The present volume is, in a large measure, the outcome of the gratifying reception with which the smaller work, “Know your Own Ship,” published in the Nautical Series, met on its first and. subsequent editions. The success of that book emboldened its Author to embark, at the suggestion of the publishers, upon the preparation of a larger and more important undertaking, the result of which is now presented to the reader in the hope that it will be found, not less than the former work, to merit the approval of that section of the shipbuilding world for whose needs it has been specially devised. A sketch of the plan of the book will be found at the end of this preface; it is therefore unnecessary here to do more than briefly outline the circumstances under which it has been written. The work has taken four years to complete, the Author having been unable to devote more than his leisure hours to its composition. A careful study of some years duration, carried out in that centre of the steel trade, the Cleveland district, has afforded the necessary basis for the first two chapters, while the subsequent chapters are the result of the Author's daily experience in the profession of ship construction and maintenance. The book has been copiously illustrated, and no expense has been spared in the preparation and execution of diagrams intended to amplify and elucidate the text. These have been placed in close juxtaposition to those portions of the work to which they refer, the Author conceiving that they will thus prove more readily available for purposes of reference than if they had been published as a separate volume, as is sometimes done in works of this class. The whole - subject has been treated from a practical point of view, and the requirements of students, ship superintendents, shipbuilders, and marine engineers have been carefully studied.

Iron and Steel supersede Wood in Shipbuilding. - The day of wooden ships has practically gone. Travelling through our modem shipbuilding districts, one can scarcely fail to be struck by the conspicuous absence of this material. Whereas, sixty years ago, wood was the principal constructive element in shipbuilding, it is now a rare sight indeed to see in this country the hull of a seagoing craft being built of this material. Even then it is only used in the construction of the smallest types of vessels, or else only as a composite part of larger ones.

This great and rapid transformation has all been brought about by the introduction in shipbuilding, first of iron, and subsequently of steel. The manufacture of iron has been carried on for thousands of years, and great skill evinced in its production, while the uses of steel have been understood and appreciated for centuries. It is only since about the year 1860, however, that the latter could be produced in sufficient quantities and of the requisite quality for its adoption in the construction of ships. Even then it was not until after the year 1880 that steel became extensively employed in the building of ships for the mercantile marine. At the present time over 99 per cent, of the vessels built in this country are constructed of this material.

While, generally speaking, iron has given place to steel, it will be shown more definitely in a subsequent chapter that it still finds favour for certain purposes on account of important qualities which experience has shown it to possess. Hence, to a limited extent, it is still employed as a constructive element in certain parts of a ship.

While the principal aim of this work is to describe the construction and the means which may be adopted for the maintenance or preservation of steel ships, it will not be out of place to convey some information respecting the process of the manufacture of steel, particularly noting those constituents of the metal whose presence or absence confers, in a marked degree, the qualities of malleability, ductility, weldability, hardness, softness, brittleness, toughness, cold-shortness and red-shortness and strength.

Although in a steamer the hull is principally composed of mild steel plates and bars, made by the Siemens process* (a process which takes its name from Sir William Siemens, the inventor of a system of producing steel which has proved especially suited to the requirements of ship construction), yet iron, in practically every form in which it is known commercially, is employed, to a greater or less extent, in the construction and equipment of a ship. We thus find, in addition to mild steel and steel castings, that iron castings, malleable iron plates, bars and forgings are also employed.

To embrace the whole subject of the metallurgy of steel and iron in what must necessarily be a few pages in a work of this kind, would be an utter impossibility. However, notwithstanding the enormous dimensions of the subject, and the complicated processes attending the manufacture of iron and steel, we shall endeavour to convey to the reader unacquainted with the subject some knowledge of the manufacture, composition, etc., in as intelligible a manner as the brevity of the treatment will permit.

Composition of Iron and Steel - As is well known, steel and iron are products of iron ore which is obtained, like all other minerals, from the earth by mining, and which, after being subjected to a course of treatment whereby most of the associated impurities are separated, yields iron or steel according to the nature and amount of the foreign elements still remaining in combination with the pure iron in the final product. There are many substances whose natures can be easily described by a simple definition. Such is not the case, however, with iron and steel as they occur commercially. Neither of them are pure metals. Indeed, absolutely pure iron, in addition to the practical impossibility of its production upon a large scale, is worthless for any industrial purpose.