Transmission of intelligence on steam vessels

The

JOURNAL OF

THE

FRANKLIN INSTITUTE OF

DEFOTED

T H E S T A T E OF

PENNSYLVANIA

T O SCIENCE AIND T H E M E C H A N I C HR~rS

VOL. C L X V I I

J U N E , 19o9

No. 6

E L E C T R I C A L S E C T I O N (Stated meeting held Thursday, April r5, ±909.)

T R A N S M I S S I O N OF

INTELLIGENCE ON STEAM VESSELS. BY

H. A. HORNOR, Electrical

E n g i n e e ~ N e w V o r k S h i p b u i l d i n g Co.

COMMUNICATION o n s t e a m vessels divides itself into signals for navigational protection from o t h e r c r a f t a n d means whereby it may securely provide for its own safe carriage o f human life and cargo ; on the one h a n d exterior communication to ward off collision, as well as maintain its own legal course, o n the o t h e r interior communication for the proper, lawful a n d safe manipulation of the vessel and the accommodation o f her passengers, officers, and crew. Exterior communications required by law are: Rumming and a n c h o r lights, searchlights (in some instances), s t e a m whistle, siren fog whistle, rockets, etc. Wireless telegraphy, submarine signals, night signal sets, electric flash lights for s t e a m whistle, are carried on many vessels to-day as a greater factor o f safety. The scope of this paper will not permit even a brief description o f these systems, if indeed a brief descrip[ N o T E . - - T h e F r a n k l i n Institute i s not r e s p o n s i b l e for t h e s t a t e m e n t s a n d o p i n i o n s a d v a n c e d by contributors to t h e J o u r n a l . ]

VOL. CLXVII, No. lOO2--3 °

403

404

H . A . HORNOR.

tion c o u l d be m a d e , and attention will be a d d r e s s e d solely to the reasons for, and the p r e s e n t m e a n s of, interior communication on s t e a m vessels. It is generally k n o w n that s t e a m vessels vary g r e a t l y in type. T h e r e f o r e a s t a n d a r d steamship is but the immaterial m i n d w a n d e r i n g s of the h o p e f u l s h i p b u i l d e r - - h e w h o w o u l d like to m a n u f a c t u r e ships as they do s c r e w s , or p e n s . But it does not o c c u r to. many that o t h e r than the v a r y i n g t y p e s the vessel usually is for some particular or special service. T h u s one m i g h t fancy that a n u m b e r of ships d e s i g n e d exactly alike in r e g a r d to form, line, propulsion, etc., and yet for a different service, must, to satisfy this service, be very differently e q u i p p e d . So passenger and f r e i g h t vessels for o u r coastwise shipping, t h o u g h resembling transatlantic Leviathans, e m p l o y d o c k i n g telegraphs b e c a u s e they can more economically and time-sparingly e n t e r t h e i r docks. The transatlantic and transpacific vessels, due t o t h e i r size or due to the d o c k i n g facilities, d e p e n d upon tug-boats for these manoeuvres. Ferry-boats w h i c h are constantly c o m i n g in or g o i n g out of t h e i r slips are provided especially with direction tellt a l e s w h i c h a s s u r e the p i l o t that the e n g i n e s are rotating in such m a n n e r that the boat will a d v a n c e w h e n he has s i g n a l e d for a h e a d motion, A v o i d a n c e of s e r i o u s m i s h a p is thus accomplished. R i v e r e x c u r s i o n steamers, w h o s e superstructures are b u i l t entirely of w o o d , t h e r e b y r e q u i r i n g g r e a t vigilance for the detection of misanthropic fires, are supplied with a complete fire-alarm equipment, this s y s t e m b e i n g so d e s i g n e d that hardly a s q u a r e yard of the v e s s e l is not g u a r d e d by such an appliance. F o r the a s s u r a n c e of the travelling p u b l i c it may be well to note here that many of t h e s e vessels also c a r r y a sprinkler s y s t e m such as is now r e q u i r e d in many of o u r land factories. D r e d g e s which hold t h e i r w o r k i n g position by m e a n s of w o o d e n poles (called s p u d s ) , w h i c h m u s t be manipulated as t h e i r work progresses, req u i r e spud telegraphs w h i c h convey s i g n a l s from the working platform to the men employed t o r a i s e or l o w e r the s p u d s . So' c o u l d be multiplied instances of differences in communication e q u i p m e n t for differences in service. T e m p t i n g as this subject is, the duty lies b e f o r e us to d e s c r i b e the m e a n s of this communication and not its v a r y i n g application. Electricity h o l d s an important p l a c e in the transmission of ships' s i g n a l s , but this place is secondary as r e g a r d s the move-

TRANSMISSION OF INTELLIGENCE ON VESSELS.

405

ments of the vessels. T h o s e signals w h i c h are necessary to navigation and manceuvring of the vessel are performed mechanically. The control of the main propelling engines from the bridge o r pilot-house is accomplished by mechanical transmitters connected by bronze wire to receivers in the engine room. Wheels are encased in each instrument traversed by brass chains. To the ends of these chains the bronze wire is attached. Where corners are encountered triple linked brass chains are led over brass pnlleys. In all c a s e s reply signals are transmitted in o r d e r that no confusion may arise. The cycle is thus : - - P i l o t house orders full speed ahead. Engine room replies by b r i n g i n g a r r o w attached to h a n d l e to the same order. This latter is p e r f o r m e d before the actual movement is given t o the engine. The m a r k ings on the dials are usually of the same character, namely : " Stop," " S t a n d b y , " " S l o w , " " H a l f speed," " Full speed," " A h e a d , " and the same " A s t e r n . " The dials used on n a v a I vessels differ a trifle, thus : " Stop," '.' S l o w , " " H a l f , " " Full " on back motion. " S l o w , " " H a l f . " " Standard," " Full " on ahea~,t motion. The dials of the transmitters for n a v a l vessels, oft accotmt of gun shock, are made of a cast-brass f r a m e work with the .openings filled in with h e a v y transparent celluloid. T h o s e for the m e r c h a n t m a r i n e are fitted with white porcelain, the o r d e r s filled in with b l a c k ename,L They are illuminated by electric or oil lamps of s m a l l c a n d l e power. The receivers in the engine room are entirely of b r a s s with the o r d e r s deeply cut in a n d filled for the " A h e a d " and " Stop " divisions.with b l a c k enamel and on the " Astern " divisions red. The dials of standard transmitters are 12 inches in d i a m e t e r and receivers a b o u t 16 inches in diameter. Smaller sized machines are recommended only for small craft, such as have pilot-houses ,too small to accommodate the standard sizes. These instruments naturally superseded the o r d i n a r y b r a s s gong and jingle bell in so much as they were the more readily operated and provided a great reliability. T o - d a y steamship rules r e q u i r e and n a v a l vessels c a r r y g o n g s and jingle bells as auxiliaries to the mechanical telegraphs in case of derangement of the latter. They are also required by law to have a " tube of proper size so a r r a n g e d as t o r e t u r n the s o u n d of the gong to. the pilot-house." This practice is justified by experience. T h e detail as will be clearly recognized is t r u l y serious; for not only

406

H . A . HORNOR.

