Steamship
A steamship, often referred to as a steamer, is a type of steam-powered vessel, typically ocean-faring and seaworthy, that is propelled by one or more steam engines that typically move propellers or paddlewheels. The first steamships came into practical usage during the early 19th century; however, there were exceptions that came before.
Steamships usually use the prefix designations of "PS" for paddle steamer or "SS" for screw steamer. As paddle steamers became less common, "SS" is incorrectly assumed by many to stand for "steamship". Ships powered by internal combustion engines use a prefix such as "MV" for motor vessel, so it is not correct to use "SS" for most modern vessels.
As steamships were less dependent on wind patterns, new trade routes opened up. The steamship has been described as a "major driver of the first wave of trade globalization " and contributor to "an increase in international trade that was unprecedented in human history".
History
Steamships were preceded by smaller vessels, called steamboats, conceived in the first half of the 18th century by Denis Papin, with the first working steamboat and paddle steamer, the Pyroscaphe, from 1783. Once the technology of steam was mastered at this level, steam engines were mounted on larger, and eventually, ocean-going vessels. Becoming reliable, and propelled by screw rather than paddlewheels, the technology changed the design of ships for faster, more economic propulsion.Paddlewheels as the main motive source became standard on these early vessels. It was an effective means of propulsion under ideal conditions but otherwise had serious drawbacks. The paddle-wheel performed best when it operated at a certain depth, however when the depth of the ship changed from added weight it further submerged the paddle wheel causing a substantial decrease in performance.
Within a few decades of the development of the river and canal steamboat, the first steamships began to cross the Atlantic Ocean. The first sea-going steamboat was Richard Wright's first steamboat Experiment, an ex-French lugger; she steamed from Leeds to Yarmouth in July 1813.
The first iron steamship to go to sea was the 116-ton Aaron Manby, built in 1821 by Aaron Manby at the Horseley Ironworks, and became the first iron-built vessel to put to sea when she crossed the English Channel in 1822, arriving in Paris on 22 June. She carried passengers and freight to Paris in 1822 at an average speed of.
The American ship first crossed the Atlantic Ocean arriving in Liverpool, England, on June 20, 1819, although most of the voyage was actually made under sail. The first ship to make the transatlantic trip substantially under steam power may have been the British-built Dutch-owned Curaçao, a wooden 438-ton vessel built in Dover and powered by two 50 hp engines, which crossed from Hellevoetsluis, near Rotterdam on 26 April 1827 to Paramaribo, Surinam on 24 May, spending 11 days under steam on the way out and more on the return. Another claimant is the Canadian ship in 1833.
The first steamship purpose-built for regularly scheduled trans-Atlantic crossings was the British side-wheel paddle steamer built by Isambard Kingdom Brunel in 1838, which inaugurated the era of the trans-Atlantic ocean liner.
, built in Britain in 1839 by Francis Pettit Smith, was the world's first screw propeller-driven steamship for open water seagoing. She had considerable influence on ship development, encouraging the adoption of screw propulsion by the Royal Navy, in addition to her influence on commercial vessels. The first screw-driven propeller steamship introduced in America was on a ship built by Thomas Clyde in 1844 and many more ships and routes followed.
Screw-propeller steamers
The key innovation that made ocean-going steamers viable was the change from the paddle-wheel to the screw-propeller as the mechanism of propulsion. These steamships quickly became more popular, because the propeller's efficiency was consistent regardless of the depth at which it operated. Being smaller in size and mass and being completely submerged, it was also far less prone to damage.James Watt of Scotland is widely given credit for applying the first screw propeller to an engine at his Birmingham works, an early steam engine, beginning the use of a hydrodynamic screw for propulsion.
The development of screw propulsion relied on the following technological innovations.
Steam engines had to be designed with the power delivered at the bottom of the machinery, to give direct drive to the propeller shaft. A paddle steamer's engines drive a shaft that is positioned above the waterline, with the cylinders positioned below the shaft. used chain drive to transmit power from a paddler's engine to the propeller shaft – the result of a late design change to propeller propulsion.
An effective stern tube and associated bearings were required. The stern tube contains the propeller shaft where it passes through the hull structure. It should provide an unrestricted delivery of power by the propeller shaft. The combination of hull and stern tube must avoid any flexing that will bend the shaft or cause uneven wear. The inboard end has a stuffing box that prevents water from entering the hull along the tube. Some early stern tubes were made of brass and operated as a water lubricated bearing along the entire length. In other instances a long bush of soft metal was fitted in the after end of the stern tube. had this arrangement fail on her first transatlantic voyage, with very large amounts of uneven wear. The problem was solved with a lignum vitae water-lubricated bearing, patented in 1858. This became standard practice and is in use today.
Since the motive power of screw propulsion is delivered along the shaft, a thrust bearing is needed to transfer that load to the hull without excessive friction. had a 2 ft diameter gunmetal plate on the forward end of the shaft which bore against a steel plate attached to the engine beds. Water at 200 psi was injected between these two surfaces to lubricate and separate them. This arrangement was not sufficient for higher engine powers and oil lubricated "collar" thrust bearings became standard from the early 1850s. This was superseded at the beginning of the 20th century by floating pad bearing which automatically built up wedges of oil which could withstand bearing pressures of 500 psi or more.
