Editing Turret deck ship

{{Short description|Type of merchant ship hull shape}}
[[File:Turret Chief, 1903.jpg|thumb|300px|''Turret Chief'' running light; stepped hull form and raised midline "turret" are shown.]]
A '''turret deck ship''' is a type of [[merchant ship]] with an unusual [[Hull (watercraft)|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 [[waterline]]s. 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.

==Development==
Turret deck ships were inspired by the visit of the US [[whaleback]] vessel {{SS|Charles W. Wetmore||2}} to [[Liverpool]] in 1891.<ref>{{harvnb|Craig|1980|p=35}}; {{harvnb|Woodman|2002|p=179}}. Woodman identifies this vessel as the ''Charles H. Wetmore''; named elsewhere as ''Charles W. Wetmore''. {{harvnb|Oakley|2005}}</ref> 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.<ref name=Oakley>{{harvnb|Oakley|2005}}</ref> The superstructure atop the hull was in round or oval "turrets", so named because of their resemblance to [[gun turret|gunhouses]] on contemporary warships.<ref>{{harvnb|Duerkop|2007}}, [https://web.archive.org/web/20110706184658/http://www.marmuseum.ca/duerkop.html definition 65, Whaleback]</ref>

[[File:Walton 1901 Steel Ships - midship section of turret steamer.jpg|thumb|upright|Cross-section of a turret ship amidships]]
In 1893 [[William Doxford & Sons|William Doxford and Sons Ltd.]] ("Doxford") of [[Sunderland, Tyne and Wear|Sunderland]], England, built one whaleback under license from the type's designer,<ref name=Doxford>[https://web.archive.org/web/20070202060156/http://www.doxford-engine.com/engines.htm Doxford Engines] (archived 2/2/2007)</ref> 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 [[Bow (ship)|bow]]s and [[stern]]s 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 (ship)|hold]].<ref name="Woodman, p. 179">{{harvnb|Woodman|2002|p=179}}</ref>

[[File:This is a view of the turret ship ‘Grangesberg’ under construction by William Doxford & Sons, Pallion, c1903. (11187433215).jpg|thumb|upright|Assembling frames of ''[[USS Beukelsdijk|Grängesberg]]'' in [[Pallion]] in 1903]]
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.{{sfn|Marine Engineer and Naval Architect (April 1, 1892)|p=11)}} ''Turret'' was designed for tonnage of {{DWT|4700}} at a load line draft of {{convert|20|ft|3|in|m|1}} at {{GRT|2850}}.{{sfn|Marine Engineer and Naval Architect (April 1, 1892)|p=12)}} 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.{{sfn|Marine Engineer and Naval Architect (April 1, 1892)|p=12)}} The ship had an unusually high righting angle which was obtained whether full or lightly loaded.{{sfn|Marine Engineer and Naval Architect (April 1, 1892)|p=12)}} In particular the design was seen as a solution to the problem of strength and economical cost.{{sfn|Marine Engineer and Naval Architect (March 1, 1895)|p=511}} 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.{{sfn|Marine Engineer and Naval Architect (April 1, 1892)|p=12)}}{{sfn|Marine Engineer and Naval Architect (March 1, 1895)|p=511}} The long, wide hatches were seen as making the design especially suitable for carrying heavy or bulky machinery.{{sfn|Marine Engineer and Naval Architect (April 1, 1892)|p=11)}} That feature later resulted in cargoes such as {{convert|75|ft|m|1}} long, {{convert|8|ft|m|1}} wide girders and a 110-ton gun being easily loaded.{{sfn|Marine Engineer and Naval Architect (March 1, 1895)|p=512}}

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.{{sfn|Marine Engineer and Naval Architect (March 1, 1895)|p=511}}

