Cruise ship poolside theater
A cruise ship poolside theater is a giant LED display screen, ranging from around 250 to 350 square feet. It is complemented with a 50,000-80,000 watt sound system; the theater is placed facing the main swimming pool of a cruise ship. The theater can be used to display news, sporting events, poolside activities and movies; the poolside theater was introduced in 2004 on the Caribbean Princess, was built with or installed on other ships in Princess Cruises's fleet. Princess named their poolside theaters as "Movies Under The Stars". For the outdoor nighttime movies and blankets are placed over the deck chairs, popcorn is provided; the "Movies Under The Stars" name refers to the service via cable television in the staterooms at night. In 2005 Carnival Cruise Lines launched their first ship with a poolside theater, the Carnival Liberty. Carnival named their poolside theaters as "Carnival's Seaside Theater". Since the launch of the Carnival Liberty, every new cruise ship built by Carnival has had the "Carnival Seaside Theater" added.
In 2005 and in 2006, Disney Cruise Lines has installed its own poolside theater on its two older ships refurbishments. Costa Cruises has introduced poolside theaters on its Concordia-class fleet. Royal Caribbean International debuted outdoor movie screens as part of the "Aquatheater" on the Oasis class, has since been added poolside screens to most of their fleet as part of the "Royal Advantage" revitalization program. AIDAluna AIDAblu AIDAsol AIDAmar AIDAstella Carnival Freedom Carnival Liberty Carnival Splendor Carnival Valor Carnival Victory Carnival Dream Carnival Triumph Carnival Sunshine Carnival Conquest Carnival Glory Carnival Breeze Carnival Pride Carnival Vista Costa Diadema Costa Favolosa Costa Fascinosa Costa Luminosa Costa Pacifica Costa Serena Disney Dream Disney Fantasy Disney Magic Disney Wonder Genting Dream MSC Fantasia MSC Musica MSC Orchestra MSC Poesia Norwegian Epic Norwegian Escape Azura Pacific Jewel Pacific Pearl Caribbean Princess Coral Princess Crown Princess Dawn Princess Diamond Princess Emerald Princess Golden Princess Grand Princess Island Princess Ruby Princess Royal Princess Sapphire Princess Sea Princess Star Princess Sun Princess Vision Class Legend of the Seas Splendour of the Seas Grandeur of the Seas Rhapsody of the Seas Enchantment of the Seas Vision of the Seas Voyager Class Navigator of the Seas Mariner of the Seas Adventure of the Seas Explorer of the Seas Voyager of the Seas Radiance Class Radiance of the Seas Brilliance of the Seas Serenade of the Seas Freedom Class Freedom of the Seas Liberty of the Seas Independence of the Seas Oasis Class Oasis of the Seas Allure of the Seas Quantum Class Quantum of the Seas Anthem of the Seas Ovation of the Seas
In broadcasting and radio communications, a call sign is a unique designation for a transmitter station. In the United States of America, they are used for all FCC-licensed transmitters. A call sign can be formally assigned by a government agency, informally adopted by individuals or organizations, or cryptographically encoded to disguise a station's identity; the use of call signs as unique identifiers dates to the landline railroad telegraph system. Because there was only one telegraph line linking all railroad stations, there needed to be a way to address each one when sending a telegram. In order to save time, two-letter identifiers were adopted for this purpose; this pattern continued in radiotelegraph operation. These were not globally unique, so a one-letter company identifier was added. By 1912, the need to identify stations operated by multiple companies in multiple nations required an international standard. Merchant and naval vessels are assigned call signs by their national licensing authorities.
