|An Incomplete Cast of Characters•|
The US Navy sought the advice of the British Admiralty, who had recently adopted an innovative system called dazzle-painting (as proposed by British artist Norman Wilkinson) in which a ship's appearance was broken up and made to look bewildering to the commander of a submerged U-boat, whose distant and brief observations were made through a periscope.
What kinds of professionals would be well-suited for ship camouflage design? Artists (who reliably fool the human eye), or zoologists (who study animal camouflage), or scientists (who conduct experiments with the physiology of vision, including light, color and optics)?
In the US, most camouflage proposals were of two kinds: There were those who spoke in favor of disruptive ship camouflage (of which dazzle-painting was one example). To make a ship invisible in an ocean setting was simply not achievable, so instead it would be wiser to paint its surface in order to distort its shape. The goal of camouflaging ships, they argued, was not to make it hard to see, but to make it hard to hit. Advocates of this approach were primarily artists.
There was a second and opposing side, which urged the government to adopt low visibility camouflage. Even if it were a challenge to make a ship invisible, they reasoned, it was still of considerable value to lessen its visibility, and to therefore afford it protection. This group, in which scientists predominated, devoted their efforts to testing low contrast, non-disruptive painting schemes, and assessing the discernability of various experimental ship models, for which they used such devices as a colorimeter and a visibility meter [see patent diagrams below]. Typically, in this approach, "dazzle-painted" camouflage schemes were assessed not just for distortion but for visibility as well.
|L.A. Jones, Patent for Visibility Meter (1,437,809)|
In 1918, when the US Navy officially established a Camouflage Section, it was purposely made of two branches: The Design Subsection [pictured below], consisting of artists, was headquartered in Washington DC, while the Research Subsection, made up of scientists, conducted their experiments at the Eastman Kodak Company in Rochester NY. The tandem sections were administrated by Harold Van Buskirk [Photo 1 above]. an architect and Olympic fencing champion. An American Impressionist artist, Everett L. Warner [Photo 3], was put in charge of the Design Subsection, while the leader of the research team at Eastman Kodak was that firm's leading scientist, Loyd A. Jones [Photo 2].
|E.L. Warner and other artists at Design Subsection (c1917)•|
Today, one hundred years later, most people react with surprise or disbelief when they see examples of WWI ship camouflage, especially dazzle-painting. It is commonly described as counter-intuitive because, off-hand, one might conclude that its heightened visibility would aid an attack by a U-boat, not deter it. But that conclusion is largely attributable to the lack of familiarity with the complexities of U-boat targeting at the time—conditions that are vastly different today.
Those complexities were addressed in 1918 in a confidential report published by the Submarine Defense Association. The first part of that report, which was written by Lindell T. Bates (the association's secretary), was titled The Science of Low Visibility and Deception as an Aid to the Defense of Vessels Against Attack by Submarines. There is a second, less extensive part, written by Loyd A. Jones, on Protective Coloration as a Means of Defense Against Submarines.
The entire report, no longer confidential, can be accessed online through Hathi Trust Digital Library. But for the purposes of blogging, we are instead reprinting below a full-page newspaper article that was published in The New York Sun in 1919. Even though Bates was clearly allied with the scientific (or low visibility) view of the debate about ship camouflage, his news article is one of the clearest accounts that we know of WWI-era U-boats attacks, and how best to survive them.
Lindell T. Bates, MARINE CAMOUFLAGE BROUGHT TO PERFECTION IN AMERICA. First Authentic Account of the Development of Illusion in Foiling Hun Pirates Written by Leader in the Work Here—Scientific Explanation of Colors, Curves and Lines Used. The New York Sun. January 19, 1919, p. 11—
Camouflage has had almost as fascinating an evolution in marine as in land warfare. In many respects, however, it is the youngest science, and until March 1918, it might rather be called an art than a science.
The Germans were the first to apply the lessons of visual deception to the sea. Early in the U-boat campaign they began to paint their vessels in various designs to make them less conspicuous.
In the late nineteenth century British warships used to be black in color, and American white. In sea fights at fairly close range low visibility was not considered of great importance. In the 90’s the Germans changed from black to dark gray. Great Britain and the other Powers shortly thereafter followed suit, but different shades of gray were used by different nations. Dark gray, called “battleship gray,” was the prevailing color. At the outbreak of hostilities the French, Italian and Austrian fleets were of a color different from those of the British and Germans. The former favored a gray and khaki mixture. The Dutch ships were greenish brown in hue. In 1914 Austria adopted the German color for the sake of uniformity with her ally.