is h u m a n life e n d a n g e r e d , but incalculable d a m a g e will r e s u l t if t h e s e s i g n a l s are not correctly transmitted when d o c k i n g the vessel. W o r k i n g upon the same principles as d e s c r i b e d a b o v e and resembling in o u t w a r d appearance the e n g i n e telegraphs, there are installed on m e r c h a n t vessels d o c k i n g , steering, h e l m , and e n g i n e direction telegraphs. D o c k i n g and steering telegraphs are u s u a l l y combined in one instrument. Two h a n d l e s are employed, one on the r i g h t hand and one on the left hand of the h e a d , the dial on one side g i v i n g the steering o r d e r s in d e g r e e s of the helm and on the o t h e r side the requisite o r d e r s for docking. The two instruments, one located on the n a v i g a t i n g bridge and the o t h e r aft near the hand-steering w h e e l , are identical. They are not a r r a n g e d for r e p l y but can t r a n s m i t s i g n a l s in either direction. The o r d e r s for d o c k i n g are interesting to a land-lubber b e c a u s e of t h e i r peculiar s a i l o r characteristics, n a m e l y : " Stop engines," Slow a h e a d , " " Slow astern," N o t d e a r , " " All clear,' .... H e a v e a w a y , " " S l a c k a w a y , " " H o l d on," " L e t go," " Make fast," A v a s t h e a v i n g , " all expressions w h i c h , floating back in m e m o r y to the days of the w o o d e n ship of s m a l l d i m e n sions, were transmitted t h r o u g h the air by the s o n o r o u s voice of the captain, w h o s e o r d e r s echoed back from the o b e d i e n t quartermaster. T o - d a y no s o u n d is h e a r d . The scene has lost its d r a m a t i c interest. A band attached directly to the r u d d e r s t o c k indicates in the pilot-house or on the bridge the e x a c t a n g l e of the r u d d e r . This is the helm indicator. In like m a n n e r the e n g i n e direction i n d i c a t o r is connected to the reversing s h a f t of the main e n g i n e so that automatically the s i g n a l is transmitted when the e n g i n e e r sets his e n g i n e for the g i v e n direction. D o c k i n g telegraphs are not in service on n a v a l vessels at the p r e s e n t time, but steering telegraphs, helm indicators and e n g i n e direction indicators are customarily installed. H e r e electrical telegraphs take the place of the mechanical. They will be d e s c r i b e d subsequently more in detail. V o i c e t u b e s of b r a s s are r e q u i r e d by law as a u x i l i a r y t o the e n g i n e mechanical telegraphs. The law is u s u a l l y fulfilled on m e r c h a n t vessels by such communication b e t w e e n the p i l o t h o u s e bridge and e n g i n e room and also b e t w e e n the c h i e f engineer's room and the e n g i n e r o o m . On n a v a l vessels the requirements "

"

"

TRANSMISSION OF INTELLIGENCE ON VESSELS.

407

far exceed this and will be treated later. The reliability of the voice tube between the engine room and bridge is altogether shattered by two elements which have not been overcome to-day. and which, as can plainly be seen, are almost beyond solution-the internal vibrations and noises of the propelling machinery and the wind whistling do.wn the pipe from the exposed position of the tube on the bridge. For this latter cause swivel mouthpieces have been tried with no appreciable effect; for the former, insulated cushio.ns where the tube attaches to hull have been employed with only greater detriment. Flexible rubber mouthpieces of three or four feet in length are installed at certain termini for convenience and portability. The steamboat inspection service makes the telephone a requirement on certain types of vessels. " On all'steamers where the distance is more than a hundred and fifty feet between perpendiculars of pilot-house and forward part of engine room, there shall be communication by means of a telephone between the pilot-house and engine room, such telephone to be installed in lieu of a speaking tube." This condition will inevitably arise in vessels where the engines are located far astern or on vessels of unusual length. With the exception of this telephone circuit, all other telephone communication is optional and employed only for convenience. The developraent of the telephone for merchant vessels has no* only been curtailed, but almost shattered by the falling off in construction of such vessels in this country. The memory must be strained to recall the last transatlantic steamer of American construction, and coastwise steamers for passengers and freight are few and rare. A glance at American shipping for the last two years will readily convince. The shipyards of the country for this period have been sustained mainly by the government. An exact description, therefore, of the telephone installed on passenger and freight vessels must be at least vague. Later it will be seen that this important land instrument has been adopted in the United States navy and a steady development has succeeded. This development work, like many others, has an immediate and intimate effect on the merchant marine. Illustrating this the writer installed some two years ago on a coastwise passenger steamer eight intercommunicating telephones. These instruments were relied upon to the extent of omitting the mechanical docking and steering telegraphs. They also estal>

408

H . A . HORNOR.

lished convenient communication for the captain and c h i e f eng i n e e r . A t that time the navy was experimenting with w h a t is k n o w n as the l o u d - s p e a k i n g " telephone ( s o m e authorities cons i d e r this a w e l l - s o u n d i n g p h r a s e ) , w h i c h has now been s u p e r s e d e d . This type of telephone was a d o p t e d for the case in h a n d . The system, as far as the telephones w e r e concerned, was a c o m m o n battery, three-wire circuit, o t h e r w i r e s naturally b e i n g installed for the intercomnmnicating feature. The telephones for e x p o s e d places and w h e r e the n o i s e s w e r e excessive were entirely enclosed in w a t e r - t i g h t b r a s s b o x e s . T o e x c l u d e external s o u n d as far as possible d o u b l e a r m receivers m a d e flexible for convenience extended from each side of the enclosing case. The non-water-tight telephones u s u a l l y installed in the staterooms had all t h e i r p a r t s directly attached and w e r e self-contained. The delicate parts w e r e also encased, 'out m o u n t e d in a h a r d - w o o d f r a m e . A revolving l e v e r b r o u g h t the transmitter into circuit. T h e s e telephones w o u l d in n e a r l y e v e r y case r e p r o d u c e the h u m a n v o i c e t o such intensity that it w o u l d be a u d i b l e some six o r s e v e n feet a w a y from the instrument. In o t h e r l a r g e installations of telephones on shipboard recurrence t o land practice u s u a l l y prevails. S w i t c h b o a r d s for o r d i n a r y land service are installed, and either batteries, or batteries and generators, i n c l u d e d therew i t h . The p r o b l e m s involved will be b e t t e r u n d e r s t o o d in v i e w ing the development from a n a v a l standpoint. A s a s y s t e m of convenience, j u s t as in land practice, the o r d i n a r y call-bell with push-buttons is w i t h o u t a rival. A s an a d j u n c t to the voice-tube s y s t e m it maintains the d i g n i t y of its importance, a l t h o u g h on many m e r c h a n t vessels its p l a c e is filled by a w h i s t l e in the voice-tube mouthpiece. Annunciators r e s e m b l i n k t h o s e f o u n d in offices and hotels are m a n u f a c t u r e d with a d r o p of such d e s i g n that the rolling and vibrations of the vessel will in no w a y affect t h e i r p r o p e r and accurate operation. F o r a b o v e all t h i n g s a s y s t e m of convenience must, as such, work consistently. Despite all the w o n d e r s of electricity and all the development by all the m i g h t y m i n d s , if you p r e s s a b u t t o n and t h e r e is no r e s u l t therefrom, you not only b e c o m e an atheist, but a positive pluperfect anarchist. W i t h push-buttons m a d e of water-tight pattern w h e r e exposed to the w e a t h e r or r o u g h u s a g e , with innocuous ones in the b e t t e r part of the ship and with w e l l d e s i g n e d annunciators, the call-bell s y s t e m not only possesses an "

TRANSMISSION

OF INTELLIGENCE

ON VESSELS.

409

enviable and convenient position, but also is as indispensable t o the c o m f o r t of the passengers and officers as the pleasant q u a r t e r s or the a g r e e a b l e cuisine. ~IO. I.

