Twistlock: Definition & Function

A twistlock is a standardised rotating connector that locks a shipping container at its corner castings. It is both the mechanism a container spreader uses to grip a container for lifting and the fitting that holds containers together when they are stacked, which makes it one of the most common pieces of port equipment hardware.

How a twistlock works

The cone-shaped head enters the container's corner casting and rotates 90 degrees, so the container cannot lift off until it is twisted back. The same principle works in two directions: pulling a container up from a spreader, and holding stacked containers down against ship motion or wind.

Types of twistlock

• Manual: locked and unlocked by hand, common on trailers and chassis
• Semi-automatic: locks automatically on landing, released manually
• Fully automatic: locks and unlocks without an operator, used on high-speed spreaders

Twistlocks and related fittings are listed under spreader parts on Portneeds.