In the case of states such as Liberia or Panama, which are flags of convenience for ship registration, call signs for larger vessels consist of the national prefix plus three letters. United States merchant vessels are given call signs beginning with the letters "W" or "K" while US naval ships are assigned call signs beginning with "N". Both ships and broadcast stations were assigned call signs in this series consisting of three or four letters. Ships equipped with Morse code radiotelegraphy, or life boat radio sets, Aviation ground stations, broadcast stations were given four letter call signs. Maritime coast stations on high frequency were assigned three letter call signs; as demand for both marine radio and broadcast call signs grew American-flagged vessels with radiotelephony only were given longer call signs with mixed letters and numbers. Leisure craft with VHF radios may not be assigned call signs, in which case the name of the vessel is used instead. Ships in the US still wishing to have a radio license are under FCC class SA: "Ship recreational or voluntarily equipped."
Those calls follow the land mobile format of the initial letter K or W followed by 1 or 2 letters followed by 3 or 4 numbers. U. S. Coast Guard small boats have a number, shown on both bows in which the first two digits indicate the nominal length of the boat in feet. For example, Coast Guard 47021 refers to the 21st in the series of 47-foot motor lifeboats; the call sign might be abbreviated to the final two or three numbers during operations, for example: Coast Guard zero two one. Aviation mobile stations equipped with radiotelegraphy were assigned five letter call signs.. Land Stations in Aviation were assigned four letter call signs; these call signs were phased out in the 1960s when flight radio officers were no longer required on international flights. USSR kept FRO's for the Moscow-Havana run until around 2000. All signs in aviation are derived from several different policies, depending upon the type of flight operation and whether or not the caller is in an aircraft or at a ground facility.
In most countries, unscheduled general aviation flights identify themselves using the call sign corresponding to the aircraft's registration number. In this case, the call sign is spoken using the International Civil Aviation Organization phonetic alphabet. Aircraft registration numbers internationally follow the pattern of a country prefix, followed by a unique identifier made up of letters and numbers. For example, an aircraft registered as N978CP conducting a general aviation flight would use the call sign November-niner-seven-eight-Charlie-Papa. However, in the United States a pilot of an aircraft would omit saying November, instead use the name of the aircraft manufacturer or the specific model. At times, general aviation pilots might omit additional preceding numbers and use only the last three numbers and letters; this is true at uncontrolled fields when reporting traffic pattern positions or at towered airports after establishing two-way communication with the tower controller. For example, Skyhawk eight-Charlie-Papa, left base.
In most countries, the aircraft call sign or "tail number"/"tail letters" are linked to the international radio call sign allocation table and follow a convention that aircraft radio stations receive call signs consisting of five letters. For example, all British civil aircraft have a five-letter call sign beginning with the letter G. Canadian aircraft have a call sign beginning with C–F or C–G, such as C–FABC. Wing In Ground-effect vehicles in Canada are eligible to receive C–Hxxx call signs, ultralight aircraft receive C-Ixxx call signs. In days gone by American aircraft used five letter call signs, such as KH–ABC, but they were replaced prior to World War II by the current American system of civilian aircraft call signs. Radio call signs used for communication in manned spaceflight is not formalized or regulated to the same degree as for aircraft; the three nations curren
Star Princess is a Grand-class cruise ship, operated by Princess Cruises. Star Princess is a sister ship to the Golden Princess. An earlier ship of the same name is now operating as Columbus in the Cruise & Maritime Voyages fleet. Star Princess was built by Fincantieri in Monfalcone, Italy in 2002, has hull number 6051. Star Princess differs in upper deck layout from her predecessors, having an extra plunge pool at the stern and with the deletion of the "Off Limits" teenagers' hot tub & sunbathing area featured further forward on her predecessors. At the end of 2017, Star Princess underwent a two-week dry-dock. Many of the onboard public spaces were updated. Another ship of similar design, Caribbean Princess, was subsequently built, featuring an additional deck of cabins to accommodate more passengers. On 23 March 2006, at about 3 am, a fire broke out in the passenger compartments, amidships, on the port side of the ship. Shortly after, the captain sounded the general emergency signal—seven short blasts followed by one long blast on the ship's whistle and the ship's horn and alarms, is the General Emergency Stations Signal.
