Propeller Shafts

I am doing a assesment and need to find a web site witch tells me what the size of the Propeller Shaft on the Inboard Port engine of the ss titanic is. Any help would be very appreciated thankz....
 
Nathan, maybe I can help. From the Midsummer 1911 magazine "The Shipbuilder" they describe the shafting arrangement of the Olympic/Titanic ships. For one thing, these ships were triple screw ships, not quadruple. Meaning they had two outside shafts, port and starboard, from the two reciprocating engines, and a single central shaft from the low-pressure turbine engine. For the reciprocating engines there were crank and thrust shafts of 27 in diameter, line shafts of 26.25 in diameter, and tail-end shafts of 28.5 in diameter. The central turbine shaft was 20.5 in diameter increasing to 22.5 in diameter at the tail end.

Sam
 
Hi all,

I've been reading "The Birth of the Titanic" & it shows the propeller shafts being installed on the slip on page 84. My question is this:

How did they install the centre shaft as the stern frame does not appear to have a cutout to allow the shaft to fit into position? If you read "Anatomy of the Titanic" on page 47 you can see the stern frame has been plated up but the shaft is not in position. Was it installed from inside the ship? And were the shafts single piece units or multiple smaller ones joined together?

Cheers,
JD.
 
JD,

The tailshafts for the wing screws were fitted with special split couplings that allowed this last portion of these shafts to withdrawn outboard. This was done to allow for ease of inspection of the tailshaft liners (the brass jackets shrunk onto the bearing surface of the tailshafts) and for inspection and renewal of the lignum vitae staves which lined the sterntubes and provided the bearing surface upon which the tailshafts rode. The remain segments of these shafts were installed from inside, with "closer" plates and watertight glands being installed in the bulkheads around them.

Because of the configuration of the center screw, outboard withdrawal of this shaft was not possible, so the arrangement typical in single screw ships of this period was employed, with a conventional bolted coupling flange being machined into the inboard end of the tailshaft. Installation was accomplished from inside the ship. In this arrangement, the tailshaft was designed to be just short enough to be withdrawn into the after shaft tunnel, where it was manhandled with the aid of overhead trolleys and hoist gear. This also required unshipping the next segment of line shafting forward of the tailshaft from its bearings and stools and moving it to one side to allow the tailshaft to be pulled forward. Like wing tailshafts, this shaft was only withdrawn occasionally for required inspection and renewal of the wooden bearing staves within the sterntube, and complete removal from the ship wouldn't have normally been required. If, however, the liner was found to be defective, or the tailshaft had become damaged and required straightening or replacement, the job was much more involved. Removing this tailshaft (or any of the other shaft segments) required the removal of certain closer plates provided in the watertight bulkheads and decks to allow this thing to be maneuvered to a place where it could be hauled up through a hatch and removed from the ship.

Regards,
Scott Andrews
 
Thanks for the info Scott. I can see now how it would have worked. So was there crew access into these shaft tunnels or was that only available once in a drydock?
 
Yes, there was crew access into the shaft tunnels, complete with watertight doors and a narrow escape tunnel that lead from the tank top level to the steering engine compartment beneath the poop deck (to make that climb, you would had to have been in very good physical condition, thin as a rail, and definitely not claustrophobic!). While under way, the engineers were constantly in and out of these spaces, monitoring the condition of the shaft bearings. Without this access, it would have been impossible for the engineers to keep an eye on all of the shaft bearings aft of the generator room -- two per each approximately 30-foot segment of shaft -- as well as keeping a watch on the sealing gland on the inboard end of each sterntube. The bearings required steady monitoring to be certain that they were getting sufficient lubrication and that they were receiving enough cooling water, while the glands had to be checked to maintain the correct amount of water seepage past the packing material. Yes, you actually want those things to leak a little bit! Too much wasn't good for rather obvious reasons, while too little starved bearing surfaces within the sterntubes, and the packing gland itself, of the water that acted as the lubricating agent and coolant for both. In port, the packing rings were tightened to keep the tunnels dry, but prior to getting under way, the packing rings were again slackened to allow a constant trickle past the seal.

