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A sea trial or trial trip is the testing phase of a watercraft (including boats, ships, and submarines). It is also referred to as a "shakedown cruise" by many naval personnel. It is usually the last phase of construction and takes place on open water, and it can last from a few hours to many days.
Sea trials are conducted to measure a vessel's performance and general seaworthiness. Testing of a vessel's speed, maneuverability, equipment and safety features are usually conducted. Usually in attendance are technical representatives from the builder (and from builders of major systems), governing and certification officials, and representatives of the owners. Successful sea trials subsequently lead to a vessel's certification for commissioning and acceptance by its owner.
Although sea trials are commonly thought to be conducted only on new-built vessels (referred by shipbuilders as 'builders trials'), they are regularly conducted on commissioned vessels as well. In new vessels, they are used to determine conformance to construction specifications. On commissioned vessels, they are generally used to confirm the impact of any modifications.
Sea trials can also refer to a short test trip undertaken by a prospective buyer of a new or used vessel as one determining factor in whether to purchase the vessel.
Sea trials are fairly standardized using technical bulletins published by ITTC, SNAME, BMT, regulatory agencies or the owners. They involve demonstrations and tests of the ship's systems and performance.
In a speed trial the vessel is ballasted or loaded to a predetermined draft and the propulsion machinery is set to the contracted maximum service setting, usually some percentage of the machinery's maximum continuous rating (ex: 90% MCR). The ship's heading is adjusted to have the wind and tide as close to bow-on as possible. The vessel is allowed to come to speed and the speed is continuously recorded using differential GPS. The trial will be executed with different speeds including service (design) and maximum speed. The ship is then turned through 180° and the procedure is followed again. This reduces the impact of wind and tide. The final "Trials Speed" is determined by averaging all of the measured speeds during each of the runs. This process may be repeated in various sea states.
To test a crash stop, the vessel is ballasted or loaded to a predetermined draft and the propulsion machinery is set to the contracted maximum service setting, usually some percentage of the machinery's maximum continuous rating. The trial begins once the order to "Execute Crash Stop" is given. At this point the propulsion machinery is set to full-astern and the helm is put hard-over to either port or starboard. The speed, position and heading are continuously recorded using differential GPS. The final time to stop (i.e.: ship speed is 0 knots) track line, drift (distance traveled perpendicular to the original course) and advance (distance traveled along the original course line) are all calculated. The trial may be repeated at various starting speeds.
During endurance trials the vessel is ballasted or loaded to a predetermined draft and the propulsion machinery is set to the contracted maximum service setting, usually some percentage of the machinery's maximum continuous rating. The fuel flow, exhaust and cooling water temperatures and ship's speed are all recorded.
Maneuvering trials involve a number of trials to determine the maneuverability and directional stability of the ship may be conducted. These include a direct and reverse spiral manoeuvres, zig-zag, and lateral thruster use. [1]
Seakeeping trials were originally used exclusively for passenger ships, but are now used in a variety of vessels. They involve measurements of ship motions in various sea states, followed by a series of analyses to determine comfort levels, likelihood of sea sickness and hull damage. Trials are usually protracted in nature due to the unpredictability of finding the correct sea state, and the need to conduct the trials at various headings and speeds. [2]
Queen Elizabeth 2 (QE2) is a retired British passenger ship converted into a floating hotel. Originally built for the Cunard Line, the ship was operated by Cunard as both a transatlantic liner and a cruise ship from 1969 to 2008. She was then laid up until converted and since 18 April 2018 has been operating as a floating hotel in Dubai.
The Cunard Line is a British shipping and cruise line based at Carnival House at Southampton, England, operated by Carnival UK and owned by Carnival Corporation & plc. Since 2011, Cunard and its four ships have been registered in Hamilton, Bermuda.
RMS Queen Elizabeth was an ocean liner operated by Cunard Line. Along with the Queen Mary, she provided a weekly transatlantic service between Southampton in the United Kingdom and New York City in the United States, via Cherbourg in France.
RMS Queen Mary is a retired British ocean liner that operated primarily on the North Atlantic Ocean from 1936 to 1967 for the Cunard Line. Built by John Brown & Company in Clydebank, Scotland, she was subsequently joined by RMS Queen Elizabeth in Cunard's two-ship weekly express service between Southampton, Cherbourg and New York. These "Queens" were the British response to the express superliners built by German, Italian, and French companies in the late 1920s and early 1930s.
The Blue Riband is an unofficial accolade given to the passenger liner crossing the Atlantic Ocean in regular service with the record highest average speed. The term was borrowed from horse racing and was not widely used until after 1910. The record is based on average speed rather than passage time because ships follow different routes. Also, eastbound and westbound speed records are reckoned separately, as the more difficult westbound record voyage, against the Gulf Stream and the prevailing weather systems, typically results in lower average speeds.
An ocean liner is a type of passenger ship primarily used for transportation across seas or oceans. Ocean liners may also carry cargo or mail, and may sometimes be used for other purposes. The Queen Mary 2 is the only ocean liner still in service to this day.
RMS Aquitania was an ocean liner of the Cunard Line in service from 1914 to 1950. She was designed by Leonard Peskett and built by John Brown & Company in Clydebank, Scotland. She was launched on 21 April 1913 and sailed on her maiden voyage from Liverpool to New York on 30 May 1914. She was given the title of Royal Mail Ship (RMS) like many other Cunard ocean liners since she carried the royal mail on many of her voyages. Aquitania was the third in Cunard Line's grand trio of express liners, preceded by RMS Mauretania and RMS Lusitania, and was the last surviving four-funnelled ocean liner. Shortly after Aquitania entered service, the First World War broke out, during which she was first converted into an auxiliary cruiser before being used as a troop transport and a hospital ship, notably as part of the Dardanelles Campaign.
