SD-1.4.4-RO-RO Ships

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RO/RO Ships

Manuel Ventura

Ship Design I

MSc in Marine Engineering and Naval Architecture

M.Ventura RO/RO Ships 2

Summary

• Definition• Types of RO/RO Ships• Profile and evolution of the fleet• Relevant aspects of design

– Arrangement of the accesses and garage zone– Cargo types and characteristics– Specific equipment for securing of roll-on/roll-off cargo– Damaged Stability: Criteria and assessment– Safety (SOLAS): Prevention and extinguishing of fire in the

garage zone• Annex A. Significant Ships• Annex B. Relevant Non-IMO Standards

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RO/RO Ships (1)

Roll-On/Roll-Off Ships - ships where the cargo is wheeled or is loaded/unloaded on board in vehicle or platforms equipped with wheels

• The first ships of this type were the Ferry, equipped with railways to allow the transport of train carriages between the margins of the rivers that were too wide for bridges

• One of the first ferry ships was the Forfarshire, across the Firth of Forth, in Scotland, built in 1861


RO/RO Ships (2)

• The WWII has motivated the development of this type of ships for the landing of military equipment

• After the war many of those military ships were converted for operation as merchant ships, such as the LST (Landing Ship Tank) MV Virginia Beach

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RO/RO Ships (3)

• The use of the RO/RO concept in merchant ships started in the late 1940’s, early 1950’s, mainly in short-sea routes


Types of RO/RO Ships

• Ferries• Freight• Ro-Pax• Pure Car Carriers• Combined carriers

– Container Ro/Ro– Ro/Ro Lo/Lo

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Ferry

Cariiage of Passengers and Vehicles


Ferry – Typical General Arrangement

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Freight Ro/Ro

Transport of Wheeled Cargo


Ro-Pax

Mixed Transport of Passengers, Vehicles and Wheeled Cargo

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Pure Car Carrier (PCC)

The largest PCC currently in service is the MV Mignon (1999), from Wallenius Lines, which after a lengthening of 28 m (2005) has the capacity to carry about 7,200 cars.

• Ships quite sensitive to the side winds due to the large exposed area

• Present a large number of ventilators on the exposed deck due to the SOLAS requirements for the garage zove

Car Transport


Pure Car Truck Carrier (PCTC)

Transport Cars and Trucks Loa = 198 m

Lpp = 188 m

B = 32.20 m

D = 14.60 m

T = 8.80 m

DW = 16,957 t

Courageous Ace (2003)

6400 cars

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Container Ro/Ro (ConRo)

Generally carries stacks of containers on the upper deck and wheeled cargo under deck

ConRo Trader (1978)

Loa = 109.60 m

DW = 4,550 t

Combined Ship, Container Carrier and Ro/Ro


Ro/Ro Lo/Lo

Ship that can carry and load wheeled cargo, but that also has lifting equipment to load/unload through the hatches

CEC Oceanic (1997)

Loa = 100.90 m

DW = 5,150 t

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Profile and Evolution of the Fleet


World Fleet of Ro/Ro Ships

Notes:• Only Ro/Ro cargo ships• Units: [1,000 tdw]

Change [%]20062005

65.648.5543636193270Added to Fleet

-8.70.6686568236754752075228172World Fleet

Same period

prev. year

Prev. Period Jul.AprilJan.Oct.Jul.April

Source: ISL Market Review 2006 – Merchant Fleet Data

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Recent Evolution of the Fleet

1.62.52750.76,8651.59,7472.91302Jul.-10.22.62730.76,7541.59,5592.81296Jan.2006-9.43.13010.87,5221.810,9602.91258Jul.0.93.43180.98,3012.112,8963.01215Jan.20050.73.63191.08,2242.212,5973.01235Jul.9.63.63111.08,1712.112,2463.01239Jan.20041.33.93010.97,4592.010,8882.91137Jul.0.94.13010.97,3652.010,6282.91128Jan.2002

[%DWT][%] Tot

1,000 TEU

[%] Tot

1,000 DWT

[%] Tot

1,000 GT

[%] Tot

No. Ships

Source: ISL Market Review 2006 – Merchant Fleet Data


Evolution of the Capacity Ro/Ro

• Global growth of abt. 14% in 3 years• Increase of capacity concentrated in established markets

_____+ 182

____1473

____1291Total all routes

+ 23222199Inter-continental

+ 1109108Intra Americas

+ 336027Intra Asian (exc. ferries)

