The life of Isambard Kingdom Brunel, Civil Engineer Part 43

Soon after the launch of the 'Great Eastern,' efforts were made to obtain funds for finis.h.i.+ng her, and Mr. Brunel proceeded to prepare designs with the view of obtaining tenders for the execution of the decks, skylights, fittings, rigging, &c. He obtained advice from persons thoroughly conversant with this cla.s.s of work; and a specification was carefully prepared, providing for the completion of the s.h.i.+p in a perfect manner.

Meanwhile it had been considered that, large as the s.h.i.+p was, she might be profitably employed in the American trade, and that it might be expedient to run her on that line for a few voyages before placing her on the Eastern route. Captain Harrison went to America to examine the harbour at Portland, and brought back a favourable report of it.

All efforts to raise the funds for finis.h.i.+ng the s.h.i.+p proved unavailing; and it was determined to reconst.i.tute the company.

The new company, which was called the 'Great s.h.i.+p Company,' was formed towards the end of the year 1858. In the beginning of December, Mr.

Brunel was compelled by ill-health to go to Egypt for the winter. On leaving England, he strongly urged the Directors on no account to fail to make a strict contract, distinctly defining the work to be done, and the manner of its execution, as provided for by the specifications he had drawn out. But his advice was not followed.

After Mr. Brunel's return to England in May 1859, he continued to give the greater part of his time to the s.h.i.+p. The difficulties which he had to encounter were certainly neither fewer nor less vexatious than those which had arisen at earlier periods in her history; but they were the last with which he had to contend.

On September 5 he left her in the morning, feeling the commencement of the illness which ten days afterwards terminated fatally.

The s.h.i.+p left her moorings on September 7, and with the a.s.sistance of several tugs steamed down the river. She stopped for a night at Purfleet, and again at the Nore, and then left for Weymouth.

On the voyage a serious accident happened, which was made the subject of much misrepresentation.

Round each of the funnels of the paddle engines was what was termed a water-casing, or jacket, consisting of an outer cylinder, about 6 inches from the inner cylinder which formed the funnel. The top of the annular s.p.a.ce between the cylinders was at about the level of the deck. From it a stand-pipe was carried up, which, after rising to a certain height, was turned over, and the end brought down into the stokehole. The object of this arrangement was to heat the feed-water before it entered the boiler, and at the same time to keep the saloons cool, through which the funnels pa.s.sed. The arrangement of the stand-pipe gave this advantage, that when the head of water in the heater and stand-pipe together became equivalent to the pressure in the boiler, the water could be run into the boiler by gravitation. The stand-pipe at the same time, being open to the air at the top, formed a safety-valve to the water-heater.

For the purpose of testing the joints of the jacket with water pressure, while the s.h.i.+p was being finished, a stop-c.o.c.k had been placed on the stand-pipe, which unfortunately had not been afterwards removed. While the s.h.i.+p was proceeding down Channel, the donkey feed-pumps were not working well, and to ease them it was thought better to cut off the water-heater, and to force the water direct into the boiler. The communication of the water-heater with the boiler was therefore cut off; and, as was afterwards ascertained, the stop-c.o.c.k at the top of the water-heater had been also closed. The water confined in the heater soon produced steam, and when the s.h.i.+p was off Hastings the casing exploded.

The funnel was thrown up on to the deck, and a body of boiling water and steam was driven down into the boiler room, severely injuring several of the firemen, who afterwards died.

That the effects of this accident were confined to one compartment of the s.h.i.+p, was due to the complete protection afforded by the transverse bulkheads.

After she arrived at Weymouth the funnel was repaired; but as an outcry was raised against the water-heaters, it was thought desirable, from deference to public opinion, to discontinue their use; although this accident had not in any way proved them to be objectionable, and they are now generally adopted.

While the 'Great Eastern' was at Weymouth Mr. Brunel died.

Many visitors went in the s.h.i.+p when she left Weymouth on a trial trip to Holyhead. At Holyhead she lay in a somewhat exposed situation; and the sudden storm came on in which the 'Royal Charter' was lost. The great advantage of having both paddle and screw was now, for the first time, felt. A portion of the temporary staging erected by the contractor at the breakwater was carried away, and drifted down upon the s.h.i.+p. During the gale her engines were kept going, in order to relieve the strain on the cables. The timbers of the staging got foul of both paddlewheels and screw; but, as it was always possible to keep one of the engines at work, the s.h.i.+p was saved from drifting.

The season being now too far advanced for a profitable voyage to America, the s.h.i.+p left Holyhead and went to Southampton Water for the winter, where several alterations and additions were made.

In Mr. Brunel's report of February 5, 1855, printed above, at p. 315, he describes the leading features of the 'Great Eastern' as she was then being constructed, but a more detailed account of them will fitly precede the history of her career as a pa.s.senger-s.h.i.+p.

