🔍 Key Concepts

• Identify which turbine is the high‑pressure (HP) unit and which is the low‑pressure (LP) unit by comparing rotor and blade diameters in the illustration. • Recall that in a cross‑compounded marine main propulsion turbine, the steam flow direction is from the HP turbine to the LP turbine and then to the condenser; this defines what is "forward" and "aft" in the drawing. • Recognize the astern elements as a distinct group of blades that are shaped opposite to the ahead stages and are usually grouped together at one end of one casing.

💭 Think About

• First decide which side of each turbine casing connects to the reduction gears and which side connects toward the condenser/shaft line. How does that tell you what is the forward and aft end? • Look closely at the blade rows at each end of the HP and LP turbines. On which end do you see a short, separate group of blades that appears different from the main ahead stages? • Once you know which casing that special blade group is in, ask: is that casing the HP or LP turbine, and is that end toward the gears (forward) or away from them (aft)?

✅ Before You Answer

• Be sure you have clearly labeled in your mind which rotor is HP and which is LP based on size and position relative to the gears. • Confirm which direction the steam path takes through HP to LP to condenser; this will define which end is considered forward or aft in the plant layout. • Before selecting an option, double‑check that the blade group you are calling the astern elements is distinct from the ahead stages and is located entirely at one end of a single turbine casing.