View source for Roll-on/roll-off

{{Short description|Vessels designed to carry wheeled cargo}}
{{hatnote group|
{{Redirect|RORO|other uses|Roro (disambiguation)}}
{{for|RORO trains|Rolling highway}}
{{distinguish|Rollout/Rollin}}
}}

[[File:Roll-on-Roll-off car carrying ship.webp|thumb|Roll-on/Roll-off car carrying ship being boarded by [[articulated hauler]]s at the [[Port of Baltimore]]]]
[[File:RoRo ports and inland waterways.webp|thumb|RoRo ports and [[Inland waterways of the United States|inland waterways]] of the United States]]
'''Roll-on/roll-off''' ('''RORO''' or '''ro-ro''') [[ship]]s are [[cargo ship]]s designed to carry wheeled [[cargo]], such as [[car]]s, [[motorcycle]]s, [[truck]]s, [[semi-trailer truck]]s, [[bus]]es, [[Trailer (vehicle)|trailers]], and [[railroad car]]s, that are driven on and off the ship on their own wheels or using a platform vehicle, such as a [[self-propelled modular transporter]]. This is in contrast to [[lift-on/lift-off]] (LoLo) vessels, which use a [[crane (machine)|crane]] to load and unload cargo.

RORO vessels have either built-in or shore-based [[Linkspan|ramps]] or [[ferry slip]]s that allow the cargo to be efficiently rolled on and off the vessel when in port. While smaller ferries that operate across [[river]]s and other short distances often have built-in ramps, the term RORO is generally reserved for large seagoing vessels. The ramps and doors may be located in the [[stern]], [[Bow (ship)|bow]], or sides, or any combination thereof.

== Description ==
[[File:Blount Island aerial.jpg|thumb|[[Blount Island]] RoRo port in [[Jacksonville, Florida]].]]
Types of RORO vessels include [[ferry|ferries]], [[cruiseferry|cruiseferries]], [[cargo ship]]s, [[barge]]s, and RoRo service for air/ railway deliveries. New automobiles that are transported by ship are often moved on a large type of RORO called a pure car carrier (PCC) or pure car/truck carrier (PCTC).

Elsewhere in the shipping industry, cargo is normally measured by [[tonnage]] or by the [[tonne]], but RORO cargo is typically measured in ''[[Lane meter|lanes in metre]]s'' (LIMs). This is calculated by multiplying the cargo length in metres by the number of decks and by its width in lanes (lane width differs from vessel to vessel, and there are several industry standards). On PCCs, cargo capacity is often measured in RT or RT43 units (based on a [[Toyota Corona#T40, T50 series|1966 Toyota Corona]], the first mass-produced car to be shipped in specialised car-carriers and used as the basis of RORO vessel size. 1 RT is approximately 4m of lane space required to store a 1.5m wide Toyota Corona) or in car-equivalent units ([[Car Equivalent Unit|CEU]]).

The largest RORO passenger ferry is {{MS|Color Magic}}, a 75,100 [[gross ton|GT]] cruise ferry that entered service in September 2007 for [[Color Line (ferry operator)|Color Line]]. Built in [[Finland]] by [[Aker Finnyards]], it is {{convert|223.70|m|ftin|abbr=on}} long and {{convert|35|m|ftin|abbr=on}} wide, and can carry 550 cars, or 1,270 lane meters of cargo.<ref>{{cite web |url=http://www.faktaomfartyg.se/color_magic_2007.htm |title=M/S Color Magic (2007) |access-date=2008-03-05 |last=Asklander |first=Micke |work=Fakta om Fartyg |language=sv |archive-url=https://web.archive.org/web/20121004211007/http://www.faktaomfartyg.se/color_magic_2007.htm | archive-date=2012-10-04}}</ref>

The RORO passenger ferry with the greatest car-carrying capacity is [[MS Ulysses|''Ulysses'']] (named after [[Ulysses (book)|a novel by]] [[James Joyce]]), owned by [[Irish Ferries]]. ''Ulysses'' entered service on 25 March 2001 and operates between [[Dublin]] and [[Holyhead]]. The 50,938 GT ship is {{convert|209.02|m|ftin|abbr=on}} long and {{convert|31.84|m|ftin|abbr=on}} wide, and can carry 1,342 cars/4,101 lane meters of cargo.<ref>{{cite web |url=http://www.faktaomfartyg.se/ulysses_2001.htm |title=M/S Ulysses (2001) |access-date=2008-03-05 |last=Asklander |first=Micke |work=Fakta om Fartyg |language=sv |archive-url=https://web.archive.org/web/20121015181355/http://www.faktaomfartyg.se/ulysses_2001.htm |archive-date=2012-10-15 }}</ref>

