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Raising the Wreck of SS Great Britain (by George Watson
and Geoff Leet) One of Victorian Wick's heroes is "James Bremner the Wreckraiser" and the obelisk on the South Head credits him with the salvaging of 236 wrecked ships. He was also a ship builder and constructor of harbours. He developed various stone-laying barges and also the harbour wall technique of placing slate slabs vertically like books in a bookcase to allow the wave force to dissipate, still a feature of harbours like Keiss, Castlehill, and Sandside. The BBC1 television programme "Coast" featured Dundrum Bay, Ireland, where Brunel's large propeller-driven iron ship, the "Great Britain", grounded in 1846 on the seventh voyage. The great ship travelled west in the dark from Liverpool, south of the Isle of Man, seeking the lighthouse there but failing to see it. Many miles later they saw the new lighthouse on the north end of Dundrum Bay and attempted to sail round it (the ship's charts may have been out of date so may not have shown the Dundrum Bay light). The TV programme credited Brunel with the refloating of the ship, but he expressed every confidence in James Bremner, whose work is described below. Following is a copy of Alexander Bremner's account of the refloating submitted to the Institution of Civil Engineers in 1861. Alexander, James's son, was present at the refloating and his account was probably written to ensure that his father got due credit. The Wreckraiser himself regarded the "Great Britain" as one of the easier tasks; it was not even sunk! James, like his son, was a member of the Institute of Civil Engineers, and had been proposed by the first President, Thomas Telford. We lack the original illustrations so have used ones from the Illustrated London News of August 21st. 1847. This account comes from the archives of the Institute and, so far as we know is previously unpublished. We now publish with the kind permission of the Institute of Civil Engineers. An Account of the Means adopted for Raising and
Floating the Iron Steam Ship "Great Britain" stranded in Dundrum Bay,
Ireland, in September 1846, and recovered in August 1847. Received April 1861 As no authentic Account has ever been put forth of the
Plans which the late Mr James Bremner, MICE assisted by the Author, his
son, adopted for raising and floating the Steam Ship "Great Britain", at
that time the largest Vessel in the World, it is thought that, even at
this remote period, a brief explanation of the subject may be useful, by
drawing the attention of this Institution to the devising of improved
means for the recovery, when stranded, of increasingly valuable Ships of
our Naval and Merchant Marine. A great number of Vessels are annually stranded and a considerable variety of means have been adopted for recovering them. The most common mode resorted to is that of filling the Hold with empty Casks, the displacement of which, when a sufficient number are place in the Ship, floats her and renders her transportable from the Beach. This method, however, is very objectionable as casks are so fragile that when a number of tiers are necessary they crush each other, and give way just at the moment when they are required to act; and 9moreover it is seldom that a sufficient number of Casks to effect the needed displacement can be got into the Ship. Other methods have been used with great success, such as filatforming, that is, the putting in of a temporary Deck and Bulkheads, tightening the same by caulking and thereby displacing a quantity of Water sufficient to raise the Ship. In cases where the Water ebbs far enough, and the ceiling is not damaged, a temporary Deck is unnecessary; the ceiling being caulked throughout only a couple of Bulkheads are required. The displacement has frequently been greatly assisted by the application of Caissons externally, but the action of the Sea is so destructive to them that they should be avoided except in special Cases. In addition to these methods the late Mr Bremner applied tarred Canvass, or Bullock's Hides, in various ways in order to make the ship float with her own displacement The preceding methods are mainly applicable to
timber-built ships; but the case to which this paper refers, was totally
different to anything that had preceded it both in its magnitude and in
its conditions. In October 1846 the late Mr Bremner and the Author were called on to report on the condition of the Vessel, and what they considered best for her protection during the Winter, and for her ultimate recovery. She was found to be situated end on to the sea and very far up on the Beach, at Tyrilla on the North side of Dundrum Bay. She lay on a sub stratum of mountain lime stone which was covered with about 3 feet of ordinary beach sand. The ship had settled through the sand down to the hard bottom, the gradient of which in the line of the Ship was about 1 in 180. As far as could be ascertained the damage done did not appear very serious, the chief visible injury to the bottom being a large hole on the landward Bilge; and from the fact of a quantity of Sand being in the Hold forward, the main damage was proved to be there, as there was but little Sand aft of the Engines. Some of the Bulk heads also were considerably started forward. In order to ascertain the probably amount of injury sustained, the sand in which the ship was embedded was sounded by sharp Iron rods, which discovered the fact that the foundation upon which she rested was tolerably regular, but at a short distance landward, and slightly