It woke passengers up all over the ship. Passengers went to muster stations and evacuees were combined into groups stationed in muster stations, theatres and other public areas, for about seven hours. In accordance with planned procedures, some passengers who needed regular medication were aided by crew members retrieving their medication from their suites for them. Passengers evacuated their cabins into public areas through smokey hallways, grabbing their life jackets on the way; the evacuation was orderly, in contrast to deadlier fires such as those on Morro Castle and Yarmouth Castle. Lifeboats were lowered, but proved to be unnecessary, as the fire was contained and doused, the ship headed into Montego Bay under her own power; the fire was caused by a cigarette left burning on a balcony, which had become hot enough to melt the balcony divides made from plastic polycarbonate, a material, approved by international cruise line safety rules. The fire caused scorching damage in up to 150 cabins, smoke damage in at least 100 more on passenger decks 9 to 12.
A passenger, Richard Liffidge, 72, of Georgia, died from "asphyxia secondary to inhalation of smoke and irrespirable gases" and thirteen other passengers suffered significant smoke inhalation. While a smouldering discarded cigarette did cause the flames, the following items were at fault for allowing the fire to spread as as it did: The balconies' polycarbonate partitions, polyurethane deck tiles, the plastic furniture were combustible and produced large quantities of thick black smoke when burned; the glass in the doors between the staterooms and balconies was neither fire retardant, to meet with the requirements of an ‘A’ class division, nor self-closing. The balconies crossed main zone fire boundaries, both horizontally and vertically, were without structural or thermal barriers at the zone or deck boundaries. No fire detection or fire suppression systems were fitted on the balconies. Passengers subsequently were flown home; the ship was en route from Grand Cayman to Montego Bay, after departing Fort Lauderdale, Florida on 19 March 2006.
With 79 cabins destroyed and a further 204 damaged, the ship was moved to the Bahamas where she was prepared for a transatlantic crossing to Bremerhaven, Germany for repairs. Her remaining Caribbean cruises and a transatlantic cruise were cancelled, with the anticipation that she would begin her summer season in the Baltic mid-May; the ship was repaired at the Lloyd Werft in Bremerhaven, set sail again on 13 May 2006, resumed its regular service on 15 May from Copenhagen. Passengers reported that the only noticeable differences were a strong smell of new carpeting, the addition of sprinklers to all balconies and the replacement of plastic furniture with non-combustible alternatives. On 10 March 2012, en route in the Pacific off South America, three passengers from Star Princess spotted a small boat drifting with waving seamen in distress, they notified the crew. Star Princess, did not change course to investigate. On 19 March, the Ecuadorean coast guard rescued the Panamanian fishing boat Fifty Cent with one survivor on board.
Subsequent communication between the survivor, a reporter, the Star Princess passengers led to allegations that the small boat sighted nine days prior was in fact the Fifty Cent, that Star Princess had failed to stop and render aid. Princess Cruises first indicated that there had been a breakdown in communication and the captain had not been notified of the sighting. A report stated that a crew member did in fact convey the passengers' concerns to the bridge, that the ship's log for that time on 10 March contained an entry recording that the ship had deviated to the west to avoid the fishing nets, that the fishermen had "signaled their thanks" for avoiding their nets."By June, two lawsuits had been filed against Princess Cruises on behalf of the fishermen of the Fifty Cent. In August, Princess Cruises responded with the claim that Star Princess and Fifty Cent were never within sight of one another and thus the accusations were the result of mistaken identity; as supporting evidence, the cruise line made public the results of a drift analysis and a photographic investigation they had commissioned.
In April 2013, the Royal Gazette reported that the Bermuda Department of Maritime Administration had closed their official inquiry into the incident. The Bermuda Police Service carried out the investigation; the Dep
Grand-class cruise ship
The Grand class is a class of cruise ships. Ships in the class are operated by the cruise lines Princess P&O Cruises; the class consists of several series of sister ships, most of which were built by Fincantieri in Monfalcone and Trieste, northern Italy. The first vessel of the original Grand class, Grand Princess, entered service in 1998. Ships of the subclasses are based on the Grand class, but have modifications such as additional decks and varied placement of facilities such as the nightclub and restaurants; the structure used as a nightclub is a signature element of Princess Cruises' ships in the Grand class and derived classes. The nightclub either is located just aft of the funnel; the Gem class of ships is based on the Grand class, but modifies the placement of the nightclub to be just aft of the funnel and modifies the number of restaurants. The two Gem-class ships were built by Mitsubishi in Nagasaki, Japan in 2004; the Caribbean class has one additional deck. As in the original Grand-class design, the nightclub is suspended on the stern.