<gallery mode="packed" heights="150">
File:Roro faehre.jpg|Loading a ro-ro passenger car ferry
File:FSRR FBQ 01.jpg|The [[MV Bali Sea|MV ''Bali Sea'']], a roll-on/roll-off [[train ferry]] operated between [[Coatzacoalcos]] and [[Mobile, Alabama|Mobile]]
File:Ulysses Arriving In Dublin.jpg|ROPAX ferry, MS ''Ulysses'', approaching Dublin Port, Ireland
File:SuperSpeed 2.jpg|Fast ROPAX cruiseferry, MS ''SuperSpeed 2'', between [[Larvik]], [[Norway]] and [[Hirtshals]], [[Denmark]]
File:Queenscliff ferry terminal.jpg|Ferry terminal for the [[Peninsula Searoad Transport]] service, with cars leaving a ferry
File:Magic_in_Oslo.JPG|The largest ro-ro passenger car ferry in the world, MS ''Color Magic'', in [[Oslo]], Norway
File:BastøElectric.jpg|[[Bastø Fosen]] is a Norwegian ferry company that operates smaller ro-ro passenger car ferries on a short route between the towns [[Horten]] and [[Moss]] in Norway, connecting the two cities and metropolitan areas of [[Tønsberg]] and [[Fredrikstad]].
</gallery>

=== Car carriers ===
{{Redirect|Car carrier||Auto carrier (disambiguation){{!}}Auto carrier}}
The first cargo ships specially fitted for the transport of large quantities of cars came into service in the early 1960s. These ships still had their own loading gear and so-called hanging decks inside. They were, for example, chartered by the German [[Volkswagen|Volkswagen AG]] to transport vehicles to the U.S. and Canada. During the 1970s, the market for exporting and importing cars increased dramatically and correspondingly also did the number and type of ROROs .

In 1970 Japan's [[K Line]] built the ''Toyota Maru No. 10'', Japan's first pure car carrier, and in 1973 built the ''European Highway'', the largest pure car carrier (PCC) at that time, which carried 4,200 automobiles. Today's pure car carriers and their close cousins, the pure car/truck carrier (PCTC), are distinctive ships with a box-like superstructure running the entire length and breadth of the hull, fully enclosing the cargo. They typically have a stern ramp and a side ramp for dual loading of thousands of vehicles (such as cars, trucks, heavy machineries, tracked units, [[Mafi roll trailer]]s, and loose statics), and extensive automatic fire control systems.

The PCTC has liftable decks to increase vertical clearance, as well as heavier decks for "high-and-heavy" cargo. A 6,500-unit car ship, with 12 decks, can have three decks which can take cargo up to {{convert|150|ST|t LT|0|abbr=on|lk=on}} <!-- Which ton? --> with liftable panels to increase clearance from {{convert|1.7|to|6.7|m|abbr=on}} on some decks. Lifting decks to accommodate higher cargo reduces the total capacity.

These vessels can achieve a cruising speed of {{convert|16|kn|mph km/h}} at eco-speed, while at full speed can achieve more than {{convert|19|kn|mph km/h}}.

{{As of|2024|August|7}}, the largest LCTC was the ''[[Höegh Aurora]]'', the inaugural vessel of a planned class of twelve, each with a capacity of 9,100 CEU.<ref>{{cite web |title=World's Largest Car Carrier Höegh Aurora Delivered |url=https://www.marinelink.com/news/worlds-largest-car-carrier-hegh-aurora-515747 |website=MarineLink |access-date=29 August 2024 |language=en |date=7 August 2024}}</ref> Meanwhile, the [[Marine Design & Research Institute of China]] (MARIC) is developing a new vessel class with a capacity of 12,800 CEU. The design has received Approval in Principle (AiP) from [[Lloyd's Register]], which was granted in June 2024.<ref>{{cite web |title=World's largest car carrier receives LR Approval in Principle |url=https://www.lr.org/en/knowledge/press-room/press-listing/press-release/worlds-largest-car-carrier-receives-lr-approval-in-principle2/ |website=Lloyd's Register |access-date=29 August 2024 |language=en |date=2024-06-07}}</ref>

