1845.] 



TriE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



4!) 



In this way Mr. While has succeeded in raising four sailing vessels and 

 three steamers, besides numerous smaller craft. Tliis plan, however, did not 

 succeed in the ease of tlie Innisfail, owing to ilie narrowness of the channel, 

 which prevented the emplojment of ships of sulhcient tonnage for weighing. 

 At the suggestion of ^ir. A. S. Deane, a colTerdam was constructed at the 

 side of the vessel which had icceived the injury, and to prevent any lealiage 

 at the other side, a few loads of clay ballast were deposlteil. The coft'erdam 

 was formed of deal planks 12 feet long by 3 inches thick, secured by wales 

 and cross-pieces. On examining the bottom, after the water had been pumped 

 out, it was found necessary to excavate to a depth of about 2 feet, in order to 

 arrive at the leak ; as the excavation proceeded, the vessel was shored up and 

 when the spot was discovered, elm planks of 1 inch thick and 12 inches in 

 breadth were nailed over the whole length of the leak, first covering the hole 

 with strips of flannel, soaked in tar, in order to make the patch water-tight. 

 I!y this means the vessel was raised in the course of ten tides, and it was 

 floated and steamed down to Passage, a distance of about 7 miles, in order 

 to undergo a thorough repair: the total expense of the work, including the 

 cotferdam, was .i'350. 



SUNDERLAND LIGHTHOUSE. 

 " An Account of the removal of the Light -house at Sunderland."* By John 

 MuiiRAV, M. Inst. C.E. (From the Minutes of the Instilutlon of Civil 

 Eytgiiteers.J 



Sunderland is rated the fourth port in the United Kingdom, as respects 

 the aggregate amount of its tonnage. The shipment of coal, which is the 

 principal business of the place, amounts annually to about 1,300,(100 tons. 

 Lime is also extensively shipped for Yorkshire and Scotland. There are 

 various manufactories in the town and neighbourhuod, and the building of 

 ships is carried on to a great extent. The population of the united towns of 

 Sunderland, Bishopwearmoutb, and Monkwearmouth, amounted, according 

 to the census of ISll, to 57,057, including about 4000 seamen. 



The harbour has been, since the reign of George 1., under the control and 

 jurisdiction of Commissioners, appointed by Parliament. For some years 

 past, the average revenue, arising principally from the shipment of coal, has 

 amounted to about .1' 10,000 per annum. The funds so collected, have been 

 expended in deepening the shoals, removing rocks and other obstructions 

 and building piers at the mouth of the river. These piers, having been ori- 

 ginally executed in a superficial manner, soon showed symptoms of decay, 

 and it was found necessary to rebuild the eastern or seaward portion of them. 

 The late Mr. John Rennie was consulted and his advice was, that the piers 

 should be prolonged with solid masonry into deeper water. 'J'he South pier 

 has, in consequence, been rebuilt in a substantial manner with ashlar ma- 

 sonry, in blocks of stone, varying from 5 to 7 tons in weight, properly back- 

 ed with a glacis of rubble stone. The eastern part of the north pier, during 

 the last ten years, has been taken down, under the author's superintendence; 

 a new pier has also been built, in the direction suggested by Mr. Rennie, and 

 approved by his son. Sir John Rennie. This pier has been executed in the 

 strongest manner and with excellent materials, forming altogether a hand- 

 some and substantial piece of masonry. The most beneficial effects have 

 been produced by the adoption of these plans ; the channel to sea has been 

 straightened and deepened by dredging, and the bar has been lowered and 

 kept iu a stationary position, so as to give 4 feet of water upon it during low 

 water, or 18.^ feet at high water of ordinary spring tides. 



Near the termination of the north pier, there was built, in 1802, by Mr. 

 Pickernell, then engineer to the Commissioners, an octagonal Light-house of 

 polished stone. Its height was 00 feet 2 inches from the base to the cor- 

 nice, terminating with a lantern, the cupola of which was IG feet above the 

 cornice, making a total elevation of 76 feet 2 inches above the pier. Its 

 breadth was 15 feet at the base and 8 feet ti inches at the cornice, having a 

 spiral staircase up the centre of the buihling. It was subsequently lighted 

 with coal gas from nine patent burners with parabolic reflectors. 



In the beginning of the year 1841, before the works at the north pier 

 head were terminated, an alarming breach was made by the sea in the pro- 

 jeeting part of the old pier (Fig. 1), on which this Light-house stood, and it 

 becauie imperative, either to take down the building immediately, or to re- 

 pair the pier in an expensive manner. 



On the 7th of April, 1841, the advantages of having a new Light-house on 

 the high ground near the fort, on the south side of the river, and the diffi- 

 culties of removing the present one from its then critical situation, were dis- 

 cussed at the 15oard of Commissioners. The result was, that the author re- 

 ceived directions to prepare the materials necessary for carrying into effect the 

 project he had suggested, of removing the buihling in an entire state, on a 

 cradle of timber, to the eastern extremity of the new pier. 



In consequence of the breach before alluded to, it w as necessary to remove 

 the Light-house in a northerly direction, on to the new pier, before it could 

 be taken to the eastward and its axis required to be turned, in order to make 

 it correspond, or be parallel with the altered direction, east and west of the 

 new pier. The raised platform of the new pier head, where the building 

 was proposed to be placed, being 1 foot 7 inches higher than the oiiginal 

 site of tlie Light-house, it became necessary, in providing a proper height for 

 the entrance doorway, either to descend a few steps from the platform, or to 



* Some account of tlic removal of tfiis Lighthouse ippoared in the Journal, Vol, IV, 

 IMl, psge ZK, i'i'o, and ilfS, togctUt-r with u view of lh« l^isUtboute, 



lift the base, and consequently the whole building, to the proper level. It 

 was deemed advisable to adopt the latter course. 



