day launched two of the pontoons and took in the cross logs and moorings. On the 26th June, left Picton, and towed the two pontoons to Bowden's bay, where the “Taranaki” lay sunk. From this time to the 10th July they

were getting the anchors and chains out of the “Taranaki” by aid of the divers, and mooring the two pontoons and the “Ladybird,” —a work of considerable difficulty; also getting the cross bearing logs bolted together in pairs, and other preliminary arrangements made. On the 12th July, got the stage for the divers into position; one of the divers went down and opened one of the port-holes, found depth to port-holes, at low-water, to be 88 feet. From this date up to the 21st, engaged getting lifting rods from these two pontoons hooked on to the ports by the divers, which required much patience, perseverance, and repeated attempts before completion. The divers seem to have remained down from twenty minutes to forty minutes, often over an hour, and on some occasions for one hundred and five minutes. On the 21st July, the “Ladybird” went to Picton, and returned on the 23rd with the third and fourth pontoons, and they now moored the “Ladybird” in position for hauling the “Taranaki' ahead, having 60 fathoms of chain ahead, and with the “Taranaki” made fast to her stern with 30 fathoms of chain; also moored the third and fourth pontoons in position, and this with getting the rest of the cross logs ready, and other work, occupied until the 26th, on which day the diver examined, and reported on, the extent of the injury the vessel had received when she struck, and which has already been described. From this time up to the 6th August, getting the lifting rods from the third and the fourth pontoons down and fixed, and getting the other gear ready. For the scupper holes, one or two of which were used, a special hook had to be extemporised, as the hooks made for the port-holes would not do for them. Extracts from Log:—“Wednesday, 14th July, 7.15 a.m., commenced work, light S. W. wind; men rigging up gear for supporting bars, and attending to diver. “One of the divers went down at 7.45 a.m. to hook on, down thirty minutes, went down again at 8.35 a.m., down sixty-three minutes, wanted stage shifted; went down at 10.16 a.m., down twenty-nine minutes, came up, reported slide too short for the port; went down at 11 a.m. to unhook and send up the slide to alter, down sixteen minutes, came up; the other diver went down at 12.55 p.m., took slide with him. Put hook in and secured it with slide, down twenty-five minutes, came up to shift stage; went down to second hook at 1.40 p.m., after trying to cut covering board, came up to shift stage a little aft, down twenty minutes; went down again at 2.5 p.m., down fifteen minutes, came up, could not work, tide too strong; put down bars ready for divers next day, and got blocks and balance weights ready. “Tuesday, July 20—Strong N. W. wind and dry weather; 8 a.m., commenced. Men putting four full lengths of bars, with hooks, etc., down, ready for the diver to hook on when the tide slacked a little; shifting stage, which was foul, and took a long time to clear, on account of the tide drifting it against the vessel's side; fitting up the remainder of the sheaves on the port side, and two on the starboard side, and altered the rope from the blocks to the sheaves, and found the balance weights worked much better. “One of the divers went down and commenced to cut out and unscrew port-hole No. 13, at 11.45 a.m., hooked on and came up after being down forty minutes; got refreshed a little, and went down at 12.40 p.m. to clear away for hook No. 12; hooked on, and screwed up and lashed up Nos. 12 and 13 to the rail, and then came up: down sixty minutes. “Part of the men went to dinner, and part remained to shift stage and ladder

ready for the other diver, who got dressed and went down at 2.40 p.m. to hook on Nos. 14 and 15; succeeded in opening three port-holes, and cut away and screwed up Nos. 14 and 15, put lashing on the rail, and came up after being down eighty-five minutes. The “Storm Bird” arrived from Wellington with some bars, etc., as the after lengths had been found 4 feet to 8 feet too short. “Saturday, July 31—Strong N. wind and rain all day, one diver went down at 9.25 a.m., as soon as the hooks were altered for the scupper hole, down thirty-eight minutes; came up and reported the hook too large for the hole; made it smaller at the point, and then diver went down at 11.12 to put it in, down forty-three minutes, came up and reported the hook half way in, and could not get it any further. “The other diver got ready and went down at 12.45 p.m., he drove it up and wedged it with three iron wedges, down sixty-five minutes and came up to refresh: went down at 2.10 to find the middle scupper hole, found it and put hook in half way and could not get it further in, nor out again; down fifty minutes, came up and could not go down any more to-day.” By the 7th August, all was ready to try a lift, and on that day we find the journal saying:—“Weather fine all day, commenced at 12.30 p.m., sunk pontoons by letting in water; connected on at 1.30 p.m., and screwed all the bars tight, and began to pump out at 2.45 p.m., assisted by the whalers from the Sound. Vessel began to lift at 3.30 p.m.; all the water pumped out at 4 p.m. The pontoons rose considerably, two of the after logs of the fore pontoons sprung, being undersized; hove in by the ‘Ladybird's’ windlass as the tide flowed, got ahead 50 feet, and ceased at 8 p.m.” This was the first lift, and rather an exciting time. The lift got was about 5 feet, of this 3 feet was due to the rise of the tide, and 2 feet to the effect of pumping out the pontoons. When she first started out of her bed in the mud, the pontoons started or jumped up nearly six inches; before this start the deck of the pontoons was 14 inches out of water on the inner side, and 2 feet on the outer. (Usually, however, it was afterwards found there was none of this jerking up, but a steady lift.) The following days the same mode of procedure went on. “12th August—4 a.m., commenced to connect bars to screws, and screwed down about 10 inches; at 6.45 began to pump the water out of pontoons, and with the tide lifted the bow up about 5 feet, but found the bank with a greater rise than was expected, which makes the after end difficult to ground, hove ahead with some of the men, and the remainder finished pumping; at 12.30 p.m. found the anchor, in heaving ahead, ‘come home; ’ could not heave any more until it is lifted, and placed farther in shore, with one of the pontoon's mooring anchors to back it.” They had now got the wreck hauled ahead close to the rise of the steep bank, and went on lifting and hauling until the bows got well up, while the stern got to the foot of the slope, not very much higher than it was originally. On the 17th August, they sounded and found the vessel to be 26 ½ feet higher at the bows than at the stern, being about the angle of the bank at this place. On Saturday the 21st August, they found as the steamer settled down aft, that she slid down the bank for 16 feet; so they concluded that she would have to be lifted over the bank by the screws only. They now began to put more men on the screws in the after pontoons, so as to lift the stern a little more than the bows, at each lift, so as gradually to get a more even keel on the wreck, and as they did so, hauled the stern sideways on to the bank, as well as hauling her ahead; the log going on thus on the 25th and 26th:—Divers commenced to take off some of the long lengths of the bars. “30th August—6 a.m., commenced work; fine clear weather.

