There was also an independent storage battery and coil, in event of the failure of the current supply, which came from the ship's dynamos.
_Submarine signaling._--The Submarine Signal Co.'s apparatus was provided for receiving signals from the submarine bells. Small tanks containing the microphones were placed on the inside of the hull of the vessel on the port and starboard sides below the water level, and were connected by wires to receivers situated in the navigating room on the port side of the officer's deck house.
_Various._--The whistles were electrically actuated on the Willett Bruce system. The boiler-room telegraphs, stoking indicators, rudder indicators, clocks and thermostats were also electrical. The water-tight doors were released by electric magnets.
_Emergency circuit._--A separate and distinct installation was fitted in all parts of the vessel, deriving current from the two 30-kilowatt sets above mentioned, so that in the event of the current from the main dynamos being unavailable an independent supply was obtainable.
Connected to the emergency circuit were above 500 incandescent lamps fitted throughout all passenger, crew, and machinery compartments, at the end of passages, and near stairways, also on the boat deck, to enable anyone to find their way from one part of the ship to the other.
The following were also connected to the emergency circuit by means of change-over switches: Five arc lamps, seven cargo and gangway lanterns, Marconi apparatus, mast, side, and stern lights, and all lights on bridge, including those for captain's, navigating, and chart rooms, wheelhouse, telegraphs and Morse signaling lanterns, and four electrically-driven boat winches. These latter, situated on the boat deck, were each capable of lifting a load of 15 hundredweight at a speed of 100 feet per minute.
_Ventilating._--There were 12 electrically-driven fans for supplying air to the stokeholds, 6 electrically-driven fans for engine and turbine room ventilation. There were fans for engine and boiler rooms.
MACHINERY.
_Description._--The propelling machinery was of the combination type, having two sets of reciprocating engines driving the wing propellers and a low-pressure turbine working the center propeller. Steam was supplied by 24 double-ended boilers and 5 single-ended boilers, arranged for a working pressure of 215 pounds per square inch. The turbine was placed in a separate compartment aft of the reciprocating-engine room and divided from it by a water-tight bulkhead. The main condensers, with their circulating pumps and air pumps, were placed in the turbine room.
The boilers were arranged in six water-tight compartments, the single-ended boilers being placed in the one nearest the main engines, the whole being built under board of trade survey for passenger certificate.
_Reciprocating engines._--The reciprocating engines were of the four-crank triple-expansion type. Each set had four inverted, direct-acting cylinders, the high-pressure having a diameter of 54 inches, the intermediate pressure of 84 inches, and each of the two low-pressure cylinders of 97 inches, all with a stroke of 6 feet 3 inches. The valves of the high-pressure and intermediate cylinders were of the piston type, and the low-pressure cylinder had double-ported slide valves, fitted with Stephenson link motion. Each engine was reversed by a Brown type of direct-acting steam and hydraulic engine.
There was also a separate steam-driven high-pressure pump fitted for operating either or both of the reversing engines. This alternative arrangement was a stand-by in case of breakdown of the steam pipes to these engines.
_Turbine._--The low-pressure turbine was of the Parsons reaction type, direct coupled to the center line of shafting and arranged for driving in the ahead direction only. It exhausted to the two condensers, placed one on each side of it. A shut-off valve was fitted in each of the eduction pipes leading to the condensers. An emergency governor was fitted and arranged to shut off steam to the turbine and simultaneously change over the exhaust from the reciprocating engines to the condensers, should the speed of the turbine become excessive through the breaking of a shaft or other accident.
_Boilers._--All the boilers were 15 feet 9 inches in diameter, the 24 double-ended boilers being 20 feet long, and the single-ended 11 feet 9 inches long. Each double-ended boiler had six and each single-ended boiler three furnaces, with a total heating surface of 144,142 square feet and a grate surface of 3,466 square feet. The boilers were constructed in accordance with the rules of the board of trade for a working pressure of 215 pounds per square inch. They were arranged for working under natural draft, assisted by fans, which blew air into the open stokehold.
_Auxiliary steam pipes._--The five single-ended boilers and those in boiler rooms Nos. 2 and 4 had separate steam connections to the pipe supplying steam for working the auxiliary machinery, and the five single-ended boilers and the two port boilers in boiler room No. 2 had separate steam connections to the pipe supplying steam for working the electric-light engines. A cross connection was also made between the main and auxiliary pipes in the reciprocating-engine room, so that the auxiliaries could be worked from any boiler in the ship. Steam pipes also were led separately from three of the boiler rooms (Nos. 2, 3, 5) above the water-tight bulkheads and along the working passage to the emergency electric-light engines placed above the load line in the turbine room. Pipes were also led from this steam supply to the pumps in the engine room, which were connected to the bilges throughout the ship.
_Main steam pipes._--There were two main lines of steam pipes led to the engine room, with shut-off valves at three of the bulkheads. Besides the shut-off valves at the engine-room bulkhead, a quick-acting emergency valve was fitted on each main steam pipe, so that the steam could at once be shut off in case of rupture of the main pipe.
_Condensing plant and pumps._--There were two main condensers, having a combined cooling surface of 50,550 square feet, designed to work under a vacuum of 28 inches with cooling water at 60 F. The condensers were pear shaped in section, and built of mild steel plates.
