Steering / Rudder engines

[David G. Brown]

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

 

[Tim Aldrich]

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.

 

[B-rad]

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.
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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.

 

[Oliver K]

So the entire travel of the piston is what moved the tiller? Interesting.

 

[B-rad]

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.

 

[Lars Lunden]

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.

Nice information. I will add two diagrams of the helm indicator; I don' know if Titanic used the old or new pattern. You will have a transmitter on the steering engine and have a cable all the way to the bridge's helm indicator. A long way!

 

[Tim Aldrich]

IDK if this is what you were looking for, but perhaps.

Yes, that is one of the little details I'm interested in. Thanks for sharing that.

 

[nicholas morrison]

May I confess to being a Grandson of Willian Gregory Gibbons (1864-1952) who was involved in the steering system, the family have never known why he chose not to take his free passage.

 

[khokhar1912]

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.

View attachment 41759

Brad, what percentage of glycerine goes in the control fluid, do you have a a primary source, or a technical report?

 

[Stephen Calcutt]

Here's a video of Mr. AE Karnes explaining how the analogue computer of these steering engines worked, if anyone is curious.