forward of the fore end of the boilers, a lump of Rock cropped out at the surface of the Sand. The Captain's attention was immediately called to this, with an urgent request that he would have it removed by blasting, as in case of strong inshore Winds driving the ship upon it, it would inevitably have caused great injury to her bottom. After making minute inspection of the ship and her position a plan of a breakwater, for protecting the ship through the winter, was submitted to the Directors at Bristol, and, when good weather set in, in Spring, the work of taking the ship off was to begin. This Breakwater was adopted by the Directors, and the Author was instructed to superintend its erection. On arriving at the Ship it was found that sufficient materials for the Breakwater were not provided and that the Rocky projection, previously alluded to, had been left untouched, and that the fear then expressed was only too fully realized, as the ship was driven on top of it, so as to render its removal impossible. Shortly after this the memorable tremendous Gale of the 19th Nov 1846 occurred, when this rock supported the ship under the Boilers and Engines, so that the force of the Waves striking her under the quarters kept her working on it as a pivot, like an immense tilt hammer. Her forepart striking the Rock quarried it out, and the sea cast up the debris in a heap at the lee bow. This Gale altered the position of the Ship, her 9ft mark forward being now down to the top of the sand, and her Heel elevated considerably above it. The ship had come more broadside on to the Waves and lay in fact suspended on the projecting Rock which had forced up the Boilers and the deck above fully 19 inches causing at the same time extensive destruction to the Engines. The Author then reported the altered position of the
Ship to the Directors, stating that larger timbers would be required for
the Breakwater, and that it would have to be extended on the weather
quarter. As may be readily seen by a glance at the map of Ireland the Bay of Dundrum is very much exposed, which rendered it necessary for the lifting power to be as much as possible clear of the influence of the waves, for it is obvious that, were it otherwise, the whole apparatus would be liable to be overturned by any in-shore wind. It is also necessary to construct the whole machinery so as to work simultaneously. To effect this, recourse was had to the following plans; as shewn in Fig 1, a number of Balks of Timber were placed along the Ship's sides forward at regular intervals and onto the Heads of each of these a cast metal sheave was fitted, 12in diameter by 5in thick; iron plates being let into the Motices to prevent the pin of the Sheave from bending. There were in all 20 pairs of Balks, and to each pair a Box was suspended. Each Box was of American 3in deal, 12ft x 14ft x 8ft framed of American Rock Elm, fixed with screw bolts. The bottoms of the boxes were formed at different angles to fit the Ship's sides, so as to assist the displacement after she had been raised. These boxes were hoisted into their places by Derricks, and purchases suspended from the Ship's masts, and as each was put in position chain cables from 1 l/8in to 1 1/4 in. diameter were put round the box, the end being united with a shackle. The other end of the Chain was passed over the pulley in the Head of the Balk, and thro' another pulley of the same size which was attached by chains to a ?teagle? in the lower Deck side lights, the end of each Chain being tied to the upper end of the Balk by a clove hitch; thereby doubling the weight in each box, which was 25 tons of sand, added to which the Boxes weighed 3 tons each - thus making 28 in all In order to keep the Ship from straining, the two Boxes that were placed opposite the Boilers and Engines had 4 powers to each, which gave, after deducting � th for friction an effective lift by all the Boxes of 924 tons. In adition to the power thus obtained there were 3 levers; one at each side and one under the forefoot. The lever on the Starboard side was of 6 powers. It consisted of American balks, and was loaded with one of the Ship's iron boats filled with sand which weighed altogether 27 tons. The lever on the port side was formed of Beech trees and American timber [end of page 6] It was of 6 powers and was loaded with chain cables, fire bars and some moveable parts of the Engine. These materials were selected for this position as presenting the least surface to the Sea, and weighed in all about 29 tons /Section No II The fulcrums of the side Levers were formed by a series of piles driven to the Rock, upon which were fixed longitudinal pieces with a half Balk cut cornerwise as a Coping. The inner ends of these Levers rested against the Bilge Keels which had been fixed to the Ship to prevent her rolling. The Levers were immediately under the Machinery, and together gave a lifting power of about 350 tons. The fore lever consisted of 3 whole American Balks, and was fished with 3 half balks lashed to them edgewise. They were fitted and bolted together at the inner end and spread outwards, so as to carry a platform loaded with 8 tons of Anchors, Stones, etc. This lever had 7 powers. After allowing � th for friction on the boxes there were 1330 tons of lifting power, - this was considered ample for all the weight, but, in case of accident to any of the Levers or Boxes, 3 very powerful screw jacks one capable of lifting 60 tons and 2 forty tons each were set on a platform secured by shoring and acted upon timber cleats bolted to the stem.
