Alaska | --- | --- |\2 @ 100 /| 72 | ---- | ---- | 100 | | | | | | | | | | | |/1 @ 44 \| | | | | Aller | --- | --- ||1 @ 70 || 72 | 22,630 | 799 | 150 | | | |\1 @ 100 /| | | | | | | | | | | | | | | |/1 @ 62 \| | | | | Ems | --- | --- |\2 @ 86 /| 60 | 19,700 | 780 | 100 | ----------------+-----+------+-------------+------+--------+
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  ¹Mean speed of a voyage across the Atlantic Ocean.

The author next considered the strains to which a ship is exposed, and stated that he had before him the calculations for three of the largest vessels, two of them of iron and the other of steel; and he found, in the case of the iron, the maximum tension on the gunwale during the greatest hogging strains likely to be endured at sea would not exceed about six tons per square inch, while in the case of the steel ship it is only about 61/2 tons.  These strains are well within the limits of safety, and a comparison of the scantlings of these with the others justifies the assertion as to their general safety from a structural point of view.  The sections of these three ships are shown in Figs. 1, 2, and 3, with their principal scantlings.  It will be seen from these sections that the three ships differ materially in their mode of construction.  In the case of Fig. 1, which represents the City of Rome, the largest of the three, it will be seen that the main framing of the vessel is entirely transverse, with very heavy keelsons in the bottom, and large partial bulkheads or web frames, and the outside plating arranged on what is termed the edge to edge principle, with a great portion of it double.  In the next section, Fig. 2, the Servia, which is built of steel, on the other hand, the bottom is built on the longitudinal cellular system, the first application, he believed, of this system to an Atlantic liner.  The plating of the Servia is of the usual alternate outer and inner strake system, partly double; while the third section, the Oregon, approaches more nearly to the ordinary system of framing and plating usually adopted, but it will be seen that she was well tied in the bottom by very heavy intercostal and plate keelsons, as well as in the top by heavy stringers and sheer strakes, with much of her plating doubled, and heavy web frames inside.  The author next considered the question of stability, and went on to deal with the subject of twin screws, and stated that the Barrow Shipbuilding Company has done more in the way of planning and designing for the adoption of twin screws lately than for any other mode of propulsion, and this chiefly for passenger steamers.  He did not attach much importance to the particular form of the blade either in single or twin screws, as he believed