Prior to the entry of the United States into the war the Allies had made no notable effort to disguise their vessels as a help in the struggle against the U-boat. When American entered the only instruction to merchant vessels was to paint their white or light-colored upper works gray or dull stone color. Some vessels were decorated early with false painted bows and bow waves, or a silhouette of a destroyer, a submarine or a sinking ship.
Artists Took Up the Work
In the course of the war several American artists, noting the rapid development of land camouflage, became interested in its marine possibilities. William A. Mackay [Photo 4] and Lewis Herzog, both of New York, appear to have been the pioneers of elaborate camouflage both of this country and abroad, although in 1917 attention was beginning to focus on this question simultaneously in many quarters. Gerome Brush [Photo 5], Maximilian Toch [Photo 6] and Everett L. Warner soon entered the new field. Mr. Mackay even established a marine camouflage school in New York City, the first of its kind.
These artists were divided at the outset into two groups, those who favored painting for low visibility and those who favored a so-called “dazzle” system. Mr. Mackay’s original system was for low visibility, as was that of Mr. Brush. Mr. Warner considered deception of major and low visibility of minor importance. Messrs. Herzog and Toch sought to reconcile both aims.
The United States Shipping Board took interest in the possibility of camouflage as a defensive measure for American merchant ships. On October 1, 1917, the Treasury Department through the Bureau of War Risk Insurance issued an order requiring under penalty of one-half per cent increase in war risk premium the painting of vessels for protective purpose. Ship owners were at liberty to select either of five systems mentioned. Should an owner wish to try his own or a different scheme, the order required him to obtain for it the prior approval of William L. Saunders, chairman of the naval consulting board.
Little experimental work was conducted with reference to marine camouflage prior to the adoption of the five systems. Mr. Mackay had painted some submarine chasers at the navy yard, and Mr. Herzog had conducted visibility experiments on the northeast coast of the United States. The other artists had not enjoyed suitable experimental opportunities.
In July 1917, the Submarine Defense Association was organized by the shipping and insurance interests in New York in an effort to see that all measure were duly taken to safeguard vessels. Nearly a hundred leading American and British companies joined, and all the leading marine insurance concerns. Lucius H. Beers, counsel for the Cunard company, was elected chairman. J.A.H. Hopkins of Johnson and Higgins was chosen vice-chairman, and Lindon W. Bates chairman of the engineering committee. Admiral William S. Benson assigned a naval vessel to the association for experimental purposes and the new organization, although entirely independent, enjoyed the closest and most cordial relations with the American and foreign authorities.
The association’s technical staff soon set about ascertaining which, if any, of the five systems was the best, and if none was satisfactory, then to devise one that would be more acceptable. It proposed to approach the subject from a scientific, rather than an artistic, standpoint, so the chairman of the engineering committee, Lindon W. Bates, enlisted the active cooperation of George Eastman and the facilities of the great research laboratory of the Eastman Kodak Company of Rochester. Lloyd[sic] A. Jones of the research staff was assigned to collaborate with the writer and others of the association’s organization. From the summer of 1917 to March 1918, exhaustive investigations were conducted at Rochester, on Lake Ontario and at sea upon the vessel assigned by the Navy Department under Mr. Bate’s directions.
|Testing apparatus on the shore of Lake Ontario (1917)|
|Ship cut-outs used in testing. Photo courtesy James Dodge.|
During the time in which these research labors were being conducted the British and French navies began to look seriously into the camouflage question. Early in 1918 the British adopted a “dazzle” system devised by Lieutenant Norman Wilkinson, RNVR, a London artist.
In February 1918, it was learned in this country that Lieutenant Wilkinson was to be sent to the United States to initiate our navy into the mysteries of the new art. Ninety “dazzle” patterns preceded. Prior to his arrival the United States Navy Department decided to establish a camouflage section of its own and authorized the adoption of a “dazzle” system. Whatever system, therefore, was adopted had, perforce, to be called a “dazzle,” and as the meaning of that term was still uncertain, practically any type of camouflage was authorized.
