SKF (Muff) coupling

Outside dia's at end of outer muff measured before fitting
After fitted, dia's should be approx. 0.5mm greater Restraining devices must be fitted to prevent the muffs separating too quickly

Emergency astern arrangement

 

This is fitted to ships, the purpose of which is to prevent the shaft from slipping out of the stern tube if the muff coupling should fail. Its purpose is not to transmit torque.