The telephone installation is divided into two sections, viz., the navigating group and the internal system. The navigating group provides for communication between the wheel house on the bridge and the forecastle, crow’s nest, engine room, and poop; also between the chief engineer’s cabin and the engine room, and between the engine room and the various stokeholds.
The instruments employed are Messrs. Alfred Graham & Co’s loud-speaking Navy telephones of the latest type. Except in the chief engineer’s room, where the cabin type is fitted, the telephones are of the “Universal “pattern, in which calls are given by means of an interrupter or bell as well as by voice. The apparatus is mounted in special forms to suit the various positions.
At the forecastle and poop (Figs. 15 and 16) the instruments are contained within a polished brass casing mounted on a pillar, and the whole fitting is arranged in portable form, so that the apparatus can be used at two alternative positions in the case of the forecastle set and a second position at the poop. For the crow’s nest, the telephone is mounted within a metal hood, and this set also is portable.
In the wheel house on the bridge (Fig, 17) four instruments are fitted, and each telephone is provided with an indicating device, and in addition to a flag showing, as is usual, a signal lamp is caused to glow upon a call being received.
In the engine room (Fig. 18) three telephones are employed, and the instrument for communicating with the boiler rooms operates in conjunction with a combined switch and indicator giving both lamp and flag signals as previously referred to. In each boiler room, the telephone is mounted within a metal hood, and in addition a special calling receiver is provided at each station as well as a visual indicator.
The current for operating the system is obtained from the ship’s lighting circuit, the pressure being reduced for telephonic working by means of resistances, and the noise of commutation, inherent in machine generated supply, is eliminated by the introduction of inductance coils. A standby battery is also provided, and is introduced in the circuit, should the main supply fail, by means of an automatic switch.
The internal system provides for inter-communication between a number of cabins through a central exchange, which has a capacity of 50 lines.
The switchboard is arranged to give a lamp signal upon a call being made, and in addition to the usual audible signal, a voice call can be given to the exchange from any station in connection, so that the rapidity of operation is assured.
The user in one of the cabins has simply to pick up the telephone and say straightaway the station he wishes to speak to and a loud receiver at the exchange gives the instruction, and the operator seeing a lamp glowing corresponding with the calling station then connects the calling station with the station required, thus obviating the usual delay in communicating with the calling station and ascertaining the position required.
The current supply is obtained from the lighting circuit, as in the case of the navigating telephone system, and the automatic switch and standby battery is contained within the exchange switchboard casing.
The telephone sets in each cabin are of Graham’s intermediate loud-speaking type, and comprise a hand set with a circular metal push and terminal box. At the majority of the positions the fittings are silver plated, and at others of polished and lacquered brass. Junction boxes have been introduced so as to facilitate testing and extension of the installation.
In addition to the exchange system, a separate group of circuits is provided for direct communication between the various pantries and the galley, baker’s shop, butcher’s shop, &c.
In foggy weather, when approaching land or in the vicinity of a lightship, submarine bells are sounded, attached thereto, under the sea, and the signals are heard by a telephone in the chart room, enabling those in charge of the vessel, to tell its precise position, whilst wireless telegraphy embodying Marconi’s latest inventions for long-distance transmission gives additional security, and provides facilities for communication between ship and ship, and ship and shore, which are now too well recognised to need further description.
No modern liner is complete without a wireless telegraph installation. With such an equipment not only is communication with ship or shore possible in case of accidents, but the passenger is enabled during the voyage to keep himself in touch with the world’s news. The “wireless” apparatus on the “Olympic” is of the Marconi type and consists of a 5 kw. motor-generator set combined with the latest type of valve receiver installed as a standby. The installation is designed to provide, when employed with a suitable aerial having mean height of 170 ft., a working range of 250 nautical miles over water, and a maximum range considerably exceeding the above figure. It is arranged to tune when transmitting to waves of 300 and 600 metres, and to tune when receiving to all waves between 100 and 2,500 metres. Two masts, 200 ft. high, placed 600 ft. apart, are used for the support of the aerial, which is of the twin T type, one aerial only of appropriate type being employed for the double purpose of transmitting and receiving. The earth connection is made by insulated cable to convenient points on the hull of the vessel.
Continuous current at 110 volts is supplied to a continuous-current motor which is mounted on a common bed with and direct-coupled to an alternating-current generator. The latter has an output of 5 kw. at 300 volts. The manipulating gear consists of a Morse key which actuates electrically an electro-magnetic relay key in the transformer primary circuit. The Morse key is provided with telephone short-circuiting contacts to prevent the operator’s ear becoming insensitive owing to the noise in the telephone during transmission. The receiver is a standard magnetic detector and multiple tuner, by which all waves between 100 and 2,500 metres wave length can be received. The multiple tuner is calibrated to permit of the instrument being set to any pre-arranged wave length, and is further provided with a change-over switch permitting an instantaneous change of the circuit from a highly syntonised tuned condition to an untuned condition (for standing by). This arrangement has been especially devised for picking up incoming signals of widely different wave lengths. By reason of its robust nature the magnetic detector may be kept permanently connected to the transmitting aerial, thus dispensing with all mechanical change-over switching arrangements between the transmitting and receiving circuits. Further, in conjunction with the short-circuiting contacts on the manipulating key, it allows the operator to be interrupted during the transmission of a message in the event of there being erroneous reception at a corresponding station. A suitable testing buzzer is provided and is kept permanently installed for the purpose of instantaneously testing the receiving circuits, and a tuning lamp and adjustable choking coil are also permanently installed for the purpose of indicating the condition of syntony of the transmitting circuits, while a wave-meter, covering the full range of the transmitting circuit is supplied. The Marconi Apparatus is shown in Figs. 19 and 20.
The bell installation comprises no fewer than 1,500 pushes, which, in the staterooms, are for the most part grouped with the switches for controlling the lights on combination plates placed within convenient reach of teach berth.
In conclusion, we would like to express our indebtedness to Messrs. Harland & Wolff for the information given above and to our contemporary ”The Shipbuilder” for the loan of the blocks of Figs. 1, 3 and 12.