As the navy authorities were familiar with the scientific research work which the Submarine Defense Association was conducting, the chairman of the engineering committee was consulted regarding the proposed navy organization. For scientific questions in connection with the subject it was obvious that Mr. Jones was the best equipped person in this country. For the executive direction under the higher naval officers, Harold Van Buskirk was designated because he was the most available, and he had shown tact and ability and could be released from duty with the association to go to the navy. These men were made Senior Lieutenants and they were the nucleus of the new Navy Camouflage System.
Of the five American camouflage artists, Everett L. Warner was chosen for a post with them, but Mr. Mackay remained in New York as a local executive of the Shipping Board of ship painting from designs supplied by the navy. While these developments were taking place, Lieutenant Wilkinson arrived, bringing with him ninety more “dazzle” patterns. The previous ninety were already considered obsolete.
|Norman Wilkinson camouflage plan Type 8 Design BX (1917)|
In March the Submarine Defense Association terminated its research work and published two marine camouflage reports entitled The Science of Low Visibility and Deception Against Attack by Submarines by Lindell T. Bates, and Protective Coloration as a Means of Defense Against Submarines by Lloyd[sic] A. Jones.
Difference of the Reports
The writer’s report gave the history of camouflage, discussed the question of reduction of superstructure, the means of smoke elimination and of making smoke screens as well as deceptive coloration. Mr. Jones limited his study to low visibility coloration and how to reconcile deception coloration with low visibility at the blending distance.
|Submarine Defense Association low visibility schemes (1917)|
The association advocated a system combining low visibility and deception, recommended the abolition of the five earlier systems and considered that the British “dazzle” system was subject to criticism largely because of its total neglect of low visibility. The navy thereupon adopted for certain war vessels a low visibility color only, and for destroyers and merchant ships a materially modified British “dazzle,” changed so as to give it a low visibility feature.
The Shipping Board organized also a camouflage section and applied the designs received from the navy to the merchant vessels under its jurisdiction.
The results of the research work of the association, the adoption by the United States Navy of a low visibility, deception system, and the practical experience at sea led the British in the late summer of 1918 practically to abandon their own ‘dazzle,” which disregarded the low visibility factor. Camouflage based on more scientific principles then began to take the place of the original English system. Checkerboard bow and funnel patterns and perspective distortion bands began to appear.
Lieutenant Jones has perfected a colorimeter [see patent diagram below] to measure the weather coefficient and two expeditions left in December 1918 to measure this factor in various seas. Protective coloration for American submarines has been investigated and a special color determined. Navigation signs of a particular variety and clever navigation light schemes also been evolved.
|L.A. Jones, Patent for Colorimeter (1,496,374)|
The geographical position of a vessel at sea and the circumstances under which she is seen have an important bearing upon her visibility. The submarine danger zone included all the Mediterranean, North Sea, and Atlantic beyond even the Azores, Cape Verde and Canary Islands. The approaches to the Irish Coast were particularly hazardous as were the other places where trade routes intersect or converge such as the Strait of Gibraltar.
Hostile U-boats were most likely to be met in the Irish Sea and English Channel. They were frequently encountered anywhere in the Mediterranean and North Sea, and in the Atlantic as far as longitude 25 degrees west, and as far south as latitude 30 degrees north. They were also encountered near Madeira and the Azores. Thirty per cent of the shipping losses, according to Sir Eric Geddes, occurred in the Mediterranean.
The visibility problem is affected also by the manner in which ships voyage, whether alone or in a group. Prior to the entry of the United States into the war the escort and convoy systems did not extend to many vessels other than transports. In 1917 and 1918, however, large convoys of from twenty to forty ships proceeded from American and Canadian ports to Europe. Merchant vessels proceeding to the Mediterranean occasionally so voyaged, as well as ships coming back from Europe to America. Convoys sometimes split up on the journey and single vessels proceeded to other ports than that of the convoy.
An effort was made to group vessels according to speed. It happened, however, that vessels of less than a certain minimum rate hamper a convoy overmuch and were not included in it. Fast vessels were also excluded, as with their speed and maneuvering ability they were about as safe alone. There were numerous vessels which were not given he protection of convoy. Such are, for example, ships about 16 and below 6 knots in speed, European coastwise vessels and ships proceeding to certain Mediterranean ports. Sometimes therefore victims were alone on the sea, sometimes they were escorted or convoyed.