The car carrier ''[[Auriga Leader]]'', belonging to [[Nippon Yusen]] Kaisha, built in 2008 with a capacity of 6,200 cars, is the world's first partially solar powered ship.<ref name="pressrelease">{{cite web |url=http://www.nyk.com/english/release/31/NE_090105.html | title=Using Solar Power for Ship Propulsion The World First Solar-Powered Ship Sails |publisher=NYK Line |work=NYK-Nippon Oil Joint Project | access-date=30 May 2013 |date=5 January 2009}}</ref>
<gallery mode="packed" heights="150px">
File:Roll-On Roll-Off (RO-RO) ship, starboard ramp.jpg|A pure car carrier ship's starboard side showing side [[Link span|ramp]]
File:MV Tønsberg R01.jpg|{{MV|Tønsberg||6}}, a large car/truck carrier
File:Cross Sound Ferry MV "John H" interior.jpg|Vehicle bay of the ''John H'', of [[Cross Sound Ferry]]
J32 394 Split, MFS Petar Hektorović.jpg|The front of the [[MT Petar Hektorović|MT ''Petar Hektorović'']] opens up, allowing cars to enter the vehicle bay.
</gallery>

=== Seaworthiness ===
{{Further|List of RORO vessel accidents}}
The seagoing RORO car ferry, with large external doors close to the waterline and open vehicle decks with few internal [[Bulkhead (partition)|bulkheads]], has a reputation for being a high-risk design, to the point where the acronym is sometimes derisively expanded to "roll on/roll over".<ref>{{cite book |last=Bryson |first=Bill |author-link=Bill Bryson |year=1995 |title=Notes from a Small Island |publisher=Doubleday |location=London |isbn=978-0-385-40534-8 |url-access=registration |url=https://archive.org/details/notesfromsmallis00bill_0 }}</ref> An improperly secured loading door can cause a ship to take on water and sink, as happened in 1987 with {{MS|Herald of Free Enterprise}}. Water sloshing on the vehicle deck can set up a [[free surface effect]], making the ship unstable and causing it to [[Capsizing|capsize]]. Free surface water on the vehicle deck was determined by the court of inquiry to be the immediate cause of the 1968 capsize of the {{ship|TEV|Wahine}} in New Zealand.<ref>{{cite book |first=Emmanuel |last=Makarios |title=The Wahine Disaster: a tragedy remembered |page=50 |year=2003 |publisher=Grantham House |location=Wellington |isbn=1-86934-079-5}}</ref> It also contributed to the wreck of {{MS|Estonia}}.

Despite these inherent risks, the very high [[Freeboard (nautical)|freeboard]] raises the seaworthiness of these vessels. For example, the car carrier {{MV|Cougar Ace}} listed 60 degrees to its port side in 2006, but did not sink, since its high enclosed sides prevented water from entering.

In late January 2016 {{MV|Modern Express}} was listing off [[France]] after cargo shifted on the ship. Salvage crews secured the vessel and it was hauled into the port of Bilbao, Spain.<ref>Wright, Paul (2016 February 4) [http://www.ibtimes.co.uk/abandoned-cargo-ship-modern-express-successfully-dragged-into-port-after-rescue-operation-1541939 "Abandoned cargo ship Modern Express successfully dragged into port after rescue operation"]. ''International Business Times''.</ref>

