Question 350Steam Plants - 1st Asst/Chief

The correct answer is D) admit astern steam to the turbine after securing the ahead steam. To stop the rotor of a main turbine while underway at sea, the proper procedure is to first secure all ahead steam to the turbine, and then admit astern steam to the turbine. This creates a reverse thrust that will slow down and eventually stop the turbine rotor. The other options are incorrect because they do not directly address the process of stopping the turbine rotor. Applying a prony brake (A) or tightening the stern tube packing gland (B) would not effectively stop the turbine rotor. Securing all steam to the turbine (C) without admitting astern steam would also not stop the rotor, as the momentum would continue to keep it spinning.