The visibility problem in further complicated by certain war emergency navigation rules. The instructions to American and allied vessels called for precautionary zigzag maneuvers while the danger zone was being traversed. Frequently ships proceeded three miles to port or starboard of their normal course, sometimes five miles. These measures meant that a wide belt was navigated through the submarine infested area.
Smoke a Dangerous Factor
Fueling practice is also a factor in the visibility study. American vessels were required by the Bureau of War Risk Insurance, under penalty of increased premium, to burn smokeless fuel or anthracite in the danger zone. Inasmuch as other ships were not always similarly regulated and convoys were composed of foreign as well as American vessels, smoke clouds always formed above convoys. It was not possible either in all cases to obtain smokeless fuel or to use it the full time necessary. Telltale plumes therefore issued from the funnels of vessels traveling alone or in company through the danger zone.
The most important of all visibility factors is weather. The yearly “proportion of sky covered with clouds” for the North Atlantic is from 60 to 70 per cent, for the ocean off the south English and French coasts 60 per cent, off the Azores 50 per cent, off the Canaries 40 per cent and off the Cape Verde Islands 40 per cent. In the Mediterranean it is from 30 to 40 percent, while in the waters off Greece it is 50 per cent.
The hours of sunshine a year total 1,300 off the north coast of Ireland and Scotland, 1.500 off England, 1,700 off the southern coast of Ireland, 2,500 in the Mediterranean. These are out of a total of 8,760 hours of day and night a year. In the English Channel westerly gales are prevalent in the winter months from October to March, inclusive. They are rare from May to July, inclusive, and seldom last long. During twilight hours in the morning and evening there is generally a haze over the sea. In the danger zone near the British Isles daylight is frequently modified by more or less heavy sea fogs. Haze on the water is almost constant from October to April.
In the sections of the danger zone near the Azores, Canaries and in the Mediterranean the percentage of clear days is much greater; there are fewer storms, even in winter, and the atmosphere is freer.
Visibility is also concerned with the question of the distance from which the observation of the U-boat is taken. The distance at which a ship is potentially visible at sea depends upon the height of the point of observation, the height of the vessel and the curvature of the earth’s surface.
Submarines are able to receive and send wireless messages carrying maritime information such as the location of Allied war craft. Sound signals may be used also for signaling between U-boats. They are now provided with hydrophones able to detect the presence of other craft several miles off. If the vessel or convoy is found to be passing at some distance, necessitating considerable running on the surface at high speed to bring the U-boat within attacking distance the attempt will not be made unless the ship or group is known to be an important one. If the earliest observations give encouragement the submarine, unless already ahead of the vessel on her course, takes a direction at 90 degrees to the line of first observation and toward the vessel’s route.
If the ship is alone and it is decided to use the naval gun, the U-boat approaches to a range of from four to eight thousand yards and opens fire. The caliber of the submarine’s deck guns was in 1914 3.5 inches; at the close of the war it was 5.9 inches or 6 inches on most submarines. The guns on merchant vessels were often out-ranged. The latest U-boats even dared to attack an Allied cruiser.
If, on the other hand, for tactical reasons the torpedo is selected as the best weapon to use, the submarine submerges while still out of sight and proceeds to the firing position. This is abreast or slight ahead of the victim and about 1000 yards off. German U-boats have endeavored to come as close as 300 yards before launching the torpedo. If the ship is part of a convoy the U-boat will either attack the convoy flank or seek to rise in the center. In case of such attack no particular ship is selected during the early approach.
While submerged the submarine commander takes from six to eight periscopic observations in order to obtain the course, range and speed of the merchantman or convoy. These data enable him to calculate where the firing position will be against a single vessel or where to attack a convoy. The duration of the periscopic sights is from thirty seconds to five seconds. In ordinary periscopes, all but about a third of the light is lost by reflection or absorption. If there be dust or moisture on the lenses the loss of light is even greater. This defect in the instruments is largely compensated among other ways, however, by the natural dilation of the pupil of the eye to admit more light.