Caribbean-class vessels introduced a poolside theater, added to other Princess ships. The Crown class is the fourth Princess Cruises version of the Grand class. Crown-class ships have returned the placement of the nightclub adjacent to the funnel. Crown-class ships feature a poolside theater like the Caribbean class; the Ventura class has 19 decks like the Crown class. These ships both owned and operated by P&O Cruises and are marketed as Grand class, although they were given the Ventura class designation because they are not owned by Princess and are modified internally and externally. Ventura is the largest ship in the Grand class; the second Ventura-class ship is MS Azura, launched in March 2010. Azura is the only P&O Cruises ship to feature a poolside theater style outdoor screen; this class, for a short time boasting the largest cruise ships in the world, pioneered the design, carried through each modified class. A design difference on these ships is the relocation of the nightclub to directly aft of the funnel, rather than suspended over the stern.
The two Gem-class ships, Diamond Princess and Sapphire Princess, are the only two ships based on the Grand class to be built at Mitsubishi's Nagasaki Yard. The design for Caribbean Princess derives directly from the original Grand-class ships, with none of the Gem-class modifications being included. Caribbean Princess with an additional deck; this additional deck increases the ship's passenger capacity from 2,600 to 3,100. Caribbean Princess was the first ship to have a poolside theater; the three ships in the Crown class, Crown Princess, Emerald Princess, Ruby Princess, were built with this feature included. It has since been added to the all of the ships in the class; these ships, which build on Caribbean Princess' design differ slightly. These ships have one more passenger deck than the original Grand class as well as the poolside theater. A nightclub is aft of the funnel. Ships in the Ventura class are based on the Crown-class design; the ships in this class are operated by P&O Cruises. Azura has a modified stern
Carnival Cruise Line
Carnival Cruise Line is an international cruise line with headquarters in Doral, Florida. Its logo is the funnel like the funnels found on their ships, with red and blue colors; the funnels are shaped like a whale's tail. Carnival is the largest cruise line in the world, based on passengers carried annually, annual revenue, total number of ships in fleet. Carnival is one of ten cruise line brands owned by the world's largest cruise ship operator, the American-British Carnival Corporation & plc. In 2018 Carnival Cruise Line was estimated to hold an 8.9% share of cruise industry revenue and 22.0% of passengers. It is the largest fleet in the Carnival group; the ships fly flags of convenience. Its headquarters are in Miami, the United States; the North American division of Carnival Corporation has executive control over the corporation and is headquartered in Doral, Florida. Carnival Cruise Line was founded in 1972 by Ted Arison. To finance the venture, Arison turned to his friend Meshulam Riklis, who owned Boston-based American International Travel Service.
Arison and Riklis set up the new company as a subsidiary of AITS. AITS was to promote the new venture. In 1974, due to regulatory issues, Riklis sold AITS's interest in the company to Arison for $1, but subject to Arison taking over the substantial company debts; the split enabled Arison to enter into new relationships with independent travel agents. He promoted his cruises to fun-loving younger people; the format was successful financially. Until 1975, the line consisted of the Mardi Gras. In 1975 another ship was acquired, the Carnivale. In 1996, Carnival Destiny of 101,000 GT became the largest passenger ship in the world at the time and first to exceed 100,000 tons. In 2001, Robert H. Dickinson President and CTC, participated in a BBC documentary, Back To The Floor. Dickinson went to work at the lowest crew levels on the MS Imagination in the Caribbean, where he shadowed a Romanian cleaner, Alina. In 2004, Carnival Corporation ordered for a development program for Carnival's new ships, the Pinnacle Project, calling for a 200,000 GT prototype, which would have been the world's largest cruise ship at the time.
