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Steering / Rudder engines

Discussion in 'Technical Construction Design' started by Andy Carter, Feb 11, 2018.

  1. Andy Carter

    Andy Carter Member

    Hi everyone,

    I been looking in for a while but have decided to post now, I've been interested in the technical side of Titanic since 1983

    My questions are regarding the engine and spare engine for the Rudder;
    1 How many crew where in that station and did they sleep in there?
    2. Where did the steam exhaust go?
    3. Where was the boiler for this engine or did it run of the main boilers?
    4. Anything else anyone can tell me about this section of the Ship

    Thank you and thanks for a great website

    all the best Andy Carter
     
  2. If you mean C Deck with the steering gear, no one was stationed there or sleep in there.
    I am not sure (my memory might be wrong) a crew member (might have been the deck engineer or a quartermaster) checked it from time to time.
    There were two sets of steam engines which got their steam from the main boilers. As the question goes into much technical detail I would like to recommend the book "Titanic -The Ship Magnificent Volume 1" which might have the answers you are looking for.
     
  3. Andy Carter

    Andy Carter Member

    I think someone must have been stationed in there, surely they wouldn't leave a large Steam Engine running without anyone there?

    Also shows bunks on the deck plans
     
  4. Had a look the cabin was for the assistant plumber and a deck engineer.
    I guess I was right in my above post #2 it was the deck engineer who had a look.
     
  5. Typically, steering room engines are unmanned. Aside from people having to check in on the machinery as a matter of routine, there's no reason to keep anybody in there 24/7.
     
    Ioannis Georgiou likes this.
  6. Andy Carter

    Andy Carter Member

    Thanks for the replies.

    How about the exhaust steam from the engine, does anyone know where it exited the Ship?
     
  7. Exhaust steam does not exit the ship. Steam is condensed back into feedwater, reheated, and fed back to the boilers.
    If you are really that interested in the technical side of the ship, I strongly recommend buying the reference book that Ioannis listed above.
     
  8. Rancor

    Rancor Member

    Hi Andy,

    If I recall correctly exhaust steam from the steering engines was directed to the main condensers, not the direct contact heater like most of the other auxiliary engines.
     
    Andy Carter likes this.
  9. codad1946

    codad1946 Member

    It seems you are right about exhausting to the main condensers, and that makes sense to a certain extent - Steering gear
    - has a lot of information on the steering engines. On ships with electro-hydraulic gear, 30 one way to passing 30 the other is usually achieved in around 25s on one engine, 18s on two if I remember correctly. Titanic's steering engines had to be jacked into place to engage the wheels - not sure if you could use both at once as you can and do on a modern ship.

    It seems however that you couldn't test the steering engines unless your main condenser was fired up, which of course it would be if the ship was ready to sail. There could have been a line back to either the surface feed heater or the auxiliary condenser for port use. Tom Bates sent me some schematics, but they are on another computer; they may show the steam from the steering gear.
     
  10. The steering system was patented by Andrew Betts Brown, the system used hydraulics and was called "Browns Patent Telemotor" which was stamped on the wheel(s) to denote the system, it was hydraulic (the main unit was the master cylinder) and the slave cylinder was located at the valve for the steering engine, the steering engine was what performed the mechanical work, when the wheel was turned, it pushed the fluid throughout the system and into the steering engine valves, which will allow it to run and steer the ship.

    The steering gear was of the Wilson-Pirrie type, it had odd teeth, like tire tracks, designed for less vibration and more accuracy i believe, the main gear was connected to a Wilson-Pirrie Elastic Quadrant, which was connected to a Keyed tiller via stiff springs, to try and dampen out negative feedback caused by waves and other stuff.

    The wheel on the stern docking bridge was directly connected, and a fourth "fake" wheel was used to test the engine(s) directly.

    The standard for the telemotor was 8 turns for hard-over, springs were fitted to the cylinders and the backlash from the rudder will cause the wheel to give resistance (negative feedback) the more you spin it round (releasing it at this point will cause it to spin round really fast).


    More modern systems are hydro-electric, I'm not sure if they have tried "steer-by-wire" (via servo motor) on a ship before.
     
  11. Somewhere in my files I have a period description of how the springs on the rudder end of the telemotor system worked. It came from a depth article in a now-obscure publication. The springs were not meant to provide rollback on the steering wheel. They were to give the quartermaster a sense of increase pressure as the helm was put over and less so as it returned to dead center. The copywriter of the company's ad got it wrong and that wording not only became part of the Titanic legend, but was reprinted into the 1970s in many shiphanding textbooks.