Normally the vessel’s image is enlarged from 1.2 to 1.5 times, but magnification three to six times is not unusual. To ascertain range from periscopic observations there are only two available methods. Telemeter scales or cross hairs graduated vertically and horizontally in hundredths are generally used. The other method is the double image micrometer. Two images of the same object are made to cut each other in the lens, and are shifted with reference to one another until the masts, funnels or other high parts of the vessel under observation are on a level with the water line or deck line of the second images. The angle of shift determines the distance.
|Harold Van Buskirk assessing ship camouflage model (1918)•|
The range of a vessel as the various times that she is observed will give an idea of her course unless she is zigzagging. At close range the apparent perspective of the ship, her bow position and alignment of masts are the course indices used. Speed calculation is also approximate only. It should be emphasized that course, range and speed estimated from periscopic observation is by no means an exact science. The human eye may be deceived when its view is so limited and brief.
With respect to protective camouflage there are two purposes which may be subserved—namely, a reduction in the visibility of vessels in order that they may traverse the danger zone unobserved or less well observed by submarines, and a change in the appearance of a vessel so that if observed the calculation of her course, speed and range may be thereby rendered in accurate. While U-boats are equipped with sound detection apparatus of considerable hearing radius, the low visibility purpose if well worth securing, because the hearing radius of sound detectors does not in every case extend as far as vision at sea. Sound, furthermore, does not give the precise direction, distance and course of a vessel which are necessary for an approach to torpedo firing position.
Hard to See, Hard to Hit
A ship that is hard to see is hard to hit. It is still, therefore, a real advantage for a ship to be as nearly invisible as possible. This is especially true from the point of view of naval strategy. The area that a U-boat can patrol and still be sure of meeting ships of low visibility is much smaller than it can patrol and be sure of meeting vessels more readily seen.
Were low visibility secured, to cover the same sea area with a submarine cordon would require more submarines. If it were possible so to “dazzle” the eye as to render it incapable or partly incapable of observing the image of the target, this “dazzle” effect would be desirable. As, however, in taking the most important periscopic observations, the vessel’s outline, masts and funnels are chiefly noticed, the program of low visibility and of disturbing range, speed and course estimate is preferred.
It is a serious matter to decide the nature of the deception to be sought. Deception as to range can affect gunfire less than torpedo fire, as when the former “spot firing” is resorted to. In the case of torpedo attack, which is nearly always at close range, deception may, however, have a decided influence. Should one make the vessel’s course as seen from a submarine seem directed away from the U-boat or toward it? Each has its advantages and disadvantages, depending upon the respective position, speed and other characteristics of the submarine and target vessel.
If the ship is made to appear as coming toward the submarine, the latter may be cause to maneuver to a torpedo firing position at a range further than, and astern of, the normal one. On the other hand, if the course is made to appear as away from the U-boat, the latter may submerge and rise at a point where the vessel could run it down.
Should an attempt be made to give an aspect of speed faster or slower than the actual? A slower apparent speed may cause the U-boat, to its cost, to take leisure in approaching the firing position. An illusion of faster speed may induce the submarine to overrun the firing position.
Should an effort be made to give the range a longer or shorter appearance? If the vessel seems to be closer to the U-boat then she really is, the torpedo fire will be actually at longer range than the submarine captain anticipates. If, on the other hand, the ship is made to appear more distant than she really is, then the torpedo maybe be aimed to pass actually ahead of the vessel.
A choice cannot be arbitrarily made between the alternatives cited, but that there should be deception in relation to the three factors is clear. The extent of the deception desired cannot be precisely prescribed. It would be well not to seek too much. An error of 15 degrees in course of two knots of speed or of two to three hundred yards in range is sufficient to add materially to the safety of a vessel against a torpedo attack. Any illusion, even a slight one, along these lines will be an advantage, since accuracy in gun and especially in torpedo fire as well as the maneuver of approach depends intimately upon exactness in the estimates of the target’s range, course and speed.
The bearings of vessels are first taken by a U-boat from observation of smoke or superstructure. While for ships in convoy the smoke, noise and breadth of area covered lessen the utility of superstructure reduction to lower visibility, it remains of value as an aid to the defense of the solitary ship.
The safety of a ship subject to attack may be said to vary inversely as the area over which she is visible to the submarine.
On sailing ships all superstructure is usually needed, but on steamers considerable reduction is possible. Masts on modern vessels serve little purpose save for the wireless antennae, the crow’s nest and the light. One mast, in many cases, will suffice. The Marconi Company informed the International Mercantile Marine Company that the aerial of the wireless on their vessels could be fun from one mast to the funnel and still meet the requirements of service.