Metallic thermostat and theralostat annunciators.

The distinction b e t w e e n the mechanical instruments used on n a v a l vessels and t h o s e employed on m e r c h a n t ships has been punctuated. T h e r e are t h r e e systems of such communication

4Io

H . A . I-IORNOR.

that are not ordinarily fitted on the latter type of s h i p s , but which are n e v e r omitted from battleships, namely, fire-room telegraphs, b l o w e r telegraphs, and turret-hoist telegraphs. The principles of t h e i r operation and m e t h o d s of installation r e m a i n the same. Turret-hoist s i g n a l s were only lately c h a n g e d from electrical to mechanical, due to the s l u g g i s h n e s s of the c a r b o n filament incand e s c e n t l a m p s as c o m p a r e d to the increase in s p e e d of the hoist, the latter lifting the c h a r g e from the handling-room to the gun b r e e c h in five. seconds. The s i g n a l s are very simple, to wit: " H o i s t , " " L o w e r . " The fire-room telegraphs control the mana g e m e n t of the fire-rooms (o1" boiler-rooms). F o r the accomplishment of ichis p u r p o s e t h e i r d i a l s are accordingly designed. They read as f o l l o w s : " More f e e d , " " All right," " Less feed," " Stop firing," " P r i m i n g , " " S t o p , " " S l o w , ' " Full speed," " S t a r t a u x i l i a r y feed," " More steam." In battleships, w h e r e the d e s i g n of the compartments has r e q u i r e d that the forced-draft b l o w e r s be located at some remote place as r e g a r d s the fire-room floor, the use of telegraphs was occasioned for the p u r p o s e of prod u c i n g more or less d r a f t as the conditions m i g h t d e m a n d . The r e g u l a r fire-room telegraph has 1]een requisitioned for this object with naturally its dial r e a d i n g s c h a n g e d t o t h o s e w h i c h w o u l d follow from the application. The s i g n a l s indicate to the operators at the b l o w e r s t o increase or decrease the s p e e d of the motors. Electric motors are now the p r i m e m o v e r s for these auxiliaries instead of s t e a m engines. Mechanical g o n g s and j i n g l e b e l l s for the operation of the a n c h o r w i n d l a s s engine, ash hoists, and on the t r a n s f e r platforms of the t u r r e t s complete the s i g n a l s that are not e i t h e r electrical or electro-mechanical, if the l a t t e r classification i n c l u d e the voice-tube system. T o the questions of pure electrical engineering t h e r e is augm e n t e d on n a v a l vessels the important f a c t o r of military efficiency. E x p a n d e d this m e a n s that all a p p a r a t u s m u s t be so d e s i g n e d that it will be accurate and t r u s t w o r t h y u n d e r any and all conditions of war. That the m a t e r i a l and instruments must w i t h s t a n d shocks from w i t h i n when the vessel is offering her def e n s e in action and will maintain stolidly the hot shells of her e n e m y in return. Development on military l i n e s is perforce g r a d ual when the b a s i s of the m o v e m e n t revolves a r o u n d the theory of battle. W a r is by good fortune q u i t e rare in t h e s e " p i p i n g t i m e s of peace." But as the wise nation m u s t p r e p a r e for w a r in

TRANSMISSION OF

INTELLIGENCE

ON VESSELS.

4II

time of peace, the development work on military lines can a d v a n c e only by the observation of past n a v a l engagements and sensible deductions from them. It m i g h t be g e n e r a l l y s t a t e d that t h e s e interior communications d i v i d e themselves i n t o t h o s e w h i c h are used for the o r d i n a r y p e a c e f u l movements of the vessel and those w h i c h are u s e f u l and necessary in time of a c t u a l conflict. F o r the p u r p o s e of b e i n g continually prepared t h e s e latter s i g n a l s are a l w a y s employed in d r i l l and gun practice. W i t h such a c c u m u lation of s y s t e m s it does o c c u r that certain ones make themselves factors in both c a s e s to such a d e g r e e that it w o u l d a p p e a r that no taxonomy c o u l d be a s s u m e d . S u c h systems as the call bells, telephones and voice-tubes illustrate this clearly. T h e s e s y s t e m s are j u s t as important in battle service as in p e a c e f u l c r u i s i n g . The f o l l o w i n g arrangement, t h o u g h open to question, will be adopted for the p u r p o s e of this d i s c u s s i o n : S y s t e m s employed for both battle and c r u i s i n g : * a. E n g i n e revolution telegraph. b. E n g i n e s h a f t revolution indicator. c. S t e e r i n g telegraph. d. H e l m a n g l e indicator. t'. F i r e - r o o m t i m i n g . f. Call bell. Exposed. Unexposed. g. V o i c e t u b e . h.. Telephone. General. E n g i n e and fire-room. Bridge and e n g i n e room. Battle. S y s t e m s employed d u r i n g c r u i s i n g only : a. Fire a l a r m . b. G e n e r a l a l a r m g o n g . c. A n c h o r h a n d l i n g and boat h o u r g o n g . d. W a r n i n g signal. e. Fuel oil tank indicator. * I t must be held in mind that these systems are available under all conditions. The w r i t e r adopts this classification merely for convenience.

412

H . A . HORNOR. S y s t e m s employed d u r i n g battle o n l y : a. B r o a d s i d e a m m u n i t i o n hoist. b. B r o a d s i d e salvo-firing. c. T u r r e t salvo-firing. d. C e a s e firing. e. Gun firing. f. T o r p e d o firing. g. Gyro indicating. h R a n g e and deflection. i. L o c a l t u r r e t gun firing indicator. j. T u r r e t d a n g e r zone.

It will be noted that of the systems enumerated n e a r l y 5 ° per cent. are devoted t o the control of the g u n s . L a t e r it will be b r o u g h t out that b e s i d e s t h e s e special s y s t e m s the telephone and voice-tubes are important factors t o - d a y in the n a v a l w a r d r a m a . _At the p r e s e n t time electric e n g i n e revolution telegraphs, steering telegraphs and helm a n g l e indicators are d e s i g n e d a f t e r the " lamp pattern " type of instrument. They are identical in t h e i r m e t h o d of w i r i n g and g e n e r a l d e s i g n , so that a description of one will suffice for all. E n g i n e revolution telegraphs are d e s i g n e d for the p u r p o s e of increasing or d e c r e a s i n g the s p e e d of the v e s s e l d u r i n g s q u a d r o n formation.* The vessel b e i n g u n d e r o r d e r s for maintaining s t a n d a r d speed, this b e i n g indicated by the mechanical telegraphs, one, two, three, or f o u r more revolutions, will be signalled by this electrical telegraph. On the bridge the transmitter of the pedestal type, by the operation of m o v i n g a h a n d l e a r o u n d the circumference of the h e a d , r i n g s a bell and lights a lamp in the e n g i n e r o o m , w h i c h latter s i g n a l r e q u i r e s the m o v i n g of a s i m i l a r h a n d l e on the engine-room indicator to the revolutions d e s i r e d . This d o n e , the lamp in the transmitter is l i g h t e d , g i v i n g a s s u r a n c e that the s i g n a l has been received and the operation accomplished. The contact-maker in the t r a n s mitter o r indicator consists s i m p l y of carbons w h i c h are revolved by the h a n d l e a c r o s s insulated c o p p e r segments t o complete the lamp circuits. The o l d e r type of instrument r e q u i r e d the r a p i d * The adoption of steam turbines for propelling purposes now requires an entirely new design of instrument, due to the lack of close control of turbine speeds and increase in propellor revolutions. Therefore these instruments are designed to transmit any number of revolutions. The proposed type is similar to the familiar carriage call" device. "

TRANSMISSION

OF

FIG. 2.

