The Synchro-Self-Shifting (SSS) overrunning clutch is well known, particularly in the Naval Marine field. This paper reviews the clutch operating principle, then outlines some of the service experience since 1962, particularly in naval main propulsion drives beginning with CODOG, CODAG, COGOG and COGAG plant, and then the experience with more recent applications such as combined electric motor propulsion with either gas turbines or diesel engines and hybrid electric plants.
Extra features are then described such as a lock-out control as is usually necessary for turbine applications to permit turbine testing, e.g., when in harbor; also a lock-in control as is essential when the clutch has to transmit power in both directions of rotation. Various clutch mounting arrangements will be presented with respective advantages. The paper concludes with information regarding reliability during many years of service experience.