SS Normandie was a French ocean liner built in Saint-Nazaire, France, for the French Line Compagnie Générale Transatlantique (CGT). She entered service in 1935 as the largest and fastest passenger ship afloat, crossing the Atlantic in a record 4.14 days, and remains the most powerful steam turbo-electric-propelled passenger ship ever built.
RMS Mauretania was a British ocean liner that was launched on 28 July 1938 at the Cammell Laird yard in Birkenhead, England, and was completed in May 1939. She was one of the first ships built for the newly formed Cunard-White Star company following the merger in April 1934 of the Cunard and White Star Line. On the withdrawal of the first Mauretania in 1935, to prevent a rival company using the name and to keep it available for the new liner, arrangements were made for the Red Funnel paddle steamer Queen to be renamed Mauretania in the interim.
RMS Majestic was a British ocean liner working on the White Star Line’s North Atlantic run, originally launched in 1914 as the Hamburg America Liner SS Bismarck. At 56,551 gross register tons, she was the largest ship ever operated by the White Star Line under its own flag and the largest ship in the world until completion of SS Normandie in 1935.
MS Queen Victoria (QV) is a Vista-class cruise ship operated by the Cunard Line and is named after the former British monarch Queen Victoria. The vessel is of the same basic design as other Vista-class cruise ships, including Queen Elizabeth. At 90,049 gross tonnage (GT) she is the smallest of Cunard's ships in operation. Her facilities include seven restaurants, thirteen bars, three swimming pools, a ballroom, and a theatre.
Parsons Marine Steam Turbine Company was a British engineering company based on the River Tyne at Wallsend, North East England.
MV Ventura is a Grand-class cruise ship of the P&O Cruises fleet. The 116,017 GT ship was built by Fincantieri at their shipyard in Monfalcone, Italy and is 288.6 m (947 ft) long. She officially entered service with the company in April 2008 and was named by Dame Helen Mirren. Ventura underwent a refit at the Blohm & Voss shipyard in Hamburg, Germany, during March and April 2013, and re-entered service on 7 April 2013 with a voyage to Spain and Portugal. In February 2023 she underwent a minor refit again at the Hamburg shipyard, re-entering service four weeks later.
MS Queen Elizabeth (QE) is a cruise ship of the Vista class operated by the Cunard Line. The design is modified compared to earlier ships of the same class, and slightly larger than Queen Victoria, at 92,000 GT. This is due to a more vertical stern, and additional cabins for single travelers. The bow of Queen Elizabeth and Queen Victoria are both reinforced having thicker than the standard for hull plating, to handle North Atlantic weather. The ship is able to carry up to 2,092 passengers.
RMS Ivernia was a British ocean liner owned by the Cunard Line, built by the company C. S. Swan & Hunter of Newcastle upon Tyne, England, and launched in 1899. The Ivernia was one of Cunard's intermediate ships, that catered to the vast immigrant trade. Like her sisters, she saw military service during World War I, and was sunk in 1917 after being struck by a torpedo.
RMS Ivernia was a Saxonia-class ocean liner, built in 1955 by John Brown & Company at Clydebank, Scotland for Cunard Line, for their transatlantic passenger service between the UK and Canada. In 1963 she was rebuilt as a cruise ship and renamed RMS Franconia, after the famous pre-war liner Franconia (1922). She continued to sail for Cunard until being withdrawn from service and laid up in 1971. In 1973 she was sold to the Soviet Union's Far Eastern Shipping Company and, renamed SS Fedor Shalyapin, cruised around Australia and the far East. In 1980 she was transferred to the Black Sea Shipping Company fleet, and for a time returned to cruising in the Mediterranean and around Europe. In 1989 she was transferred again, to the Odessa Cruise Company, and continued her career as a cruise ship until 1994. She was then laid up at Illichivsk, a Black Sea port 40 km (25 mi) southwest of Odesa, until 2004 when, as the Salona, she sailed to Alang, India, where she was scrapped.
RMS Carinthia was an ocean liner built in 1956 as one of the four Saxonia-class ships. She sailed for Cunard Line from her completion until 1968 when she was sold to Sitmar Line, rebuilt into a full-time cruise ship and renamed SS Fairsea. She sailed with Sitmar until 1988, when Sitmar was sold to P&O. She was renamed SS Fair Princess and sailed for Princess Cruises and P&O Cruises until 2000. She was then sold to China Sea Cruises and renamed SS China Sea Discovery. In 2005 or 2006 she was scrapped at Alang, India.
SS Archimedes was a steamship built in Britain in 1839. She was the world's first steamship to be driven successfully by a screw propeller.
RMS Queen Mary 2 (QM2) is a British ocean liner. She has served as the flagship of the Cunard Line since January 2004, and as of 2024, is the only active, purpose-built ocean liner still in service. Queen Mary 2 sails regular transatlantic crossings between Southampton and New York City, in addition to short cruises and an annual world voyage.
Captain John Treasure Jones was a British naval officer who became a well-known media figure in the mid-1960s following his appointment as the last master of the Cunard liner, RMS Queen Mary. He has been described as one of the 20th century's most distinguished mariners, in war and in peacetime. His forebears were men of the sea, who had captained sailing ships, and he elected to follow in their tradition.