+ 53447394Intra Mediterranean

+ 51573522Intra European NW

AbsolutGrowth20062003

1,000s lane metres

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Comparison of Ships Ro/Ro Cargo - RoPax

• Increasing trends to build RoPax ships– Market of passenger ferries declining due to the low cost air transport

companies– RoPax ships present a larger increase in the intra-European low cost

transport

Only Cargo

Ropax

+ 10%7467

+ 27%235185

Change20062003Capacity of service (lane metres)

Source: MDST Containership Databank


World Fleet – Evolution of the Orders

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Arrangement of Access Way and Garage Zones


Dimensions of Access Ways

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External Access Ramp

Ramp angle < 12º


Internal Access Ways

• Capacity expressed in total lane length• Parking space requirements:

4.7

2.0

height [m] *

15.0 (double wheels) 12.0 (single wheels)

2.8 ~ 3.110.0, 12.0, 15.0Trucks

1.02.2 ~ 2.54.0 ~ 5.5Cars

Load [t/axis]width [m]length [m]

(*) Minimum free height, must add margin for upper deck structure

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Parking Spaces

• For road trailers, semi-trailers and roll trailers the width of the lane is typically 2.90 m

• The width of the cargo space should be a multiple of 2.90 m


Internal Ramps

• The slope of the internal ramps is normally between 1 :7 to 1 : 10 (abt. 8° – 6°) and the width should be carefully selected in relation to the cargo stowed at each deck.

• Widths between 7 and 12 meters are used in the large ships• Anti-skid surfaces are important.

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Initial Dimensioning Guidelines


Length Estimate

• Ro/Ro Cargo Ships

• Ro/Ro Passenger Ships

( ) 25/1000110 −+= LmLpp Lm = Lane length [m]

Ncars = max. Number of cars

Ncars > 500Lpp = 150 + (Ncars - 500)/10

320 < Ncars < 500Lpp = 130 + (Ncars - 320)/9

100 < Ncars < 320Lpp = 80 + (Ncars - 100)x(5/22)

Ncars < 100Lpp = 30 + (Ncars - 15)x(10/17)

Kristensen, Hans Otto (2006), “Cargo Transport by Sea and Road –Technical and Economical Environmental Factors, Naval Engineers Journal, Vol.118, No.3.

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Typical Midship Section Configurations

Overseas Ro/Ro

Shortsea Ro/Ro


Deck Configuration

• The number of decks increases with ship size.• For ships up to about 15000 tdw, 2 decks are most common. • Bigger ships have often 3 permanent decks. • Movable car decks are frequently installed in between the

permanent decks.

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Ro/Ro Deck Configurations (1)


Ro/Ro Deck Configurations (2)

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Trailers – Stowage in Lanes

Ro/Ro for Carriage of Trailers (Semi-Reboques) - Stowage

Cargo Equipment for Ro/Ro Ships

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Cargo Equipment for Ro/Ro Ships (1)

RO/RO ships require a wide range of access equipment.


Stern Ramp Configurations

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Cargo Equipment for Ro/Ro Ships (2)

• Bow doors• Bow ramps• Internal doors• Hoistable car

decks• Hoistable car

ramps


Ramps/Bow Access Doors

• Stern ramps, for ships that attend Ro/Ro terminals

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Ramps/Stern Access Doors

Quarter ramp, which allows access with the ship in a peer (without Ro/Ro terminal)


Ramps/Bow Access Doors

• Bow ramp “Folding Frame Type”

• Allows a complete separation of the door in the collision bulkhead from the remainder of the ramp

www.tts-marine.com

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Bow Ramp Folding Frame Type

Opening sequence of the bow ramp.


Side Shell Doors

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Internal Ramps

Internal ramps typically have inclination of abt. 7°


Internal Doors

Watertight door designed for the subdivision of the cargo spaces with a minimum of interference

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Movable Car Decks

• Intermediate decks of lightweight construction that allow the stowage of cars inside the deck for heavy vehicles


Moveable Car Decks

• There are 2 types of moveable car decks:– Hoistable Car decks – with integrated lifting device, electrically or

hydraulically driven– Liftable Car Decks - do not have integrated lifting mechanism, they

are moved by lifts of the scissors type

Liftable Car Deck

Hoistable Car Deck

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COREX Cardecks

• Stainless steel sandwichpanels from MacGreggor

• A 3D truss-core is built-upbetween top and bottompanels

• Compared with conventionalsteel cardecks they haveabout 1/3 of the depth andabout ½ of the weight


