A turret deck ship is a type of merchant ship with an unusual hull, designed and built in the late 19th and early 20th centuries. The hulls of turret deck vessels were rounded and stepped inward above their waterlines. This gave some advantages in strength and allowed them to pay lower canal tolls under tonnage measurement rules then in effect. The type ceased to be built after those rules changed. The last turret deck ship in existence was scrapped in 1960.
Turret deck ships were inspired by the visit of the US whaleback vessel Charles W. Wetmore to Liverpool in 1891. [1] Like others of the type, Wetmore had a hull in the form of a flattened cigar, with a continuous curve above the waterline to where the sides met amidships. [2] The superstructure atop the hull was in round or oval "turrets", so named because of their resemblance to gunhouses on contemporary warships. [3]
In 1893 William Doxford and Sons Ltd. ("Doxford") of Sunderland, England, built one whaleback under license from the type's designer, [4] but had already built its first turret deck ship to a design by Arthur Havers, the concern's chief draughtsman. Havers toned down the more radical features of the whaleback. His design retained conventional bows and sterns instead of the upswept conoid "snout" of the whaleback. Instead of a rounded hull, the hull of a turret ship was stepped inward above the waterline, but the horizontal and vertical surfaces of the hull met in curves rather than by right angles as in conventional ships. Finally, the design joined the rounded turrets of whalebacks into one long and narrow rectangular structure (also called a "turret") of about half the beam, and used that space as part of the hold. [5]
The design was patented. Doxford's first ship, Turret, was notable for her abnormally long and wide hatches in the turret, and self-trimming due to the rounded shape in the upper hold and lower turret. She was thus ideal for grain. [6] Turret was designed for tonnage of 4,700 DWT at a load line draft of 20 feet 3 inches (6.2 m) at 2,850 GRT. [7] With engines aft the design was seen as ideal for the bulk oil trade meeting the latest Suez Canal regulations in which coal bunkers would be separated from oil cargo by a double bulkhead filled with water. [7] The ship had an unusually high righting angle which was obtained whether full or lightly loaded. [7] In particular the design was seen as a solution to the problem of strength and economical cost. [8] On well deck ships the lack of a continuous line of the deck, one the turret ship design solved with a continuous line and solid structure up to the top of the turret, resulted in weakness with classification societies taking notice by requiring increased strengthening in construction. [7] [8] The long, wide hatches were seen as making the design especially suitable for carrying heavy or bulky machinery. [6] That feature later resulted in cargoes such as 75 feet (22.9 m) long, 8 feet (2.4 m) wide girders and a 110-ton gun being easily loaded. [9]
By March 1895 the design had considerable acceptance. Nine ships were in use: Turret, Turret Age, Turret Bay, Bencliff, Turret Bell, Progressist, Royalist, Hopedale and Forest Abbey; and five more were being built. [8]
In side profile, turret deck ships resembled other merchant ships with flush decks or with small forecastles and poop decks. [10] In cross-section the differences between turret deck ships and more conventional ships are apparent. There was no gunwale; the vertical side of a turret ship curves inward above the load line to a horizontal plane. This flat area was known as the harbour deck. [11] Further inboard, this "deck" arced to the vertical again by a reverse curve. That vertical plane then joined the weather deck atop the turret at a right angle. [12] Structurally these elements were part of the hull, not of the superstructure, and the cargo holds of the ship extended up to the true weather deck atop the turret. [13]
This design, and that of its near relative the trunk deck ship, [14] were said to maximize strength, allowing larger ships and reduced the amount of steel needed for construction. [15] In reality, it is more likely that the geometry inhibited the development of cracks in the sheer strake but ships to this design were not any lighter than conventional ships due to their unique geometry. In operation their hull form promoted self-trimming of homogenous cargo and inhibited shifting. [5]
The design also called for a cellular double bottom, which was the probable reason for claims of the type's exceptional hull strength, but it also raised the centre of gravity of the cargo. A higher centre of gravity increased the roll period and reduced the violence of rolls. [16] But loading heavy cargo too high, and failing to properly ballast the bottom tanks, raised the centre of gravity and led to instability. This led to accidents, a Board of Trade investigation, and cautions from Doxford on proper loading. [17] The design was also inconvenient, as the narrowness of the turret made for smaller cargo hatches and restricted habitation spaces in the superstructure atop the turret. [13]
