🔍 Key Concepts

• Safe Working Load (SWL) and how it’s rated for different fittings • The difference between a closed shape (shackle) and an open shape (hook) under tension • How stress concentration and risk of opening/bending affect allowable load

💭 Think About

• If two fittings have the same metal diameter, what effect does the shape (open vs closed) have on how much load they can safely carry? • Which fitting is more likely to spread, open, or bend if overloaded in a straight pull: a hook or a shackle? • Think about which fitting is normally chosen where maximum strength and security of connection are needed, such as in padeyes or permanent lifting points.

✅ Before You Answer

• Compare the typical working load limits for standard hooks and shackles of the same nominal size in a rigging table (not exact numbers, just which is usually higher). • Consider which item gives a continuous load path around the connection pin: the hook throat or the shackle body. • Ignore overall length; focus on diameter and shape as the controlling factors for strength.