The first of these operations was to take the building northward. On the 

 loth of June, the masons began to cut apertures on the north and south 

 sides of the building, for the reception of the cradle or platform of timber 

 (Figs. 2 and 3) ; the two niiildle balks were threaded through consecutively 

 and the apertures were made no larger than absolutely necessary for that 

 purpose. The upper course of stones below the torus moulding was not dis- 

 turbed, and the bottom of this course was made to rest immediately upon 

 the cradle timbers. The upper surfaces of the beams, where they were in 

 contact with the masonry, were covered with thin sheet lead, to equalise tho 

 pressure. Uhen the timbers were threaded through the building, screws 

 were applied beneath them, until they were closely pressed to the course of 

 masonry, and uprights of timber were then inserted and firmly wedged up, 

 which allowed the screws to be removed. Less difliculty was experienced iu 

 inserting the next timbers, which were parallel to the other pair, and sup- 

 potted the external masonry ; they were covered with lead like the others, 

 screwed up and shored with timber uprights and wedges in a similar way. 

 Care was taken to place all these shores in such positions, that thev should 

 not interfere with the insertion of the lower transverse tier of timbers. 



An aperture was next cut on tlie eastern side of the base fthc entrance 

 door on the west side not requiring any), to admit the two transverse beams, 

 which were firmly screwed up underneath the beams previously inserted, anil 

 then shored with u]irights and wedges to relieve the screws. Other timbers 

 were next inserted and shored up in pairs, in a similar way to the others, and 

 when all these were secured, other apertures were cut through the building 

 to admit the upper timbers. The next operation was the insertion of the 

 timbers, with rails fixed upon them. The centre timbers immediately below 

 the upper beams were fixed first. These were firmly bedded on the stone 

 pavement of the pier and upon the solid [masonry of the new work. The 

 sheave balks to each, were then threaded threaded through the building and 

 firmly wedged to the timbers above, and to the rails below, by a series of 

 wedges. The other rail and sheave balks were placed in a similar manner, 

 underneath each upper timber and in the order in which they were inserted 

 in the building. Finally, when all these wheels were brought to their bear- 

 ing, the small portions of the original masonry, left in the four corners of 

 the building, were cut away at one time and the two remaining intermediate 

 upper timbers were threaded through and secured. 



While these works were in operation, the octagonal shaft was tied toge- 

 ther in the following manner. Two planks, 44 feet in length and 3 inches 

 in thickness, were suspended from the cornice at each angle of the shaft and 

 then lashed closely to the masonry by ropes and wedges. Five horizontal 

 tiers of iron straps, 2i inches broad, and |ths inch thick, were made to em- 

 brace the building, and these were drawn closely up by screws to the above- 

 mentioned planks and filling-ia pieces. Immediately above the cornice and 

 on a level with the light-room floor, eight apertures were made through the 

 walls (which were here only 10 inches in thickness), and pieces of timber 

 were pushed through the apertures from the inside and drawn back again 

 till they met in the centre. Strong plates of malleable iron covered the 

 joints above and below the timbers and screwed bolts passed through the 

 whole. This upper platform was connected with the cradle below by a large 

 chain, passing round a strong bar of iron at the top of the platform, and 

 round a similar bar of iron on the lower side of the cradle, and the chain was 

 drawn tight by a large screw. 



The upper platform was further connected externally with the cradle, hy 

 eight main uprights of timber, 12 inches square, tenoned into the horizontal 

 timbers at the cornice, and brought close to the masonry of the buildiog at 

 the base, and secured to the cradle and upper platform by stirrup-straps and 

 bolts. The uprights were united togetiier by three tiers of chock-pieees. 

 Three iron straps, 3^ inches broad, and 1 inch thick, passed round the chock- 

 pieces and uprights, and the whole was drawn closely to the building hy 

 screws. The raking braces were next erected and their feet passed between 

 the timbers of the cradle and ciU-beams fixed thereon, so that the whole 

 framing could be firmly bound together (Fig. 4.) The four diagonal beams 

 and ledges, fixed to the raking braces, further prevented any of the timbers 

 from springing or twisting. 



Up each angle of the building, above the cornice, battens, 2J inches 

 thick, were fixed, with two tiers of horizontal junction pieces, kept together 

 by binding screw straps. The dome of the building, which is of iron, 

 covered with lead, was fastened by chains passing round the summit 

 and the upper cornice, and continued down (to the projecting timber 

 of the upper platform, each chain being tightened by screws. The large 

 plates of glass of the light-room were taken out, and window sashes, with 

 ordinary crown glass, were put in their place. The light, however, was 

 exhibited nightly, as usual, dnring all the operations of removal ; a lead 

 pipe, lengthened as required, being connected with the gas-works on the 

 pier. 



On the 2nd of August everything was prepared for drawing the building 

 northward. For this purpose, five pulling screws were strongly fixed to the 

 glacis of the pier, north of the building and chains were attached to them 

 and to the cradle upon which the Light-house rested. These screws were 

 worked by twenty-four men. Four forcing screws, worked by three men to 

 each, were applied behind the cradle, to assist in propelling it. The total 

 number [of men employed on the occasion was forty. The cradle was sup- 

 ported on one hundred and forty-four wheels, which travelled on eight paral- 

 lel lines of rails, but the extreme ends of the cradle were supported and 



7 