Engine revolution transmitter. Electric lamp type.

INTELLIGENCE

ON V E S S E L S .

413

FIG. 3.

Engine revolution transmitter. Electric lamp type with diaI removed.

movement of the h a n d l e of the transmitter or indicator for the purpose of operating a magneto-generator t o ring the bell, but the latest d e s i g n provides b e l l s d e s i g n e d for 125 volts, the s t a n d a r d used in the U n i t e d S t a t e s navy.

414

4 H

H . A . HORNOR.

TRANSSIISSION OF

INTELLIGENCE

ON VESSELS.

415

Ill like manner steering telegraphs * of the Fedestal and bulkhead type are installed on the bridge, in t h e steering-engine room, a n d central station for giving signals, usually in degrees, for the proper manceuvring o f the vessel. The helm indicators are built on the same lines, are located in the same places, and are for purposes of signalling the number of degrees the hehn makes when the r u d d e r has been actually moved from the midship line. The indicators are all wired in parallel with the transmitters, but are so arranged with cut-out switches that onh, those indicators desired may be in service. The transmitter is located near the r u d d e r stock and the contact FIG.

5.

Engine shaft speed indicator.

arm directly attached thereto. Carbon brushes move over insulated segments of copper, which are designed in accordance with the mechanical arc t h r o u g h which the r u d d e r moves. The vital parts of these instruments are enclosed in water-tight brass cases, which carry with them sufficient protection from mechanical injury. Engine-shaft indicators are located in the pilot-house and central station and by direct mechanical attachment t o the main engine-shaft permit the direction and number of revolutions of the engine to be read a t any time. The dials of the indicators now made of b r a s s are marked " A h e a d " and " Astern." Be* The dials of the steering telegraphs have recently been changed to read as follows: "Amid," " Course," " Steady,' " Starboard," " Port," "Meet Her," "Ease Helm," "5 Degrees," " IO Degrees," " 15 Degrees," " Standard,, " Hard Over."

416

t-I. A. HORNOR.

tween these indicators rests a pivoted arrow actuated by a double set o f magnets. As these magnets are p u t into circuit by the transmitter they move the arrow intermittently either to the right o r left, m a r k i n g thus each revolution of the shaft. With a stop watch the revolutions per minute may be easily and quickly noted. The shaft-speed transmitter has received very beneficial development in the past three years. From a device, which was not only very careless in its operation, but so overworked t h a t its parts could not s t a n d the continued strains, there emerges a n instrument thoroughly reliable and not a p t to lead t o the engineer's increase of vocabulary. A worm-band is securely fastened to the main shaft, into which engages a worm-wheel. This latter by an extension shaft carries and operates the electrical contacts fixed on a drum. The worm-wheel revolves once for every ten revolutions o f the main shaft, thereby lessening greatly all strains. The electrical contacts can be so arranged t h a t they mark every revolution o r any proportional number. The brushes, as in the o t h e r instruments, are of carbon.* While great improvements are made in important large systems and apparatus, it is remarkable how long crude methods remain by which the desired results are attained. Contractors for battleships are required t o demonstrate t h a t the vessel will u n d e r certain stipulated conditions acquire and maintain a g u a r a n teed speed. It can be plainly seen that the greatest requisite to meet this condition is sufficient and constant s t e a m pressure. P a s s i n g from this s t a g e the smooth and regular firing of the boilers becomes the point of vital interest for the accomplishment o f the result, of interest not only to the builder but as well to the owner, for he also desires t h a t the vessel be capable a t all times o f producing this guaranteed speed. Until recently the method employed was by word of mouth from the engine r o o m with men calling off the time intervals from watches, these latter posted in each fire-room. To-day these signals are automatically and chronologically regulated and transmitted from the engine room to each fire-room. The transmitter consists essentially of a small motor driving t h r o u g h gear a n d two steel discs a d r u m containing o n its periphery contact segments. Between the steel discs is placed a raw-hide pinion movable from the circumference o f the * This instrument is now to be superseded by a direct reading instrument --designed to indicate continuously any and all speed changes.

TRANSMISSION OF INTELLIGENCE ON VESSELS.

417

disc to the centre. By varying the position of this pinion the revolutions of the contact drum are controlled. A graduated pointer on the exterior of the water-tight case permits the interval of firing from twenty seconds to ten minutes. This transmitter is connected by a cable of wires to the various indicators, one usually in each fire-room. These are designed to produce both aural and visual signals, i . e . , a large gong and incandescent lamp. They are about I4 inches in diameter, marked with raised letters " Fire Furnace No. --" above a small opening. In the interior a brass dial cut with the figures of the furnace numbers is revolved by a ratchet movement accomplished by magnets, as they are energized by the closing of the circuits controlled by the transm,itter. In this way the number appears in the opening of the indicator simultaneously with the sounding of the gong. This is the simplest system that has found favor at the present time, although there are others which, being more complicated, still provide the same results. Employed for use in the officers' quarters the call-beU system is one entirely o.f comfort and convenience. The various pantries and orderlies are supplied with annunciators connected with push-buttons located in the officers' state-rooms and offices. This system divides into groups corresponding to the military grouping or rank of the officers; There are calls for the admiral and captain, ward-room calls, junior officers' calls and warrant officers' calls. Since the general change in type of installation from moulding to conduit, the design of all annunciators, push-buttons, and accompanying appliances take the prevailing characteristics of water-tightness. The annunciator drops are carefully constructed on the gravity principle with sufficient safety to protect against false signals due to vibrations or gun shock. The callbell system, which operates in conjunction with the voice-tube system, is sharply divided for military safety into exposed and unexposed calls. In such manner the circuits that may be required in the opening of an engagement, and thereby made useless when the conflict rises to its height, will not: make unavailable those circuits which in the interior of the vessel are still of vital necessity. It is the practice to duplicate the call, that is, that a pushbutton and bell are required at both ends of the voice-tube. As may be surmised, it often transpires that many voice-tubes with their calling apparatus meet in one compartment. This leads to

418

H . A . HORNOR.

a s y s t e m of stations located at important points t h r o u g h o u t the vessel. A t t h e s e stations it is convenient to g r o u p all the voicetube mouthpieces, push-buttons, bells, or b u z z e r s and annunciator on a b r a s s panel. This preserves s p a c e and p r o d u c e s an excellent installation. The push-buttons are all carefully labelled so that communication can be q u i c k l y and, with the aid of the annunciator, intelligibly established. It m a y be w r i t t e n w i t h o u t fear of contradiction that voicet u b e s parallel every, important system of interior eommunication~ t ~ G . 6.

Call-bell and voice-tube panel.

They are seamless h a r d - d r a w n b r a s s t u b e s v a r y i n g in external d i a m e t e r from I35 to 4 inches. T u b e s vary in thickness for the p u r p o s e of mechanical strength, t h o s e w h i c h are led in s t r a i g h t runs No. 2o B . W . G . and t h o s e for b e n d s and w h e r e s u b j e c t to mechanical strains No. 14 B.W.G. W h e r e t u b e s connect two terminal points by a d i r e c t path, or of a l a r g e diameter, so that they may be utilized for shouting-tubes, or w h e n they are employed for gun-firing control, they are not p r o v i d e d with calling arrangements as a h o v e explained. C e r t a i n of these t u b e s are

TRANSMISSION OF

INTELLIGENCE

ON VESSELS.

