What is the purpose of safety devices fitted on lifeboat davits?

The purpose of safety devices fitted on lifeboat davits primarily revolves around preventing the over-stressing of falls during the deployment and recovery of lifeboats. These safety devices, such as limit switches or mechanical stops, are designed to monitor and limit the load on the falls, ensuring that they do not exceed their safe working load. This is crucial for the lifting mechanism's integrity and the safety of the crew and lifeboat during operations. By preventing over-stressing, these devices help avoid potential equipment failure, which could lead to dangerous situations during a lifeboat launch or recovery.

The other choices do not fully align with the primary function of the safety devices on lifeboat davits. Enhancing the speed of deployment focuses on operational efficiency rather than safety; assisting in navigation pertains to the direction and control of the vessel rather than the lifeboat's launching mechanism; and signaling for help is associated with communication methods rather than the structural safety features of the davits.