    NO, I don't plan to ferret out the details. Even if I found them chiseled on two stone tablets in a golden ark nobody would believe me. So, I intend to leave the myth undisturbed. Not worth the effort of getting to the truth on something so trivial.

    What I will say is that any steering system that developed rollback as claimed would make life a Medieval torture for the quartermasters at the helm. You often need to run with several degrees of rudder to maintain proper course in a seaway or wind. Holding the wheel against the steering system would wear out Popeye's biceps in half a trick.

    -- David G. Brown
     
    Tim Aldrich likes this.
  12. B-rad

    B-rad Member

    The hydraulic system worked by having two cylinders, connected by pipes, in which there were two pistons. The cylinders were filled with a water/glycerin mixture (to lower its freezing point). As one piston was moved, due to the liquid being practically uncompressible, the other piston was displaced. When one piston is at rest, so is the other. I've included a picture of such system along with a snippet about the springs.

    telemotor steering.png
     
  13. Yep, basically the same as the brakes in your car, and thanks for me letting me know the liquid used, the original patent for the telemotor just mentions "water".
     
  14. Hydraulic steering systems are not like other mechanical devices. They have no “dead center.” That is, eight turns to hard over does not mean the rudder will be amidships by turning eight turns back. This nature of hydraulic system comes from the inevitable “blow by” of fluid around the piston seals and, in 1912, the introduction of air into the system both at the pistons and at joints connecting up the piping and tubing. The lack of a true mechanical dead center is why the springs had to be installed.

    Four pistons were involved in the total system. Two in the telemotor on the bridge controlled flow of fluid in the system. Two others on the steering motor operated the steam-powered steering engine that actually turned the rudder. When the telemotor was turned say to port, the steering engine would rotate the quadrant gear to the starboard and, thus, cause the rudder to wing to port and the ship would go left. Letting go of the wheel simply stopped the steering engine from rotating the quadrant so that the amount of rudder applied would remain constant.
    Rotating the bridge steering wheel back the same number of turns as had been made to port did not return the rudder to exact dead center due to the “slippage” outlined above. As the wheel rotated through the desired dead center a small pump injected fluid into the system to replace any leakage. This pump made an audible “thunk” and told the quartermaster the steering wheel was centered. A small tank for extra fluid remains in position near the top of Titanic’s telemotor and is easily spotted in photographs.

    Back aft, the rudder was not necessarily dead center. So, bypass valves in the telemotor allowed fluid to circulate freely in the system. Here’s where the springs performed their primary duty. They provided the power to center the pistons on the steering engine which would, in turn, center up the rudder. Once that happened, all pressure in the hydraulic system effectively disappeared and the rudder remained centered until the steering wheel was turned once again.

    While the system depended upon those springs for centering the wheel and rudder, they also provided “live” feedback to the quartermaster. The steering became noticeably more difficult as the wheel neared hard over. Likewise, any resistance to coming back to dead center changed as the system neared center.

    As I have said before, rollback as needed for safely steering an automobile would have been anathema in a ship. Vessels need steering systems that do exactly the opposite – allow the steering apparatus to hold a set angle without the “driver” (a.k.a. quartermaster) forced to fight the wheel.

    Sometime prior to 1906 a Brow’s telemotor magazine ad appeared extolling the system’s alleged “rollback” characteristics. I suspect is was a lubber of a copywriter who originated this myth. But, it stuck. And it stuck hard, even in the company’s later advertising. I’ve even seen generic telemotor systems described in textbooks with exactly the same wording as in the pre-Titanic advertisements. And, a half century of repetition in otherwise reputable publications has made the myth impossible to overcome. But, I’ve had the privilege of studying up close and in person with hands on a telemotor nearly identical to Titanic’s. The machine does not match the myth.

    – David G. Brown


    PS -- If you want to see some early 20th century mechanical engineering a its finest, explore the various valves used to open and close the throttles of steam steering engines upon command from the ship's helm.
     
  15. Tim Aldrich

    Tim Aldrich Member

    The steering engines are fascinating. I understand hydraulics, I understand steam engines but the operation (the details, not the overall operation) of the steering engine gives my brain fits. David, your last post answered a question I had regarding the rudder being moved and then held in position. Thank you for that, it had been driving me nuts. These are some of the other things that rattle around in my head.