=== RORO variations ===
[[File:Opaline - IMO 9424869 - Callsign 9HA2478, Calandkanaal pic1.JPG|thumb|right|ConRO carrying trailers and containers]]
[[File:USNS Shughart gangplank.jpg|thumb|right|[[USNS Shughart (T-AKR-295)|USNS ''Shughart'']], a non-combat RORO vessel, unloading [[Stryker]] armored vehicles]]
[[File:Bulldogs vor Mannheim.jpg|thumb|RoRo [[barge]] carrying tractors]]
{| class="wikitable sortable"
|-
|+ RORO variations
|-
! Variation
! Remarks
|-
| ConRO
| The '''ConRo''' (or '''RoCon''') vessel is a hybrid of a RORO and a [[container ship]]. This type of vessel has a below-deck area used for vehicle storage while stacking  [[Intermodal container|containerized]] freight on the top decks. ConRo ships, such as the [[G4-class freighter|G4 class]] of the Atlantic Container Line, can carry a combination of containers, heavy equipment, oversized cargo, and automobiles. Separate internal ramp systems within the vessel segregate automobiles from other vehicles, [[Mafi roll trailer]]s, and [[break-bulk cargo]].
|-
| LMSR
| [[Large, Medium-Speed Roll-on/Roll-off]] (LMSR) refers to several classes of [[Military Sealift Command]] (MSC) roll-on/roll-off type cargo ships. Some are purpose-built to carry military cargo, while others are converted.
|-
| RoLo
| A '''RoLo''' (roll-on/lift-off) vessel is another hybrid vessel type, with ramps serving vehicle decks but with other cargo decks only accessible when the tides change or by the use of a crane.
|-
| ROPAX
| The acronym '''ROPAX''' (roll-on/roll-off passenger) describes a RORO vessel built for freight vehicle transport along with passenger accommodation. Technically this encompasses all ferries with both a roll-on/roll-off car deck and passenger-carrying capacities, many of those with facilities for more than 500 passengers may be described as [[cruiseferry|cruiseferries]].
|-
|}

==History==
At first, wheeled vehicles carried as cargo on oceangoing ships were treated like any other cargo. Automobiles had their fuel tanks emptied and their batteries disconnected before being hoisted into the ship's hold, where they were chocked and secured. This process was tedious and difficult, and vehicles were subject to damage and could not be used for routine travel.

An early roll-on/roll-off service was a [[train ferry]], started in 1833 by the [[Monkland and Kirkintilloch Railway]], which operated a wagon ferry on the [[Forth and Clyde Canal]] in [[Scotland]].<ref name="Marshall-Guinness">{{Marshall-GuinnessRail}}</ref>{{page needed|date=October 2016}}

===Invention===
[[File:Floating railway 1850.jpg|thumb|''Floating Railway'', opened in 1850 as the first roll-on roll-off [[train ferry]] in the world]]

The first modern train ferry was ''[[Leviathan (1849)|Leviathan]]'', built in 1849. The [[Edinburgh, Leith and Newhaven Railway]] was formed in 1842 and the company wished to extend the [[East Coast Main Line]] further north to [[Dundee]] and [[Aberdeen]]. As bridge technology was not yet capable enough to provide adequate support for the crossing over the [[Firth of Forth]], which was roughly five miles across, a different solution had to be found, primarily for the transport of goods, where efficiency was key.

The company hired the up-and-coming civil engineer [[Thomas Bouch]] who argued for a train ferry with a roll-on/roll-off mechanism to maximise the efficiency of the system. Ferries were to be custom-built, with railway lines and matching harbour facilities at both ends to allow the rolling stock to easily drive on and off.<ref name="Ferries">{{cite web|url=http://www.grantonhistory.org/transport/train_ferry.htm |title=The Train Ferries}}</ref> To compensate for the changing [[tide]]s, adjustable ramps were positioned at the harbours and the gantry structure height was varied by moving it along the slipway. The wagons were loaded on and off with the use of [[stationary steam engine]]s.<ref name="Ferries" /><ref name="Marshall-Guinness" />{{page needed|date=October 2016}}

[[File:Granton train ferry.jpg|thumb|left|[[Thomas Bouch|Bouch's]] ferry design. Note the [[adjustable ramp]].]]
Although others had had similar ideas, Bouch was the first to put them into effect, and did so with an attention to detail (such as design of the [[ferry slip]]) which led a subsequent President of the [[Institution of Civil Engineers]]<ref>[[George Parker Bidder]]; not to be confused with the lawyer (his son)who represented Bouch at the Tay Bridge Inquiry</ref> to settle any dispute over priority of invention with the observation that "there was little merit in a simple conception of this kind, compared with a work practically carried out in all its details, and brought to perfection."<ref>{{cite journal|title=Memoirs of Deceased Members|journal=Minutes of the Proceedings of the Institution of Civil Engineers|date=January 1881|volume=63|series=Part 1|issue=1|pages=301–308|url= https://www.icevirtuallibrary.com/toc/jmipi/63/1881 |access-date=17 February 2012|issn=1753-7843}}</ref>

The company was persuaded to install this train ferry service for the transportation of goods wagons across the [[Firth of Forth]] from [[Burntisland]] in [[Fife]] to [[Granton, Edinburgh|Granton]].<ref name="ODNB">{{cite ODNB|id=2969|title=Bouch, Sir Thomas (1822–1880)|first=J. S.|last=Shipway}}</ref> The ferry itself was built by [[Thomas Grainger]], a partner of the firm Grainger and Miller.