Cargo Lifts

• Lifts to carry vehicles between decks, in ships where the longitudinal space is limited

• There are configurations in which the platform itself works as watertight hatch cover when secured in its lower position

• Types of cargo lifts:

• Scissors

• Telescopic

• Chain driven

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Cargo Handling

MAFI Trailer

Connection System

Used to move containers on chassis in the terminals


MAFI Tractor

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Tugmaster

www.kalmarind.se

Goose neckTerminal Tractor


Roll Trailers

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Truck and Semi-Trailer

1.2 mTandem axle spread6.2 mWheelbase

Truck Tractor

2.5 – 2.6 mWidth23.0 mOverall Length16.2 mLength2.6 mOverall Width

Semi-Trailer4.15 mOverall Height


Semi-Trailers

Trailer horse

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Trailer Trestle

• A terminal trailer trestle is a device which releases the towing truck for more productive use while the semi-trailer is loaded or unloaded in a terminal.


Cassettes for Containers

• The cassettes are detachable steel platforms, which containers can be loaded on for transporting.

• The containers can be double-stacked so that either 2x40ft or 4x20ft containers can be moved. This cassettes are able to handle 80 tons (there are examples of120-ton versions used in the steel industry).

• One of the advantages of using cassettes is that they act as a “floating” buffer, since containers can be placed on the cassettes with or without being coupled to a vehicle.

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Cassettes

cassette translifter


Translifter

www.ttsgroup.com

• A translifter is a steerable lifting trailer which can be used with pallets or trestles

• It has soft wheels

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Types of Cargo (1)

• Road Trailer - Including tractor and the trailer with the container on top. The dimensions, including allowances, are 12.5 m x 3.0 m x 4.5 m. Weight of 30 – 35 t and centre of gravity at 3.0 m height.

Load: 15.0 t/axle, 1.3 m distance between axis.

• MAFI trailer - Platforms for cargo towing, moved by tractors designated byTugmasters.

Load: 18.0 t/axle, 0.7 m distance between axis.

• Tugmaster - Tractor for moving cargoes in the terminals and in the ship.

Load: 21.0 t/axle.


Types of Cargo (2)

• Palette- Rectangular shaped structure where the cargo is stowed. Many different sizes, with rectangular shapes whose sides vary in a range from 0.8 m to 1.5 m. The size currently more used is 1.25 m x 1.0 m. The height of the cargo depends from the stowage conditions but can be assumed a value of 1.8 m to 2.0 m from the base, including the pallette.

• Car - Change a lot, but for European cars, average values of 4.5 m x 2.0 m x 1.7 m can be assumed, with an average weight of 1.0 t and max. of 2.0 t.

• SECU - (Storabox unit) specialized container for the carriage of paper, with dimensions 13.8 m x 3.6 m x 3.6 m and weight of 90t.

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Types and Characteristics of Cargo (1)

10020.01.02.01.41.64.0Car EU

8011.010.035.04.52.512.340’Trailer

8014.010.022.04.52.56.120’Trailer

8016.010.038.04.42.515.0Truck (articul.)

8016.010.024.04.42.511.0Truck

3016.08.010.02.21.34.04 tPaletes

3012.554.057.04.43.29.020’Contentor

SpeedMax.

[km/h]

SlopeMax. [%]

Load/axis[t]

WeightMax.[t]

HeightMax.[m]

Width[m]

Length[m]

TypeCargo


Types and Characteristics of Cargo (2)

3011.010.040.04.53.96.01 TEUStraddle carrier

3014.030.060.04.63.79.01 TEUSide carrier

1511.048.0247.05.94.918.8

8 TEU/

2 layers

Tractor LUFmaster

1514.02 x 13.052.03.4/6.04.714.040’Wagon w/ container

SpeedMax.

[km/h]

SlopeMax. [%]

Load/axis[t]

WeightMax.[t]

HeightMax.[m]

Width[m]

Length[m]

TypeCargo

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Vehicle Securing


IMO Guidelines – Securing Points

• Guidelines for Securing Arrangements for the Transport of Road Vehicles on Ro-Ro Ships.

