Physical Configuration of Engine-Order Telegraphs

Before attempting to assign functions to the individual telegraphs on Titanic's bridge, an understanding of how the telegraphs physically operated might be helpful.

Exterior Features

Weather Deck Telegraphs: All examples of Titanic’s telegraphs (as known from period photos and recovered artifacts) consisted of a double-faced order drum mounted on a pedestal. This was certainly the arrangement on the captain’s bridge and aft docking bridge. All are of identical construction, with the exception of the main engine telegraphs, each of which was fitted with a third “tell tale” dial to report instantaneously on the engines' movements.

Typically (but not always), these “dual” telegraphs deal with a single function (such as rope handling for docking procedures) but one face carried orders for the port side of the vessel; the other, for the starboard.

The command dials were made of glass. Paint was applied to the interior side to spell out the commands required.

A square aperture was cut into the forward face of the drum, which permitted the attachment of an external lamp to backlight the order dial. The base of the lantern body was curved to match the drum and included keyhole slots that fit over existing mounting screws on the drum.

Normally, an electrical bulb was used; however, in the event of electrical failure, fuel burning lamps (probably kerosene) could be used as backups.

It is interesting to note that the electrical lamp cover looks to be a converted kerosene unit, complete with chimney and smoke diffuser. This was probably an ad hoc arrangement that allowed J.W. Ray to electrify their pre-existing telegraph line without extensive modification to the telegraph design or re-tooling of the factory.

Folding wire handles attached to the sides of the lantern body facilitated the removal of a hot lantern.

Original artwork by Parks Stephenson

Left: The electrical switches themselves are interesting in that they seem to have two distinct switching elements. The night-light is switched on and off through a dust- and water-proof toggle switch, actuated by a rod ending in a ball grip. The ball grip would be attached through a rod to the gland at the bottom of the switch case, but in this example it is sheared off.

 

Right: A similar switch made dust- and explosion-proof for the British coal mining industry, ca. 1911.

Images courtesy of RMS Titanic, Inc.
Author's collection

Another interesting point is the knurled cap. This may have been an access cap used to replace a damaged switch.

However, the author has inspected a telegraph switch recovered from the wreck, and found that the knurled knob rotated.

The range of motion (and the fact the cap did not come off) suggested at the time that this might be a rheostat to dim the telegraph lights to comfortable levels when operating at night.

Images courtesy of RMS Titanic, Inc.
Author's collection

Left: The back of the switch. The manufacturer's name, Lektrik, is legible.

 

Right: This photo shows one of the telegraphs on the sea bed with a ball grip visible. When the ball was pulled out, the link operated an ordinary toggle switch to close the circuit and turn on the light.

Images courtesy of RMS Titanic, Inc.
Author's collection

Left: It should be noted that, customarily, once a ship was at sea, the telegraph lights were extinguished completely. Weather permitting, they would remain unused for the balance of the voyage as even low levels of white light would impair the night vision of the deck officers.

 

Right: On the after face of each telegraph pillar was an access panel. This allowed engineers access to the turnbuckles that adjusted the tension on the wires.

Because the pulley chains ran over toothless pulley sheaves, there was a tendency for the command handle and order arrow to drift a few degrees apart over the course of time. This access plate allowed both indicators to be lined up again.

Original artwork by Parks Stephenson

Telegraphs Mounted in Engine Room

The telegraphs in the engine room pose a special problem since no telegraphs have been recovered that can be positively identified as having come from the engine room, and no documentation exists regarding their configuration.

Jim Cameron has carefully explored the space between the reciprocating engines on one of his recent trips to the wreck. By special arrangement, the author was allowed to study the original digital film masters and a close review of the video recovered shows no remains of instrumentation. This leaves the configuration of the engine room telegraphs in doubt.

Occasionally, the engine room units are pedestals identical to those used on the weather decks, but more usually, they are mounted directly on the engine to save space.

Interior Components

The recovery of actual telegraphs from the Titanic permits direct inspection of the interior mechanism.

All telegraphs consist of two concentrically-mounted shafts carried by ball or roller bearings. It is fascinating to note that many of these bearings still operate perfectly and the handles and order arrows on newly recovered artifacts must be lashed to keep them under control.

For most of the length between telegraphs, multi-strand steel cables are used; however, when passing over pullies, chains are used to reduce friction and prevent chafing at vulnerable points in the system.

The shaft bearings are carried by three-legged “spiders” that are rigidly bolted to the casing drum. The outer shaft ends of course carry the order transmitting handle, while the inner shaft end carries a pulley “order wheel”, around which is wrapped a bicycle-like chain, cinched tight with a turnbuckle.

Images courtesy of RMS Titanic, Inc.
Author's collection

The telegraph drum heads do not connect with the support pillar directly, but rather are supported by brass brackets. These brackets serve to steady the drum head. In addition, they also carry small guide pullies to keep the chains in alignment and prevent tangling and rubbing in the tight-fitting support pillar.

Images courtesy of RMS Titanic, Inc.
Author's collection

In order to “lock” the order handle and arrow in the dead center of a command and thereby prevent ambiguity, the receiving arrow was linked to a “star wheel.” This was a gear with widely spaced teeth that meshed with a prawl kept in tension with a spring.

The star wheel and prawl served two functions. First, the number of gaps between the teeth corresponded to the orders on the dial face. As mentioned, the prawl was kept under spring tension, which forced it between the gear teeth. This meant that as the order handle was moved, it made a distinct “click” and locked in place over the intended order.

Second, a bell was attached to the prawl arm. As the prawl jumped over the teeth, a clapper struck a small gong to indicate that the order arrow was moving to a new command. This of course was to draw attention to the fact that a new command had been issued.

This drawing is purely diagramatic. Because of space restrictions inside the telegraph head, the prawl arm and bell clapper are folded over in a rather complicated way. Rather than attempting to deptict the acutal linkage used on Titanic, the author has substituted this schematic of the linkage.

From the author's collection

Having discussed the basic configuration of the engine-order telegraphs, we can now identify the purpose of Titanic's telegraphs as seen in archival photographs and recovered from the wreck.


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