The service commenced on 3 February 1850.<ref>{{cite web|url=http://www.subbrit.org.uk/sb-sites/sites/s/scotland_street_tunnel/index.shtml |title=Subterranea Britannica: Sites:Scotland Street Tunnel|work=subbrit.org.uk}}</ref> It was called "The Floating Railway"<ref>{{cite news |url=http://nla.gov.au/nla.news-article62215901 |title=News of the Week |newspaper=[[The Bathurst Free Press and Mining Journal|Bathurst Free Press (NSW : 1849–1851)]] |location=[[Bathurst, New South Wales]] |date=10 August 1850 |access-date=30 May 2013 |page=3 |publisher=National Library of Australia}}</ref> and intended as a temporary measure until the railway could build a bridge, but this was [[Forth Bridge|not opened until 1890]], its construction delayed in part by repercussions from the catastrophic failure of Thomas Bouch's [[Tay Bridge disaster|Tay Rail Bridge]].<ref name="ODNB"/>
{{clear}}

===Expansion===
Train-ferry services were used extensively during [[World War I]]. From 10 February 1918, high volumes of railway rolling stock, artillery and supplies for the Front were shipped to France from the "secret port" of [[Richborough]], near Sandwich on the South Coast of England.

This involved three train-ferries to be built, each with four sets of railway line on the main deck to allow for up to 54 railway wagons to be shunted directly on and off the ferry. These train-ferries could also be used to transport motor vehicles along with railway rolling stock. Later that month a second train-ferry was established from the [[Port of Southampton]] on the South East Coast. In the first month of operations at Richborough, 5,000 tons were transported across the Channel, by the end of 1918 it was nearly 261,000 tons.<ref name="Pratt-Edwin A">{{cite book|last=Pratt|first=Edwin A|title=British Railways and the Great War Book|year=1921|publisher=Selwyn and Blount, Ltd.|location=London|isbn=1151852406|url=https://archive.org/stream/cu31924092566128#page/n7/mode/2up}}</ref>

There were many advantages of the use of train-ferries over conventional shipping in World War I. It was much easier to move the large, heavy artillery and tanks that this kind of modern warfare required using train-ferries as opposed to repeated loading and unloading of cargo. By manufacturers loading tanks, guns and other heavy items for shipping to the front directly on to railway wagons, which could be shunted on to a train-ferry in England and then shunted directly on to the French Railway Network, with direct connections to the Front Lines, many man hours of unnecessary labour were avoided.

An analysis done at the time found that to transport 1,000 tons of war material from the point of manufacture to the front by conventional means involved the use of 1,500 labourers, whereas when using train-ferries that number decreased to around 100 labourers. This was of utmost importance, as by 1918, the [[Railways in the United Kingdom|British Railway companies]] were experiencing a severe shortage of labour with hundreds of thousands of skilled and unskilled labourers away fighting at the front.  The increase of heavy traffic because of the war effort meant that economies and efficiency in transport had to be made wherever possible.<ref name="Pratt-Edwin A"/>

After the signing of the Armistice on 11 November 1918, train ferries were used extensively for the return of material from the Front.  Indeed, according to war office statistics, a greater tonnage of material was transported by train ferry from Richborough in 1919 than in 1918. As the train ferries had space for motor transport as well as railway rolling stock, thousands of lorries, motor cars and "B Type" buses used these ferries to return to England.

===The landing ship, tank===
[[File:LST Sicily.jpg|thumb|A [[Canada|Canadian]] LST off-loads an [[M4 Sherman]] during the [[Allied invasion of Sicily]] in 1943.]]

