🔍 Key Concepts

• Sheave to wire rope diameter ratio (D/d ratio) and why it matters for rope life • How tight bending over a small sheave increases fatigue and internal wire breakage • Typical Coast Guard guidance for minimum sheave diameter relative to wire rope diameter

💭 Think About

• If a wire rope is bent over a very small sheave, what happens to the individual wires inside the rope over time? • Is the Coast Guard rule closer to a small multiple of the rope diameter, or a much larger multiple, to reduce bending stress? • Think about typical manufacturer recommendations: would they prefer a D/d ratio in the low single digits or in the tens?

✅ Before You Answer

• Compare each choice to what you’d expect for a reasonable D/d ratio (sheave diameter divided by rope diameter). • Eliminate any answer that would cause sharp bending of the wire rope (too small a sheave). • Focus on which answer best matches a minimum recommended multiple of rope diameter used in Coast Guard guidance and textbooks.