Coupling conundrum

摘要

Joining together two sections of propeller shaft is not the greatest engineering problem on a ship. But taking it apart again has caused more than one shipowner a headache. In theory the coupling is simple because as the shaft is under compressive stress most of the time - transmitting the propeller thrust - there is only the torque to transmit. That said, the torque is very high, shock loads are not unknown, and any misalignment will lead to trouble.