Question 35 LB01 - Lifeboat Operator

The Correct Answer is C **Why Option C is Correct:** The primary function of the limit switches on a lifeboat davit system is safety and prevention of mechanical damage. As the lifeboat is being recovered (hoisted back up), the limit switches are strategically positioned to automatically interrupt (cut off) the electrical power supply to the winch motor just before the boat makes full contact with the davit structure or the final stowed position (the davit head bumpers). This action ensures that the hoisting motor stops running, preventing over-hoisting, snapping of wires, or violent impacts that could damage the lifeboat, the davit arms, or the winching mechanism. **Why the Other Options are Incorrect:** * **A) To control the ascent rate of a lifeboat:** The ascent rate (speed of hoisting) is controlled by the speed of the electric motor and the gearing of the winch, not by simple on/off limit switches. * **B) To cut off power to the winch when the lifeboat reaches the davit bumpers:** While the power is cut off *before* impact, stating "when the lifeboat reaches the davit bumpers" implies the boat has already struck them. The function of the limit switch is to activate just *before* contact to prevent the impact itself. Option C ("nears the final stowed position") is a more accurate description of the switch's intended activation timing. * **D) To control the descent rate of a lifeboat:** The descent rate (lowering) of a lifeboat is controlled primarily by the mechanical brake (usually a centrifugal brake) and the manual winch brake handle, not by electrical limit switches, as lifeboats are often gravity-launched (lowered without requiring power).