On Some Results of Recent Improvements in Naval Architecture and Marine Engineering, by Mr William Pearce. Lectures on Naval Architecture and Marine Engineering: Glasgow, William Collins & Sons, 1881.

The Speed and Carrying of Screw Steamers, by Mr William Denny. Lecture delivered to the Greenock Philosophical Society, 20th January, 1882, in honour of the birthday of James Watt (19th Jan.): Greenock, Wm. Hutchison.

On the Advantages of Increased Proportion of Beam to Length in Steamships, by Mr J. H. Biles: Trans. Inst., N.A., vol xxiv., 1883.

Cast Steel as a Material for Crank Shafts, by Mr J. F. Hall, Inst. N.A., vol. xxv., 1884.

CHAPTER III.
SAFETY AND COMFORT OF MODERN STEAMSHIPS.

Every advance—whether it be in dimensions or power of steamships, or whether it consist of modifications in their structure or appointment—toward that ideal period when sea-voyaging will have attained its maximum of comfort and its minimum of risk, is deserving of record. The qualities of safety and comfort, even more than increase of speed and the consequent shortening of sea passages, are first essentials in the realisation of this great end. The structural modifications, and the great development in size of recent vessels, affect the qualities named in ways which already may have been made evident, but which call for more detailed treatment. The more minute watertight sub-division of the hulls of vessels, for instance, and especially the presence of an inner skin or cellular bottom, are marked accessions to their safety.

The primary object and ruling principle of all proper watertight sub-division, is so to limit the space to which water can find access, that in a vessel with one, or even two, compartments open to the sea, the accession of weight due to the filling of these compartments would not exceed the surplus buoyancy she should possess. Until within recent years this was not so fully regarded as it ought, owing chiefly to the objections of shipowners to minute sub-division, as impairing a vessel’s usefulness and capacity for stowage of miscellaneous cargo. These objections have still doubtless much weight for vessels in certain trades, but the tendency of modern passenger traffic to estrange itself from cargo-carrying mediums, makes them almost inapplicable to a large section of our mercantile marine. There is now, indeed, more faith in well divided ships generally as being in the long run no less efficient and more economical than scantily divided ones.

FIG. 5.