419

fitted with w h i s t l e mouthpieces in lieu of the bell and push-button. Mouthpieces differ in d e s i g n for n e a r l y e v e r y condition of use, and only a detailed description c o u l d f a i r l y represent and explain them. I n d e e d , as new conditions arise, or more efficient m e t h o d s present themselves, the mouthpieces are immediately attacked and the old t y p e s o r d e r e d i n t o exile. B e t w e e n compartments that are w a t e r - t i g h t special mouthpieces of water-tight d e s i g n are installed; b e t w e e n non-water-tight compartments, or non-watert i g h t and water-tight, a s i m p l e covered or open type. F o r shouting-tubes, u s u a l l y 3 inches or 4 inches in diameter, a d e s i g n of the pattern of a m e g a p h o n e is p r e f e r r e d . In the b o i l e r r o o m s , w h e r e the forced d r a f t occasions a d i s t u r b i n g pressure, the d e s i g n provided is that of a d i a p h r a g m in the mouthpiece, w h i c h can be only affected by the h u m a n voice. The t u b e s used solely for the control of gun-fire are a r r a n g e d so that a long flexible tube can be p l u g g e d i n t o the p e r m a n e n t mouthpiece. This flexible tube ends in a h e a d g e a r containing in some conditions only two earpieces and in others the a d d i t i o n of a mouthpiece. This d e s i g n permits the men at the guns t o have the f r e e d o m of t h e i r h a n d s , at the same time receiving d i r e c t a u r a l o r d e r s from the officer in c h a r g e of the g u n s . It will be observed l a t e r how this s y s t e m has t a k e n its cue from the p r e s e n t adaptation of the telephone for this like d u t y . T o o b t a i n the g r e a t e s t good from the voice-tube system e x t r e m e care is obggrved in all requirements of its installation. T h o s e points of inefficiency w h i c h were indicated in the description of this s y s t e m for m e r c h a n t v e s s e l s are o v e r c o m e as far as possible in n a v a l vessels. The navigating b r i d g e is in most recent d e s i g n s entirely enclosed, and the voice-tube connecting the e n g i n e r o o m , irrespective of o t h e r considerations, is led in the most d i r e c t line t o the engine-starting platform. M a c h i n e r y noises and vibrations are not, to be s u r e , entirely overcome, but every effort is exerted t o accomplish the intelligent transmission of the voice. The criterion at the p r e s e n t m o m e n t m u s t a p p e a r in the a b u n d a n t and important uses that o u r navy f i n d s for t h e i r increased employment. Retrospectively the development of the telephone on battleships is remarkable. A s late as I9o 3 a few telephones of the commercial type w e r e installed m e r e l y as a m a t t e r of experiment. They consisted s i m p l y of a box telephone with transmitter and receiver on a hook such as were prevalent in office b u i l d i n g s , enVOL. CLXVII, No. Ioo2--3I

420

H . A . HORNOR.

c a s e d in b r a s s for protection in exposed places. T h e i r use was p u r e l y a m a t t e r of convenience, doubtless little reliance b e i n g a s c r i b e d t o them. The patents covered by the Bell Telephone C o m p a n y n e a r i n g proscription, o t h e r p a r t i e s b e g a n experiments for a suitable telephone for m a r i n e purposes. T h e q u e s t i o n had FIG. 8.

FiG. 7.

Water-tight type " loud-speaking" telephone.

Non-water-tight type "loud-speaking" telephone.

not been l a r g e l y d i s c u s s e d nor experimentation fruitful. Howe v e r , one observation, that of noises w i t h i n the vessel, conspired t o the desig-n of a telephone w h i c h w o u l d by its volume, or intensification of the h u m a n voice, and by the exclusion of external n o i s e s c o m p a s s the solution of the problem. This type of telep h o n e was d e s i g n e d , as had been its predecessors, to m o u n t on b u l k h e a d s . All portable receivers w e r e d i s c a r d e d and the i n s t r u -

TRANSMISSION OF INTELLIGENCE ON VESSELS.

421

ment performed its functions with as little human aid as possible. Double receivers to exclude sounds other than the established circuit wouldpermit were an important adjunct to the water-tight type. The non-water-tight type, as explained previously, could speak so audibly that it was unnecessary to place the ear to the receiver or to hold the lips near to the transmitter. The receivers were wound for a low resistance, so that the energy necessary was that of a few batteries, usually five. These telephones supplied communication for the general service, and were therefore, interconnected as desired by a water-tight telephone switchboard located in the central station. This telephone switchboard is interesting. It is still employed. No cords or plugs or jacks can be found on it. This will probably surprise our telephone engineers. All the interconnections are made by small " throwo v e r " or " t u m b l e r " switches. Other features of the board are recognizable, night-bell, visual drops, clearing-out drops, operator's head-set, etc. The circuits were divided up into groups of five, which for a forty-line board and the general use of the system on shipboard was found to be ample. ]But to return to the telephones. It was early pointed out that though ships' noises did affect the hearing qualities, vibrations transmitted to the various bulkheads acted more to their disparagement and disuse• Coupled with the interferences of the proper hearing quahtles, came the effect of the packing of the carbon granules in the transmitters. These two salient objections told upon the advantages thought to be realized in this excellently made telephone and led to the types now specified and installed. No stint of praise should be allowed to the achievement of the "loud-speaking" telephones, for in their passing they have confirmed the telephone for yet greater service--that of controlling the engines of war. So the order was issued that all telephones must be taken off of bulkheads; no more low-resistance receivers; back to the standard voltage in commercial practice and back to a simple two-wire system. From a system depending only on batteries without any intervening coils, emerges a system replete with condensers, induction coils, alternating current ringer, etc. Another step in advance breaks up the whole into four distinct divisions: A general telephone system for the convenience of the officers; a special and independent set of circuits connecting the fire-rooms and engine rooms; another special

_,122

J

I-{. A . HORlX'0R.

TRANSMISSION OF INTELLIGENCE ON VESSELS.

_[2~

circuit between the engine room and the b r i d g e ; and last, but by far the mightiest, an elaborate system for the control of the guns d u r i n g battle. I n the officers' state-rooms and compartments, w h e r e the telephone is not subject to exposure, the hand telephone set consisting of one transmitter and one receiver is suspended when not in use from a water-tight case w h i c h contains the condenser and bell mechanism. The act of t a k i n g the telephone down for use, or returning it thereafter, automatically operates a switch on the top of the case w h i c h establishes the circuit to, the switchboard. The water-tight telephone is s i m i l a r in operation, differing only in that the telephone hand-set is enclosed in a s t o w a g e box; when this is o p e n e d the circuit is established t o the switchboard. The telephones connecting the fire-rooms and engine ro o ms are like the water-tight type used on the general telephone system with this difference, that no bells are provided. The system does not pass t h r o u g h the telephone switchboard, and therefore the calling apparatus is t a k e n from the general interior communication system, consisting of direct-current bells and push-buttons. The circuits between the bridge and engine room are direct, as in the latter system, h a v i n g no connection whatever with the general telephone system. The telephones are e x a c t l y the same as those installed for gun control,.~. The live w i r e s are b r o u g h t to a terminal in a brass box, w h i c h serves as a permanent fixture wherein to stow the telephone set. A portable twin wire is led to two receivers w i r e d in multiple a r r a n g e d to fit comfortably on the head. By m e a n s of a hard-rubber plug and jack cut into the portable twin conductor a breast type of transmitter may be introduced t o complete the outfit. This permits the use of the h a n d s and produces continuous communications. The breast transmitter has a vertical adjustment of t h r e e inches, a back and f o r w a r d movement of 3o degrees and a side movement of 18o degrees. Energy is supplied to all of these systems, including the battle telephones, t h r o u g h a transfer panel located in the central station. T h e r e is f u r t h e r provided for the bridge and engine telephone circuits a t r a n s f e r switch, so that the exposed circuit t o the bridge may be cut out in case the bridge is destroyed in action, and communication safely maintained from the central station. It w o u l d only w e a r y the r e a d e r to describe each and e v e r y sub-division of battle telephone system unless he were deeply interested in