During [[World War II]], [[Landing Ship, Tank|landing ships]] (LST, ''"Landing Ship, Tank"'') were the first purpose-built seagoing ships enabling road vehicles to roll directly on and off. The British [[Operation Dynamo|evacuation from Dunkirk]] in 1940 demonstrated to the [[British Admiralty|Admiralty]] that the Allies needed relatively large, seagoing ships capable of shore-to-shore delivery of [[tank]]s and other vehicles in [[amphibious assault]]s upon the continent of Europe. As an interim measure, three 4000 to 4800 GRT tankers, built to pass over the restrictive bars of [[Lake Maracaibo]], [[Venezuela]], were selected for conversion because of their shallow draft. Bow doors and ramps were added to these ships, which became the first tank landing ships.<ref>{{Cite book| title=British and Dominion Warships of World War II |author1=Lenton, H.T.  |author2=Colledge, J.J.  |name-list-style=amp |publisher=Doubleday and Company |year=1968|page=577}}</ref>

The first purpose-built LST design was {{HMS|Boxer|F121|6}}. It was a scaled down design from ideas penned by Churchill. To carry 13 [[Churchill tank|Churchill]] [[infantry tank]]s, 27 vehicles and nearly 200 men (in addition to the crew) at a speed of 18 knots, it could not have the shallow draught that would have made for easy unloading. As a result, each of the three (''Boxer'', ''Bruiser'', and ''Thruster'') ordered in March 1941 had a very long ramp stowed behind the bow doors.<ref name="Brown">{{cite book|author=Brown, D.K.|title=The Design and Construction of British Warships 1939–1945|volume= 3 Amphibious Warfare Vessels and Auxiliaries|year=1996|isbn=0-85177-675-2|pages=142–143|publisher=Conway Maritime Press }}</ref>

In November 1941, a small delegation from the British Admiralty arrived in the United States to pool ideas with the [[United States Navy]]'s [[Bureau of Ships]] with regard to development of ships and also including the possibility of building further ''Boxer''s in the US.<ref name="Brown" /> During this meeting, it was decided that the Bureau of Ships would design these vessels. As with the standing agreement these would be built by the US so British shipyards could concentrate on building vessels for the [[Royal Navy]]. The specification called for vessels capable of crossing the Atlantic and the original title given to them was "Atlantic Tank Landing Craft" (Atlantic (T.L.C.)). Calling a vessel {{convert|300|ft|m|abbr=on}} long a "craft" was considered a misnomer and the type was re-christened "Landing Ship, Tank (2)", or "LST (2)".

The LST(2) design incorporated elements of the first British LCTs from their designer, Sir Rowland Baker, who was part of the British delegation. This included sufficient buoyancy in the ships' sidewalls that they would float even with the tank deck flooded.<ref name="Brown" /> The LST(2) gave up the speed of HMS ''Boxer'' at only {{convert|10|kn}} but had a similar load while drawing only {{convert|3|ft|m|abbr=on}} forward when beaching. In three separate acts dated 6 February 1942, 26 May 1943, and 17 December 1943, Congress provided the authority for the construction of LSTs along with a host of other auxiliaries, [[destroyer escort]]s, and assorted [[landing craft]]. The enormous building program quickly gathered momentum. Such a high priority was assigned to the construction of LSTs that the previously laid keel of an [[aircraft carrier]] was hastily removed to make room for several LSTs to be built in her place. The keel of the first LST was laid down on 10 June 1942 at [[Newport News, Virginia]], and the first standardized LSTs were floated out of their building dock in October. Twenty-three were in commission by the end of 1942.

===ROROs for road vehicles===
[[File:Theb3356 - Flickr - NOAA Photo Library.jpg|thumb|Ferry boat in the southern Philippines in 1925]]
[[File:Lst3041.jpg|thumb|[[HMS LST 3041|SS ''Empire Doric'']] was one of the first commercial roro ferries. It was built as an LST and is pictured entering the harbour in [[Malta]].]]

At the end of the first world war vehicles were brought back from France to [[Richborough|Richborough Port]]<ref>'Richborough Port' by Rob Butler p. 21 (photo) p. 20 (text) published by Ramsgate Maritime Museum</ref> drive-on-drive-off using the train ferry. During the war British servicemen recognised the great potential of landing ships and craft. The idea was simple; if you could drive tanks, guns and lorries directly onto a ship and then drive them off at the other end directly onto a beach, then theoretically you could use the same landing craft to carry out the same operation in the civilian commercial market, providing there were reasonable port facilities. From this idea grew the worldwide roll-on/roll-off [[ferry]] industry of today. In the period between the wars Lt. Colonel [[Frank Bustard]] formed the [[Atlantic Steam Navigation Company]], with a view to cheap transatlantic travel; this never materialised, but during the war he observed trials on [[Brighton Beach|Brighton Sands]] of an LST in 1943 when its peacetime capabilities were obvious.

