Length over all. 882' 9"
Length between perpendiculars . 850' 0"
Breadth extreme.92' 6"
Depth moulded to shelter deck. 64' 3"
Depth moulded to bridge deck. 73' 3"
Total height from keel to navigating
Loaddraught. 34' 6"
Indicated horse-power of reciprocating engines. 30,000
Shaft horse-power of turbine engine... 16,000
A comparison of the foregoing information with the table of dimensions of other vessels given in the preceding chapter will show that the Great Eastern was 170 feet shorter and 20,600 gross tons less ; the Kaiser Wilhelm II, and the Kronprinzessin Cecile are each 172 feet shorter and 25,600 tons less ; the Adriatic 141 feet shorter and 20,500 tons less ; and the Mauretania 90 feet shorter and about 13,000 tons less.
The structural design of the Olympic and Titanic is shown by the midship section (Fig. 14) and the elevation on Plate III.
There are eight steel decks amidships—the boat deck, promenade deck (A), bridge deck (B), shelter deck (C), saloon deck (D), upper deck (E), middle deck (F), and lower deck (G)—while at the ends an extra deck—known as the orlop deck —is fitted, making nine decks in all.
The main structure of the vessels ends at the bridge deck, which is carried for 550 feet amidships. To raise the ends of the ships well above the waterline without having recourse to a large sheer, a poop 106 feet long and a forecastle 128 feet long are provided. Above the bridge deck, the deckhouse sides and deck plating are of lighter scantling and have two expansion joints, one forward and one aft, to prevent heavy stresses coming upon the thin plating in a seaway. The main scantlings have been determined by Messrs. Harland and Wolff’s long experience with large vessels. Material is massed at the upper flange of the equivalent girder by making the bridge and shelter deck plating and sheer strakes of great thickness and fitting doubling at these points, while the lower flange is strengthened by doubling the bilge plating. The material used throughout is mild steel.
The keel of each vessel is formed by a single thickness of plating 1½in. thick and a flat bar 19½in. wide by 3in. thick. The bottom plating is hydraulic riveted up to the bilge, the strakes being arranged clincher fashion for this purpose ; and the frame bottoms are joggled to avoid the use of tapered packing pieces. To reduce the number of butts and overlaps to a minimum, plates of large size are adopted. The shell plates generally are 6 feet wide and about 30 feet long, with a weight of 21 to 3 tons. The largest shell plates are 36 feet long and weigh 4½ tons each.
A cellular double bottom extending right out to the ship’s sides, with floors on every frame, is fitted throughout each vessel. This double bottom is 5ft. 3in. deep, and is increased to 6ft. 3in. in the reciprocating engine room. The subdivision of the double bottom into separate tanks is arranged to provide ample facilities for trimming the vessel or for correcting any list due to unequal disposition of coal or cargo. The double bottom is divided into four compartments transversely by the watertight centre keelson and watertight longitudinals on each side 30ft. from the centre line, the subdivision being completed in the usual manner by transverse watertight floors. The subdivision into four tanks transversely is also of benefit to the stability of the ship, owing to the limited width of the free water surfaces in the tanks used for the boiler feed water and for the passenger water services. Besides the continuous tank girders mentioned above, there are five intercostal tank girders amidships on each side of the centre keelson, disposed as shown in Fig. 14, and additional girders are fitted beneath the engine rooms.
The spacing of the frames is 3ft. amidships, reduced to 24in. forward and 27in. aft. The frames are of 10-in. channel sections, except at the extreme ends, where a built section of frame and reverse bar is adopted. Web frames 30in. deep are fitted on every third frame (9ft. apart) in the boiler and turbine rooms, and on every second frame (6ft. apart) in the reciprocating engine room. The channel frames extend from the tank top to the bridge deck, some of these bars having a length of about 66ft. and weighing nearly one ton. The beams of the main structure are also of channel section 10in. deep amidships, the largest being 92ft. long and weighing 1¼ tons. The beams are connected to the frames by bracket knees. The transverse strength is also maintained by the watertight bulkheads, of which there are fifteen in all, and a number of non-watertight bulkheads forming the cross bunker ends. The decks have a camber of 3 inches.
The beams of the bridge, shelter, saloon, and upper decks amidships are supported by four longitudinal girders, which are in turn carried by solid round pillars spaced 9ft. apart. Below the middle deck in the boiler rooms round pillars are also adopted, 9ft. apart, in conjunction with strong beams carried across at the lower deck level in way of each web frame. In the case of the inner rows the pillars are spaced out so that they do not interfere with the working passage. In the engine rooms and holds the pillars below the middle deck are wide spaced and of circular built section, the deck girders being increased in strength to suit the longer span. As the ship gets narrower at the ends the number of rows of pillars is reduced.