Regards,
Scott Andrews
 
That's interesting. I didn't realise that they used water on the bearings for lubrication. Although I have seen how slippery pine steps can be when they get wet and slimy so I can understand that it was a good idea. Did the shafts actually lie partially submerged (like in a car gearbox) to throw the water up over themselves or were there pumps etc? Are there any pictures of the inside of these tunnels? I've looked in a couple of my books but have not seen any. Thanks for the information there Scott. It is truly helping me understand the workings of the ship.
 
Jim,

I think you're missing my meaning here. The portion of each shaft that ran in water as the "lubricant" was only the very last segment -- the tailshaft -- which was almost fully contained within a component called a "sterntube". The sterntube for the center shaft was housed between the end of the bossing in the propeller aperture within the stern frame casting and the after peak bulkhead at frame 133 aft, while the sterntube for each wing shaft was located between the aft face of the after shaft brackets and the forward face of the forward shaft brackets. The remaining bearings which supported the shafts -- collectively often referred to as the "tunnel bearings", and individually called "plummer blocks" -- stood in the open and were situated upon fabricated steel supports called "stools. The stools were solidly built onto the frames and bottom structure of the ship. Oil, not water, was used to lubricate the bearing surfaces within the plummer blocks; this served not only to reduce friction between the bearing surface and the journal faces on the shafts, it also carried away some of the heat generated as the shafts rotated upon these bearings. To further regulate the temperature of these bearings, the cap and base castings of the plummer blocks were cored-out to provide surrounding water passages, much like the water jackets within the block and cylinder head of an automobile engine. Seawater from a water service line was piped into these passages, after which it drained off to the bilges and was pumped overboard with any other waste water that collected, such as the seepage from the sterntube glands, drainage from the waterways on interior decks, drainage of condensate from the turbine case, and blow-off from the various steam traps and separators.

You may want to purchase a set of Bruce Beveridge's general arrangement plans to add to your references. These plans contain far more in the way of technical details than the average g/a, including a layout of the shafts and the location of their respective bearings. These plans can be obtained here: http://titanic-model.com/ga-plans/ . It was these plans that the Discovery Channel used on their web site. In the mean time, to help you visualize and understand the details described above, if you will go to the following link, where you can preview these plans; click on the "Tank Top" and drag the view frame back over the stern area: http://dsc.discovery.com/convergence/titanic/explorer/explorer.html Using the left mouse button, you can click to zoom, or you can pan by hold the button down and dragging the mouse.

Regards,
Scott Andrews
 
I have in my hands a book called "The great ocean liners" that contains a huge photograph of the fitting out of the SS Vaterland. In the picture you can see some workers installing one of the stardboard propellers in a shaft with the help of a crane. It is a pity because that picture is not available on the web, but I hope it helps.
 
Hi Ruth, welcome to the board! The propellers themselves were positioned on the shaft by crane. As for how they were fitted, the following information comes from the book "Titanic: The Ship Magnificent (Vol. 1)" by Bruce Beveridge et al, in which more detailed information is available. The ends of the shafts were tapered with a threaded tip. The propellers had a tapered hole through the centre which matched the tapered end of the shaft. A keyway was milled in both the hole and the shaft end in which a key was inserted to keep the propeller from turning relative to the shaft. A huge nut threaded onto the end of the shaft and held the propeller in place. The nut was covered with a cone-shaped cap called a "fairweather".

Hope that was what you were looking for!
 
Hello. I'm new to the board, and I have a question about the central propeller shaft on the Olympic Class ships. I'm working on a set of general arrangement plans for all three of the Olympic's at a scale of 3/32" = 1' 0". In the Midsummer 1911 special number of The Shipbuilder, they show the centerline of the central propeller shaft as being 3' higher than the centerlines of the wing shafts, but on the outboard profile (and also on Bruce Beveridge's inboard profile posted on this site, the shaft centerlines are shown as exactly the same height at the propellers. For this to be correct, there must have been a "step" in the center shaft somewhere aft of the Electric Engine Room. The only reason I can think of for the provision of such a "step" in the shafting is if the central shaft had been fitted with reduction gearing, but The Shipbuider makes no mention of reduction gearing being fitted, and no such gearing is shown or noted on Bruce's Tank Top plan. So my question, for the sake of making accurate drawings, is this; are the centerlines of all 3 propellers the same height, or does the center prop's centerline need to be 3' higher than the wings'?
 
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