In the spring of 1946 the company approached the Admiralty with a request to purchase three of these vessels. The Admiralty were unwilling to sell, but after negotiations agreed to let the ASN have the use of three vessels on [[bareboat charter]] at a rate of £13 6s 8d per day. These vessels were LSTs ''3519'', ''3534'', and ''3512''.  They were renamed ''[[HMS LST 3519|Empire Baltic]]'', {{SS|Empire Cedric||2}}, and {{SS|Empire Celtic||2}}, perpetuating the name of [[White Star Line]] ships in combination with the [[Empire ship|"Empire" ship]] naming of vessels in government service during the war.

On the morning of 11 September 1946 the first voyage of the Atlantic Steam Navigation Company took place when ''Empire Baltic'' sailed from [[Port of Tilbury|Tilbury]] to [[Rotterdam]] with a full load of 64 vehicles for the Dutch Government. The original three LSTs were joined in 1948 by another vessel, ''[[LST 3041]]'', renamed ''Empire Doric'', after the ASN were able to convince commercial operators to support the new route between [[Preston, Lancashire|Preston]] and the Northern Ireland port of [[Larne]]. The first sailing of this new route was on 21 May 1948 by ''Empire Cedric''. After the inaugural sailing ''Empire Cedric'' continued on the Northern Ireland service, offering initially a twice-weekly service.  ''Empire Cedric '' was the first vessel of the ASN fleet to hold a passenger certificate, and was allowed to carry fifty passengers. Thus ''Empire Cedric'' became the first vessel in the world to operate as a commercial/passenger roll-on/roll-off ferry, and the ASN became the first commercial company to offer this type of service.

[[File:Whittier Boarding the MV Kennicott Ferry.jpg|thumb|All ships of the [[Alaska Marine Highway]] employ RORO systems.]]

The first RORO service crossing the [[English Channel]] began from [[Dover]] in 1953.<ref>{{cite web|title=''Dinard'' – ''Viking''|url=http://www.simplonpc.co.uk/BR_Dinard.html|work=Simplon Postcards: The Passenger Ship Website|year=2005|access-date=2012-10-22}}</ref> In 1954, the [[British Transport Commission]] (BTC) took over the ASN under the Labour Governments [[nationalization]] policy. In 1955 another two LSTs where chartered into the existing fleet, ''[[Empire Cymric]]'' and ''[[Empire Nordic]]'', bringing the fleet strength to seven. The Hamburg service was terminated in 1955, and a new service was opened between Antwerp and Tilbury. The fleet of seven ships was to be split up with the usual three ships based at Tilbury and the others maintaining the Preston to Northern Ireland service.

During late 1956, the entire fleet of ASN were taken over for use in the Mediterranean during the [[Suez Crisis]], and the drive-on/drive-off services were not re-established until January 1957. At this point ASN were made responsible for the management of twelve Admiralty LST(3)s brought out of reserve as a result of the [[Suez Crisis]] too late to see service.
[[File:RoRoVera(gwz).jpg|thumb|A river barge carrying [[tractor]]s]]

===Further developments===
[[File:Atlantic Conveyor .jpg|thumb|left|''Atlantic Conveyor'' approaching the [[Falkland Islands|Falklands]] on or about 19 May 1982]]

The first roll-on/roll-off vessel that was purpose-built to transport loaded semi trucks was ''Searoad of Hyannis'', which began operation in 1956. While modest in capacity, it could transport three semi trailers between Hyannis in Massachusetts and Nantucket Island, even in ice conditions.<ref>[https://books.google.com/books?id=SeEDAAAAMBAJ&dq=Popular+Mechanics+Science+installing+linoleum&pg=PA87 "Roll-On Roll-Off Ship"] ''Popular Mechanics'', April 1956, p. 87</ref>

In 1957, the US military issued a contract to the [[Sun Shipbuilding & Drydock Co.|Sun Shipbuilding and Dry Dock Company]] in [[Chester, Pennsylvania]], for the construction of a new type of motorized vehicle carrier. The ship, [[USNS Comet (T-AK-269)|USNS ''Comet'']], had a stern ramp as well as interior ramps, which allowed cars to drive directly from the dock, onto the ship, and into place. Loading and unloading was sped up dramatically. ''Comet'' also had an adjustable chocking system for locking cars onto the decks and a ventilation system to remove exhaust gases that accumulate during vehicle loading.

