The earlier modern ocean-going steamers were usually flush-decked. This left the machinery openings bare in the deck, so a bridge was added for their protection, and the flush deck was further encroached upon by the addition of a forecastle and poop. In some cases the quarter deck was raised, which was an awkward arrangement on account of the change it necessitated in the structure and framing, and in others the bridge and poop were joined. What is sometimes called the “three island” type, a very appropriate name in rough weather when the steamer takes a sea on board, came into great favour; it consists of a forecastle, bridge, and poop, and many vessels of considerable size have been built in that style. The cattle trade was responsible for some important changes in design, the “wells” where the cattle are carried being given iron and steel shelters, which thus form the shelter decks, a type of light deck introduced into the superstructure of most ocean-going steamers. The secret of the turret steamer is strength without unnecessary weight. Every ton of steel that can be kept out of a ship without reducing her strength adds a ton to her carrying capacity. This object is partly achieved in the turret steamer by the large amount of flanging adopted in the construction of these vessels. This is shown in the whole of the sheer strake and stringer plates, in the deck and frames of the cellular bottom work, and with great success in the joggled plating of the hull. Since 1895, when the Doxfords introduced a new method of rolling ships’ plates with joggled edges, they have built all their vessels under this system, making “packing” unnecessary. The turret gives longitudinal strength in the hull and leaves the hold clear. The strength is so great that in a steamer in which, by the substitution of deep for ordinary frames, all internal supports, beams, and girders are dispensed with, a clear hold is obtained. The firm claims that 58 cubic feet per ton dead weight under hatches is secured against 52 to 54 cubic feet per ton in the ordinary type. Thus the turret carries more on a given displacement, and having a lower registered tonnage, can earn more freight and save expenses. There are several designs of turret steamers adapted to different trades. Their suitability for bulk cargo, such as coal, or for large and heavy packages, is evident, while other types are equally suitable as passenger steamers, not a few lines having adopted them. Another advantage is that deck cargoes of wood can be carried with perfect safety on the turrets. Some of the cargo-boats designed for the ore and coal trade have their machinery right aft, and their holds are absolutely clear of obstruction of any kind whatever. Many of these are mastless but are fitted with twin derricks, a 10,000-ton boat carrying as many as seven pairs. The first of the mastless type was the _Teucer_. Convention fixed the depth of hold at about 15 feet,