Scenic Artist’s Effort
Homer F. Emens, the well-known scenic expert, devoted considerable attention to the problem of distorting the apparent perspective of the upper works of a vessel. He prepared a model in which a large triangular screen was placed below the bridge, extending from side to side, the point of the triangle facing the bow of the vessel. On each side of this triangular screen he painted a perspective view of the normal structure which actually faced the base of the triangle. The effect os this was to make the ship when seen from the side appear nearly bow on, provided the error was not corrected by a normal view of other portions of the ship.
|Homer F. Emens camouflage model (1917)|
The new ships for the Emergency Fleet Corporation have been designed with low superstructure. A notable example of a vessel with superstructure reduced is the steamship Valeria. The vessel was a Cunarder supplied to Thomas A. Edison by the Submarine Defense Association for this experimental purpose. The funnels and masts were cut short and character deception was sought by Mr. Edison by means of canvas screens strung between the funnels and certain other parts of the superstructure. They were blown off, however, a short time after the vessel left New York. As the vessel thereafter traveled in convoy no conclusive data have become available. Owing to the inherent difficulty of screening, it seems hardly practical to radically change the character of a vessel.
The field of protective coloration is an important one, but on which is limited. Vessels in convoy or with escort can hardly hope to be invisible whatever paint is used. But paint may render even a convoyed or escorted vessel less liable to torpedo attack, as low visibility and deception are possible. Vessels proceeding alone cannot expect often to be invisible to ordinary vision within about 5,000 yards, unless there is a haze or a fog or it is night, as their bulk distinguishes them from the sky. For ranges beyond about 5,000 yards, in such a case, low visibility and even invisibility is frequently possible.
But, if a vessel lies between the U-boat and the sun, no amount of paint will render her invisible, since the side of the ship seen will be in the shadow and the background will be illuminated. Deception to ordinary vision is possible, on the other hand, within approximately 5,000 yards, or a greater distance if the periscope used magnifies to several times normal. It is difficult so paint a large warship as to cause real deception, because her naval masts and upper works give away her character and heading. On the other hand low visibility for all ships is possible.
The System Analyzed
One may now analyze the respective merits of five American systems, the British “dazzle" and the navy camouflage, for these represent the systems of camouflage practiced during the European war. The Naval Consulting Board recorded on July 9, 1917, regarding the Mackay system:
“Fundamentally it is based on mottling the surface with the three primary colors which at a distance blend to produce a gray having the quality of a gray light. He also proposes to shade the tints so as to lower highlights and raise the low areas of illumination.”
This was classed as a system for vessels “which is our opinion will lower their visibility.” The theory of Mr. Mackay’s low visibility system is given by him in the following language:
“The proportion of constituent colors to give white are: Violet 44, red 36, green 20. Therefore areas covered with these three colors in this proportion would give a general over-all gray. With the colors in this proportion the ground color would be violet.”
|William Andrew Mackay camouflage system (1917)|
It is not clear how three different color effects can be produced by the same formula. At a subsequent date Mr. Mackay supplemented his “low visibility” object with a “dazzle” purpose and produced a system which he calls one of “disruptive coloration.”
The Warner system aims primarily to “dazzle” rather than to reduce visibility. Various irregular patterns are carried out in the shades red, blue, pink green and white. Particular stress is laid by the artist upon the value of strong contrasts with a view to giving a deceptive appearance to familiar parts of the vessel. But Mr. Warner regards the question of pattern as of paramount importance. He does not ask to give low visibility within five miles of a vessel.
|Everett Longley Warner camouflage system (1917)|
The Toch camouflage system applies four color, a very light blue gray, a dark blue gray, a dark green and a light pink purple. The colors are said to have been selected for their so-called “vibrating” qualities. The dark colors predominate in the lower part of the hull and the lighter in the upper part along the skyline and on the extremities. All lines, both vertical and horizontal, are broken by the alternation of colors.
|Maximilian Toch camouflage system (1917)|
The superstructure, masts and funnels are painted mainly in a very light blue gray irregularly splotched with a dark gray and a light pink purple. The green does not appear in the superstructure. The colors are intended to blend and fade out in long distances into the general tone of sky and water, which are assumed to b the same. Low visibility is sought by the use of colors of alleged low visibility qualities and a “dazzle” effect by placing them in strong contrast and in large splotches.