424

H . A . HORNOR.

military questions. Such information he would hardly seek from this paper. A s nearly every battleship differs as to h e r comp,lement o f guns, their arrangement o r calibre, it is evident that a description of one particular vessel would not apply to others. Suffice it to add, therefore, that in general there will be f o u n d a separate and complete system for the guns of large size mounted in t u r r e t s ; one for the secondary battery (or torpedo-defense g u n s ) ; one for searchlights which are necessary for t o r p e d o defense a t night; one for t o r p e d o firing; and one for the exclusive use o f the range-officer. The utilization o f these battle telephones will be more clearly appreciated when shown later in conjunction with their correlated system o f fire control. Of the systems which are not actually necessary for military operations unquestionably the fire-alarm system is the most important. Until recently metallic thermostats, acting upon the difference o f the expansion of two dissimilar metals, were installed in all the coal bunkers, magazines and store-rooms; but this type has been f o u n d deficient in many ways a n d so has been superseded by a simple mercurial type. The circuits from the thermostats are all led to annunciators constructed like those for the call-bell system, having as an auxiliary a switch for each line in o r d e r that the bell may be cut out o f circuit after a n alarm has been given. The general alarm g o n g system, consisting of two o r three contact-makers and 3o odd I2-inch electric gongs, serves the purpose of calling the crew to drill o r arms o r giving an alarm in case of danger. The purpose of anchor handling and boat hour g o n g s is implied in their names. The gongs are usually 8 inches in diameter and are actuated by push-buttons. The former give directions from the forecastle deck for the control o f the a n c h o r windlass engine; the latter provide a call notice t o the officers' quarters that the shore-cutter is ready t o depart. A warning is provided for the closing of all water-tight doors in cases of collision. The necessity here is for a sound t h a t will b e distinguishable from the noises o f machinery. The first means devised and one long used was that of an electric magnet compressing enough air and allowing it to escape t h r o u g h a shrill whistle. The sound produced greatly resembled the familiar chirp of the cricket. This has now been superseded b y what is

TRANSMISSION

OF

INTELLIGENCE

ON VESSELS.

425

k n o w n as the electric " h o w l e r . " A m a g n e t actuates a h a m m e r a g a i n s t a t i g h t p i g s k i n d i a p h r a g m , the n o i s e b e i n g intensified by a horn such as seen on automobiles. The s o u n d is not as shrill as the whistles, but is sufficiently differentiated from the ship noises t o be entirely satisfactory. In vessels c a r r y i n g oil for fuel it b e c o m e s e v i d e n t that some indication m u s t be g i v e n as to the h e i g h t of the oil in the t a n k s when filling s a m e . An o r d i n a r y float in the tank p r o v i d e s the s w i t c h for closing the necessary circuits. Indications are s h o w n on an annunciator of the o r d i n a r y type. It is essential a m o n g the systems p u r e l y for the control of the guns that primarily provision be m a d e to q u i c k l y h a n d l e the ammunition. F o r the l a r g e t u r r e t guns it has been explained that mechanical s i g n a l s are employed. In the case of the secondary. battery., a l t h o u g h voice-tubes a l l o w v e r b a l s i g n a l s t o be t r a n s mitted, t h e r e has lately been installed a s y s t e m designated as b r o a d s i d e a m m u n i t i o n h o i s t signals. The indicators consist of a simple b r a s s w a t e r - t i g h t case with r o u n d w h i t e d i s c s properly m a r k e d and illuminated by 5-candle p o w e r incandescent l a m p s . The m a r k i n g s p r o v i d e for s i g n a l s to hoist, l o w e r and stop as well as to determine the kind of ammunition d e s i r e d . Transmitters consist of several s t a n d a r d switches m o u n t e d in one case and properly designated. A s a check a s i m i l a r indicator is installed at the l o a d i n g end of the h o i s t and the l a m p s w i r e d in series, the transmitter with indicator b e i n g located at the u p p e r or receiving end of the hoist. In o r d e r that the t u r r e t guns and secondary b a t t e r y may fire a b r o a d s i d e simultaneously, s y s t e m s of b e l l s , b u z z e r s and contact makers have been d e s i g n e d . T h e s e systems have been nominated respectively for the t u r r e t g u n s - - t u r r e t salvo-firing, and for the smaller ~ m s - - b r o a d s i d e salvo-firing. S m a l l 3-inch electric b e l l s are permanently installed in and a b o u t the guns so as t o be distinetly a u d i b l e ; they give the o r d e r to " stand-by." P o r t a b l e buzzers strapped t o the chests of the g u n n e r s are operated by push-buttons and give the s i g n a l to " F i r e . " The contact m a k e r s and push-buttons are located at the two principal fighting-tops, the captain's battle station and the sub-stations. The p o i n t interesting to n o t e in this s y s t e m is that of strapping the b u z z e r s t o the g u n n e r s . This is done in o r d e r that t h e r e can be no m i s t a k e in the interpretation of the s i g n a l s , for t h o u g h it may not be

426

H . A . HORNOR.

audible, the vibrations of the b u z z e r will be communicated t o the body. The cease-firing s y s t e m is identical t o the g e n e r a l a l a r m system. The" d i a m e t e r of the g o n g s for this s y s t e m is m a d e IO inches instead of 12 inches. On some battleships in o r d e r to better differentiate the s o u n d one s y s t e m will have v i b r a t o r y g o n g s , the o t h e r single-stroke. This s y s t e m p r o v i d e s s i g n a l s to comm e n c e and c e a s e firing and p e r v a d e s the entire vessels. Thus it is a g e n e r a l gun signal. A t the p r e s e n t w r i t i n g the a c t u a l electric f i r i n g of the guns from the vessel's electric p l a n t has n e v e r been r e q u i r e d . The guns are p r o v i d e d with a l o c a l battery s y s t e m and the considera t i o n t o - d a y is not only to r e t a i n this m e a n s , but also to p r o v i d e a s i m i l a r s y s t e m t a k e n from the vessel's p e r m a n e n t installation. S p e c i a l m o t o r generators are t o be d e s i g n e d so that only the requisite v o l t a g e and c u r r e n t will be delivered to the g u n s . S w i t c h e s of a portable type, receptacles for connection at the guns and o t h e r n e c e s s a r y appliances will be furnished. No det a i l s have yet been considered, and it is problematical w h e t h e r such a s y s t e m will not in the end find much objection in the opinion of t h o s e vitally concerned. M o r a l e in w a r f a r e is an i m p o r t a n t factor. The e n e m y must be more or less affected by w h a t he estimates as the fighting strength of his opponent, or w h a t the latter may hold in r e s e r v e as reinforcement. So t h e r e are retained in o u r l a r g e battleships a t l e a s t two t o r p e d o t u b e s . F r o m stations located on the s u p e r structure deck the firing of the torpedos is not only directed but actually accomplished. F i r i n g k e y s , not u n l i k e telegraph keys, are located at t h e s e firing stations in conjunction with s i g n a l s that p e r m i t no complication b e f o r e the firing keys are actuated. T o give the necessary directive action to the torpedoes a system of telegraph indicators and transmitters of the lamp pattern, as described u n d e r the head of electric e n g i n e revolution and electric steering telegraphs, is installed--one transmitter at each t o r p e d o firing station with indicators a t each t o r p e d o t u b e . T h e s e transmitters indicate at the t o r p e d o t u b e s the n u m b e r of d e g r e e s from zero centre r e a d i n g to 9 ° d e g r e e s port and s t a r b o a r d . This s y s t e m b e a r s the n a t u r a l title of the gyro-indicator system, as by this m e a n s the t o r p e d o gyroscope is so, a d j u s t e d . Of all essential matters in battleship d e s i g n that of properly

TRANSI~IISSION

OF INTELLIGENCE ON ~fESSELS.

