Written by Robert Hahn
Now, back to Titanic.
Figure 1 shows the beautiful profile of the inboard side of the engine, which faced the centerline of the hull. Figure 2 shows the outboard side, the side that faced the side of the hull. You can see nearly all of the detail, which will be described below.
Figure 3 shows a view from the forward end, or that part of the engine that faced the bow, and shows a pulley with which the model is turned during display at shows and model fairs. When actually run, the engine will run on steam, but to avoid corrosion in the cylinders and pipes, only compressed air is used.
In June 1996, after his model of the portside engine of the Deutschland
was completed, Mr. Pohlmann started the research for his new project.
The only resources Mr. Pohlmann had available were the various books,
with which most of us are familiar, containing pictures of the engines
in the workshop of Harland & Wolff, and the drawings of the engines
printed in The Shipbuilder. As you may know, those plans are
only basic drawings, intended to show the arrangement of the machinery
rather than any detail of the engines themselves. Mr. Pohlmann tried
to contact Harland & Wolff for assistance, but unfortunately they
were uncooperative. This is sad, because as you see this was a serious
project. I hope that the people at H&W read this and will be more
cooperative in the future. Due to the lack of detailed drawings, Mr.
Pohlmann had to improvise in some cases, especially for the small
pumps and auxiliary engines. Here his immense knowledge about old
steam engines was very helpful and he did an incredible job.
Cylinder, Bedplate and Columns
The eight columns required extensive machine work after casting, to make sure, that all four cylinders could be mounted parallel to each other. The guides for the cross heads inside the columns were made of bronze and screwed in.
The cylinders are fitted with sleeves made of cast iron, because the pistons are made of aluminum too as well as the cylinders. As some may know aluminum on aluminum is not a very good combination for proper sliding, like aluminum on cast iron is. After this, the steam holes in the cylinders were milled and the 168 (!) threaded holes for the cylinder head bolts were drilled and tapped in.
Unfortunally this arrangement is not correct for Titanics engine.
The reason for it is the lack of information and missed support from
Harland&Wolff. Mr. Pohlmann told me he though to see it in pictures
of the wreck and for the steam valve of the high pressure cylinder
he is right, but not for the cylinders themselve. Anyway it was a
common arrangement for steam engines in those days and this was the
reason, why he made the decission to construct it that way.
To turn the engine, the vertically oriented shaft fitted with the worm gear was swung to the left to put the worm gear in contact with the main toothed wheel. After this the two small cylinders, fed by steam, turned the vertical shaft, thereby turning the crankshaft of the main engine. The model needs 45 seconds for a complete 360° turn. Their full-sized counterparts were required to be able turn the main engines through one complete revolution every eight to ten minutes.
In the next issue of the Docking Bridge, part 2 of this article will describe the thrust block and many more wonderful details of this model steam engine. If you have questions regarding the model, please send them to me, I will forward them to Mr. Pohlmann. Send your mail to Hahn@titanic-model.com.