Last October the writer of this submitted to the commander-in-chief of the North Atlantic fleet plans for a system by which all tactical signals may be made by a single display. This system may be used without making any change whatever in the rules of signaling now in use and does not require learning a new code. The addition to the apparatus now in use being an efficient four-arm semaphore and four pulsators in the Ardois keyboard instead of one.
There are in the navy a few officers who advocate the adoption of the two-arm semaphore, such as used in the British and German navies. My greatest objection to the two-arm semaphore is that it cannot be applied to the proposed single display system, but there are other serious defects in it.
It is not possible to arrange this semaphore so that displays can be read in all directions at once; the reading is limited to one direction, or two if the displays are read backwards. Therefore it is not efficient for tactical signals of any kind.
The code used is different from the Myer code, which is used throughout all our own systems, except the flags, and it has two characters less.
The code cannot be represented by any form of night signals so that knowledge of more than one code will always be required if it is adopted.
For word messages the two-arm semaphore has a reputation for great rapidity, but it must be remembered that the rapid signaling of the British is done with their small semaphores at the bridge ends. The size and weight of the mast-head semaphores prohibit rapidity of operating, which is the reason for the existence of the small ones. So it is only convenient for rapid signaling at short distances and in one direction. (Reading displays backwards violates the principle of rapid reading of signals.) A two-arm semaphore carried at the truck, if of large enough size to be used at long distances, cannot, on account of its weak support, be used in a high wind, and even when not in operation they have been known to come down from aloft in the British service.
Its code when applied to the hand semaphores gives a little more rapid method than the wig-wag system with the Myer code. But this advantage is outweighed by the facts that the wig-wag system may be used at night with a torch or searchlight, the same code can be used in a fog with a whistle, and a wig-wag signal can be sent from behind a trench or any kind of protection without the least exposure to the signalman. In sending a hand semaphore signal, all the vital parts of the signalman must be exposed. The army is not likely to adopt such a system and if we do, we must still have signalmen proficient in the wig-wag code so that our means of communication with the army will not be lost.
The writer has been experimenting with various forms of semaphores since 1897, when Lieutenant-Commander Fiske's four-arm semaphore was installed on the New York for trial, and has always considered that an efficient semaphore must approach as nearly as possible the advantages of the Ardois night system, while exceeding it in range of visibility. The best system in use for all-around efficiency is the four-light Ardois; for general (and tactical) signals, the answering of displays by their repetition reduces the chances of error in reading; in word messages, where the displays are not repeated, a greater speed is attainable than in any other visual system; the displays can be read in all directions at once, except the small arc that may be masked by the topmast; the one disadvantage is the rather short range of visibility, but this can be much improved by using higher power marine glasses and increasing the candle power of the lights. There are advantages in any semaphore over flap; a semaphore is not affected by the direction or lack of wind, nor by the position of the sun, and if constructed of a suitable size, exceeds the flags in range of visibility. Besides it may be used at that period of time, dawn or twilight, when it is too dark to distinguish the colors in the flags and too light to see the lights of the Ardois. For word messages (Telegraphic Dictionary) flag signals are hopelessly slow.
As a result of the experiments and keeping to the qualifications mentioned above, the writer this summer submitted to the commander-in-chief of the North Atlantic fleet plans for a four-arm semaphore which were approved and recommended for trial by the fleet signal board, and its construction for trial recommended by the general board. This semaphore may be called a modification of the Fiske semaphore as it has four arms and is designed to be read from any direction, but in other respects it is different. There is not space for a detailed description with drawings, but the following will explain the general ideas of the system.
It is a four-arm semaphore of two elements, so the Myer code is applied, and it is used in the same manner and for all Signals made by the Ardois.
It is operated by eight suction magnets connected up to the Ardois light leading wires, so that the same keyboard is used for semaphore and Ardois; the advantages of one keyboard which can be used in a protected place, for both night and day signals, are obvious.
The elements are a long and narrow arm, "2," and a shorter and broader arm, "1." In each element there are about sixteen square feet of surface, so the range of visibility will be greater than that of any day system we now have and will be about that of the British mast-head semaphore.
A display on the topmast will have the appearance of a succession of military tops; the element "1" appearing as a deep-sided top of rather small diameter and the element "2" appearing as a shallow-sided top of large diameter; the semaphore being carried well above the ship's tops, a display will not get confused with them. The distance at which it is possible to distinguish the tops of a ship gives a good idea of the visibility of the system. The displays are read from the upper element down as in the Ardois.