The Brush system [based on countershading] seeks low visibility by rendering uniform the illumination of the vessel. Dark areas are raised by light paint and light areas are darkened. Black and white is occasionally used, or a dark gray. The resulting shade upon blending is a gray somewhat lighter than battleship gray, but resembling it.
|Gerome Brush camouflage system (1917)|
Short Ray Colors Used
Lewis Herzog devised a system which uses the short ray colors—that is, those from the lower side of the spectrum—avoiding the use of red, yellow and orange. He remarks concerning this system:
“Interference of light rays setting up vibrations is sought by means of more or less concentric sets of panels of blue, green and violet as a gray base, which at a distance takes on a tone scintillating with the atmosphere and blending into it, and thereby lowering the visibility of the ship. The lines of color application are broken as much as possible and change frequently in direction. All color bands are applied in arcs of circles each of considerable radius. Straight lines are avoided on the principle that the eye is more confused by the use of circular forms.”
|Lewis Herzog camouflage system (1917)|
The effect which it is desired to produce on the sight by this system is best described as a “shimmer” or “scintillation” very similar to that produced by heat waves over the surface of land or water.
The British “dazzle” is made up of such colors as black, dark blue, scarlet, dark red, olive green, yellow, gray and white. These colors are laid in large patches of contrasting colors. In some of the patterns the light colors are concentrated at one end of the vessel and the dark colors at the other in order to distort the apparent heading and view of the vessel.
This scheme is based upon the idea that invisibility at sea being unattainable, some protection may be afforded by painting ships in such a way as to confuse the enemy and by causing some doubt as to the course, speed and distance.
It may be seen from this brief review upon how fragile a base the early systems rested. They were impressionistic systems devised by artists, and not scientific systems devised by light and color experts. Their sponsors deserve, however, the greatest credit for introducing the subject and for opening a new field for research.
In his elaborate technical report upon Protective Coloration as a Means of Defense Against Submarines, Lloyd[sic] A. Jones expressed the physical laws and factors which govern visibility. For special research he determined that low visibility is attainable and that a particular shade of gray which he calls omega gray is best suited for vessels navigating the northern portion of the danger zone, where the average weather is 70 per cent cloudy, and below that line where there is frequent haze. For the southern portion of the danger zone a bluer tone of gray called psi gray was found the best. Latitude 45 degrees north is a suitable dividing line of the areas in which a ship should appear omega and psi gray, respectively.
It is of supreme interest to note the sacrifice of low visibility by the various camouflage systems heretofore presented. This is shown by Mr. Jones in a scientific and convincing manner with the aid of a “visibility meter” invented by him in the course of experiments. The British “dazzle” system, with its large masses of black and dark colors, is particularly vulnerable in this respect. No one of these systems produces the least visibility attainable. Omega and psi gray alone comply in their respective fields with low visibility requirements.
The USS [Gem], the naval experiment ship of the association, has shown as law as 0.2 in clear weather at 1,500 yards and invisibility at 3,000 yards and in foggy weather 0.1 at 800 yards. The average weather coefficient for the northern, most hazardous portion of the danger zone, is calculated as .43.
The great superiority of omega gray for low visibility may be deduced from this table. Under average weather conditions a ship so painted is forty-six times less visible than one painted according to the British “dazzle.” On one of the tests off New London several persons on shore could not pick up the USS [Gem] at 3,000 yards distance, even with binoculars. There was a slight mist over the water, such as is frequently noted in the northern portion of the danger zone. But other vessels, painted battleship gray, were visible at a greater distance than 3,000 yards.
False bows, sterns and bow waves have frequently been painted on vessels and are of value. It is of little use to try to reverse the apparent direction the ship is taking or to paint another ship on her, as such deception attempts too much to accomplish anything. But by a false painted bow and stern placed so as to distort the apparent perspective the course may be made to appear somewhat other than it is.
Checkerboard patterns blur outline. In art and architectural drawing the principles of perspective representation have been scientifically studied for centuries. It is quite feasible to paint a vessel in such a fashion as that the apparent perspective is different from the real. This will induce an error in course estimate. A vessel painted with converging bands of colors properly contrasted will offer a deceptive appearance as to course. It is possible also to distort perspective by curves or by vertical bands closer together at the bow or stern of the vessel than at the opposite end.