==Description and design==
[[File:StateLibQld 1 234980 Loading cargo on to the Orange Branch at Townsville docks.jpg|thumb|The turret deck ship ''Orange Branch'' in [[Port of Townsville|Townsville]], Queensland about 1901. This view, almost bow-on, shows her hull's distinctive profile.]]
In side profile, turret deck ships resembled other merchant ships with [[flush deck]]s or with small [[forecastle]]s and [[poop deck]]s.<ref>{{harvnb|Craig|1980|loc=inside front cover}} – ''Different types of vessels classified in Lloyd's Register Book'' (illustration); {{harvnb|Woodman|2002|p=180}} (illustration of exemplars of trunk and turret deck ships, taken from Paasch, ''From Keel to Mast-Truck'', a marine dictionary).</ref> 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''.<ref>[https://web.archive.org/web/20070217031543/http://patriot.net/~eastlnd2/rj/swpa/marshall.htm An Australian's Experience, Walter Rignold Marshall (1901–1988)]. ''See'' section entitled ''Mokatam'' at bottom of page, with profile and accompanying text.</ref> 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.<ref>{{harvnb|Craig|1980|loc=inside back cover}} – illustration reproduced from ''Transactions of the Institute of Naval Architects'', XLIX (1907)</ref> 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.<ref name="Turret Steamers On Our Inland Seas">{{harvnb|''The Scanner'', 1971}}</ref>

This design, and that of its near relative the [[trunk deck ship]],<ref>Trunk deck ships differed from turret ships in that the formers' sides and decks joined at right angles, rather than arcs as in turret ships. {{harvnb|Woodman|2002|p=180}} (diagram); {{harvnb|Craig|1980|loc=inside front cover}}</ref> were said to maximize strength, allowing larger ships and reduced the amount of steel needed for construction.{{sfn|Craig|1980|p=35}} In reality, it is more likely that the geometry inhibited the development of cracks in the [[strake|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.<ref name="Woodman, p. 179"/>

[[File:Turret Age (1893) of Newcastle-upon-Tyne in the Dry Dock St. Johns Newfoundland in 1899 (1902) (14793900823).jpg|thumb|''Turret Age'' in dry dock at [[St. John's, Newfoundland and Labrador|St. John's, Newfoundland]] in 1899]]
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 [[Metacentric height#Stability|roll period]] and reduced the violence of rolls.<ref>{{harvnb|Woodman|2002|p=179}}; {{harvnb|Duerkop|2007}}, [https://web.archive.org/web/20110706184658/http://www.marmuseum.ca/duerkop.html definition 62, Turret Deck Ship]</ref> 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.<ref name=Clan>{{cite web |url=http://www.merchantnavyofficers.com/clanline2.html |last=Bax |first=John |title=Clan Line. Part Two |work=Merchant Navy Officers |access-date=2021-11-23 |archive-date=2009-03-29 |archive-url=https://web.archive.org/web/20090329064846/http://www.merchantnavyofficers.com/clanline2.html |url-status=bot: unknown }}</ref> 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.<ref name="Turret Steamers On Our Inland Seas"/>

Turret deck ships had a low [[net register tonnage|net tonnage]] (an approximate measure of cargo space) in comparison to their [[tonnage|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.<ref>Several sources state that Suez tolls were based on the area of the uppermost deck; as a turret's deck was narrow, this measurement effectively excluded from consideration those portions of the [[hold (ship)|hold]] under the harbour decks, which were outboard of the turret. E.g., [https://web.archive.org/web/20090329064846/www.merchantnavyofficers.com/clanline2.html Clan Line]; {{harvnb|Duerkop|2007}}, [https://web.archive.org/web/20110706184658/http://www.marmuseum.ca/duerkop.html definition of Turret Deck Ship]. Another source states that the type "had special advantages over the Suez Canal tonnage measurements, as the hull above the harbour deck was regarded as an 'erection.'" {{harvnb|Hardy|1924|pp=70–71}}, reproduced in [https://web.archive.org/web/20110716112909/http://www.southwestmafia.com/forumswm/showthread.php?p=35305 SS Claverly Wreck Report]. This may suggest that the turret was treated as superstructure rather than hold space. In either case, part of the cargo hold was excluded from measurement.</ref> Turret and trunk deck ships therefore paid less in tolls than conventional ships of the same capacity.<ref name="Some Marine Terminology">{{harvnb|Duerkop|2007}}, [https://web.archive.org/web/20110706184658/http://www.marmuseum.ca/duerkop.html Some Marine Terminology] (definition of Turret Deck Ship).</ref>

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.{{sfn|Craig|1980|pp=35–37}} Construction of the type therefore ceased.<ref name="Some Marine Terminology"/>

