Steamship

 ( Steamships ) 

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 that typically move (turn) or Paddle steamer. The first steamships came into practical usage during the early 19th century; however, there were exceptions that came before. Steamships usually use the ship prefix designations of "PS" for paddle steamer or "SS" for screw steamer (using a propeller or screw). 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 (1870–1913)" and contributor to "an increase in international trade that was unprecedented in human history".

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.Carlton, 2012 p.23

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 Great 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.

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.

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 from the firm of Henry Maudslay, 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.

Brunel was given a chance to inspect John Laird's English 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.

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.

Another partial solution was the Steam Auxiliary Ship – a vessel with a steam engine, but also rigged as a sailing vessel. The steam engine would only be used when conditions were unsuitable for sailing – in light or contrary winds. Some of this type (for instance Erl King) were built with propellers that could be lifted clear of the water to reduce drag when under sail power alone. These ships struggled to be successful on the route to China, as the standing rigging required when sailing was a handicap when steaming into a head wind, most notably against the southwest monsoon when returning with a cargo of new tea. Though the auxiliary steamers persisted in competing in far eastern trade for a few years (and it was Erl King that carried the first cargo of tea through the Suez Canal), they soon moved on to other routes.

What was needed was a big improvement in fuel efficiency. While the boilers for steam engines on land were allowed to run at high pressures, the Board of Trade (under the authority of the Merchant Shipping Act 1854) would not allow ships to exceed . Compound engines were a known source of improved efficiency – but generally not used at sea due to the low pressures available. SS Carnatic, a P&O ship, had a compound engine – and achieved better efficiency than other ships of the time. Her boilers ran at but relied on a substantial amount of Superheater.

Alfred Holt, who had entered marine engineering and ship management after an apprenticeship in railway engineering, experimented with boiler pressures of in Cleator. Holt was able to persuade the Board of Trade to allow these boiler pressures and, in partnership with his brother Phillip launched Agamemnon in 1865. Holt had designed a particularly compact compound engine and taken great care with the hull design, producing a light, strong, easily driven hull.

The efficiency of Holt's package of boiler pressure, compound engine and hull design gave a ship that could steam at 10 knots on 20 long tons of coal a day. This fuel consumption was a saving from between 23 and 14 long tons a day, compared to other contemporary steamers. Not only did less coal need to be carried to travel a given distance, but fewer firemen were needed to fuel the boilers, so crew costs and their accommodation space were reduced. Agamemnon was able to sail from London to China with a coaling stop at Mauritius on the outward and return journey, with a time on passage substantially less than the competing sailing vessels. Holt had already ordered two sister ships to Agamemnon by the time she had returned from her first trip to China in 1866, operating these ships in the newly formed Blue Funnel Line. His competitors rapidly copied his ideas for their own new ships.

The opening of the Suez Canal in 1869 gave a distance saving of about on the route from China to London. The canal was not a practical option for sailing vessels, as using a tug was difficult and expensive – so this distance saving was not available to them. Steamships immediately made use of this new waterway and found themselves in high demand in China for the start of the 1870 tea season. The steamships were able to obtain a much higher rate of Freight rate than sailing ships and the insurance premium for the cargo was less. So successful were the steamers using the Suez Canal that, in 1871, 45 were built in Clyde shipyards alone for Far Eastern trade.

The theory of this was established in the 1850s by John Elder, but it was clear that triple expansion engines needed steam at, by the standards of the day, very high pressures. The existing boiler technology could not deliver this. Wrought iron could not provide the strength for the higher pressures. Steel became available in larger quantities in the 1870s, but the quality was variable. The overall design of boilers was improved in the early 1860s, with the Scotch-type boilers – but at that date these still ran at the lower pressures that were then current.

The first ship fitted with triple expansion engines was Propontis (launched in 1874). She was fitted with boilers that operated at – but these had technical problems and had to be replaced with ones that ran at . This substantially degraded performance.

There were a few further experiments until went into service on the route from Britain to Australia. Her triple expansion engine was designed by Dr A C Kirk, the engineer who had developed the machinery for Propontis. The difference was the use of two double ended Scotch type steel boilers, running at . These boilers had patent corrugated furnaces that overcame the competing problems of heat transfer and sufficient strength to deal with the boiler pressure. Aberdeen was a marked success, achieving in trials, at 1,800 indicated horsepower, a fuel consumption of of coal per indicated horsepower. This was a reduction in fuel consumption of about 60%, compared to a typical steamer built ten years earlier. In service, this translated into less than 40 tons of coal a day when travelling at . Her maiden outward voyage to Melbourne took 42 days, with one coaling stop, carrying 4,000 tons of cargo.

Other similar ships were rapidly brought into service over the next few years. By 1885 the usual boiler pressure was and virtually all ocean-going steamships being built were ordered with triple expansion engines. Within a few years, new installations were running at . The tramp steamers that operated at the end of the 1880s could sail at with a fuel consumption of of coal per ton mile travelled. This level of efficiency meant that steamships could now operate as the primary method of maritime transport in the vast majority of commercial situations.

was the largest steamship in the world when she sank in 1912; a subsequent major sinking of a steamer was that of the , as an act of World War I.