What should a vessel's auxiliary steering gear test demonstrate?

The correct answer demonstrates that a vessel's auxiliary steering gear test should show the ability to move the rudder from 15 degrees to 15 degrees. This parameter is crucial as it ensures that the auxiliary steering system can effectively control the vessel's direction in case the primary steering gear becomes inoperative. The test confirms that the auxiliary steering gear is functional, reliable, and capable of providing sufficient maneuverability to navigate safely, especially in emergency situations.

The range of movement specified is typically chosen to fall within operational standards set by regulatory agencies and safety protocols, which prioritize the ability to execute significant steering changes. This range also allows for safe navigation in various scenarios, reinforcing the importance of having a robust auxiliary steering capability on board.