The main arrangements of the s.h.i.+p are shown in the woodcut (fig. 16, p.

397).[173]

The s.h.i.+p is 680 feet long, 83 feet wide, and 58 feet deep. Her gross tonnage is 18,915 tons. She is divided into water-tight compartments by ten bulkheads (_a_ and _b_), all of which, except two (_b_), extend completely across the s.h.i.+p, and up to the upper deck. These two are complete to 6 feet above the 28-foot water line. In addition there are partial bulkheads (_c_), which form the ends of coal bunkers, and aid materially in strengthening the flat bottom of the s.h.i.+p. The more remarkable parts of the construction of the s.h.i.+p will be understood by means of the transverse section. The bottom is made double, and between the two skins are webs, running longitudinally. Mr. Brunel considered that the double skin would greatly diminish the chance of such an accident occurring as would cause any of the compartments to be filled with water. The material being arranged in the direction of the length of the s.h.i.+p is all capable of taking part in the strains that are thrown on the bottom, as well as on the top, by forces tending to bend the s.h.i.+p.

Mr. Brunel also made the upper deck cellular, in order to resist the compressive strain that would come on it when the s.h.i.+p was heavily loaded in the middle of her length. Great additional strength to the s.h.i.+p, considered as a girder, is given by two longitudinal bulkheads, 36 feet apart, extending for 350 feet. These bulkheads, with the sides of the s.h.i.+p, form the vertical web plates of the girder. Her structure resembles the tubes of the Britannia bridge; the cellular top f.l.a.n.g.e being connected with the cellular bottom f.l.a.n.g.e by plate-iron webs.

[Ill.u.s.tration: Fig. 16. _Longitudinal Section_

_Plan showing Machinery and Coals_

_Mids.h.i.+p Section showing Cabins and Boiler Room._

'GREAT EASTERN' STEAM-s.h.i.+P

_a._ Complete transverse watertight bulkhead _b._ Transverse watertight bulkheads complete up to water line _c._ Partial transverse bulkheads _d._ Longitudinal bulkheads E. Cable decks F. Chain cable lockers, &c.

G. Ice-house, stores, &c.

H. Forward cargo s.p.a.ce I. Paddle boiler rooms J. Paddle engines K. Cross coal bunkers L. Paddle auxiliary engines M. Screw boiler rooms N. Screw engines O. Screw auxiliary engines P. Screw alley Q. Grand saloon R. Ladies' saloon S,U. Lower saloons T. Upper saloons V. Pa.s.sage tunnel W. Steam-pipe tunnel X. Aft cargo s.p.a.ce Y. Aft cable deck, &c.

Y'. Deck for auxiliary tiller, &c.

Z. Cabins

NOTE.--_The masts of the s.h.i.+p, six in number, are not shown on this woodcut._]

The two skins of the s.h.i.+p, with the web plates between them, forming the cellular bottom of the great girder, may also be considered as a number of smaller girders placed side by side, each resisting the excess of the pressure of the water over the load that may happen to be resting on it inside the s.h.i.+p. The difference of pressure or upward strain is transmitted by the cross bulkheads (_a_, _b_, _c_) from the bottom of the s.h.i.+p to the sides and longitudinal bulkheads.

The double skin extends up to about 6 feet above the water level throughout the whole length of the s.h.i.+p, with the exception of the extreme ends.

The foremost compartment next the bow has two cable decks (E), with capstans and all the necessary riding-bitts, stoppers, and other appliances for working the cables. These arrangements answer well, and the 3-inch chain cables are worked with great facility. The capstans were originally driven by a shaft from the paddle auxiliary engines, but this was found inconvenient, and a small independent engine has been put to work them. The cables are stowed in chain lockers on a deck (F) below the cable decks, and below this (G) are ice-houses and store-rooms. The next compartment of the s.h.i.+p (H) is intended for cargo. It is at present occupied by the forward cable tank.

The main part of the s.h.i.+p, 350 feet in length, up to the level of the lower deck, 34 feet above the bottom, is occupied with her engines, boilers, and coal bunkers. The s.p.a.ce above the lower deck was occupied with saloons and cabins for pa.s.sengers, except at the paddle engine room (J). The boilers, four in number, two in each boiler room (I), which supply steam to the paddle engines, are placed forward of the engines; and forward of the boiler rooms is a coal bunker (K), 20 feet long; and abaft of the paddle engines are the six boilers, two in each boiler room (M), that supply steam to the screw engines (N). These three boiler rooms are separated by coal bunkers (K), 20 feet long. On either side of the boilers and engines, and also upon plate iron arches above the boilers, are bunkers for coal. This will be seen on the transverse section of the s.h.i.+p. Between the paddle engines and boilers is a water-tight compartment, 10 feet long (L), in which are placed a pair of auxiliary engines of sixty horse-power, which pump water out of the s.h.i.+p and also work fire-pumps. There are two other auxiliary engines of sixty horse-power in a compartment (O) aft of the screw engines, intended to keep the screw propeller turning round, either when the s.h.i.+p is at anchor, to relieve the strain on the cables, or when, for any reason, she is only using her paddle engines. They also work bilge-pumps and fire-pumps. Each set of auxiliary engines has two independent high-pressure boilers. Throughout the bottom of the s.h.i.+p there are two bilge-pipes, fitted with valves, with branch-pipes leading to the various compartments of the double skin. These bilge-pipes can be connected with either of the auxiliary engines, and so the water can be pumped out of any part of the s.h.i.+p.