Turret deck ships had a low net tonnage (an approximate measure of cargo space) in comparison to their deadweight capacity (weight of cargo), allowing them to operate at a lower fee structure than a conventional hull. Net tonnage is a computation of volume, and the method of measurement used at the Suez Canal to determine tolls was based on a measure of net tonnage which excluded some of the cargo spaces of these unconventional hulls. [18] Turret and trunk deck ships therefore paid less in tolls than conventional ships of the same capacity. [19]
In 1911, the toll measure changed at Suez to account for all cargo spaces, and contemporaneous refinements in the design of ships of more conventional hull form eliminated the structural advantages of turret deck ships. [20] Construction of the type therefore ceased. [19]
Over 180 ships of the type had been built before the design was abandoned, [19] 176 of them by William Doxford and Sons. [4] They were used in both line voyage and tramp service [19] until retired, wrecked, or lost in the First or Second World War. [17] The British Clan Line, which traded globally in cargos such as foodstuffs, timber, metals, manufactured goods, case oil, jute, tea, nitrates, and general cargo, used 32 of the type. [21]
While used for general freight, these ships were particularly suited to the carriage of bulk cargos such as grains, coal, and ores. [15] Several were sold to Canadian interests for use in the latter trades on the Saint Lawrence River and Great Lakes of North America. The last of them, Turret Cape, operated until mid-century [22] and was not scrapped until 1959. [13] Only the former Nonsuch was in operation a little longer. The ship was kept in business as Hermann Fritzen until 1959 by owner Johs. Fritzen & Sohn of Emden. Finally sold for demolition in April 1959, Hermann Fritzen arrived for breaking at Eckhardt & Co. in Hamburg in the first quarter of 1960. [23]
Tonnage is a measure of the cargo-carrying capacity of a ship, and is commonly used to assess fees on commercial shipping. The term derives from the taxation paid on tuns or casks of wine. In modern maritime usage, "tonnage" specifically refers to a calculation of the volume or cargo volume of a ship. Although tonnage (volume) should not be confused with displacement, the long ton of 2,240 lb is derived from the fact that a "tun" of wine typically weighed that much.
A merchant ship, merchant vessel, trading vessel, or merchantman is a watercraft that transports cargo or carries passengers for hire. This is in contrast to pleasure craft, which are used for personal recreation, and naval ships, which are used for military purposes.
SSMeteor is the sole surviving ship of the unconventional "whaleback" design. The design, created by Scottish captain Alexander McDougall, enabled her to carry a maximum amount of cargo with a minimum of draft. Meteor was built in 1896 in Superior, Wisconsin, United States, and, with a number of modifications, sailed until 1969. She is now a museum ship in the city of her construction.
A whaleback was a type of cargo steamship of unusual design, with a hull that continuously curved above the waterline from vertical to horizontal. When fully loaded, only the rounded portion of the hull could be seen above the waterline. With sides curved in towards the ends, it had a spoon bow and a very convex upper deck. It was formerly used on the Great Lakes of Canada and the United States, notably for carrying grain or ore. The sole surviving ship of the "whaleback" design is the SS Meteor, which is docked in Superior, Wisconsin, as a museum ship.
The Thomas Wilson was a whaleback freighter built in 1892 and used to haul bulk freight on the Great Lakes. The ship sank in Lake Superior just outside the harbor of Duluth, Minnesota, United States, on 7 June 1902, after a collision with the George Hadley. The wreck of the Thomas Wilson is one of the best remaining examples of a whaleback steamer, and it is also significant for the changes made in operating procedures at the Duluth harbor. The remains of the ship were listed on the National Register of Historic Places in 1992.
The SS Christopher Columbus was an American excursion liner on the Great Lakes, in service between 1893 and 1933. She was the only whaleback ship ever built for passenger service. The ship was designed by Alexander McDougall, the developer and promoter of the whaleback design.
The SS City of Everett was an important whaleback steamship. She sailed from 1894 until 1923, and was the first U.S. steamship to pass through the Suez Canal, as well as the first to circumnavigate the globe. Her radio call letters were GF and her signal letters KMCQ.
A trunk deck ship is a type of merchant ship with a hull that was stepped inward in order to obtain more favourable treatment under canal toll rules then in effect. As those tolls were set by net tonnage, a measure of volume, and as the tonnage rules did not account for all of the cargo space of such vessels, trunk deck ships incurred lower tolls than more conventional ships of equivalent capacity. When the measurement rules were changed, the type was no longer built.