Fig. 14.—Midship Section of “Olympic” and “Titanic.”
Bilge keels 25in. deep, as shown on the section in Fig. 14, are fitted for about 300ft. of the vessel’s length amidships, to minimise rolling in a seaway.
The two decks forming the superstructure of each ship and the navigating bridge are built to ensure a high degree of rigidity. At the sides they are supported on built-up frames in line with the hull frames, but at wider intervals. The deckhouses are specially stiffened by channel section steel fitted in the frame work ; and where, as on the boat deck, the public rooms pierce the deck, heavy brackets are introduced to increase the resistance to racking forces when the ship is steaming through a heavy seaway. The boat and promenade decks are increased to 94ft. wide, to enlarge the promenade space. All exposed decks are sheathed with wood, but inside deckhousse and on all decks not exposed to the weather Harding’s Litosilo is adopted as the deck covering. This Litosilo was supplied by Messrs. C. S. Wilson & Co., of Liverpool, some 40,000 square yards being required for each vessel.
Some idea of the great importance of the riveting in the Olympic and Titanic will be gathered from the fact that there are half a million rivets in the double bottom of each vessel, weighing about 270 tons, the largest rivets being 1¼. diameter ; while in each ship when completed there will be something like three million rivets, weighing about 1,200 tons. To ensure the best workmanship, hydraulic riveting has been adopted whenever possible. Nearly the whole of the double bottom, including the bottom shell plating up to the turn of the bilge and the topside shell and stringer plates and doublings, have been riveted by hydraulic power. A hydraulic riveter at work on the vertical keel plate of the Olympic is shown in Fig. 15, the adjacent portable furnace being used for heating the rivets. Similar riveters can also be observed at work in a number of the illustrations showing the various stages in the building of the ship, and the great extent and strong appearance of the topside hydraulic riveting are very clearly shown in Fig. 16.
The seams of the bottom plating are double riveted, and of the topside plating treble and quadruple riveted. The butts of the bottom plating are overlapped and quadruple riveted, as are also the butts of the side plating, except in the way of the topside shell and doublings, where double straps are adopted.
Stem and Stern Castings.
The general arrangement of the stern castings of the Olympic and Titanic; will be seen from Fig. 17. As each vessel has triple screws, the stern frame is provided with a boss and aperture for the centre or turbine propeller; while the wing or reciprocating propeller shafts are carried by boss arm castings, round which the shell plating is carried to form “ bossing ” of Messrs. Harland and Wolff’s improved type. All these castings have been supplied by the Darlington Forge Company, and are of Siemens-Martin mild cast steel, with, the exception of the rudder stock which is of forged ingot steel. Some idea of the immense size of the stern castings will be obtained from the particulars of their weights given in the following table —
TABLE III.—WEIGHTS OF CASTINGS
Stern frame (two pieces). 70 tons.
After brackets (two pieces) . 73¾
Forward brackets (two pieces). 45
Rudder (six pieces).101¼
Stem bars ... 7¼
Stem connection piece to keel . 3½
The stern frame is of dished section, 18in. by 11in., increased to 21in. by 11in. solid in way of the aperture, and is in two pieces connected by specially designed scarphs, as shown in Fig. 17. The total height is 68ft. 3in. and length 37ft. 4in.
A large palm is provided at the forward end to form a strong connection to the after boss arms and the main structure of the vessel. The scarphs are connected with best Lowmoor iron rivets 2in. dia., there being 59 rivets in the forward and 53 rivets in, the after scarph, with a total weight exceeding one ton. The great care exercised in fitting these to ensure a strong connection is suggested by the fact that they were all turned and fitted and specially closed with rams. The after boss arms are in two pieces, connected at the centre line of the vessel by strong deep flanges to form a continuous web right across the ship. This web, again, is riveted to a 2-in. steel plate of special quality, extending from side to side of the vessel. The immense size of these castings is well illustrated by Figs. 18 and 19, which also show the holes for the rivets by means of which they are securely attached to the stern frame, shell plating, floors, and framing of the ship. The centres of the wing shafts are 39ft. at the after brackets, and the bosses are 4ft. 10in. diameter. The manner in which1 the shell plating is carried round the bossing is well shown in Fig. 20. The introduction of the forward brackets as a means of increasing the strength of the ship at this part is noteworthy. In this case also the two arms have been made in separate pieces and connected by bolts at the centre line of the ship, as will be seen from Fig. 17, the whole being securely attached to the ship’s plating and framing.