==History of use==
[[File:Men using crane to unload crate from SS TURRET CROWN at dock in Anchorage, Alaska, circa 1917 (AL+CA 5499).jpg|thumb|300px|Unloading ''Turret Crown'' in Anchorage, Alaska in about 1917]]
Over 180 ships of the type had been built before the design was abandoned,<ref name="Some Marine Terminology"/> 176 of them by William Doxford and Sons.<ref name=Doxford/> They were used in both [[Freight liner (ship)|line voyage]] and [[Tramp steamer|tramp]] service<ref name="Some Marine Terminology"/> until retired, wrecked, or lost in the First or Second World War.<ref name=Clan/> 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.{{sfn|Clarkson|Fenton|Munro|2007|p=38}}

While used for general freight, these ships were particularly suited to the carriage of bulk cargos such as grains, coal, and ores.{{sfn|Craig|1980|p=35}} 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<ref>''Turret Cape'', by then renamed ''Walter Inkster'', was still in service in 1950, departing [[Port Arthur, Ontario]] on [[Lake Superior]] in September of that year and arriving in [[Manitowoc, Wisconsin]] on [[Lake Michigan]].{{cite web |title=Crew Lists of Vessels Arriving at Manitowoc, Wisconsin, 1925-1956 |work=Publication No. M-2045 (from INS records) |year=1996 |url= https://www.archives.gov/research/microfilm/m2045.pdf |access-date=15 November 2007 }}</ref> and was not scrapped until 1959.<ref name="Turret Steamers On Our Inland Seas"/> 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.<ref>{{cite web |title=Wear Built Ships |url= http://sunderlandships.com/view.php?ref=101184 |access-date=27 January 2020}}</ref>

==See also==
{{commons category|Turret deck ships}}
*{{SS|Clan Ranald|1900|6}}
*{{USS|Beukelsdijk}}

==References==

===Notes===
{{Reflist}}

===Sources===
* {{cite web |last=Bax |first=John |title=Clan Line |publisher=Merchant Navy Officers |url=http://www.merchantnavyofficers.com/clanline2.html |archive-url=https://web.archive.org/web/20090329064846/www.merchantnavyofficers.com/clanline2.html |archive-date=2009-03-29  |access-date=13 November 2007}}
*{{cite book |last1=Clarkson |first1=John |last2=Fenton |first2=Roy |last3=Munro |first3=Archie |year=2007 |title=Clan Line Illustrated Fleet History |place=Preston |publisher=Ships in Focus |isbn=978-1-901703-47-4 |pages=35–38}}
* {{Cite book |last=Craig |first=Robin |year=1980 |title=Steam Tramps and Cargo Liners 1850–1950 |series=The Ship |publisher=National Maritime Museum / WS Cowell Ltd for [[Her Majesty's Stationery Office]] |place=London |volume=5 |isbn=0-11-290315-0 |url-access=registration |url= https://archive.org/details/steamtrampscargo00crai}}
* {{cite web |last=Duerkop |first=John |title=Some Marine Terminology |work=Research Resources |publisher=Marine Museum of the Great Lakes at Kingston |date=July 2007 |url= http://www.marmuseum.ca/duerkop.html |access-date=6 June 2014 |url-status=unfit |archive-url= https://web.archive.org/web/20110706184658/http://www.marmuseum.ca/duerkop.html |archive-date=6 July 2011}}
* {{cite web |title=Engines |work=Doxford Engine Friends Association |url=http://www.doxford-engine.com/engines.htm |access-date=11 November 2007 |archive-date=20 December 2007 |archive-url=https://web.archive.org/web/20071220213443/http://doxford-engine.com/engines.htm |url-status=dead }}
*{{cite book |last=Hardy |first=AC |year=1924 |title=Merchant Ship Types: A survey of the various units engaged in the water transport of people and merchandise |place=London |publisher= D Van Nostrand Company |pages= [https://books.google.com/books?id=kBUEAAAAMAAJ&q=The+Turret+deck+vessel 69-71]}}
* {{cite journal |last=Marine Engineer and Naval Architect |year=1892 |title=Doxford's Patent ''Turret'' Cargo Steamer |journal=The Marine Engineer |volume=14 |issue=1 April 1892 |pages=10–12 |place=London |url= https://books.google.com/books?id=AQ0AAAAAMAAJ&pg=PA6 |access-date=6 June 2015 |ref={{sfnref|Marine Engineer and Naval Architect (April 1, 1892)}}}}
* {{cite journal |last=Marine Engineer and Naval Architect |year=1895 |title=The "Turret" Steamships |journal=The Marine Engineer |volume=16 |issue=1 March 1895 |pages=511–512 |place=London |url= https://books.google.com/books?id=EA0AAAAAMAAJ&pg=PA511 |access-date=6 June 2015 |ref={{sfnref|Marine Engineer and Naval Architect (March 1, 1895)}}}}
* {{cite web |last=Oakley |first=Janet |title=Whaleback freighter ''Charles W. Wetmore'' arrives in Everett on December 21, 1891. |work=Essays |publisher=HistoryLink.org |date=27 July 2005 |url= http://www.historylink.org/essays/output.cfm?file_id=7362 |access-date=12 November 2007}}
* {{cite web |title=SS Claverly |work=Wreck Reports |publisher=SouthWestMafia.com |year=2007 |url= http://www.southwestmafia.com/forumswm/showthread.php?p=35305 |access-date=10 November 2007 |url-status=bot: unknown |archive-url= https://web.archive.org/web/20111001054138/http://www.southwestmafia.com/forumswm/showthread.php?p=35305 |archive-date=1 October 2011}}
* {{cite journal |title=Turret Steamers On Our Inland Seas |journal=The Scanner |volume=3 |issue=7 |publisher=Toronto Marine Historical Society |place=Toronto |date=April 1971 |url= http://www.maritimehistoryofthegreatlakes.ca/Documents/Scanner/03/07/default.asp?ID=c011 |access-date=10 November 2007 |ref={{harvid|''The Scanner'', 1971}} }}
*{{cite book |last=Walton |first=Thomas |year=1908 |title=Steel Ships: Their Construction and Maintenance |place=London, Philadelphia |publisher=Charles Griffin & Co./Lippincott |lccn=20003198 |page=[https://archive.org/details/steelshipstheir00waltgoog/page/n198 154]–60 |url= https://archive.org/details/steelshipstheir00waltgoog |access-date=5 June 2015}}
* {{Cite book |last=Woodman |first=Richard |author-link=Richard Woodman |year=2002 |orig-year=1997 |title=The History of the Ship |place=London |publisher=Lyons Press (Globe Pequot Press) / Conway Maritime Press |isbn=1-58574-621-5}}

