Everything You Need to Know About RoRo Ships

Everything You Need to Know About RoRo Ships

Eve Jones

Do you want to know what a RoRo ship is? If so, you’ve come to the right place. RoRo stands for roll-on / roll-off which means it’s a vessel that has been designed to carry wheeled cargo: Think cars, vans, trailers, busses and trucks. Anything that can be ‘rolled on' and then 'rolled off’ the ship.

But there’s a little more to the RoRo ship than just that, including some variations on the RoRo theme. In this article we’re going to take a deeper dive into the world of the roll-on / roll-off vessel and find out more about this often overlooked member of the world’s merchant navy fleets.

After all, who says that cargo ships and container ships should get all the glory!

a cargo ship on a turquoise sea.

This article is part of our series that explores different vessels, so if you’ve ever wondered what a lightship is, how icebreaker ships work, what a heavy lift vessel transports, or what really goes on behind the scenes of a cruise liner, keep on reading and hopefully we’ll have some answers for you!

But for now, let’s focus our attention on the RoRo vessel.

Everything you need to know about RoRo ships

First of all, you might also see RoRo ships being called Ro-Ro ships. This is the same thing, just a different spelling.

the word 'same' spelt out using small font that says 'different'

So what makes the RoRo different from the majority of other ships used to carry cargo? For a start, container and cargo ships use cranes to load and unload their freight. These cranes are usually located on the port, although some smaller ships, such as feeder vessels will have cranes onboard. Vessels that use cranes are known at LoLo ships - lift-on / lift-off.

Clearly, given the nature of its cargo - namely wheeled vehicles - a RoRo doesn’t need to rely on cranes: Instead the vehicles it carries can simply be driven on and off the ship via a ramp.

In the majority of RoRos, the ramp is located at the stern of the vessel. For others, the ramp will be in the bow or at the sides of the ship. Ramps are also situated at the port for those vessels which don’t have their own built-in ramp.

a ferry with the ramp at the stern.

The history of the RoRo ship

RoRo ships first started appearing in the 19th Century (1801-1900). And with the first motor vehicle not being patented until 1886 by Carl Benz, clearly the early RoRo wasn’t being used for the transportation of cars and trucks.

What it was developed for was the transportation of railway cars and carriages which were proving to be too wide for the bridges located en route to their destination. The obvious choice was to look below the bridges to the river instead, and hence the RoRo ship was born.

One of the earliest RoRo ships was the Firth of Forth ferry which began plying her trade in Scotland in 1851. The train tracks were laid on the vessel in such a way that they could connect to the land-based rails. The trains were then simply rolled onto the ship and then rolled off when they’d reached their destination. These days you can book cruise tours around the Firth of Forth.

the Firth of Forth river and bridge.

But did you know that RoRo ships are not just merchant navy or commercial vessels? They also had a role to play in the Second World War. It was then that it was realized how valuable the roll-on and roll-off method of transportation could be when it was used in tank landing craft - the amphibious vehicles that - as the name suggests - landed tanks on the beaches, for example on D-Day and in other battles.

Shortly after, in the late 1940’s, merchant ships began to benefit from the RoRo principle and it became popular on short ferry crossings, especially as motor cars and other vehicles became increasingly popular.

Fast forward to today, and most of us have, at some point, been on a RoRo ship, whether it’s as a foot passenger, a vacationer ‘rolling on and rolling off’ to explore everything the other side of the river or sea has to offer, a commercial truck driver, or even a commuter who works on the other side of the water.

cars, motorbikes and tuk-tuks on a ferry crossing.

Types of RoRo ships

The benefits of the RoRo ship are undeniable, for both the passenger and the shipping company, owner or operator. Consider how long it takes to typically load and unload freight by crane compared to how long it takes for vehicles to literally drive on to the ship, park, and then drive off again at the port on the other side.

Therefore it’s not surprising that different iterations of the RoRo vessel have developed since those early days of transporting train wagons in Scotland!

Different types of RoRo vessels

A RoRo ship that is used for transporting vehicles as freight falls under the umbrella of ‘cargo ship’ however, there’s more to the humble roll-on and roll-off vessel than that. As seen, passenger ferries can also be RoRo ships, as can cruise ferries and barges.

a barge transporting sand and a tractor

These are some different types of RoRo ship:

  • PCC - Pure Car Carriers: Exclusively used for transporting cars.
  • PTCC - Pure Truck & Car Carriers: You guessed it - used for transporting trucks and cars - as well as other vehicles.
  • ConRo - a cross between a container ship and a RoRo ship, this vessel normally uses the area below the deck for the storage of vehicles and the top decks for stacking shipping containers.
  • RoLo - you might have guessed this one - this is a roll-on / lift-off vessel. Ramps are used to load and unload the wheeled cargo while cranes are used for containerized cargo.
  • LMSR - Large, Medium-Speed Roll-on / Roll-off vessel. The majority of LMSR ships are Military Sealift Command (MSC) RoRo cargo ships that were either built specifically for military cargo, or converted from commercial RoRo ships.
  • RoPax - short for roll-on / roll-off and passengers: These are used for the transportation of wheeled freight but also have passenger accommodation onboard. However if a ship can accommodate more than 500 passengers it is referred to as a cruise ferry, a vessel which combines the RoPax’s freight handling abilities with some of the facilities of a cruise ship.
ferry or cruise ship.

How is a RoRo ship’s cargo measured?

Normally, cargo and container ship freight is measured in metric tonnes. However it's not quite as simple when we’re talking about a RoRo ship’s cargo as obviously this won’t be neatly split up into stackable shipping containers, but will involve a whole medley of vehicles of different sizes, shapes and weights.

Therefore RoRo ship cargo is measured in something called Lane in Meters, or LIMs. To calculate it you follow the simple equation below:

Length of the cargo in meters x the cargo’s width in a lane = mystery number

Then

Mystery number x the number of decks on the vessel = LIMs

equations written on a chalkboard.

However, just in case you ever find yourself in a situation where you need to calculate the cargo on a RoRo ship, bear in mind that there are a number of different industry standards for lane width and so your end result will depend upon the particular vessel you are on.

Everything you need to know about RoRo ships: Conclusion

The RoRo ship might not be the first vessel that comes to mind when you think of cargo ships or the merchant navy, but they are the unsung hard workers of the seas!

Thanks to their quick port turnaround times and their versatility when it comes to the cargo (and passengers) they can carry, the good old roll-on / roll-off model - and all of its variants - shows no signs of going anywhere soon.

Read the previous article in this series: Everything You Need to Know About Cargo and Container Ships
Read the next article in this series: Everything You Need to Know About Feeder Vessels