introduction of steam.

[Sidenote: Iron Hulls] The introduction of iron for wood began about the same time as the substitution of steam for sails, and there was even more prejudice against it. This was due not merely to the sentiment attaching to the oaken timbers that typified “hearts of oak,” or to the “Wooden Walls of England.” In all seriousness it was objected that iron would not float! It was feared that iron bottoms would be more easily perforated when ships grounded; but this was found not to be the case when construction was careful. It was proved that fouling of iron bottoms from weeds and barnacles might be remedied by frequent cleaning and repainting. The most serious objection against iron was that it affected the compass; but in 1839 Sir G. B. Airy laid down rules for the correction of compass errors due to iron in construction. But even to-day wood is preferred for the construction of ships for scientific expeditions to the Polar regions where the slightest disturbance of the compass is to be avoided. Iron and steel (first used in shipbuilding to any extent in 1870–75) have three advantages over wooden ships: less weight; greater durability; greater ease in securing the necessary general and local strengths. But while iron was coming into use largely because it is more durable, there was a great increase in the durability of wooden ships, due to the improved knowledge of wood-preservation. At the end of the 18th century 15 or 20 years was the average life of a wooden ship; but there are several instances of ships built in the first decade of the 19th century—or even earlier—which were still in commission at the beginning of the 20th century. [Sidenote: Early Steamships] Full details are given in regard to the first ships used for canal and river navigation in Great Britain and the United States; the comparatively rapid adoption of steam vessels on the Irish and English channels; and the first steamships to make long trips—the American-built “Savannah” which crossed the Atlantic in 1819 in 25 days using steam only a part of the time, the “Enterprise” which went from London to Calcutta in 1825 in 103 days (64 under steam), the “Sirius,” the “Great Western,” etc. All these were propelled by paddle-wheels. Jet propulsion had been suggested by Benjamin Franklin in 1775 and was tried several times with some success. But the greater success of the screw-propeller, perfected by Colonel John Stevens and Captain John Ericsson, soon caused jet-propulsion to be abandoned. The screw-propeller made possible—and was quickly followed by—great improvements in engines; the gearing used with paddles was soon given up for direct-acting engines—compound about 1854, triple-expansion in 1874. Statistics of shipping for all countries are given in tables and diagrams equivalent to 18 or 20 pages of this Guide. A brief summary outline of the remainder of this article SHIP is all that can be given here. Merchant Vessels Sailing Ships Barges, Smacks or Cutters, Schooners, Brigs and Brigantines Steamships Types: Turtle-back, etc. Cargo Ships: Modern Developments, Great Lake Freighters, Oil Tank Steamers, Motor Tank Vessels. Passenger Steamers: Ferries, River and Sound, Cross-Channel, Ocean Liners (Atlantic: Canadian, Emigrant Vessels, Liners on other Routes; Pacific Liners). Special Vessels (Dredge, Train Ferries, Ice Breakers, Surveying Vessels, Lightships, Coastguard and Fishery Cruisers, Salvage and Fire Vessels, Lifeboats, Yachts). Propulsion by Electricity, by Naphtha Engines, by Internal Combustion Engines War Vessels Battleships and Armour Protection; Sir E. J. Reed and the British Navy Turret Ships; American Monitor; Sir Nathaniel Barnaby in England; the work of Sir W. H. White; Development from 1885 to 1902; The “Dreadnought” type—in England, United States, Germany, France, Japan, Russia, Italy, Austria, Brazil, Argentina, etc., with Table, “Development of Some of the Leading Features of Notable Armored Battleships from 1860 to 1910.” Cruisers, Second-Class Cruisers, Third-Class, Armored Cruisers, Dreadnought Cruisers, Cruisers in Different Navies Gunboats and Torpedo Craft and Torpedo-boat Destroyers Submarines: American experiments in the 18th Century; inventions of Holland and Nordenfeldt; the Goubet System in France; Submarines in different navies. [Sidenote: History of Shipping] The article SHIPPING (Vol. 24, p. 983) is devoted to the history and practice of maritime transportation. It outlines the early period of trade, and the contest for trade among Spain, Portugal, the Netherlands and England, especially in the period after the