    The engine would have to run in both directions so I would assume the hydraulic system would be changing the valve gear from ahead to astern (maybe port and starboard would be more appropriate?) instead of acting on a throttle valve. Or were, perhaps the hydraulics acting on both a throttle valve and valve gear?

    In regards to the valve gear, I wonder if it would only have three positions. Off, full port, full starboard. I'm trying to figure out if the valve gear could be notched back but I don't think there would be a need as the engine would only run to move the rudder and once the rudder was in the desired position it would stop running.

    Steam and condensation in the cylinders. I know water and cylinders don't go together. The steam engines I've seen running in person and via the countless videos I've watched I know that engines are usually warmed first and cylinder drain cocks are opened for the first few revolutions allowing any condensation to escape the cylinders. I would assume that for an engine that only runs intermittently there would have to be provisions, aside from the normal lagging, to keep the engine warm and/or automatic cylinder drains.
     
  16. Tim --

    Haven't seen one of Titanic's steering engines in person, but have managed to get grease stains off a few in Great Lakes freighters of the period. Damdest things I've ever seen. On those freighters it was not possible to use glycol/water hydraulics becuase of the long 450 to 500 foot run through unheated holds. Rods were used instead. These terminated in a gear that opened the steam valve to the steering engine. Otherwise things were pretty similar.

    I'm not a snipe, so I don't have full command of the technical words used for the various pieces parts of the valving. In simple, the steering command from the wheel on the bridge opened one of two throttles -- port or starboard. The engine would then rotate the control valve as it swung the rudder. In effect, the "closed" position of the valve train was chasing the "open." When the closed caught up, the steering engine stopped moving and the rudder assumed the position dialed up by the steering wheel. Nothing more would happen until a new steering order came down from the wheel.

    Should the rods fail (or the hydraulics in a telemotor system give out) there was a "trick wheel" that opened or closed the appropriate valves manually. In theory, a man could steer the ship with that wheel by orders sent down from the bridge. Both lakes freighters had telephones, but they were probably not new with the ship. I suspect they replaced a steering telegraph sometime in the past.

    By the way, rod steering has zero rollback because of the number of bevel gears and universal joints in the system. No feedback meant the king spoke on the steering wheel was always up when the rudder was centered. No centering springs were needed like those used in hydraulic systems.

    The steering quadrants, however, were spring-loaded against shocks such as swinging too far hard over or the rudder striking an underwater object. If either the steering engine or quadrant failed, provision was made to steer using a block-and-tackle arrangement on deck. The wire rope of this system led to one of the ship's steam-powered mooring winches. And, there was a wheel on the fiddly roof which led by rod down to the steering engine as another backup system. Talk about belt, suspenders, and clothespin security.

    -- David G. Brown
     
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  17. Tim Aldrich

    Tim Aldrich Member

    Two throttle valves, I never would have thought of that but it makes sense. I'm familiar with the rudder quadrant from an article I read a few years ago, can't recall if it was here on ET or at the TRMA site. It's pretty cool how the quadrant works. I appreciate the reply.
     
  18. B-rad

    B-rad Member

    Here is the operation of the engines as explained in the publication 'Scientific American':

    The control is by means of a Brown's telemotor from the bridge actuating the steam valves. There is also fitted a Brown's Economic valve – or “get-out-of-the-way valve,” if we may be allowed to coin a word- to prevent leakage of steam while the engine is standing, due to absence of lap on the piston valves. This valve consists of a conical-seated valve in the steam admission port, with a coned projection extending into the engine valve chest, and when closed shuts steam completely off the engine. When the engine valve is moved by the telemotor it acts in the coned projection and pushes the valve back off its seat and admits steam a strong spring returning the valve to its seat when the engine valve has resumes its current position. We understand that the engines are capable of putting the helm from hard-a-port to hard-a-starboard in twenty seconds.

    IDK if this is what you were looking for, but perhaps. :)
     
    Tim Aldrich likes this.
  19. So the entire travel of the piston is what moved the tiller? Interesting.
     
  20. B-rad

    B-rad Member

    Here is a report I created a while ago about the steering engines. It has no information about the telemotor as I have yet to compile all info that I've gathered.
     

    Attached Files:

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