In lifting everything went on as was anticipated, and when the Ship rose 2ft 9in, the height intended for the first lift, the water was admitted which prevented her rising further. But when the Tide receded the stones and wedges under the Ship were found to be inadequate to support her, as there was a considerable Head of water inside the vessel, and the sand which filled the lower fore hold had much greater weight when the water left her. The Ship thus settled back so far, that out of the 2ft 9in only 15in were retained. While settling however 5 of the boxes broke either the Balks or the Chains suspending them, and were rendered useless for water tight purposes. The Balks that broke did so above the gunwale so that when the sheaves were fitted again they were ready for the boxes which were patched up to hold the sand, and reset. The self acting shores, as formerly intended, were constructed. Cleats were fixed to the Ship's sides at convenient heights and distances, - opposite these, piles of small timber were driven closely together, so as to make a solid footing at the surface of the Sand. Short planks were fixed to the pile Heads, upon which was placed a deal 12ft long, with thin boards on each side, which formed a groove. To the inner end of this a pulley was attached. The upper end of the Shores was suspended to the cleats by a piece of Rope, fixed by Staples, which formed a hinge. The upper ends of the Shores were mitred to fit the Ship's sides and the cleat when perpendicular. Each Shore of course, lay out at a considerable angle before the Ship rose. A rope was attached to the foot of the Shore, rove thro' the pulley below and thro' another at the Ship's rail above, and to the end a weight of about 2 cwt of fire bars was attached. To shew when the shore was at the perpendicular the distance it had to travel was marked on the rope at the Gunwale, so that when she rose it was known whether each Shore was in place and a stop piece was fixed on the guide to prevent it going too far. On the 29th of July, all being ready, the Ship was
lifted, the whole proceeding being attended with the utmost success, which
was principally attributable to the fact of the Shores and Lifting power
being self acting and simultaneous; indeed the only thing giving trouble,
or needing exertion was the pulling in of the various wedges, and shooting
in and ramming down the stones. As soon as the tide ebbed the Ship was
further secured by additional shores and wedges, forced in by long
battering Rams suspended from the Gunwale. The Ship was raised 4ft 3 in in
the 2 operations, and the last time only settled back 2 ins. The ship being raised and shored up sufficiently the
Sand was let out of the Boxes thro' valves made for the purpose. The Boxes
were then strengthened internally, and covered so as to act as Caissons. The Boxes were taken down and moved to Leeward of the Ship, and a grid iron was formed on which to tighten those that were injured, but a storm coming on in spite of every precaution only 10 were fit for use as Caissons. The late Mr Bremner's previous experience led him to direct that the whole of the Chain Cable for hauling off should be laid out in one Line with 2 anchors attached, one about 30 fathoms ahead of the other. For this purpose 450 fathoms of Cable stowed in the sloop "Betsy" which had a balk with a roller at the outer end fitted at the stern and one of the Great Britains Best Bower Anchors was put at each Bow. A warp was run out to a kedge a little off the port quarter of the Great Britain at a distance of 520 fathoms. By this warp the Sloop was hauled off and each anchor dropped into place. The warp being then made fast to the Sloop and hauled in by one of the after Capstans on board the Great Britain. The cables were paid out leaving no slack. The inner end of the cable reached a little within lowwater mark of Spring tide and to it 4 stout hawsers were attached; 3 were led to Crab Winches on the lower Saloon Deck and one along the port side to a very powerful Crab Winch in the forecastle. Owing to the loss of the 10 boxes which were destroyed, and the leaky state of the Ship, it was determined to make use of the "Betsy" Sloop and another vessel as Caissons. They were pinned down amidships beneath the coal ports. The "Betsy" was down within 6ins of the Gunwale, and the other vessel within 12. The "Betsy's" displacement was equal to lifting power of 80 tons and the other 150. The displacement of the 10 boxes amounted to about 30 tons, but as they were in a somewhat leaky condition, it was necessary to bale them out at intervals. A chain was passed longitudinally thro' Ring bolts, fixed in the Ship's sides, to which these Boxes were lashed down. The whole displacement thus effected was equal to a lifting power of 530 tons. On the 27th of August the "Birkenhead" moved right astern of the "Great Britain", dropping her anchors a long way out , and backed in for 2 stout hawsers that were attached to the screw Shaft of the latter. The ship was relieved of the Weight of those Hawsers by their being passed over the paddle Box Boats of the "Birkenhead", which were secured together by 2 spars lashed across them.