==Photographs==
* [http://collections.rmg.co.uk/collections/objects/66044.html Colour photographs of model of SS ''Nonsuch''], a highly detailed full-hull builder's model in the collections of the [[National Maritime Museum]]. ''Nonsuch'' was built by Doxford in 1906 for Bowles Brothers and lost to air attack in 1944. {{cite web|title=Description, Turret deck cargo ship 'Nonsuch' |work=Collections Online, ship models |publisher=[[National Maritime Museum]] |url= http://www.nmm.ac.uk/collections/explore/object.cfm?ID=SLR0083 |access-date=6 June 2014 |url-status=unfit |archive-url= https://web.archive.org/web/20060127084849/http://www.nmm.ac.uk/collections/explore/object.cfm?ID=SLR0083 |archive-date=January 27, 2006}}
* [https://web.archive.org/web/20111001054138/http://www.southwestmafia.com/forumswm/showthread.php?p=35305 SS Claverly Wreck Report], showing a stern view of SS ''Claverley'' showing narrow harbour decks a short distance above the water. ''Claverley'', {{GRT|3,829|disp=long}}, was built by Doxford in 1907, owned by Sutherland Steamship Company, and torpedoed by a German U-boat near the [[Eddystone Rocks|Eddystone]] in 1917. {{cite web |title=SS Claverly |work=Wreck Reports |publisher=SouthWestMafia.com |year=2007 |url= http://www.southwestmafia.com/forumswm/showthread.php?p=35305 |access-date=12 November 2007 |url-status=bot: unknown |archive-url= https://web.archive.org/web/20111001054138/http://www.southwestmafia.com/forumswm/showthread.php?p=35305 |archive-date=1 October 2011}} That source also reproduces pages 70–71 of Hardy (1924), with figure 28 showing a midships cross-section of a turret vessel.
* ''Historical Collections of the Great Lakes'' maintained by [[Bowling Green State University]] has some photographs of turret ships. The [https://greatlakes.bgsu.edu/search?q=%22turret%20chief%22&limit%5Bresource_template_s%5D%5B0%5D=Vessel photograph of ''Turret Chief''] shows a heavily laden vessel with harbour decks nearly awash.

[[Category:British inventions]]
[[Category:Naval architecture]]
[[Category:Ship types]]
[[Category:Shipbuilding]]