🔍 Key Concepts

• Flexible (gear-type) couplings purpose in propulsion systems • Difference between slight vs gross misalignment in a shaft line • Relationship between torque capacity and coupling design features (gear teeth, lubrication)

💭 Think About

• Ask yourself: Is a gear-type coupling mainly for alignment correction, overload protection, or power transmission efficiency? • Compare what would realistically happen in a long shaft line if there were gross misalignment – would any coupling be designed to tolerate that safely? • Think about whether gear teeth running under load would normally operate dry or lubricated in marine service.

✅ Before You Answer

• Verify which option mentions slight vs gross misalignment, and which of those is more realistic for precision marine shafting. • Check if any choice describes behavior that sounds like a safety clutch or disconnect device rather than a coupling. • Confirm that the correct choice should match both: (1) realistic torque transmission capability, and (2) how a coupling copes with minor misalignment in practice.