427

controlling the fire of the guns is without question the most important. A battleship is primarily a fighting machine, and therefore the necessity of so controlling the gun fire as to obtain the greatest battle efficiency. This subject of fire-control has called forth every consideration by the naval authorities, and investigation, experiment, and money have not been spared in providing the most reliable systems suggested. Every idea that was worthy a passing notice has been given due trial and the liberal spirit of the government to-day would gladly respond to any suggestions whereby greater improvements would result. To clearly understand the arrangements now provided on the latest battleship designs some reference must be made to the arrangement of compartments and the disposition of the guns. The design of recent battleships has been rightly dubbed the " all big gun " type. Our most powerful battleships, those of over 21,00o tons displacement. carry five turrets, containing two I2-inch guns in each turret. Two are located forward, one raised slightly above the other, and three aft, two on the same level and one slightly raised above them. The 5-inch guns used for defense against the attacks of torpedo boats are distributed at important points on the gun deck. The range, deflection, and battle orders for these guns are communicated solely by telephones, as referred to in the description of the telephone syst~tn. Not only are the i2-inch turret guns supplied with telephones for this purpose, but also with special instruments for visually presenting the range, deflection, and battle orders continuously before the sight setters and gun trainers. The orders all emanate from what are called sub-stations, compartments well below the protective deck and water-line, sheltered in every possible way from hostile shell. The rangefinding instruments are located in lofty towers, one forward and one aft, with their respective " spotters" and range officers. The spotters, watching each shot as it falls and gauging the r a n g e and deflection, communicate directly with the sub-stations by means of the telephone. The r a n g e and deflection transmitters in the sub-stations are immediately called into operation and in turn send forth to each gun the proper order. The problem contains another factor. In naval warfare both parties to the conflict are in motion, and by virtue thereof the r a n g e is constantly varying. For this condition there is provided in the sub-stations a r a n g e

428

t-I. A. HORNOR.

clock c a r r y i n g a rate of c h a n g e d i s c , by m e a n s of w h i c h the rate of c h a n g e of r a n g e may at all t i m e s be m a r k e d . This r a n g e clock has a m a x i m u m r e a d i n g of 14,ooo y a r d s . W h e n the shotspotter reports from the fire-control t o w e r , the rate of c h a n g e of r a n g e is set on the clock. The clock continues then t o marl< off r e g u l a r r a n g e s w h i c h , t h r o u g h the p r o p e r official, are then communicated by the r a n g e transmitters to the g u n s . Deflections are n o t e d by the same shot-spotter and in the same w a y transnlitted t h r o u g h the sub-station to the g u n s . Deflections are m e a s u r e d in y a r d s up to a m a x i m u m of IOO. F o r m e r l y zero was arbitrarily t a k e n at the centre, w h i c h r e q u i r e d the f u r t h e r d e s i g n a t i o n of r i g h t or left deflection. By a s s u m i n g 5 ° y a r d s as the zero deflection any n u m b e r b e l o w 5 ° indicates r i g h t and any n u m b e r a b o v e 5 ° indicates left deflection. The c a u s e for all this care in firing guns originates from the d e s i d e r a t u m of " b u n c h i n g " the hits. W h e n s e v e r a l guns are firing particularly in r a n g e and their shots are dispersed, poor hitting e n s u e s . Therefore such fire-control s y s t e m s are important and necessary in that they maintain all the s i g h t s of the guns set alike w h i l e in the act of firing. Two s y s t e m s for accomplishing this r e q u i r e m e n t have been experimented with and have s h o w n a b o u t e q u a l a d v a n t a g e and d i s a d v a n t a g e from a practical standpoint. It is unnecessary to elaborate a description of either system, suffice it t o say that one s y s t e m is d e s i g n e d on the simple incandescent lamp principle, and the o t h e r on a s y s t e m of magnets in conjunction with ratchet-motion escapements. In the f o r m e r indications are p r o d u c e d by illuminating n u m b e r s by 5-candle p o w e r l a m p s ; in the latter the r a n g e and deflection n u m b e r s rev o l v e by increments of 5 ° y a r d s for r a n g e and unit increments for deflection. The latter instruments, t h o u g h rectangular ins t e a d of r o u n d , r e s e m b l e in t h e i r movements the f a m i l i a r fare registers w h i c h are seen in all trolley c a r s . This s y s t e m provides also for the repetition of the s i g n a l a f t e r it has been conveyed to the gun at the s e n d i n g station. R e a d y m e a n s are also provided for cutting out the instruments w h i c h m a y b e c o m e d e r a n g e d w i t h out affecting the o t h e r instruments on the system. This reply or checking f e a t u r e is convincingly accomplished in the lamp-pattern d e s i g n by introducing s i m i l a r indicators at the s e n d i n g station connected in series with the indicators at the g u n s . The transmitters in both systems, t h o u g h the instruments are dissimi-

FIG.

I0.

Assembly of fire-eontro] instruments.

43 °

H . A . HORNOR.

lar in outward design, are in principal merely switches for closing the desired circuits. The essential difference between the lamppattern and the electro-magnet systems is t h a t the former is purely a n electric contact method and the latter an electromechanical movement. The vital importance which attaches to. this fire-control system is shown by the regard with which it is installed. With all these instruments located behind a n d below armor, in the event that the fire-control towers be completely demolished, communication can be transmitted from the captain's battle station, which is a small elliptical armored compartment on t h e superstructure deck. If again by a n y chance this invulnerable citadel b e destroyed, retirement to the sub-statio,n is offered. This latter place can only be made untenable by the sinking of the vessel. W h e n this happens the hull becomes only a hulk and the engine-of-war becomes a derelict. The last two systems in this classification, namely, local turret gun firing indicator system and turret d a n g e r zone system, may consistently be considered together. T h e y have been required mainly because to-day it is t h o u g h t one system cannot accomplish all that is desired. And certainly a detailed investigation will convince even the most conscientious designer that a division was absolutely unavoidable. It has been stated that in the all big g u n " design the turrets are disposed, two forward, one above the o t h e r and three aft, two on t h e same level and one above them. With this alone in mind it becomes apparent t h a t unless due provision is made there will o c c u r in time o f war, or target practice, exceedingly dangerous interferences, not only by the various positions of the guns, but also by the turrets which c a r r y them. Casually the suggestion would be t o guard the turrets and guns by positive mechanical blocking devices; but this is impractical inasmuch as it restricts to an alarming extent the radius of gun action, a restriction which would reduce the efficiency o~ the fighting qualities of the vessel t o a mere show in battle. The guns have a certain radius o f elevation and depression, just as the turret has a fixed radius o f t r a i n on a horizontal plane. One gun o r set of guns in one turret, let it be t h e raised turret, are set for extreme depression, while the guns in the lower turret are fixed a t m a x i m u m elevation on the same degree of train. If u n d e r these conditions the raised turret guns are fired, they throw their charge with disastrous results a t the lower turret guns. A "

TRANSMISSION OF INTELLIGENCE ON VESSELS.

