Thanks to the rapid industrial progress, the mid-XIX century witnessed the birth of the transatlantic steamer, the liner, the ocean liner, which as a consequence of the increased reliability of marine propulsion, would change the way man had gone to sea since immemorial times, freeing him from the dependence on winds that conditioned routes and seasons in which it was possible to set sail for long ocean voyages.
The increase in large-scale migration, which went hand in hand with the evolution of the passenger liner and the establishment of large merchant fleets, would lead to a kind of further colonisation of the “New Worlds”, especially the Americas. From the marriage of the two phenomena, the Industrial Revolution and the Great Emigration, the steady growth of the passenger ships was secured.
Just looking at the external profile of the ocean liners over the years, it is possible to appreciate their gradual transformation from large sailing ships, the so-called “screw-clippers” (where the steam engine was merely the auxiliary means of propulsion and the sails were still the prime movers), until assuming their distinctive aspect of the steamers. Thanks also to the evolution of metallurgy, mild steel replaced wood as the primary means of construction of the hulls, making it possible to increase significantly the dimensions of the hulls. Afterwards, with the introduction of carbon steel, from the late XIX century onwards the size of the liners grew further, until they assumed the nickname of “floating cities”. At the same time, the evolution of the steam engine, in terms of higher power and performance and reduced size and weight, allowed the introduction of double steam engines and double screws. The number of masts was reduced accordingly and, in particular, the bowsprit disappeared to give way to a straight bow, incidentally much easier to build in steel.
The reduction in the weight of the hull made it possible to expand the liner upwards, with her superstructures increasing constantly and generously so that they could accommodate lounges and luxury cabins, which had previously been situated at the stern, which had been considered the most confortable area because it was more sheltered from the waves and which traditionally housed the officers of the ship.
The fuel also had an influence on the appearance of the ship; at the time of the First World War, oil began to quickly replace coal; oil had a much higher calorific power, could be stowed more easily and quicker in the tanks of the ship and required far fewer firemen who before, in almost inhuman conditions, were forced to feed the voracious furnaces of boilers in exhausting shifts spent shovelling coal. The boilers themselves would become more and more efficient and less cumbersome, enabling the reduction of the number of funnels and, with the forced draft and less soot, their height.
Around the mid-'Twenties, the diesel engine began to be installed on ocean liners as a valid alternative to the steam turbine; in order to promote and to distinguish a motorship from a steamship, the designers invented new forms of stacks which greatly altered the external view of the liner.
Social changes in the World of the XX century also had their influences on the appearance of the large passenger ship. At the end of the Great War, for example, the strict quotas imposed on the numbers of new migrants allowed into the U.S.A. led to the invention of the Tourist Class, intended to replace the Third Class with its humble facilities; the new stereotype of passenger, the American tourist, would facilitate and accelerate the alternative use of the liner as a cruise ship. The 'Twenties also saw the affirmation of the middle class, the emancipation and the diffusion of the culture for fitness and outdoor sports; ships had to cater to the demands of passengers and therefore they were equipped with outdoor decks, lidos and swimming pools and countless other attractions intended for the recreation of the guests on board.
In the 'Thirties, considered by historians the golden era of ocean liners, the ship becomes an object of design and of architectural and artistic confrontation, assuming the role of an ambassador for the country whose flag she hoists. The aesthetic continuity between smart, modern-looking interiors and the external appearance of the liner became a ground of debate that consecrated the largest self-moving object ever built by man: the “floating city” certainly deserves to be included in the list of the inventions that have characterised the XIX and XX centuries.
The English-speaking world clearly distinguishes the ship designers into naval architects and marine engineers, who are normally, respectively, the designers of the hull and of the propulsion plant. These are indeed two very different disciplines which, although interfaced, have differently influenced the evolution of the ocean liner.
Italy has a long tradition of naval architecture which, in modern times, was emphasised by the opening of the first test tank in Continental Europe for the towing of scale hull forms in La Spezia; the shape and appearance of the top of the ship was, unlike that of the hull, mainly influenced by the type of service, of routes and by the demands for transport of passengers, freight or both.
The hull shape was obviously affected by the type of propulsion used, whether paddle wheels or propeller; the first deep sea-going screw steamer, the Civetta, had been successfully tested by her inventor Josef Ressel (1793-1857) in 1829 in the Gulf of Trieste but it would take many more years before the paddle wheels were definitively supplanted.
The proverbial prudence of the Ligurian people (that is, the inhabitants of Genoa and the neighbouring area) would lead in the middle years of the XIX century to the development of the first hybrid sailing/steam ship, known as "screw clipper", i.e. a fast sailing ship fully fledged with masts and sails full kit but also with a steam engine and its propeller. In those days the steam engine was not reliable enough to convince shipowners to adopt it, its operating costs were high due to the huge consumption of costly coal; it was still a rooted conviction that, especially for long journeys, the steamer could not compete with the sailing ship, whose “free-fuel” compensated the longer duration of the trip. The screw clipper would therefore constitute the first shy step towards the embracing of modern technology at sea.