During the 1982 [[Falklands War]], {{SS|Atlantic Conveyor}} was requisitioned as an emergency aircraft and helicopter transport for British [[Hawker Siddeley Harrier]] [[STOVL]] fighter planes; one Harrier was kept fueled, armed, and ready to VTOL launch for emergency air protection against long range Argentine aircraft. ''Atlantic Conveyor'' was sunk by Argentine [[Exocet]] missiles after offloading the Harriers to proper aircraft carriers, but the vehicles and helicopters still aboard were lost.<ref>{{cite web|url=http://www.fleetairarmoa.org/pages/fleet_air_arm_history/history.shtml|title=History of Fleet Air Arm Officers Association, FAAOA|work=fleetairarmoa.org}}</ref>

After the war, a concept called the shipborne containerized air-defense system (SCADS) proposed a modular system to quickly convert a large RORO into an emergency aircraft carrier with ski jump, fueling systems, radar, defensive missiles, munitions, crew quarters, and work spaces. The entire system could be installed in about 48 hours on a container ship or RORO, when needed for operations up to a month unsupplied. The system could quickly be removed and stored again when the conflict was over.<ref>{{cite web|url=http://www.wingweb.co.uk/aircraft/Harrier_VTOL_Jump-Jet_part4.html |title=The full story of the Harrier "Jump-Jet" Part Four – the "Second Generation" Harriers – The BAe / MDD AV-8B Harrier II, GR.5, GR.7, GR.9 & T.10 Harriers |work=wingweb.co.uk |url-status=dead |archive-url=https://web.archive.org/web/20131019135316/http://www.wingweb.co.uk/aircraft/Harrier_VTOL_Jump-Jet_part4.html |archive-date=2013-10-19 }}</ref> The Soviets flying [[Yakovlev Yak-38]] fighters also tested operations using the civilian RORO ships ''Agostinio Neto'' and ''Nikolai Cherkasov''.<ref>{{cite web|url=http://www.acig.org/artman/publish/article_488.shtml|archive-url=https://web.archive.org/web/20050217202728/http://www.acig.org/artman/publish/article_488.shtml|url-status=usurped|archive-date=February 17, 2005| title=The Soviet Navy Forger: Yak-36M, Yak-38, Yak-38U and Yak-38M|work=acig.org}}</ref>

==See also==
* [[Autorack]], or auto carrier or car transporter, a specialized piece of railroad rolling stock used to transport automobiles and light trucks
* [[Car carrier trailer]], or car hauler or auto transport trailer, is a type of truck trailer or semi-trailer to transport vehicles
* [[Car float]]
* [[Cruise ferry]]
* [[Frank Bustard]]
* [[Intermodal container]]
* [[Lift-on/lift-off]]
* [[List of cargo types]]
* [[List of roll-on/roll-off vessel accidents]]
* [[Merchant vessel]]
* [[Roll-on/roll-off discharge facility]]
* [[Rolling highway]]
* [[Train ferry]]
* [[Washington State Ferries]]
* [[Yacht transport]]
{{Portal|Transport}}
{{Commons category|RoRo ships}}

==References==
{{Reflist|30em}}

==Further reading==
{{refbegin}}
* {{cite news |last1=Belson |first1=Ken |title=Around the World With 5,500 Cars |url=https://www.nytimes.com/2012/07/15/automobiles/around-the-world-with-5500-cars.html |access-date=25 May 2021 |work=[[The New York Times]] |date=July 13, 2012}}
* {{cite journal|author=Liston, Jim|title=Oceangoing Drive-In|journal=Popular Mechanics|url=https://books.google.com/books?id=O9gDAAAAMBAJ&pg=PA100|access-date=8 March 2011|date=November 1969|publisher=Hearst Magazines|pages=100–103|issn=0032-4558}}
* {{cite book|last1=Todorov|first1=Delyan Mihaylov|title=Ro-Ro Handbook: A Practical Guide to Roll-On Roll-Off Cargo Ships|date=2016|publisher=Schiffer Publishing|location=Atglen, PA|isbn=9780764351235}}
{{refend}}

{{ModernMerchantShipTypes}}
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[[Category:Ro-ro ships| ]]
[[Category:Freight transport]]
[[Category:Scottish inventions]]

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