Straddle Carriers

What Does a Straddle Carrier Do?

The straddle carrier is a large vehicle that is used to carry containers to different parts of the container terminal.

They literally straddle the container and pick up the container with a special frame called a spreader, which spreads over the top of the container and with special hooks, twistlocks, and locks onto the specially reinforced corners of the container.

The straddle carriers will take containers to the lorries and trailers as well as to the quay where the large cranes load the containers on to the container ships.

How Big are the Straddle Carriers?

Most of the straddle carriers are 13 metres tall and can lift one container over another two stacked on top of each other. Newer straddle carriers are nearly 16 metres tall and can lift one container over three others. Some straddle carriers can lift two containers at a time, these are known as ‘twin lifters’.

All straddle carriers can lift between 40 and 50 tonnes of container and cargo, although the heaviest containers do not weigh much over 30 tonnes.

How Does the Straddle Carrier Driver Receive the Instructions to Pick up and Move a Container?

All straddle carriers are fitted with computers specially designed for their ruggedness and ease of operation.

The container terminal’s central computer system has programs that are designed to track and organise the flow of containers.

The straddle carrier computer receives instructions from the central computer by sending the information by radio transmission. The process is called Radio Data Transfer (RDT).

• The driver is told where to go by a grid reference, e.g. A15 – 9A, pick up the 9th container in the bottom position of row A15.
• The driver is then asked to confirm which container is being picking up.
• The computer will check that this container exists in this location.
• The driver is then told where to take the container, e.g. to a lorry, to a crane or to another part of the terminal.
• A global satellite positioning system confirms the final location of each container.
  

By always tracking the movement of the container can keep track of up to two million movements each year.