An element has exactly the same appearance from every direction; this is effected by having three arms or vanes to each element carried on shafts set at angles of 1200 in azimuth; the same shafts carry the vanes of the other element.
To attain speed in transmitting and at the same time make the arms of adequate size, it was found necessary to reject any form of arm that is pivoted on the end or in the center. It is impossible on account of the inertia of such arms, if they are large, to operate them rapidly. The arms or vanes in this system when in the "off" position lie in the horizontal plane with their edges only appearing. To display an element the vanes are rotated about their longitudinal axes through an angle of 90° into the vertical plane. As the shafts are fixed, and no part of a vane is at a great distance from its supporting points, the vanes may be constructed lighter than any equal sized pivoted arm, and as the amount of motion is much smaller, they may be operated very rapidly.
Another advantage of this form of arm is that in pulsating an element, the arm moves from its "on" to "off" position and back again without passing through a position which may have a different signification; as is the case in pulsating a semaphore in which the elements are represented by angular positions of an arm.
The parts of this apparatus which are carried aloft can be constructed so that they are not too heavy, although the arms are large; for the arms will not interfere with two shrouds and a stay and the weights and pressures are distributed on the topmast instead of being concentrated at the truck is the case with a two-arm semaphore. The construction is much simpler than would appear from this brief description. On account of the clear method of pulsating, long range of visibility, greater speed, the more convenient method of operating, and because an element actually has the same appearance in all directions, the semaphore described above will be superior to other semaphores for general use and particularly for the proposed system of single display signals, a description of which now follows.
The Tactical Signal Book now used contains 229 signal numbers; to make any of 118 of these we require by day a three flag hoist and by night six displays on the Ardois (not counting the signal of execution); for any one of 101 of them we require a two-flag hoist or five displays on the Ardois; for any one of the remaining ten, we require a one-flag hoist or four displays of the Ardois.
Using the four-arm semaphore by day and the Ardois by night, both operated by a keyboard with four pulsators, we can make any one of these signals by a single display. We now pulsate the upper light of the Ardois for all numerals, so there is no reason why other lights of a display should not be pulsated as long as there is always at least one steady light in the display to prevent confusing it with a ship's or division's call which is flashed.
It would appear that this would entail learning a new code of a great number of characters, but this is obviated by the form of the proposed tactical signal book.
With four pulsations the following displays are possible:
30 unpulsated displays: the alphabet and the displays cornet," "letters," "interval" and "code call," the last four and "I" and "T" have special significations, which leaves 24 available for signals.
28 displays with the upper element pulsated: the alphabet (except "I" and "T") and the displays "cornet," "letters," "interval" and "code call;" of these all have special significations except the numerals, which leaves 10 available.
28 displays with the second element pulsated: the same as the preceding, all of which are available.
24 displays with the third element pulsated: all displays but those of one and two elements "I," "T," "A," "E," "O,"
24 with the first and second elements pulsated: the same as the preceding.
24 with the first and third elements pulsated: the same.
24 with the second and third elements pulsated: the same.
16 with the fourth element pulsated: all the four element displays; “B,” “F,” “G,” “J,” “K,” “M,” “P,” “O,” “V,” "W," "X," "Z," "cornet," "letters," "interval" and "code call."
16 with the first and fourth elements pulsated: the same as the preceding.
16 with the second and fourth pulsated: the same.
16 with the third and fourth pulsated: the same.
16 with the first, second and third pulsated: the same.
16 with the first, second and fourth pulsated: the same.
16 with the first, third and fourth pulsated: the same.
16 with the second, third and fourth pulsated: the same.
Thus it is possible to make 310 different displays; of these 24 now have special significations, viz.:
"A" (first pulsated)=Cipher A use.
"C" (first pulsated)=Repeat
"D" (first pulsated)=Telegraphic dictionary use.
"B" (first pulsated)=Error.
"H" (first pulsated)=Compass signals use.
"K" (first pulsated)=Negative.
"L (first pulsated)=Geographical list use.
"N" (first pulsated)=Cipher B use.
"O" (first pulsated)=Cipher C use.
"P" (first pulsated)=Affirmative.
"Q" (first pulsated)=Interrogatory.
"R" (first pulsated)=International code use.
"S" (first pulsated)=General signals use.
"U" (first pulsated)=Navy list use.
"W" (first pulsated=Annulling.
"X" (first pulsated)=Numerals.
"Y" (first pulsated)=Vessels numbers use.
"Letters"=Word message.