• Apply to Ro-Ro ships which carry road vehicles on either long or short international voyages in unsheltered waters

• Are applicable to:– Road vehicles with an authorized total mass of vehicle and

cargo between 3.5 and 40 t– Articulated road trains with an authorized total mass not more

than 45 t• The decks shall be provided with securing points with:

– Longitudinal spacing < 2.5 m– Transverse spacing 2.8 < S < 3.0– Minimum strength without permanent deformation: 20 KN

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Securing Points on Decks


Securing Points on Decks (Cars)

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IMO Guidelines – Lashing

• Lashing shall consist of chain or any other device made of steel or other material with equivalent strength and elongation characteristics

• The strength of lashing without permanent deformation should not be less than 120 KN

• Lashings should be attached to the securing points with hooks or other devices

• Lashings should only be attached to the secure points• The angle between the lashings and the horizontal and

vertical planes shall be preferably between 30° and 60°


Car Lashing Equipment

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Trailer and Truck Lashing

Chain lashing

Web lashing


Accidents due to Improper Lashing

Accident due to an articulated vehicle being only lashed at the 4 corners

(www.shipownersclub.com)

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Aspects of Hull Structural Design


Scantlings of Decks for Wheeled Cargo (BV)

The thickness of plate panels submitted to wheeled cargoes shall no be less than the following, in [mm]:

with:

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When the tyre print area, AT, is not known, can be used the value in [m2] computed by the expression:

with:

n – number of wheels on the plate panel

QA – load in t/axis

nW – number of wheels in the axis considered

PT – pressure of the tyres [kN/mm2] (When the value is knot known, use the ones from Table 6)



In the vehicles where the 4 wheels of the axis are on the plate panel (Figure 1) the plate thickness shall be the largest of the values obtained from the following expressions:

with:

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Damaged Stability


Accidents with Ro/Ro Ships

• Princess Victoria (1953), 135 casualties

Estonia (1994), 852 casualties

Herald of Free Enterprise (1987), 193 casualties

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Damaged Stability (1)

• The shipwreck of the “Harald of Free Enterprise”, in 1987, called the attentions for the damaged stability of Ro/Ro ships, which are characterized for NOT having watertight subdivision above the main deck

• In a first approach R&D has focused on the residual stability ofexisting ships and in the identification of the main causes of the shipwrecks

• The sinking of the “Estonia” has increase the urge to find solutions

• Measure of Survivability – Critical height of the water on deck. Based in probabilistic concepts.

• The total probability of survival has 2 factors:– The probability that a given compartment is flooded– The probability that the ship survives to that flooding


Damaged Stability (2)

• The probability of survival can be divided in 2 factors:– The probability of surviving the pure lost of stability, moments

of heel, displacement of the cargo and angle of heel– The probability of surviving the effect of the water

accumulated on deck due to the action of the waves

• The computation of this last factor designated by survival factor with water on deck, sW, is based in the concept of the critical height of the wave at which capsize (sossobrar) occurs, and so sW is just the probability that this wave height is not exceeded

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Static Equivalent Method (SEM)

• Based on the results from experimental tests it was determined that the capsizing happens at an heeling angle close to ΘMax, the angle corresponding to the maximum value of the righting moment

• ΘMax is determined by the traditional constant displacement method, allowing the progressive flooding of the car deck until the immersion of the deck at side

• Based in these assumptions, it was developed the Static Equivalent Method (SEM), that allows the calculus of the critical amount of water accumulated on deck from the results of static stability computations


Static Equivalent Method

with:

hcrit – difference in height between the internal and external waterlines

HScrit – critical significative wave height

• It is considered a flooding scenario in which the ship has a only a damage under the car deck, but there is a quantity of water accumulated on the deck, considered intact

• The critical amount of water is the one that takes the ship to assume an equilibrium heeling angle equal to ΘMax

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Safety – Impact of SOLAS


Fire Prevention and Extinguishing

• In Ro/Ro ships, the closed decks for wheeled cargo shall have levels of protection equivalent to machinery spaces– Must be limited by class A boundaries (in steel or equivalent material)– Closed spaces to be protected by a fixed fire extinguishing system,

typically CO2 in cargo ships and sprinklers (DeLuge system) in car ferries

– Smoke detection system– Open cargo decks do not require a fixed fire extinguishing system– Portable systems and hoses

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Ventilation of Cargo Spaces for Vehicles

• The ventilation system of the cargo spaces shall be completely segregated from the others ventilation systems

• In ships with a number of passengers <N>, the system shall guarantee– N > 36 -> 10 renewals/hour– N ≤ 36 -> 6 renewals/hour