43i

change in t r a i n of the raised or l o w e r t u r r e t w o u l d a v o i d any such mishap. Here it must be understood that the t u r r e t g u n n e r s are excluded from e x t e r n a l view, hemmed in b e h i n d 12 inches of armor. The s i g h t i n g of the guns is accomplished by prismatic telescopes, w h i c h present t o the s i g h t setters the image of the object upon w h i c h they fire. Augment the many interferences which will arise by the above illustration, by the movement of one turret body into the fighting line of an a d j a c e n t turret, and the problem is not only magnified to the extremity of hopeless solution, but becomes utterly exasperating. No. instruments for this system have at the present time been manufactured. Designs have been drafted in a c c o r d with models of guns and turrets prepared to illustrate the many d a n g e r o u s interferences. It remains for experimentation and actual t r i a l to demonstrate the need or practical usefulness of a system w h i c h perforce must carry with it complications proportional with the results to be obtained. Several methods have been suggested; but t o the writer's knowledge only one system has f o u n d acceptance at the present t i m e . The principle of the design is based on the desire to eliminate at least as much as possible the use of s m a l l shafting and p e r m i t the signals to be conveyed by electric currents. Yet the m e t h o d must introduce the mechanical feature, because the every m o t i o n of one gun a.gd one t u r r e t must be transmitted t o each of the o t h e r turrets o r guns w h e r e interferences may occur. The system comprises two sets of instruments, one set b a s e d on purely the lamp-signal system--the transmitter mechanically attached to the gun or turret, and similar, save in size and number of contacts, to the o t h e r electrical telegraphs--and the o t h e r based on a magnet floating in a circumferential g r o u p of magnet coils whose poles alternately present a n o r t h pole and then a south pole. This, producing a revolving m o t i o n in a c c o r d with a mechanically-operated contact m a k e r atttached either to a gun or turret, reproduces the movement in another turret. The principle is here briefly stated. The details are not conclusively prepared at present; but the o b j e c t of accomplishing this work by electrical methods r a t h e r than by mechanical are at least set forth. I f reliability is f o u n d to be more necessary than space, weight, and inconvenience, then the mechanical system will prevail. Thus the entire success of the t u r r e t danger zone system must a w a i t the final v e r d i c t of the future. Many t i m e s d u r i n g the explanation of the a b o v e systems men-

432

H . A . HORNOR.

tion h a s been m a d e of the central station. This compartment is located b e l o w the protective deck and covered from d a n g e r by a r m o r . B e s i d e s furnishing a protected station from w h i c h to g u i d e the vessel when the u p p e r pilot-house has been destroyed, it also g i v e s a c o v e r to the necessary s w i t c h i n g m e c h a n i s m s for the s u p p l y of c u r r e n t t o the interior communication systems. F r o m the captain's battle station, w h i c h has been a l r e a d y briefly a l l u d e d to, an a r m o r e d tube t h r e e feet in d i a m e t e r is fitted ending in the central station. This tube protects the steering g e a r leads as well as the important w i r e s and c a b l e s of the essentially battle and navigating circuits. In this room will be f o u n d the steering w h e e l , e n g i n e mechanical telegraphs, revolution indicators, helm a n g l e indicator, electric steering telegraph, voice-tube panel, cutout s w i t c h b o a r d , interior communication s w i t c h b o a r d (controlling the s u p p l y of all circuits for t h e s e s y s t e m s ) , telephone switchb o a r d , telephone transfer s w i t c h b o a r d , g e n e r a l a l a r m g o n g contact m a k e r , and w a r n i n g s i g n a l contact m a k e r . Two dynamotors for the e n e r g y necessary for the g e n e r a l s y s t e m s of interior communication are a part of this equipment, but due to t h e i r n o i s y character are d e b a r r e d from the s i l e n t c o m m u n i o n with t h e i r fell o w s . This control station is lined on all s i d e s with s o u n d proofing material, that t h e r e may be no interruptions t o the service occasioned by the ship machinery. The m o t o r generators for the s u p p l y of p r o p e r voltages, with alternating and d i r e c t c u r r e n t t o the telephone system, are located w i t h o u t the central station for the same reasons. The dynamotors for the g e n e r a l communicating circuits are w o u n d to t r a n s f o r m the standard v o l t a g e of I25 volts i n t o t h r e e voltages, 6.6, I3. 3 and I9. 9 volts. M o t o r generators in duplicate for the telephone s y s t e m consist of a m o t o r w o u n d for I25 volts ; a d i r e c t c u r r e n t g e n e r a t o r transf o r m i n g t o a n o r m a l v o l t a g e of I6 with rheostatic control from z2 to 2o volts, m o u n t e d on the same shaft, and an alternating c u r r e n t g e n e r a t o r p r o d u c i n g 8o volts a t I6 cycles, m o u n t e d on the same bed plate. T h e s e m o t o r generators are controlled by the telephone t r a n s f e r switchboard and the dynamotors are controlled by the interior communication s w i t c h b o a r d . This latter switchboard is interesting for the a m o u n t of control it provides c r o w d e d in so s m a l l an a r e a . It is f u r n i s h e d with many sets of b u s - b a r s t o accommodate the differences in potential characteristics of the v a r i o u s systems. It supplies I25, 6.6, I3. 3, I9.9

TRANSMISSION OF INTELLIGENCE ON VESSELS.

433

volt bus-bars as well as a special set of bus-bars for the batteries which are connected to supply 6.6, I3.3 and I9.9 volts. Adjacent to the central station and made sound proof in like manner are found the sub-stations for fire-control. The two sub-stations permit of duplicate operation of the fire-control, that is to say, that the control of all the turret guns can be accomplished from one sub-station or divided between them. Sub-stations are provided to agree with the number of batteries. A change is now contemplated in this arrangement of compartments whereby there will be secured a further structural division, allowing a special compartment to interior communication apparatus. This arrangement will separate and make distinct the steering compartment, the commtmicating or central station and that reserved especially for the control of the gunfire. Although briefly described the extensiveness of these systems goes far to prove their importance and necessity. Embracing as they do every possible need of the navigator, the engineer, the gunner, the passenger and the crew they metaphorically typify the human nervous system with all its sensitiveness and delicacy. As the human is debilitated by some injury or shock to his nerves, in like manner does the vessel suffer from an interruption to its interior signals. Following this simile to even a greater degree, man has ingeniously provided the vessel with means of premonition like unto the intuition or fear of approaching danger which man himself possesses. These advantages have transpired through man's experience, study, and persevering interest in the making of vessels secure in the carriage of human life and cargo. Not one iota should be spared from the praise of man's achievement as shown in the advantages to the English-speaking races of the two transatlantic fast mail steamers " L u s i t a n i a " and " Mauretania." In diminishing the time of travel between our shores and that of the Fatherland they have advanced the nadir of world civilization. No attempt has been made to discuss in this paper any practice other than that of our own country. A comparison of the practice of other nations would be interesting, but would extend beyond the prescribed intention of this treatment. It is obvious to those who are well acquainted with American characteristics that in all paths that lead to progress and advancement in science, art, and civilization our countrymen will be found in the vanguard.