Linkspan in the context of MV Red Eagle (1996)

Roll-on/roll-off (RORO or ro-ro) ships are cargo ships designed to carry wheeled cargo, such as cars, motorcycles, trucks, semi-trailer trucks, buses, trailers, and railroad cars, 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 to load and unload cargo.

RORO vessels have either built-in or shore-based ramps or ferry slips that allow the cargo to be efficiently rolled on and off the vessel when in port. While smaller ferries that operate across rivers 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, or sides, or any combination thereof.

A ferry slip is a specialized docking facility that receives a ferryboat or train ferry. A similar structure called a barge slip receives a barge or car float that is used to carry wheeled vehicles across a body of water.

Often a ferry intended for motor vehicle transport will carry its own adjustable ramp - when elevated it acts as a wave guard and is lowered to a horizontal position at the terminus to meet a permanent road segment that extends under water. In other cases, the ramp is installed at the ferry slip and is called a linkspan or apron. Such a ramp is adjustable to accommodate varying water heights and ferry loadings and to move it out of the way during approach and exit. If railcars are carried by the ferry the apron will have tracks for them.

A train ferry is a ship (ferry) designed to carry railway vehicles, as well as their cargoes and passengers. Typically, one level of the ship is fitted with railway tracks, and the vessel has a door at the front and/or rear to give access to the wharves. In the United States, train ferries are sometimes referred to as "car ferries", as distinguished from "auto ferries" used to transport automobiles. The wharf (sometimes called a "slip") has a ramp, and a linkspan or "apron", balanced by weights, that connects the railway proper to the ship, allowing for tidal or seasonal changes in water level.

While railway vehicles can be and are shipped on the decks or in the holds of ordinary ships, purpose-built train ferries can be quickly loaded and unloaded by roll-on/roll-off, especially as several vehicles can be loaded or unloaded at once. A train ferry that is a barge is called a car float or rail barge. Some train ferries are considered pure train ferries that only carry rail traffic, whereas others are defined as train/vehicle ferries that also carry vehicles.