The rudder (see Fig. 17) is of solid cast steel, built in five sections and coupled together with bolts varying from 3½in. to 2in. diameter. The rudder stock is of forged steel 23½in. diameter, and was made from a special ingot of the same quality as used for gun jackets. On the completion of the forging an inspection hole was bored through the stock of the rudder in order to ensure that there were no flaws. The length overall of the rudder is 78ft. 8in., and width 15ft. 3in. The pintles are 11in. diameter, of hard steel, and are arranged each to take their own proportion of the rudder weight, bearing upon hard steel discs inside the stern post gudgeons. A special feature is that the bottom of the rudder is so arranged that screw jacks can be employed for lifting it in dry dock.
The stem bar is of the usual rolled section, and is connected by a steel casting to the centre keelson and keel of the ship. A special feature is the cast-steel hawsepipe attached to the upper portion of the stem bar, to take the steel wire hawser provided for use with the central bower anchor. The weight of this casting is 6¼ cwt.
The watertight subdivision of the Olympic and Titanic is very complete, and is so arranged that any two main compartments may be flooded without in any way involving the safety of the ship. There are fifteen transverse watertight bulkheads extending from the double bottom to the upper deck at the forward end of the ship, and to the saloon deck at the after end—in both instances far above the waterline. The room in which the reciprocating engines are placed is the largest of the compartments, being 69ft. long, while the turbine room is 54ft. long. The boiler rooms are generally 57ft. long, with the exception of that nearest the reciprocating engine compartment. The holds are 50ft. long.
The watertight doors giving communication between the various boiler rooms and engine rooms are arranged, as is usual in White Star vessels, on the drop system. They are of Messrs. Harland and Wolffs special design, of massive construction, as will be seen from Fig. 21, and are protected with oil cataracts governing the closing speed. . Each door is held in the open position by a suitable friction clutch, which can be instantly released by means of a powerful electro-magnet controlled from the captain’s bridge, so that in the event of accident, or at any time when it may be considered advisable, the captain can, by simply moving an electric switch, instantly close-the doors throughout and make the vessel practically unsinkable. Each door can also be closed from below by operating a lever fitted in connection with the friction clutch. As a further precaution floats are provided beneath the floor level, which, in the event of water accidentally entering any of the compartments, automatically lift and thereby close the doors opening into that compartment if they have not already been dropped by those in charge of the vessel.
A ladder or escape is provided in each boiler room, engine room, and similar watertight com¬ partment in order that the closing of the doors at any time shall not imprison the men working inside, but the risk of this happening is lessened by electric bells placed in the vicinity of each door, which ring prior to their closing and thus give warning to those below.
Building Stages of the “Olympic.”
A commencement was made with the laying of the keel of the Olympic on the 16th December, 1908. The progress made by the 1st January, 1909, is shown in Fig. 22. The next photograph (Fig. 23), taken on the 18th February, 1909, shows the flat keel and vertical keel plate completed and a commencement made with the erection of the floors. Fig. 24 is a striking photograph taken from the top of the gantry on the 15th April, 1909, and shows the erection and riveting of the double bottom floors well advanced, with the exception of the wing tank floors which will be seen lying on the ground alongside. The next illustration (Fig. 25), taken on the 30th July, shows the tank top partly plated and a commencement made with the after end framing, of which a nearer view is shown in Fig. 26, taken on the same date. The vessel was almost framed when the next photograph (Fig. 27) was taken on the 18th November, 1909, the last frame being raised into position on the 20th of that month (Fig. 28).
Work was all the time proceeding apace in the interior of the vessel in connection with the beams and plating of the various decks. The view of the shelter deck looking aft, reproduced in Fig. 29, gives a very good impression of the vessel's size and shows clearly the deck beams and plating. The shell plating of the Olympic was completed and almost entirely riveted by the beginning of April, 1910, as will be seen from the next photograph (Fig. 30), taken on the 7th of that month. It will be noticed that the sister ship Titanic, on the adjoining berth, was by this time fully framed. Other work besides the steel work now began to make rapid headway. Fig. 31 shows a photograph of the first-class dining saloon taken on the 6th June, 1910. It will be seen that a commencement had then been made with the grounds for the joinerwork. This photograph also shows the novel arrangement of sidelights in double rows adopted for lighting the saloon.
The support of the vessel during construction by means of shores under the bottom is shown in Fig. 32, which also gives an interesting view of the bottom riveting. The final illustrations of the vessel on the stocks show a view of the forecastle deck (Fig. 33) and a bow and stern view taken shortly before the launch (Figs. 34 and 35).
Launch of the “Olympic.”