Source: SOLAS Chap. II-1 Regulation 38 – Cargo Spaces for Motor Vehicles


Conclusions from the Analysis of the Fires

• In accordance to SOLAS, the large fires are rare in ships and the casualties are generally related with situations when the passengers are in the interior of the vehicle during the voyage (which is no longer acceptable by SOLAS and by the ISM code)

• Many of the big fires started when the ship is in port, during load or unload. The detection system is often temporarily switched off and the CO2 can not be released quickly by the system because the ramps (internal and external) are still open

• The reliability of the low pressure CO2 systems for cargo space is generally quite low

• The sprinkler systems for Ro/Ro decks in Ferries have shown goodresults

Source: DNV, “Fires on Ro-Ro Decks”, DNV Technical Paper, 2005

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Fires in Ro/Ro Ships (1990-2003)



Fires in Ferries (1990-2004)


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Bibliography (1)

• Boulougouris, V., Papanikolaou, A., Zaraphonitis, G., “Optimization of Arrangements of Ro-Ro Passenger Ships with Genetic Algorithms”, Journal Ship Technology Research, Vol. 51, No. 3, 2004.DNV, “Guidelines - Design and Classification of Roll On/Roll Off Ships”, 1988.

• DNV, “Fires on RoRo Decks”, DNV Technical Paper, 2005Kreuzer, E.; Schlegel, V. and Stache, F. (2007), "MultibodySimulation Tool for the Calculation of Lashing Loads on RoRoShips", Journal of Multibody System Dynamics, Vol.18, No.1, August, 2007. (CD-ROM#52)Krinstensen, Hans Otto (2006), “Cargo Trasnport by Sea and RoadTechnical and Economical Envoronmental Factors”, Naval EngineersJournal, Vol.118, No.3. (CD-ROM#83)


Bibliography (2)

• Papanikolaou, A., Spanos, D., Boulougouris, E., Eliopoulou, E., Alissafaki, A., “Investigation into the Sinking of the Ro- Ro Passenger Ferry Express Samina”, Journal International Shipbuilding Progress, Vol. 51, No. 2, 2004.Ravn, Erik Sonne (2003), “Probabilistic Damaged Stability of Ro/Ro Ships”, PhD Dissertation, Technical University of Denmark.

• Turnbull, Stuart R. (2004), “Roll-on/roll-off semi-trailer models: a comparison of results”, Journal of Marine Science and Technology, Vol.5, No.3, Feb. 2004, pp. 101-106.

• Vassalos, D., Papanikolaou, A., "Stockholm Agreement - Past, Present, Future (Part 1)", Journal Marine Technology, Vol. 39, No. 3, July 2002, pp. 137-158.

• Vassalos, D., Papanikolaou, A., "Stockholm Agreement - Past, Present, Future (Part 2)", Journal Marine Technology, Vol. 39, No. 4, Oct. 2002, pp. 199-210.

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Relevant IMO Guidelines and Codes

• IMO Resolution A.533(13) - Elements to be taken into account when considering the Safe Stowage and Securing of Cargo Units and Vehicles in ShipsIMO Resolution A.581(14) (1985) - Guidelines for Securing Arrangements for the Transport of Road Vehicles on Ro-Ro Ships.IMO MSC.1/Circ.1355 (2010) - Amendments To The Guidelines For Securing Arrangements For The Transport of Road Vehicles on Ro-Ro Ships (Resolution A.581(14))

• IMO Resolution A.714(17) (1991) Code of Safe Practice for Cargo Stowage and Securing (CSS Code)


Relevant Links

Suppliers of Ro/Ro Equipment• www.macgregor-group.com• www.nordana.com• www.tts-technology.no

Other• www.shipownersclub.com

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Annex A. Significant Ships


Ro/Ro Ferry (1)

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Ro/Ro Ferry (2)


Ro/Ro Ferry (3)

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Ro/Ro Ferry (4)


Tor Petunia

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MV Tamesis

Annex B. Relevant Non-IMO Standards

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Some Relevant ISO Standards

• ISO 9367-1:1989 - Lashing and securing arrangements on road vehicles for sea transportation on Ro/Ro ships -- General requirements -- Part 1: Commercial vehicles and combinations of vehicles, semi-trailers excluded

• ISO 9367-2:1994 - Lashing and securing arrangements on road vehicles for sea transportation on Ro/Ro ships -- General requirements -- Part 2: Semi-trailers

Documents

SD-1.4.4-RO-RO Ships