“Began to screw up; went to breakfast 8 a.m., began work 8.45, finished up the length of the screws, and fleeted down again, and recommenced to screw up; went to dinner at noon; commenced at 1 p.m., screwed up the full length, and began to fleet part of the screws; ceased work at 5 p.m., having lifted the fore end 3 feet, and the after end 4 feet. “31st August—Day fine throughout, with light N. W. wind. “At 6 a.m. commenced to take off the second length of long bars of the two after pontoons, and fleet down the screws on the fore pontoons. “At 10 a.m. commenced to heave up the length of the screws; hove in by the north-west chains, and hove the ‘Ladybird’ ahead; 2 p.m., fleeted down the screws and commenced to heave up the second lift, got about two-thirds of the screwing up, and ceased work 6 p.m., having lifted about 3 ½ feet during the day, and gone well up the north-west bank, as well as ahead. “September 2nd—Fore lower-mast head about 2 feet out of water. “September 3rd—Found two of the hooks had torn away the plate of the port-holes, not having hold of the angle iron. Let water into pontoons to ease the bars, the vessel resting on bottom, and sent down both divers to put in the two hooks properly. Shifted the whole of the logs forward upon the after pontoon, and took the foremost log into the middle to the two ports left vacant. “Having pumped water out of pontoons, after dinner commenced to heave up, and got a lift of 2 feet. Ceased at 5.30 p.m. “September 4th—Fore-top out of water. “September 6th—Fore-top 2 feet, and main-mast head 1 foot out of water. “September 11th—Lifted to-day 3 feet 9 inches at fore-mast, and 4 feet 3 inches at mainmast; forecastle deck 10 feet under water, quarter-deck 25 feet under water. “September 13th—Screwed up 3 feet at fore-mast, and 4 feet aft; found the seams of the pontoons opening a good deal from exposure to the sun. “September 14th—Lifted 3 feet 4 inches forward, and 4 feet aft. “September 15th—The divers began to take off last lengths of long bars: lifted at fore-mast 2 feet 5 inches; the fore end of the forecastle deck out of water, found the pine deck very much worm-eaten. “September 16th—Lifted forward 1 foot 5 inches, and aft 2 feet. “September 17th—Let water into pontoons to slack the bars; shifted all the logs to a more direct lift, and took one log and screws from the after pontoons, and put them on the fore pontoons, fleeted the screws down, after placing the logs in position; pumped water out of pontoons, and lifted with the screws; lifted to-day at fore-mast 2 feet, and aft 2 feet 2 inches, and hove the vessel ahead about 20 feet. “September 18th—Lifted at fore-mast 2 feet 6 inches, and aft 4 feet. “September 20th—Raised the logs which were over the forecastle and the deck-house; came ahead to-day about 70 feet; lifted at fore-mast 1 foot 3 inches, and aft 3 feet. “September 21st—Hove ahead at high-water; let water into pontoons; cut two logs for blocks for packing up; screwed about 6 inches, and pumped out water from pontoons; lifted about 2 feet 6 inches; floated over the bank and ran ahead with the strong wind towards the beach for about 300 feet. “September 22nd—Hove ahead at high-water, and let water into pontoons to block up logs, which are now upon the rail of the “Taranaki.” The two divers down to examine the cracks in plates, and stop up holes, pumped out the pontoons. “September 23rd—Commenced to pump out the fore hold of the wreck. “September 24th—Continued pumping.

“September 25th—Pumping out wreck and stopping leaks and port-holes. (This was done by putting a sheep-skin and a board over the hole, and screwing it tight up to a cross bar placed inside.) “September 26th—Pumping out and repairing cracked plate. (This was temporarily done by the diver with wooden wedges, and afterwards, when the water was got under inside, by the engineers putting a plate and a sheep-skin over it.) “September 27th—Removed the lifting rods, screws, etc., and put them on board the ‘Ladybird,’ repaired cracked plate, and fitting up donkey engine. “September 28th—Got the donkey engine to work, cleaning out vessel, etc. “September 29th—Moved the ‘Taranaki’ alongside of the ‘Ladybird.’ “September 30th—Taking coals out of the ‘Taranaki’ into the ‘Ladybird,’ and mooring pontoons. Covering the worm-eaten decks with planks to walk upon. “October 1st—The steamer ‘Wanganui ’ arrived from Wellington with tow-ropes. Left Tory Channel in tow of the ‘Ladybird ’ and the ‘Wanganui,’ at 10 a.m., and reached Wellington safely in the afternoon at 4.30, after a fine passage across Cook's Straits. The vessel very tight, and not making any water.” The total lift was 92 feet; the weight of wreck about 400 tons.