Must Break the Water Line
Inasmuch as the water line of a ship is known to be horizontal the bands should break the water line. This point is of great moment. No two ships should be painted exactly alike in regard to pattern and convergence of lines. Perspective deception patterns should blend at a distance where deception is no longer possible but low visibility is possible.
It should be carefully borne in mind that the blending distances of bands and patterns are based upon the hypothesis that the periscope does not enlarge the image much above normal vision. If magnification of three to six times normal should be resorted to the blending distances should be reduced in order that low visibility is not sacrificed. It may also be necessary to modify the blending distances of the bands and patterns to meet a possible attempt to nullify by light filters and deceptive effects.
Deception is a matter of psychology and is less susceptible than visibility of scientific determination. What will deceive on submarine observer will not delude another. The Submarine Defense Association has experimented with perspective distortion bands and checkerboard outline blurring patterns. Officers who viewed the USS [Gem] as she entered New Haven harbor said the diamond pattern on her bow gave her a scow bow. The British toward the end of the war came to favor also such checkerboard patterns for certain portions of the ship.
“Dazzle” patterns have been tried on American warships, but so long as the upper works and masts are of their special character no radical deception is possible. Experiments have been made with squares, rectangles, patches, band and other designs to overcome this handicap, but without success so far. It is for this reason that the low visibility object alone is favored for the larger warships.
Tests were also made in July 1918, off Fort X to determine the effect of a low visibility‚ deceptive coloration—upon the ability of coast defenses to follow a vessel with searchlights at night. The USS [Gem] proceeded between Point Y and Island Z at 8,000 yards mean range, steering a sinuous course until opposite the end of the latter, and then went straight through a channel at a distance of about 3,000 yard from the nearest searchlight.
Although the approximate time of her departure was known she passed through all five searchlights wholly undetected and picked up only when, after passing through the channel she turned on her own lights. This was repeated on another occasion with a modification in program. She left a known point at a known time on a known base course. The vessel was located for only three minutes out of forty.
Report of the Fort Test
While a considerable part of her ability to avoid searchlights was attributed to the “S” course the following remarks were made concerning the camouflage effect:
“At the range (9,000 yards) she gave the appearance of a bright streak of silver recognizable as the [USS Gem] only when in the leading edge of the beam. Her starboard camouflage was such that as soon as she got well back in the the beam she was of the same gray-blue-white color as the beam itself. Of course it is well known that a searchlight beam blankets a target in the center or rear edge thereof, but this was more pronounced in the case of the [USS Gem].”
The United States Navy Department had the benefit of much prior experience when it came to adopt a navy system. It made use to a large extent of the data previously obtained. The dreadnoughts and submarine chasers were duly painted with low visibility gray. For merchant vessels, contrasting masses and bands of black, blue, gray and white have chiefly been used.
In regard to the success of camouflage there is practically no data available, save in German hands, because it is hard to determine to what cause escape from a submarine has been due. It is largely a matter of guesswork how much marine camouflage has added too a vessel’s safety, but that it had a substantial effect is not open to question.
Ships in convoy or passing each other at sea have been deceived as to the course of the camouflaged vessel. We do know, however, that of about 1,300 American vessels painted with the navy system, only eleven have been lost since March 1918. The convoy system, zigzagging and improved armament have, no doubt, contributed materially to the result and probably all of them much more than has protective coloration.
Should the writer hazard an estimate he would say that the systems of camouflage, heretofore used, have increased the chances of safety between 3 and 15 per cent.
Just as the submarine has come into the world to stay, so too has marine camouflage. It has developed during the great war from a crude fantasy into science. Practical application always follows some distance behind the advances of abstract knowledge and research, so that marine protective coloration did not reach a final form in the great war.
The low visibility color is now determined, but the means of reconciling deceptive painting with it requires further transformation in practice. Science has pointed out the directions which must be taken. The importance of defensive coloration is not so great as many believe, and new ways may be found to counteract its effect, but marine camouflage will in years to come play a notable role in naval warfare.
• Photographs marked by raised dot have been digitally colorized. All others are original WWI-era coloring.