The paddle engines, of 1,000 nominal horse-power, consist of four inclined oscillating cylinders, 14 feet stroke and 6 feet 2 inches diameter, each pair of which work on to a single crank. There are means for disengaging either paddlewheel from the engines.

The screw engines, of 1,600 nominal horse-power, consist of four fixed horizontal cylinders, 4 feet stroke and 7 feet diameter, the two cylinders of each pair working opposite to each other on one crank.

In each boiler room are two donkey engines for supplying the boilers with water, and the main engines are also fitted with feed-pumps. Each of the donkey engines is capable of pumping water out of the s.h.i.+p, and of being used in case of fire.

The screw shaft pa.s.ses along what is termed a screw alley (P). The weight of the screw rests on the bearing where the screw shaft pa.s.ses out through the stern-post of the s.h.i.+p. To prevent the water that leaks in through this bearing from penetrating into the screw alley, there is a bulkhead with a stuffing-box round the screw shaft, a short distance forward of the stern-post. To enable access to be gained to the bearing, a tube was provided leading down from the main-deck. This was intended to be fitted with appliances for pumping air in so as to drive the water out, and to admit men to get at the bearing under air pressure.

Another arrangement was also provided for the same purpose. On the after side of the stern-post was placed a ring of india-rubber; and, by pulling in the screw-shaft, the screw was pressed tightly against the india-rubber ring, which prevented the water from entering. By means of this arrangement the stern-bearing was examined and repaired at Southampton.

The screw propeller has four blades, and is 24 feet in diameter and 44 feet pitch. The paddlewheels were 56 feet in diameter, with 30 floats, each 13 feet broad and 3 feet deep.

Over the boiler rooms run two tunnels; one of them (V) serves as a pa.s.sage to enable the engineers to pa.s.s from one compartment to another throughout the part of the s.h.i.+p occupied by the boilers and engines. The openings leading from the tunnel to the engine or boiler rooms are provided with watertight doors, which can be shut in the event of any of the compartments getting full of water. The other tunnel (W) serves as a pa.s.sage for the steampipe, which leads from the boilers to the engines.

Though the boilers are divided into two sets, one for the paddle engines and one for the screw, the steampipes are connected, so that the whole of the ten boilers, or any of them, may be used to supply steam for either of the engines.

In one point a deviation was made from Mr. Brunel's arrangements. It was his intention that there should be no apertures in the water-tight bulkheads except at the tunnel (V), from which the various boiler and engine rooms were to be entered by openings, to be closed by water-tight doors. The tunnel was placed high up, so that in the event of a leak there might be ample time to close the door. The inconvenience of ascending and descending by ladders was, however, considered an evil; and it was found necessary at times to carry coals from one compartment to another. For these reasons, upon the requirement of the Board of Trade, doorways, fitted with sliding doors, which can be closed by handles on the upper deck, have been cut in the bulkheads between the boiler rooms. This arrangement exists in other s.h.i.+ps; and in the 'Great Eastern,' even without closing these doors, there are eight watertight compartments.

At the stern of the s.h.i.+p (Y) on the main-deck are arrangements for working cables, similar to those at the bow.

These appliances are required when the s.h.i.+p has to be moored so as not to swing with the tide; and they would allow of the s.h.i.+p's riding by the stern instead of by the bow, which it might often be useful for her to do in narrow waters. On the lower deck (Y), at the stern of the s.h.i.+p, is a spare tiller and wheel for working the rudder, in case anything goes wrong with the main tiller, which is on the upper deck. The weight of the rudder is carried on the lower deck by a grooved collar, resting on a ring of cannon b.a.l.l.s.

The compartment (X) immediately aft of the screw engine room is for cargo.

The saloons and cabins are all in the middle of the length of the s.h.i.+p, where there is least motion. The usual plan of putting the first-cla.s.s pa.s.sengers at the stern was not adopted, and they were placed forward.

As the smoke generally drifts towards the stern of a s.h.i.+p, the first-cla.s.s pa.s.sengers in the 'Great Eastern' are not annoyed by the smoke, or by the dust and smell from the boiler and engine rooms.