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Old 11-05-2011, 01:18 PM
Frank X. Prudent Frank X. Prudent is offline
 
Join Date: Apr 2006
Posts: 1,064
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Gosh, Bob, thank you very much. I greatly appreciate the compliment, but Dan Lewis is the licensed Chief Engineer here. Kenny Howe might have posted once or twice too.

Jon is right about the NATCHEZ. That type of valve gear saved her life; she can be shipped up without stopping. Right before her impending meeting with the EXXON BALTIMORE, "Doc" rushed up into the pilothouse to ring her to back for all she was worth. The striker or chief could just throw her into reverse, which was done, and the damage was probably lessened a great deal when the two did meet.

There are different types of reversing mechanisms that were used over the years. The DELTA QUEEN and NATCHEZ has a Stevenson (sp?) link. The BELLE OF LOUISVILLE has a yoke. Whatever the set up, their job was the same. In simple terms the reversing set up adjusted the engine's valves to take in live steam and exhaust the spent steam from the cylinder in order to come ahead or back. On a horizontal marine engine The after admission valve is opened to push the piston forward to bring the wheel ahead . At that time the forward exhaust valve would also be open to let the used steam escape. To back the forward admission valve is open first along with the after exhaust valve. This will push the piston aft to back the wheel.
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