The SS Charles W. Wetmore was a whaleback freighter built in 1891 by Alexander McDougall's American Steel Barge Company shipyard in Superior, Wisconsin, USA. She was named in honor of Charles W. Wetmore, a business associate of Alexander McDougall, officer of the shipyard, and associate of the Rockefeller family.
An oil tanker, also known as a petroleum tanker, is a ship designed for the bulk transport of oil or its products. There are two basic types of oil tankers: crude tankers and product tankers. Crude tankers move large quantities of unrefined crude oil from its point of extraction to refineries. Product tankers, generally much smaller, are designed to move refined products from refineries to points near consuming markets.
SS Sagamore was a steam cargo ship that was launched in 1893 and sunk in 1917. She was the only whaleback ship built in the United Kingdom, and one of only three whalebacks to operate outside the Great Lakes.
SS Clan Ranald is a steamship wreck off the coast of South Australia that is of unique historic importance. She is the only example in Australian waters of a turret deck ship: a type of steel-hulled cargo ship with an unusual hull shape that was built in the 1890s and 1900s.
SS Clifton, originally Samuel Mather, was a whaleback lake freighter built in 1892 for service on the Great Lakes. She was 308 foot (94 m) long, 30 foot (9.1 m) beam, and 24 foot (7.3 m) depth, and had a 3,500 ton capacity. The self-propelled barge was built by the American Steel Barge Company in West Superior, Wisconsin. Her builders used a design well-suited to carry iron ore, her intended trade. The new vessel was christened Samuel Mather, after a cofounder of Pickands Mather and Company, which at the time was the second largest fleet on the Great Lakes.
Messrs Robert Napier and Sons was a famous firm of Clyde shipbuilders and marine engineers at Govan, Glasgow founded by Robert Napier in 1826. It was moved to Govan for more space in 1841. His sons James and John were taken into partnership in 1853.
The Henry Cort was a 320-foot (98 m) long whaleback freighter. It sank four times during its career; finally running aground at Muskegon, Michigan in November, 1934. The ship broke apart over the winter and was scrapped in 1935.
Clan Alpine was a steam ship built in 1899 by the William Doxford & Sons of Pallion. She was the second ship named Clan Alpine in service with the Clan Line used on their Oriental routes.
115 was an American whaleback barge in service between 1891 and 1899. She was built between May and August 1891, in Superior, Wisconsin by Alexander McDougall's American Steel Barge Company, for the "McDougall fleet", based in Buffalo, New York. She was one of a class of distinctive, experimental ship designed and built by McDougall. The whalebacks were designed to be more stable in high seas. They had rounded decks, and lacked the normal straight sides seen on traditional lake freighters. 115 entered service on August 25, hauling iron ore from Superior.
129 was an American whaleback barge in service between 1893 and 1902. She was built between December 1892 and May 1893, in Superior, Wisconsin,, by Alexander McDougall's American Steel Barge Company, for McDougall's fleet of the same name, based in Buffalo, New York. She was one of a class of distinctive and experimental ships designed and built by McDougall. The whalebacks were designed to be more stable in high seas. They had rounded decks, and lacked the normal straight sides seen on traditional lake freighters. 129 entered service on May 22, hauling wheat from Superior. She was sold to the Bessemer Steamship Company of Cleveland, Ohio, in 1900. In 1901, she became owned by the Pittsburgh Steamship Company of Duluth, Minnesota, when the Bessemer fleet merged into it.
104 was an American whaleback barge in service between 1890 and 1898. The fourth whaleback constructed, she was built between October 1889 and February 1890, in Duluth, Minnesota by Alexander McDougall's American Steel Barge Company, for McDougall's fleet of the same name, based in Buffalo, New York. She was a whaleback, a class of distinctive, experimental ship designed and built by McDougall. The whalebacks were designed to be more stable in high seas. They had rounded decks, and lacked the normal straight sides seen on traditional lake freighters. 104 entered service on April 21, hauling iron ore from Two Harbors, Minnesota.
This glossary of nautical terms is an alphabetical listing of terms and expressions connected with ships, shipping, seamanship and navigation on water. Some remain current, while many date from the 17th to 19th centuries. The word nautical derives from the Latin nauticus, from Greek nautikos, from nautēs: "sailor", from naus: "ship".
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