🔍 Key Concepts

• Cross-compound steam turbine arrangement (how HP and LP turbines are physically laid out on their shafts) • Where the astern turbine is placed in relation to steam flow direction (from high pressure to low pressure stages) • How designers minimize piping and casing complexity when adding astern elements

💭 Think About

• Visualize the steam flow: it enters which turbine first, then where does it go next? Now, where would it be simplest to tap off or reverse flow for astern power? • Think about which end of a turbine (high-pressure or low-pressure) has larger blade sizes and lower steam pressure—would that be more suitable for adding an astern section mechanically? • In a cross-compound setup, HP and LP turbines are usually on separate shafts. On which turbine and at which end would the astern element most efficiently share casing/rotor space?

✅ Before You Answer

• Be clear on the difference between high pressure turbine and low pressure turbine and which one normally carries the astern stages in marine practice • Consider the direction of steam expansion (from HP to LP) and which end of that turbine (inlet vs exhaust) corresponds to high pressure and low pressure • Eliminate any choice that would require overly complex steam piping or separate casing when adding the astern turbine stages