Name prefix
Steam-powered ships were named with a prefix designating their propeller configuration i.e. single, twin, triple-screw. Single-screw Steamship SS, Twin-Screw Steamship TSS, Triple-Screw Steamship TrSS. Steam turbine-driven ships had the prefix TS. In the UK the prefix RMS for Royal Mail Steamship overruled the screw configuration prefix.First ocean-going steamships
The first steamship credited with crossing the Atlantic Ocean between North America and Europe was the American ship, though she was actually a hybrid between a steamship and a sailing ship, with the first half of the journey making use of the steam engine. Savannah left the port of Savannah, Georgia, US, on 22 May 1819, arriving in Liverpool, England, on 20 June 1819; her steam engine having been in use for part of the time on 18 days. A claimant to the title of the first ship to make the transatlantic trip substantially under steam power is the British-built Dutch-owned Curaçao, a wooden 438-ton vessel built in Dover and powered by two 50 hp engines, which crossed from Hellevoetsluis, near Rotterdam on 26 April 1827 to Paramaribo, Surinam on 24 May, spending 11 days under steam on the way out and more on the return. Another claimant is the Canadian ship in 1833.The British side-wheel paddle steamer was the first steamship purpose-built for regularly scheduled trans-Atlantic crossings, starting in 1838. In 1836 Isambard Kingdom Brunel and a group of Bristol investors formed the Great Western Steamship Company to build a line of steamships for the Bristol-New York route. The idea of regular scheduled transatlantic service was under discussion by several groups and the rival British and American Steam Navigation Company was established at the same time. Great Western's design sparked controversy from critics that contended that she was too big. The principle that Brunel understood was that the carrying capacity of a hull increases as the cube of its dimensions, while water resistance only increases as the square of its dimensions. This meant that large ships were more fuel efficient, something very important for long voyages across the Atlantic.
Great Western was an iron-strapped, wooden, side-wheel paddle steamer, with four masts to hoist the auxiliary sails. The sails were not just to provide auxiliary propulsion, but also were used in rough seas to keep the ship on an even keel and ensure that both paddle wheels remained in the water, driving the ship in a straight line. The hull was built of oak by traditional methods. She was the largest steamship for one year, until the British and American's British Queen went into service. Built at the shipyard of Patterson & Mercer in Bristol, Great Western was launched on 19 July 1837 and then sailed to London, where she was fitted with two side-lever steam engines from the firm of Maudslay, Sons & Field, producing 750 indicated horsepower between them. The ship proved satisfactory in service and initiated the transatlantic route, acting as a model for all following Atlantic paddle-steamers.
The Cunard Line's began her first regular passenger and cargo service by a steamship in 1840, sailing from Liverpool to Boston.
In 1845 the revolutionary, also built by Brunel, became the first iron-hulled screw-driven ship to cross the Atlantic. SS Great Britain was the first ship to combine these two innovations. After the initial success of its first liner, of 1838, the Great Western Steamship Company assembled the same engineering team that had collaborated so successfully before. This time however, Brunel, whose reputation was at its height, came to assert overall control over design of the ship—a state of affairs that would have far-reaching consequences for the company. Construction was carried out in a specially adapted dry dock in Bristol, England.
File:SS Great Britain by Talbot.jpg|thumb|right|Great Britain in the Cumberland Basin, April 1844. This historic photograph by William Talbot is believed to be the first ever taken of a ship.
Brunel was given a chance to inspect John Laird's channel packet ship Rainbow—the largest iron-hulled ship then in service—in 1838, and was soon converted to iron-hulled technology. He scrapped his plans to build a wooden ship and persuaded the company directors to build an iron-hulled ship. Iron's advantages included being much cheaper than wood, not being subject to dry rot or woodworm, and its much greater structural strength. The practical limit on the length of a wooden-hulled ship is about 300 feet, after which hogging—the flexing of the hull as waves pass beneath it—becomes too great. Iron hulls are far less subject to hogging, so that the potential size of an iron-hulled ship is much greater.
In the spring of 1840 Brunel also had the opportunity to inspect, the first screw-propelled steamship, completed only a few months before by F. P. Smith's Propeller Steamship Company. Brunel had been looking into methods of improving the performance of Great Britains paddlewheels, and took an immediate interest in the new technology, and Smith, sensing a prestigious new customer for his own company, agreed to lend Archimedes to Brunel for extended tests. Over several months, Smith and Brunel tested a number of different propellers on Archimedes in order to find the most efficient design, a four-bladed model submitted by Smith. When launched in 1843, Great Britain was by far the largest vessel afloat.
Brunel's last major project,, was built in 1854–1857 with the intent of linking Great Britain with India, via the Cape of Good Hope, without any coaling stops. This ship was arguably more revolutionary than her predecessors. She was one of the first ships to be built with a double hull with watertight compartments and was the first liner to have four funnels. She was the biggest liner throughout the rest of the 19th century with a gross tonnage of almost 20,000 tons and had a passenger-carrying capacity of thousands. The ship was ahead of her time and went through a turbulent history, never being put to her intended use. The first transatlantic steamer built of steel was, built by Allan Line Royal Mail Steamers and entering service in 1879.
The first regular steamship service from the East Coast to the West Coast of the United States began on 28 February 1849, with the arrival of in San Francisco Bay. The California left New York Harbor on 6 October 1848, rounded Cape Horn at the tip of South America, and arrived at San Francisco, California, after a four-month and 21-day journey. The first steamship to operate on the Pacific Ocean was the paddle steamer Beaver, launched in 1836 to service Hudson's Bay Company trading posts between Puget Sound Washington and Alaska.