All equipment that is hoisting material, must have a safety factor of?

• A. 2
• B. 4
• C. 3
• D. 5

Answer: (C)

When you’re hoisting, you’re not just thinking about the load itself; you’re building in a margin for real-world conditions. The safety factor is the ratio of the material’s breaking or ultimate strength to the maximum load you expect to lift. For hoisting equipment on ships, the minimum standard is a 3:1 margin. That means the gear should be able to withstand about three times the highest load you plan to lift, providing room for dynamic effects like starting, stopping, and swinging, plus wear, corrosion, and occasional shocks caused by ship motion or misalignment.

So, a three-to-one factor is the accepted minimum because it balances safety with practicality for lifting gear. A factor of two would leave less margin against dynamic and wear factors, while factors of four or five would be more conservative than required in this context, though they may be specified in some operations.