Final answer:
The "Port-Off-Stbd" switch on an autopilot steering stand is used to specify the turn direction for the ship's autopilot system, where 'Port' is left, 'Stbd' is right, and 'Off' disengages the command.
Step-by-step explanation:
The "Port-Off-Stbd" selector switch on an autopilot steering stand is used to choose the direction of deviation when giving orders to the ship's autopilot system.
This switch allows the helmsman or navigator to give commands to the autopilot regarding which way the ship should turn. 'Port' would command the ship to turn left, 'Stbd' (starboard) would command it to turn right, and 'Off' would likely disengage the turn command. It's important to understand that this switch does not control steering mode, adjust rudder angle directly, or control autopilot power; it primarily deals with the direction of the ship's turn while under autopilot control.