The ship was cancelled and after that they came up with a project called Next Generation. In 2009, Carnival released their biggest ship at the time, the Carnival Dream, a new 128,000 GT ship. Carnival Dream entered service on 21 September 2009. After several voyages in the Mediterranean, she was set to offer weekly Caribbean cruises from Port Canaveral from 5 December 2009. A sister ship, Carnival Magic, debuted on 1 May 2011. On 1 December 2009 it was announced, it entered service in June 2012 and its homeport is now Galveston. On May 10, 2010, Carnival selected a name for their new Dream-class vessel in 2012 - Carnival Breeze. On 26 October 2012, it was announced that Carnival had ordered a brand new 133,500 GT ship for their Carnival Cruise Line brand; this ship, built by Fincantieri, was the largest ship they have built. It sailed its maiden voyage on May 1, 2016; the new ship was named Carnival Vista. In January 2017, Michael Thamm was appointed CEO of Carnival Asia to oversee operations in China and the surrounding region.
A sister to Carnival Vista, Carnival Horizon, joined the fleet with their inaugural voyages from Trieste and Barcelona, Spain on May 1, 2016 and April 2, 2018, respectively. Queen Latifah is the Godmother of Horizon for its christening in New York on May 23, 2018. Carnival Panorama is set to join the fleet in December 2019. In February 2018, the company's officials unveiled a major port development project in Ensenada, Mexico. In 2016, Carnival extended their contract with Port Everglades cruise port to 2030; the port began a $54 million renovation in anticipation of the deal. The agreement brings over $200 million in personal income. In 2018, Carnival brought the Carnival Fantasy to Alabama. Economists anticipate an increase in tourism to revenue at an estimated $35 million; the company has been paying wages under $1.50 per hour to employees with low-to-nonexistent benefits, such as holidays or minimal vacations. Monthly salaries of the high-paid workers are around $1,300. Employees report strenuous working conditions such as 14-hour shifts with no days off.
Retirement benefits were revoked in October 2013. In the aftermath of Hurricane Katrina, three of the Carnival cruise ships were chartered by the United States government for six months to serve as temporary housing until the houses can be rebuilt. After being chartered for six months, their planned voyages were cancelled, passengers were refunded. Holiday was docked in Mobile and Pascagoula, Ecstasy and Sensation were docked at New Orleans, Louisiana; the six-month contract cost $236 million. The contract was criticized, because the vessels were never utilized, Carnival received more money than it would have earned by using the ships in their normal rotation. Since 2017, Carnival Cruise Line has been on probation, after having been found to "illegally dumping oil into the ocean from its Princess Cruises ships and lying about the scheme." Carnival Cruise Line had to pay a $40 million fine. By 2019, the US prosecutors found that "ships have dumped gray water into Alaska’s Glacier Bay National Park, prepared ships in advance of court-ordered audits to avoid unfavorable findings, falsified records and dumped plastic garbage into the ocean."
Carnival Cruise has acknowledged these incidents. As a result, a US federal Judge "threatens to stop Carnival ships from docking in US." See al
Italian destroyer Caio Duilio
Caio Duilio is a destroyer of the Italian Navy. She and her sister Italian destroyer Andrea Doria form the Andrea Doria class. Caio Duilio is marked by hull number D 554 according to NATO classification; the ship takes her name from admiral Gaius Duilius. Duilius ordered the construction of 120 ships that were armed with hooked bridges called corvus, Latin for “crow”; this innovation allowed the Romans to defeat the powerful enemy fleet of Carthage transforming the naval battle into a melee combat. After the victory over the Carthaginians at the Battle of Mylae in 260 BC, Duilius was honored with a triumphal parade and the erection in the Roman Forum of a column adorned with the beaks of captured Carthaginian warships; the destroyer Caio Duilio is the fourth Italian warship with this historical name. The first, the ironclad Caio Duilio, was commissioned in 1886 and served until 1909. Fitted with the largest guns available, 100-ton 450 mm calibre muzzle-loading guns, she was regarded as the most powerful warship afloat in her day.
