In the summer of 2012 the Jeremiah O'Brien was revitalized in Dry Dock.  The Propeller and Shaft were part of the project. 
Six locations were photographed as keyed along bottom of profile [ A - F ]

           [ A ]
NOTE 1                                   [ B ]NOTE 2           
[ C ]NOTE 3                                        [ D ]
The "C" shaped fixtures are MOVING SHAFT GUARDS.                TAIL SHAFT & PROPELLER  - THRUST BEARINGS       

     [ E ]                                        [ F ]
It was helpful that part of the hull was opened.
This [RECESS area] has an escape tunnel trunk to the top of the ship.

[ G ]

NOTE 1: The JACKING GEAR (also known as a Turning gear) is a device placed on the main engine shaft. Its main purpose is to rotate the shaft and associated machinery to ensure uniform cool-down. The jacking gear motor is designed to rotate the shaft at approximately 1/10rpm. from WIKIPEDIA

NOTE 2: The ships THRUST BEARING is a powerful device. Many different types have been developed and Jeremiah O'Brien's can be called unique. It is manufactured by "KINGSBURY". An engineer from the J'O'B' has told me that the shoes within, which transfers the shaft power from the steam engine to the propeller shaft, are horse shoe shaped. The power is transferred from the rotating collar fastened to the engine shaft, forcing motor oil stored in the bearing housing over the shoe; in turn, the oil forces the collar on the propeller shaft to rotate. Read More!

NOTE 3: What is a shaft alley you ask? Well, I'll tell you. The main engine of a ship like the Jeremiah O'Brien is roughly midship. The shiny shaft you see connects the engine with the propeller. You can see that it is supported by numerous bearings. Unlike a vessel where the shaft is connected to the prime mover via a reduction gear, the Jeremiah O'Brien's steam engine connects directly to the crankshaft. The shaft runs through an alley in the stern of the vessel where it connects with the propeller via a thrust bearing. by: Rick Hawkinson