The Olympic was successfully launched on the 20th October, 1910, in the presence of the' Lord Lieutenant of Ireland, the Countess of Aberdeen, and a number of distinguished guests, the final arrangements being personally directed by Lord Pirrie. The launch¬ ing operation has already been fully dealt with in The Shipbuilder * and from our previous article we reproduce Figs. 36 and 37 showing the forward launching cradle and brackets, Fig. 38 represent-' ing one of the two hydraulic triggers by which alone the vessel was held when all the shores and blocks were removed, and Fig. 39 showing the pump and pressure gauge associated with the launching triggers. A striking photograph of the vessel immediately after leaving the ways is reproduced in Fig. 40. The leading particulars of the launch as given in our former article are repeated for the convenience of our readers in Table IV.
TABLE IV.—LAUNCHING PARTICULARS
Draught forward, 15ft. 8in.; aft, 20ft.; mean, 18ft. 0½in.
Launch weight excluding cradle.24,600 tons.
Length of standing ways..about 850 feet.
Length of sliding ways.about 750 feet.
Standing ways, of oak.. 0ft. 9in. wide.
Sliding ways, of pitchpine. 6ft. 3in. wide.
Pressure per sq. ft. of bearing surface 2’6 tons.
Declivity of ways, ⅜in. per foot for forward half length, increasing to ½in. per foot for the remainder.
Quantity of lubricants used :—
Tallow and train oil, mixed.5 tons.
Soft soap...3 tons.
Time from start till vessel left ways. 62 seconds.
Maximum velocity.12½ knots per hour.
Drags, 3 anchors each side and 80 tons cable, all disposed in the bed of the river.
Completion of the “Olympic.”
After the launch, the Olympic was moored at the new deep-water wharf belonging to the Belfast Harbour Authorities, and a commencement was made with the work of fitting the propelling machinery on board. The 200-ton floating crane belonging to the builders was employed for the purpose, and may be seen putting a boiler on board in Fig. 41. This crane, which is one of the largest floating cranes in existence, can lift a weight of 150 tons to a height of 149ft. at a radius of 100ft. with a list ofronly 4 degrees ; while the small hook can lift 50 tons at a radius of 140ft. Fig. 41 also shows the strong steel lattice girder gangway which was used for communication from the wharf to the ship, as well as one of the rafts which were provided at the forward and after ends to keep the vessel the required distance from the quay. Fig. 43 shows the ship in a more advanced stage, the four funnels and two masts having by this time been erected.
The Olympic was docked on the 1st April, 1911, in the new graving dock belonging to the Belfast Harbour Commissioners, of which the principal dimensions are given in Table V., and which has the distinction of being the largest graving dock in the world at the present time. The responsible task of docking and undocking was accomplished without a hitch. An illustration of the vessel in dock is shown in Fig. 42.
TABLE V.—THE NEW BELFAST DOCK.
Nominal length of dock on floor . 850' 0"
Length if caisson be placed against outer face quoins.886' 7½"
Width of dock on floor.100' 0"
Width at entrance to dock. 96' 0"
Width at coping level.128' 0"
Width at lowest altar course. 104' 6"
Depth of dock floor at centre below level of high water of ordinary springtides. 37' 3"
Top of keel blocks below level of high water of ordinary spring tides . 32' 9"
Height of top of blocks above floor ... 4' 6"
Level of entrance sill above dock floor at centre of dock. 2' 0"
Bottom of dock floor at sides of dock below copinglevel. 43' 6"
The Olympic was completed by the end of May, 1911, the work of fitting out having been finished in just over seven months from the date of launching, a remarkable performance, especially when it is considered that Messrs. Harland and Wolff were also completing afloat during the same period the two White Star tenders Nomadic and Traffic for use at Cherbourg, the P. & O. liner Maloja (the. largest ship of that fleet), the Aberdeen liner Demosthenes, and the Union-Castle intermediate liner Galway Castle, as well as preparing for the launch of the Titanic. Between 3,000 and 4,000 men were engaged on the completion of the Olympic, on board and in the shops, the total number of men employed by the builders at this period being about 14,000. A reference to the trial trip of the vessel and her departure from Belfast will be found near the end of the present issue.
Building Stages of the “ Titanic.”
The progress of work in connection with the Titanic is illustrated by the photographs we have used for that purpose in the case of the Olympic, the vessels having, as already stated, been built on adjoining berths. It is interesting to note, however, the dates upon which definite stages in the construction of the second vessel were reached. The keel was laid on the 31st March, 1909, or about three months after the Olympic was commenced. By the 15th May following the Titanic was framed to the height of the double bottom, and was fully framed on the 6th April, 1910, just a year after laying the keel. The vessel was plated by the 19th October, 1910, and was successfully launched on the 31st May, 1911, the launching arrangements being similar to those adopted for the Olympic. It is expected the Titanic will be completed and enter upon service early in 1912.