The second unit, the Andrea Doria-class battleship Caio Duilio, was commissioned on 24 April 1913 and was subsequently refitted in 1937, serving in the Regia Marina during World War I and World War II. Caio Duilio was launched on October 23, 2007 and transported to Muggiano shipyard on October 29 for the mounting of the combat system. Caio Duilio's motto refers to the ancient Roman tradition, in which the name acquires religious connotations; some ancient fragments point up this intimate meaning. "Nomen Numen" can be translated as "the name means power". On February 12, 2008 she made the first sea trial and, after the admission into military fleet which took place on April 3, 2009, in Gulf of La Spezia she took part, together with Andrea Doria and French ships Forbin and Chevalier Paul, in a joint exercise which brought together the whole Horizon class on May 5, 2009. Caio Duilio was, along with the aircraft carrier Cavour and the training ship Amerigo Vespucci, one of the Navy Units visitable in Civitavecchia harbour on the Day of the Unification of Italy and the Armed Forces on November 4, 2009.
She participated in the naval parades for the celebrations of the Italian Navy Day in Naples on June 10, 2010 and in La Spezia on June 10, 2011, in the presence of President Giorgio Napolitano. During the development of many complex systems on board, during the trials that led her many times in the Naval Station of Taranto, she made her debut in the international arena during NATO exercise Proud Manta 2011 from February 4 to February 17, 2011, in the waters of the Ionian Sea before the delivery of the Battle Ensign, working together with ships and aircraft of nine allied nations. Nowadays Caio Duilio is the only destroyer based in La Spezia harbour, flagship of the Commander of First Naval Group and under the command of Captain Gaetano Virgilio. Caio Duilio is a multirole ship, with a bias towards anti-aircraft warfare and short and medium-range defence capabilities, she is highly capable in anti-submarine and anti-surface warfare. The ship has been designed to take and operate with Rotary wing aircraft of much higher performance and more autonomy than previous generation helicopters.
The handling of wheeled helicopters on the flight deck is guaranteed up to sea state 6 by the semi-automatic Canadian system TC-ASIST of Indal Technologies committing to these operations a single operator. By type of ship and technology aboard Caio Duilio is able to cover a broad spectrum of maritime activities, ranging from high-intensity military operations to Maritime Security operations; the missions that the unit can perform are: Escort role in an aircraft carrier battle group or naval convoy. The ship was designed to be as little detectable by radar as possible, by using stealth technology for the hull and superstructure. Sea-keeping in unfavorable weather conditions is granted by two pairs of stabilizers; the acoustic signature was reduced with an appropriate choice of machinery and engineering solutions and verifying the intensity of the radiated noise, since the design phase. Equal attention has been directed in the infrared signature branch, by lowering the temperature of engine gases through coaxial exhausts.
After the abandonment of the old system of command and control SADOC, used in the latest modernized version in the Durand de la Penne and Maestrale classes, an integrated type CMS based on Linux OS was installed by EuroSysNav. This is provided with 10 redundant servers and 24 consoles named MFC, of which 19 are located in the Primary CIC, 3 in the secondary CIC in a remote area from the primary CIC, 1 in the Admiral CIC and 1 in the bridge for the officer of the watch. With a MFC each operator, once logged in with own user name and password, can access to all relevant tactical data to his role and has the possibility to us
A diesel–electric transmission, or diesel–electric powertrain, is used by a number of vehicle and ship types for providing locomotion. A diesel–electric transmission system includes a diesel engine connected to an electrical generator, creating electricity that powers electric traction motors. No clutch is required. Before diesel engines came into widespread use, a similar system, using a petrol engine and called petrol–electric or gas–electric, was sometimes used. Diesel–electric transmission is used on railways by diesel electric locomotives and diesel electric multiple units, as electric motors are able to supply full torque at 0 RPM. Diesel–electric systems are used in submarines and surface ships and some land vehicles. In some high-efficiency applications, electrical energy may be stored in rechargeable batteries, in which case these vehicles can be considered as a class of hybrid electric vehicle; the first diesel motorship was the first diesel–electric ship, the Russian tanker Vandal from Branobel, launched in 1903.