discovery of America, when the prizes of commerce became suddenly so much richer. The Navigation Act of 1651, confining the trade between England and her colonies and the British coasting trade to English ships, was followed by a rapid growth of English shipping. The tonnage doubled between 1666 and 1688. In the 18th century and into the 19th, the history of shipping was primarily a contest for trade between France and England, finally won by the latter. The 19th century, as has already been seen in the article SHIP, was marked by the adoption of steam as a motive power. The struggle for supremacy in the Atlantic trade and in commerce with China and the Far East between the United States and Great Britain was won by the latter largely for this reason—the American ship-builders clung to the sailing clipper too long—and they were too slow in adopting iron instead of wooden hulls. The American Civil War was an additional set-back to American commerce. Other great factors during the last 50 years in the development of shipping, treated in the article, may be catalogued here: The opening of the Suez Canal in 1869. Improved apparatus for fire prevention. Refrigerating machinery, making possible the shipment of meats and other foods. Germany’s merchant marine. Japanese merchant vessels. French efforts to get trade. The shipping combine of 1902. “Liners” and “Tramps.” The freight rate question and increased tonnage. Special passenger transport: tourists, emigrants, etc. [Sidenote: Instructions for the Ship-Builder] The third of the main articles is SHIPBUILDING (Vol. 24, p. 922) by Sir Philip Watts. The article is equivalent to 200 pages of this Guide, and the illustrations include more than 120 working drawings. A brief outline of the article is all that can be given here. _Stability_: Equilibrium, Stability of Equilibrium, Transverse Stability, Small Inclinations, Metacentric Heights, Inclining Experiment, Large Inclinations, Curves of Stability, Effect of Freeboard, Effect of Beam, Effect of Position on Centre of Gravity, Geometrical Properties, Dynamical Stability, Sailing Ships, Longitudinal Stability, Stability when Damaged, Stability in any Direction. _Rolling of Ships_: Unresisted Rolling—Froude’s Theory, Resisted Rolling, Methods of Reducing Rolling (Bilge-Keels, Water Chambers, Gyroscope). _Resistance_: Components of Force, Wake, Frictional Resistance, Law of Comparison, Model Experiments, Experimental Results. _Propulsion_: Experimental Results, Cavitation. _Strength_: Longitudinal Bending, Transverse Bending. _Steering_: Nature of Forces when Turning, Heel when Turning, Types of Rudders, Experimental Results. _Process of Design_ Registration Societies Board of Trade Supervision Load line and Freeboard Loading of Grain and Timber _Ship-yard Work_ Structural Parts Materials Cranes and Gantries _Course of Construction_ Models Laying-off Sheer Drawing Fairing the Body Contracted Method of Fairing Fairing the End Stern Mould Displacement Calculation Frame Lines Cant Frames Double Canted Frame Swell for Propeller Shaft Mould for Boss Frame Casting Shaft Struts Sight Edges in Body Plan Inner Bottom Inner Surface of Frames Outside Double Bottom Deck Lines Framing and Plating behind Armour Laying off Armour of a Warship Order of Work Keel Transverse Frames Scrive-Board Shoring Ribbands Deck Beams Longitudinals Bilge Keel Drawings Laying Keel Blocks Keels and Frames Shell or Outside Plating _Structural Arrangements_ Longitudinal System as used in New London, Conn.; Great Lake steamer; British cargo steamer; Atlantic liner; Differences between war and merchant ships; Auxiliary Machinery. [Sidenote: A Dictionary of Ships and Shipping] The student should read the article NAVY AND NAVIES (Vol. 19, p. 299) and refer to the Chapter _For Naval Officers_. The following is a partial list of the articles in the Britannica of particular value to the marine transportation man. Anchor Ballast Barge Belay Berth Bilge Binnacle Boat Bowline Bumboat Buoy Burgee Cable Cabotage Caique Canoe Capstan Catamaran Cleat Coble Commerce Coracle C. H. Cramp Sir Samuel Cunard Dahabeah Dhow Dinghy John Ericsson Felucca John Fitch Robert Fulton Gimbal Hawser Holystone T. H. Ismay Junk Kayak Keel Lateen Life-saving Service Lighthouse Log Mast Navigation Navigation Laws Oars Pilot Pinnace Pirogue Polacca Poop Pram Proa Punt Quarterdeck Quay Random Rigging Rowlock Rudder Sail, and Sailcloth Sampan Schooner Seamanship Seamen, Laws of Semaphore Ship Shipbuilding Ship Money Shipping Sloop Smack Starboard Steamship Lines Tonnage Trinity House Turbine Wharf Sir William H. White Yawl