Four gun-metal centrifugal pumps were fitted for circulating water through the condensers. Each pump had suction and discharge pipes of 29-inch bore, and was driven by a compound engine. Besides the main sea suctions, two of the pumps had direct bilge suctions from the turbine room and the other two from the reciprocating-engine room. The bilge suctions were 18 inches diameter. Four of Weir's "Dual" air pumps were fitted, two to each condenser, and discharged to two feed tanks placed in the turbine engine room.
_Bilge and ballast pumps._--The ship was also fitted with the following pumps: Five ballast and bilge pumps, each capable of discharging 250 tons of water per hour; three bilge pumps, each of 150 tons per hour capacity.
One ash ejector was placed in each of the large boiler compartments to work the ash ejectors, and to circulate or feed the boilers as required.
This pump was also connected to the bilges, except in the case of three of the boiler rooms, where three of the ballast and bilge pumps were placed. The pumps in each case had direct bilge suctions as well as a connection to the main bilge pipe, so that each boiler room might be independent. The remainder of the auxiliary pumps were placed in the reciprocating and turbine engine rooms. Two ballast pumps were placed in the reciprocating-engine room, with large suctions from the bilges direct and from the bilge main. Two bilge pumps were also arranged to draw from bilges. One bilge pump was placed in the turbine room and one of the hot salt-water pumps had a connection from the bilge main pipe for use in emergency. A 10-inch main ballast pipe was carried fore and aft through the ship with separate connections to each tank, and with filling pipes from the sea connected at intervals for trimming purposes.
The five ballast pumps were arranged to draw from this pipe. A double line of bilge main pipe was fitted forward of No. 5 boiler room and aft of No. 1.
GENERAL.
There were four elliptical-shaped funnels; the three forward ones took the waste gases from the boiler furnaces, and the after one was placed over the turbine hatch and was used as a ventilator. The galley funnels were led up this funnel. The uptakes by which the waste gases were conveyed to the funnels were united immediately above the water-tight bulkhead which separated the boiler rooms.
All overhead discharge from the circulating pumps, ballast pumps, bilge pumps, etc., were below the deep load line, but above the light line.
The boilers were supported in built steel cradles, and were stayed to the ship's side and to each other athwart ships by strong steel stays.
Built steel chocks were also fitted to prevent movement fore and aft.
Silent blow-offs from the main steam pipes were connected direct to both condensers.
CREW AND PASSENGERS.
When the _Titanic_ left Queenstown on April 11 the total number of persons employed on board in any capacity was 885.
The respective ratings of these persons were as follows:
Deck department 66 Engine department 325 Victualing department 494 ---- 885
Eight bandsmen were included in the second-class passenger list.
In the deck department the master, Edward Charles Smith, held an extra master's certificate; Chief Officer H. F. Wilde held an ordinary master's certificate; First Officer W. M. Murdock held an ordinary master's certificate; Second Officer C. H. Lightoller held an extra master's certificate; Third Officer H. J. Pitman held an ordinary master's certificate; Fourth Officer J. G. Boxall held an extra master's certificate; Fifth Officer H. G. Lowe held an ordinary master's certificate; Sixth Officer J. P. Moody held an ordinary master's certificate.
In the engine department were included the chief engineer and 7 senior and 17 assistant engineers.
In the victualing department there were 23 women employed.
The total number of passengers on board was 1,316.
------------------------------------------------------ Male. Female. Total.
------------------------------------------------------ Of these-- First class 180 145 325 Second class 179 106 285 Third class 510 196 706 ----- 1,316 ------------------------------------------------------
Of the above 6 children were in the first class; 24 children were in the second class; 79 children were in the third class; or 109 in all.
About 410 of the third-class passengers were foreigners, and these, with the foreigners in the first and second class and in the victualing department, would make a total of nearly 500 persons on board who were presumably not English speaking, so far as it is possible to ascertain.
The disposition of the different classes of passengers and of the crew in the ship has already been described (pp. 10-15). In all, 2,201 persons were on board.
II. ACCOUNT OF THE SHIP'S JOURNEY ACROSS THE ATLANTIC, THE MESSAGES SHE RECEIVED, AND THE DISASTER.
THE SAILING ORDER.
The masters of vessels belonging to the White Star Line are not given any special "sailing orders" before the commencement of any particular voyage. It is understood, however, that the "tracks" or "lane routes"
proper to the particular time of the year, and agreed upon by the great steamship companies, are to be generally adhered to. Should any master see fit during this passage to deviate from his route he has to report on and explain this deviation at the end of his voyage. When such deviation has been in the interests of safety, and not merely to shorten his passage, his action has always been approved of by the company.
A book of general ship's rules and uniform regulations is also issued by the company as a guide; there are in this book no special instructions in regard to ice, but there is a general instruction that the safety of the lives of the passengers and ship are to be the first consideration.
Besides the book of ship's rules, every master when first appointed to command a ship is addressed by special letter from the company, of which the following passage is an extract:
You are to dismiss all idea of competitive passages with other vessels and to concentrate your attention upon a cautious, prudent, and ever-watchful system of navigation, which shall lose time or suffer any other temporary inconvenience rather than incur the slightest risk which can be avoided.
Mr. Sanderson, one of the directors, in his evidence says with reference to the above letter:
We never fail to tell them in handing them these letters that we do not wish them to take it as a mere matter of form; that we wish them to read these letters, and to write an acknowledgment to us that they have read them, and that they will be influenced by what we have said in those letters.