Steam turbine–electric propulsion has been in use since the 1920s, using diesel–electric powerplants in surface ships has increased lately. The Finnish coastal defence ships Ilmarinen and Väinämöinen laid down in 1928–1929, were among the first surface ships to use diesel–electric transmission; the technology was used in diesel powered icebreakers. In World War II the United States built diesel–electric surface warships. Due to machinery shortages destroyer escorts of the Evarts and Cannon classes were diesel–electric, with half their designed horsepower; the Wind-class icebreakers, on the other hand, were designed for diesel–electric propulsion because of its flexibility and resistance to damage. Some modern diesel–electric ships, including cruise ships and icebreakers, use electric motors in pods called azimuth thrusters underneath to allow for 360° rotation, making the ships far more maneuverable. An example of this is Symphony of the Seas, the largest passenger ship as of 2019. Gas turbines are used for electrical power generation and some ships use a combination: Queen Mary 2 has a set of diesel engines in the bottom of the ship plus two gas turbines mounted near the main funnel.
This provides a simple way to use the high-speed, low-torque output of a turbine to drive a low-speed propeller, without the need for excessive reduction gearing. Early submarines used a direct mechanical connection between the engine and propeller, switching between diesel engines for surface running and electric motors for submerged propulsion; this was a "parallel" type of hybrid, since the motor and engine were coupled to the same shaft. On the surface, the motor was used as a generator to recharge the batteries and supply other electric loads; the engine would be disconnected for submerged operation, with batteries powering the electric motor and supplying all other power as well. True diesel–electric transmissions for submarines were first proposed by the United States Navy's Bureau of Engineering in 1928—instead of driving the propeller directly while running on the surface, the submarine's diesel would instead drive a generator that could either charge the submarine's batteries or drive the electric motor.
This meant that motor speed was independent of the diesel engine's speed, the diesel could run at an optimum and non-critical speed, while one or more of the diesel engines could be shut down for maintenance while the submarine continued to run using battery power. The concept was pioneered in 1929 in the S-class submarines S-3, S-6, S-7 to test the concept; the first production submarines with this system were the Porpoise-class, it was used on most subsequent US diesel submarines through the 1960s. The only other navy to adopt the system before 1945 was the British Royal Navy in the U-class submarines, although some submarines of the Imperial Japanese Navy used separate diesel generators for low-speed running. In a diesel–electric transmission arrangement, as used on 1930s and US Navy, German and other nations' diesel submarines, the propellers are driven directly or through reduction gears by an electric motor, while two or more diesel generators provide electric energy for charging the batteries and driving the electric motors.
This mechanically isolates the noisy engine compartment from the outer pressure hull and reduces the acoustic signature of the submarine when surfaced. Some nuclear submarines use a similar turbo-electric propulsion system, with propulsion turbo generators driven by reactor plant steam. During World War I, there was a strategic need for rail engines without plumes of smoke above them. Diesel technology was not yet sufficiently developed but a few precursor attempts were made for petrol–electric transmissions by the French and British. About 300 of these locomotives, only 96 being standard gauge, were in use at various points in the conflict. Before the war, the GE 57-ton gas-electric boxcab had been produced in the USA. In the 1920s, diesel–electric technology first saw limited use in switchers, locomotives used for moving trains around in railroad yards and assembling and disassembling them. An early company offering "Oil-Electric" locomotives was the American Locomotive Company; the ALCO HH series of diesel–electric switcher entered series production in 1931.
In the 1930s, the system was adapted for the fastest trains of their day. Diesel–electric powerplants became popular