🔍 Key Concepts

• How long propulsion shaft sections are connected along their length in most conventional marine installations • Difference between solid couplings (no flexibility) and flexible couplings (allow some misalignment and shock absorption) • Where along the shaft line you would expect flexibility (near engine/gear) versus pure solid alignment (intermediate shaft sections)

💭 Think About

• First, think about what you want BETWEEN two straight sections of line shaft: perfect rigid alignment, or some flexibility? Why? • Which of the listed coupling types is most commonly used to bolt one machined shaft end to another in a long straight run? • Which types in the list are usually used only where you join the shafting to an engine, reduction gear, or other machinery that may move slightly?

✅ Before You Answer

• Identify which options are solid couplings and which are flexible types • Ask yourself: in a long propulsion shaft tunnel, the intermediate connections are usually flanged and bolted or clamped/sleeved? Which is more standard practice? • Eliminate any coupling types that are mainly for flexible power transmission rather than rigidly keeping two shaft sections exactly in line