"Interval" (first pulsated)=Boat signals use.
"Interval"=-Division point, date, designator.
"Cornet"=General call, signal of execution.
"Code call."
"T" (at night)=Engines making prescribed speed.
"I" (at night)=Engines stopped.
This leaves 286 displays available for signals by which we can make all signals in the present tactical signal book and will have left 64 additional for any new manoeuvres that may be adopted.
The proposed tactical signal book is to consist of four pages, with no cover; two leaves of a stiff material that is impervious to weather, and just heavy enough to sink; the leaves are folded either way, and carried folded it is always open to half the book, so will be much handier than the book now used.
On each page are four vertical spaces: in these spaces are printed the signal numbers and their meanings; the signals being grouped in columns as they are grouped under headings in the present book, for convenience in sending.
Opposite each space in a column is the name and illustration of a display, beginning at the top with The letters of the alphabet in order except "I" and "T," and ending at the bottom with "cornet," "letters," "interval," "code call," in order.
At the head of each column will be printed in large type the number or numbers which show which element or elements of a display are pulsated. For instance, at the head of the first column, page one, will be "unpulsated," showing that any signal In that column is made by the display shown opposite its space without pulsating any element. At the head of column four, page one, will be "3rd," showing that any signal in that column is made by the display shown opposite its space with the third element pulsated.
The last column on page four contains no signals, but has a compass table like that in use now.
The appended drawing of a portion of a page will show the method of using the book.
RULES.
1. All signals in the tactical signal book shall be made without a code call; the absence of a code call showing that a tactical signal has been displayed and that there will be but one display, before the signal of execution. (Except as provided in rule 4, or in case it is to be annulled, or in case a compass or numeral signal is required after it.)
2. Tactical signals to the whole force shall be made without a general call.
3. Tactical signals to one or a few ships shall be preceded by flashing their call letters; the ship or ships concerned alone shall answer their calls and the signal.
4. Tactical signals to the whole force except one or a few ships shall be made in the same manner as to the whole force; before turning on the signal of execution, flash the calls of the ships excused, which shall answer their calls but shall not answer the signal of execution.
If it is desired to make a tactical signal by any other method than the single display system, follow the rules now laid down in the introduction to the general signal book, using the signal numbers found in the spaces of the proposed tactical signal book.
SENDING.
Find the signal to be sent in the column in which its class is grouped, turn on the display shown opposite its space and pulsate the element or elements designated at the head of the column in which it is found. (The pulsations should be made deliberately, and, if more than one element is pulsated, they should be pulsated together.) When answered by the whole force, with proper display and proper pulsations, turn off and make the signal of execution if the signal is one requiring a change of formation, course, speed, order, distance or interval, or a drill signal. (If not to the whole force follow rules 3 or 4.)
RECEIVING.
Note the display and the numbers of the elements pulsated. Refer to the column which is headed by these numbers and in the space opposite the display shown will be found the signal. When read and understood answer with proper display and pulsations.
EXAMPLES.
Flagship wishes to make signal to the whole force, "Ships right about." Turn on "G" and pulsate third element; when answered by all, make signal of execution.
Flagship wishes to make signal to Alabama (L), "Stop!" Flash "L" until answered; turn on "F" and pulsate second element; when answered by Alabama, make signal of execution.
Flagship wishes to make signal, "Steam at reserved speed," to whole force except Kearsarge (K). Turn on "E" and pulsate second element; when answered by whole force, flash "K" until answered by Kearsarge; then make signal of execution.
To show the saving in time we will make the first of these examples by the present method at night.
Flagship makes "cornet;" when answered by the whole force, makes "S" and pulsates upper element; when answered by whole force, makes "M," upper element pulsated; when answered by whole force, makes "M," upper light pulsated; when answered by whole force makes "interval;" when answered by whole force, makes signal of execution. Here are five displays instead of one, before the signal of execution.
By the proposed system it is apparent that all chances of error in reading are eliminated, for the meaning of a signal is complete in one display and is answered by the same complete signal.
Thus we will have the two most important requirements for tactical and battle signals, reliability and quickness. Besides there is the convenience and simplicity in making them and the fact that the signalman need not be exposed in action. In case of failure of the apparatus in action we have all of the present systems to fall back on, which can be done without confusion as the proposed system involves no change in the present rules or methods.
This system was investigated and recommended for trial by a board of officers in the North Atlantic fleet. Its application to night signals can be made at a small expense, involving only the installing of four pulsators in the Ardois cable, which can be done by the ship's force.