THE TURRET-SHIP “INLAND.”
From a Photograph. By permission of Messrs. W. Doxford & Sons, Ltd.
MIDSHIP SECTION OF A TURRET-SHIP.
From the Model in the Victoria and Albert Museum.
When a vessel is carrying her full cargo her stern is sufficiently immersed to prevent her propeller from racing badly in a heavy sea. But when she is making a voyage “light” there is great danger of damage to the ship through the fracturing of the propeller shaft as the ship dips her bows and raises her tail in the air. Everyone who has had experience of handling small craft of any kind is aware that the lower the ballast is placed the more the ship will roll. In an extreme case, when all the ballast is placed outside the ship on to her keel, the motion in a sea-way is more like that of the pendulum than anything else. The method which we are now about to discuss allows of water-ballast tanks being placed sufficiently high at the “wings” to counteract this rolling. [Opposite page 250] will be seen two illustrations of the patent cantilever-framed steamers which are built by Messrs. Sir Raylton Dixon and Company, Limited, of Middlesbrough, through whose courtesy the photographs are reproduced. By examining them it will be seen that water-ballast can be carried not only in the usual tank at the bottom of the ship, but in the wing tanks at the sides of the ship, and at such a height that when the ship is crossing the ocean without cargo, she will have an easy motion.
The lower illustration shows a section of one of these cantilever ships, and the water-ballast tanks, above which is a shelter deck that in the case of a passenger ship can be used as a promenade, or can accommodate live cargo in cattle-ships. It will be noticed that the ship’s frames are bent inwards, and that these, together with the vertical sides of the hull, form the triangular spaces for the tanks. Now these tanks run fore and aft on both sides and increase the strength of the ship, not merely longitudinally, but transversely. Owing to this the necessity of adding such obstructions to the hold as pillars and beams vanishes, and as will be seen in the illustrations, the hold is thus free and unencumbered for all manner of cargo. It is further claimed for this cantilever craft that she can carry a dead-weight more than three times the net register, and since these tanks are not reckoned into the tonnage they increase the safety and comfort of the ship without detracting from her utility. The reader will also notice in the upper picture to what an enormous extent the modern steamship is now being fitted with extra derricks, with a cross-piece up the mast to take the strain involved in working the latter.
As the reverse of being specially adapted for a particular service, the steam tramp is built so that she can readily engage in almost any carrying trade. Unlike the liner with her fixed routes and set times of departure and arrival, the tramp is a nomad, and wanders over the world picking up a cargo here and there, and taking it across the ocean at her economical but jog-trot speed. If there is nothing for her to pick up at the last port of call she betakes herself elsewhere with the hope of better luck. Her main income is derived as a coal-carrier, and for this she is quite suited. But the modern collier—the kind of ship which is expressly built for the coal trade—is fitted with numbers of steam winches in keeping with the modern feverish haste and hurry, so that no sooner has she come alongside than she may instantly begin to unload. In old-fashioned times the discharging was done from the shore, but nowadays the up-to-date turret-ship makes short work of handling her black diamonds. Special appliances are also provided for those steamships which bring over the seas vast quantities of New Zealand mutton, fruit, and other perishable articles of food. Elaborate refrigerating machinery has to be installed in the ship, and special means employed to facilitate the disembarking of the cargo, especially in the case of the former.
