What is the purpose of setting outriggers on a crane?

• A. To increase speed
• B. To raise the load higher
• C. To reduce operator visibility
• D. To stabilize the crane on firm ground

Answer: (D)

Outriggers are used to stabilize the crane by widening its base of support and transferring weight to the ground. When a crane lifts a load, forces from the boom and load create tipping moments. Extending the outriggers and resting them on firm ground increases the contact area and helps resist those tipping moments, keeping the crane from overturning. This stability is essential for safe lifts, especially with long booms or heavy loads and in variable ground conditions.

For proper use, outriggers should be fully extended and placed on firm, level ground (using mats or cribbing on soft surfaces as needed), and the lift planned according to the crane’s load chart. They’re not meant to speed up operations, raise loads independently, or reduce visibility—their sole purpose is to stabilize the machine during lifting.