Rick wrote:
Exhaust from Titanic's reciprocating engines, at a pressure less than
atmospheric, could be directed to the turbine or "bypass" the turbine
and exhaust directly to the condenser. The turbine was used to recover
heat energy from the main engine exhaust which would otherwise have been
wasted, and thereby increase the overall plant efficiency.

Right... it could be considered a quadruple expansion engine with the
turbine forming a fourth "stage" although it actually had several stages
inside the turbine. It was a reaction type turbine.

One thing I'm curious about is how well they could maintain vacuum with
the turbine bypassed. IIRC the air pumps were driven off the wing engine
shafts. I don't think the Olympic class plants were designed to do
crashback drills.

Regards
Doug King