The advent of the White Star liners, and the pending new German liners which are to exceed the "Olympic" in dimensions and which are to make Southampton a port of call, has resulted in great activity and enterprise at the British port named to provide docking accommodations for these leviathans. When the White Star vessels were projected the London and South Western Railway, which owns the Southampton Docks, at once took steps to complete a huge deep water dock as Southampton is the terminal point of this steamship company. Every effort was made to complete the work in time for the arrival of the "Olympic," but it was realized as a hopeless task, in view of the dock's dimensions, so the existing Trafalgar Dock was enlarged for the purpose. Owing to the energy with which the new basin has been pushed forward it will be available in the near future. The dock itself is a parallelogram with a length of 1,700 feet by 400 feet wide. The water depth at low water spring tides is 40 feet and at high tides 53 feet. There is no entrance to the lock, but the largest vessels afloat for the near future, will be able to lie in this basin at any state of the tide without danger of touching the bottom. Five vessels of the largest dimensions can berth on either side, while a short vessel can be alongside the small end berth.
The dock is surrounded with the quay walls constructed entirely of Portland cement concrete, and four large steel freight sheds are to be provided, the first for the "Olympic" berth being completed. The shed is 640 feet long by 120 feet wide, and has an annex 60 x 60 feet for baggage and dock gear. Accommodation for passengers is also provided. There is a balcony along the front side on which passengers land from the vessel, communicating with the floor of the building by two wide staircases. The train receives passengers on the opposite or land side, the customs' examination being carried out on benches near this side within easy reach of the train. The communication between the vessels' decks and the landing balcony will be effective by means of movable bridges. The quay is being equipped with the latest type of appliances for the expeditious handling of freight and baggage and when completed it will be one of the best equipped and most up-to-date docks in the world.
The construction of the dock, which has occupied about 3 1/2 years, has been carried out by the engineering firm Tepham Jones & Railton, Limited, under the supervision of Mr. F. E. Wenterworth Shields, the resident engineer, to whom we are indebted for these details and accompanying illustrations. Before the work was commenced the site comprised for the most part bare mudland facing the River Test. A chalk bank separated the waterway from this flat, but as this was not completely watertight the whole area was flooded daily at high tide. The first task was to make this barrier absolutely watertight by means of a sheeting of timber piles along the toe of the bank, and covering the slope with stone pitching grouted with cement.
Excavation to a depth of 30 feet below quay level was then carried forward by means of steam shovels, which removed about 5,000 cubic yards of spoil per day. Any water which found its way through the bank by soakage was led to a special sump whence it was ejected by electrically operated centrifugal pumps. The spoil removed was for the most part taken out to sea and dumped, but a certain quantity was used for raising the mud flats in the vicinity.
To facilitate the removal of the spoil to the barges a large stage 350 feet long by 40 feet high was built out over the River Test. This stage formed the summit of a long incline which led from the heat f the dock where the steam shovels filled the ballast cars. The latter when laden were drawn up the incline by a rope railway and there tipped, the contents falling into the steam hoppers lying alongside the stage. All this excavated material had to be carried to the far end of the Isle of Wight, a distance of 25 miles, before a dumping ground could be found which was deep enough not to be choked by dredgings. When the steam shovels had excavated the earth to the depth of 30 feet, timbered trenches were sunk in which the foundations of the quay walls were laid. These trenches were about 43 feet wide by 45 feet deep, the bottom being about 75 feet below the quay level. Massive concrete walls of Portland cement, mixed by special machinery, were built in these trenches, and by the mixing machine used for this portion of the week had a capacity of 1,000 cubic yards per day. Considerable difficulties were encountered in making these trenches as underground water found its way into making the excavations and various expedients had to be resorted to in order to overcome these floodings. When the walls had reached the quay level dry material area the dock accommodation and facilities were built. A portion of the wall at the outer end of the dock, and one of the outside quays, were not built by open excavation, but timber trenches were sunk from the quay level. The trenches in these cases were 45 feet wide by 75 feet deep in places, and were fine examples of heavy timbering. When the walls had been raised in this manner the inclosing bank at the entrance of the dock was cut through, permitting the water to enter, the excavation of the remaining portion of the floor of the dock being completed by bucket ladder dredgers. The excavation of the channel and turning basin outside the dock was carried out simultaneously. Four large dredgers were pressed into service for this work with a fleet of 13 hoppers and attendant craft for carrying the spoil to the sea. By this means the dock floor was lowered by 40 feet below low water. Two of the outer walls and part of the western entrance wall were built in a different manner. Here no attempt was made to dry the site, the whole wall being built in water. First the earth was removed to dredging level throughout the whole length of the wall by means of bucket dredger. Below this level the foundations were built in a trench between two rows of sheet piling driven along the front and back of the wall. The clay between the two rows of sheeting was excavated by steam grabs, and the trench was cleaned up by helmet divers. On the foundation thus obtained mass concrete was laid, being lowered through the water in special tipping boxes. Above dredging level the wall consists of large 8-ton concrete blocks at face and black with heating of mass concrete. This class of work is continued to a point above water level above which the water is built entirely of mass concrete laid between shutters in the usual manner. When the wall reached quay level it was backed up with ashes of select material. In addition to the dock itself there are four outside quay walls varying in length from 330 to 610 feet with depths of water at low tide of 25 to 32 feet.
Although at the time of writing the dock was not completed, the following quantities has been handed-Open excavation 873,000 cubic yards, trench excavation 318,000 cubic yards, dredging 807, 000 cubic yards, representing a total of 1, 992,000 cubic yards of spoil removed. For the constructional work 272,000 cubic yards of concrete had been laid and 42,000 tons of Portland cement used. The number of men employed on the task has been between 800 and 1,200, the whole time the work has been in progress. The plant required for the work has also been very comprehensive and modern, comprising 85 locomotives, steam shovels, cranes, pumps,pile drivers, winding en-
The widening has been effected by cutting away the faces of both walls and setting back the altars. To compensate for the weight thus lost counterfort walls are being built at the back of the existing walls. The entrance gates are also being removed to be replaces by a sliding caisson. Hitherto it has been customary to dock ships at high tide only, and owing to the long period of high water is has been possible always to complete the operation before the tide fell away. Consequently the dock gates have sufficed only for shutting water out from the dock. The new caison, however, will be double faced and capable of holding up the water within the dock while the tide is falling, in case any extraordinary delay to the docking operations should render this necessary. The present dock pumps are arranged only for emptying the dock, so a new one is being provided for the purpose of filling it. By this means it will be possible to maintain or increase the water-depth within the dock, even when the tide is falling outside.
Southampton is a unique port inasmuch as it is served with four high tides daily. The first tide rolling up the Solent is followed two hours later by that coming up the eastern channel dividing the Isle of Wight from the mainland. The London & South Western Railway have taken full advantage of this phenomenon, and have displayed considerable enterprise in meeting developments in steamship evolution since they acquired the property some years ago.