The last contrivance strictly within the province of this paper, was that for steering the Ship across the Channel, as the Rudder had been carried away when she first went ashore. Her fore yard, which was upwards of 70 feet long, had a web of planks nailed into a Box which was filled with fire bars to keep the end down in the Water. This spar was placed out of the stern, the inner end being secured loosely by chains into one of the Midship Stern Windows. On the deck close to the Stern, outriggers were placed, at the end of which were pulleys, through which Guys were rove, the outer ends being attached to the outer end of the yard, and tackles were fixed to the inner ends and secured by turns round the barrel of the ship's steering wheel; so that the yard, with the web on it, formed a large oar or sweep. All that remained to be done was to keep her afloat, and to navigate her to some port of safety. It was intended to take her into Ardglass, but a dense fog prevented the pilot from running the risk, and she was taken to Belfast. The Leaking gained so much, that it was considered necessary to lay her on a Mud Bank in Belfast Lough. When she settled at low water the mud forced itself into the interstices in the bottom and made her quite tight temporarily. A number of fresh Labourers were put to the pumps all night, and next morning she was tolerably dry. She then started for Liverpool, and altho' leaking badly, was safely deposited on the Liverpool Gridiron on the 30th of Augst 1847. On the whole the undertaking was brought to a very
successful termination, altho' the difficulty in getting Materials, and
the conduct of many of the workmen, caused considerable delays and
annoyances. The Author must here mention that the Riggers who were sent
from the Government Dockyards formed a striking contrast to the others,
being perfectly up to their work and in complete subordination. GW's Notes on the above transcript: - FURTHER HISTORY OF THE �GREAT BRITAIN� Reference |
The Author now left the Ship
thro' serious indisposition, and in the meanwhile the late Mr Brunel, the
compy's consulting Engineer, examined the vessel with the late Mr Bremner,
and they decided upon the construction of a Faggot Breakwater, designed by
the former, which Captain Claxton RN the managing Director of the Company,
was instructed to erect. As a full description of this Work has been laid
before the House of Commons, it is unnecessary here to detail its
construction and there is no space in this paper to describe the one
previously decided on. The great uncertainty of the weather requiring that
any favourable opportunity of removing such a vessel from the strand
should be seized immediately. The late Mr Bremner and the Author matured
their plans so as to proceed with the work as soon as called on by the
Directors. However a considerable part of the most favourable Season
passed, and it was not until 13th of May 1847 that the late Mr Bremner
received pressing instructions to proceed to Dundrum Bay. On reaching the
ship he found that attempts had already been made by the Company's
Managing Director to raise the Ship, -displacement being obtained by
heightening the Decks and Bulkheads. The Ship, being suspended on the Rock
formerly alluded to, the after end nearly counterpoised the fore part, and
the displacement obtained was sufficient to raise her Head until her Heel
went down to the Rock, but here the lifting was at an end, since not only
the counterpoise was unavailing but her Head being raised 3 1/3 feet the
amount of displacement was greatly reduced.
All the
means which, under the circumstances, were possible were prepared for
holding the Ship up when lifted. Four wedges of large size, built of tiers
of hard wood bolted together, and plated with iron on top, were entered
under the fore Keel near the fore Lever, and each pair was drawn in by
Tackles, on the opposite side. Several other plans of wedges were made to
be pulled by tackles under the bilges of the Ship one of these is shewn in
Section Fig 2.
Altho' the
Water gained considerably on the pumps, the Great Britain was move astern
at high water and was laid on a Sand Bank where she remained a tide in
order to tighten the bottom further and to remove the external assistance
of displacement.