Immersion Learning, a nonprofit science education organization, offers a nice "Return to the Titanic" online page as well as pages about other ocean related topics. Don't miss the neat Titanic themed games. View the links section in Return to the Titanic for other Titanic website recommendations.
PBS Lost Liners website includes information presented by Dr. Robert Ballard about five lost liner archaeological expeditions: Lusitania, Titanic, Empress of Ireland, Britannic and Andrea Doria.
Exhaust steam leaving the reciprocating engines was fed into the turbine, which was situated aft. From there it passed into a surface condenser , to increase the efficiency of the turbine and so that the steam could be condensed back into water and reused.  The engines were attached directly to long shafts which drove the propellers. There were three, one for each engine; the outer (or wing) propellers were the largest, each carrying three blades of manganese-bronze alloy with a total diameter of feet ( m).  The middle propeller was slightly smaller at 17 feet ( m) in diameter,  and could be stopped but not reversed.