The strength of a shackle is determined by which feature?

• A. Bow section diameter
• B. Screw pin diameter
• C. Width of the saddle section
• D. Working load limits of swivel

Answer: (A)

The load-carrying strength comes from the bow section because the bow is the main load-bearing part of a shackle. When the shackle is pulled, the stress concentrates in the bow, so its cross-sectional area largely determines how much force it can safely withstand. A larger bow diameter means more material to resist the tension, which translates to higher breaking strength and a higher safe working load. The screw pin diameter matters for the pin’s own strength, but it doesn’t set the shackle’s capacity as directly as the bow’s cross-section. The saddle width mainly affects fit and clearance, not the fundamental strength, and the working load limit is a rating derived from testing and standards, not the raw geometric strength.