30. On a gas turbine powered vessel equipped with a synchro-self-shifting (SSS) clutch, you are preparing for a power turbine overspeed test. What would be an important action to take prior to starting the engine?

Prior to a power turbine overspeed test on a vessel with a synchro-self-shifting clutch, the clutch must be manually locked out using the provided wrench to prevent engagement and potential damage to the reduction gear and shafting.