Giovanni Battista Lavarello (1824-1881), a native of Recco, near Genoa, was the pioneer in commissioning screw clippers. After gaining his first experience at sea as captain and owner of sailing ships on the routes to Latin America and the Black Sea, Lavarello began a regular passenger and freight service between Genoa and the ports of Rio de la Plata with screw clippers. The first to enter service was the Buenos Aires, built by the shipyard of G.B. Cadenaccio at Sestri Ponente (now Genoa Sestri); she sailed from Genoa on her maiden voyage on the 4th January 1864, arriving at Rio de la Plata after 64 days.
The design and construction procedures for iron-and steel-hulled ships remained basically unchanged from the first buildings to the outbreak of the Second World War; the revolution was to come with the advent of computer-assisted design and prefabrication. The evolution of iron and steel building techniques during the first fifty years was related essentially to the introduction of upgraded equipment in the shipyard, from the systems of transportation to increasingly powerful and sophisticated machine tools, which gradually replaced the use of human labour in several fields.
In the beginning a slipway was built on the shore and the plates were carried to its side, carted there by beasts of burden. Once in place with large shears and perforated at the edges, they were riveted together. The flat lay-out of the plates was achieved by means of scale wooden models of half-hulls on which the strakes were drawn; the scale dimensions and shape of each plate where then transferred in full scale to the floor of the tracing room mould loft (on a sort of gigantic sheet of graph paper) using large battens and leads.
Riveting was used to join the plates together, rather than welding, which made its first timid appearance in the shipyards in the early 'Twenties before becoming widespread after the World War II. The millions of metal pins were originally hot-riveted by riveters, who were extremely important skilled workers in the organisation of the yard and were represented by their own unions. Riveters were assisted by two apprentices; one used to take red-hot rivet from the brazier with a pair of tongues and pass it to the other (the receiver) on the slipway frame, who would take it and insert it into the paired holes while another pair of riveters inside the hull took it in turns to hammer it until the head was perfectly round and flush.
Aluminium alloys (for the construction of all or part of the upperworks) which provide the same strength but weigh one third of steel, would lead to a further revolution soon after the Second World War, also affecting the appearance of the ship; with the same robustness, they allow weight savings of over 60% compared to steel, and led to a further revolution immediately after the war, also in the appearance of ships.
In 1963 prefabrication was succesfully tested in Monfalcone - for the first time on large passenger ships launched in Italy - to build the Lloyd Triestino twins Galileo Galilei and Guglielmo Marconi. This method basically involved the use of prefabricated hull sections made in the factory and assembled later on the slipway. The advantages in terms of quality as well as saving of time and cost – comparable to those of an assembly line – were enormous. Nowadays, prefabrication is optimised in shipyards everywhere, with the blocks positioned in the building graving dock when they already contain the plants, technical systems and most of the fittings, for example the cabins.
When Italian shipyards began to build self-propelled ocean liners, the time of paddle-wheels was already over.
The first British-built liners fitted with triple expansion compound engines started operating in 1870. Thanks to the passage of steam from the first (high pressure) cylinder to the second (medium pressure) and then to the third (low pressure), the compound engine enabled far more economical use of the force of expansion of steam and heralded the undisputed supremacy of steamers over sailing ships.
Accordingly, in 1891 the first Italian-built liners used this type of engine, replaced ten years later by the quadruple expansion version, which was installed domestically for the first time on N.G.I's Umbria. The two 4000 horsepower engines were designed by Salvatore Orlando and built in his Leghorn factory.
In 1911 Ansaldo launched the nation's first ship equipped with steam turbines, the Città di Catania. At this time each engine consisted of a single turbine directly coupled to the propeller shaft. Only two years later, however, the Cracovia, built in Trieste, had one set of geared turbines per shaft, where the pinions of the two turbines (one high pressure and one low pressure) meshed on the main gear-wheel fixed to the fore end of the propeller shaft.
If on the one hand there was an improvement in the exploitation of steam, its production of the latter also advanced over time through the use of boilers which were able to withstand ever greater pressures and which, immediately after the Great War, switched from coal- to oil-fired.
Until the 'Sixties it was inconceivable to have 50,000-plus horsepower propulsion systems on just two shafts, fast liners such as the Roma of 1926 or the Rex and the Conte di Savoia of 1932 required four turbine sets each driving a propeller to reach speeds well over 20 knots. The Michelangelo and Raffaello of 1965 could attain top speeds of 33 knots and were fitted with just two propellers, each able to deliver a thrust of more than 50,000 HP.
It was however in the sector of motorships that Italy really established an international standing. In 1897 Germany pioneered the first internal combustion oil engine with a practical application, the invention of Rudolf Karl Diesel at the MAN factory in Augsburg. A few years later, in 1906, both Fiat and the Stabilimento Tecnico Triestino set up large factories for the manufacture of marine diesel engines. The same year Fiat opened its own shipyard in Muggiano (Fiat San Giorgio), which quickly established a reputation as World leader in the production of diesel-powered submarines.
The advantages in terms of technology and cost-savings of the oil engine as opposed to the steam turbine led many foreign shipping companies to turn to the Italian industry for the construction of their new vessels. Amongst the most striking cases there is the one of the Swedish American Line which commissioned Monfalcone in 1937 and Ansaldo in 1955 to build its large flagships for the North Atlantic service, respectively the Stockholm and the Gripsholm.
Visita agli stabilimenti della fabbrica "Macchine Sant'Andrea"
La grande motonave Vulcania.