Ship Camouflage
Instructions
United States Navy
Ships - 2
Bureau of Ships
January 1941
Chapter 4
Experimental Background
Results
of Surface Ship Experiments.
Investigation of many aspects of surface
ship camouflage initiated in 1935 by the bureau of Construction and Repair and
continued since that time is described in References 1 and 2.
Reference 1
Naval Research Laboratory Report H-1585, January
12, 1940, "Naval Camouflage, Tests at Sea June to September,
1939," and references therein.
Reference 2
Comdesbatfor Conf. Ltr. to BuShips 25 October 1940,
S19-Ser. 4888, "Camouflage of Destroyers - Low Visibility Paint."
The references summarized the results of long
continued tests at sea on low visibility painting, graded
painting, dazzle painting, and various miscellaneous experiments.
In the matter of low visibility colors it was established that no one color
was the best under all conditions of weather and illumination and that any
color finally selected would be a compromise. The observed facts are
summarized in Table 1; the notes appended to Table 1 bring out certain facts
which are readily reduced to tabulation. Other conclusions reached were,
- that graded painting produced some range
deception,
- that a painted bow wave produced some
speed deception,
- that bold dazzle camouflage was undesirable
because of enhanced visibility,
- that unobtrusive dazzle camouflage yielded some
deception without too great enhancement of visibility, but was limited in
its application.
Visibility
of Wakes.
When a ship has been painted to achieve low
visibility, the visibility of the wake becomes important. In the case of
destroyers making speeds above 20 knots the wakes are so apparent that little
advantage can be had from camouflage (see note 6, Table 1). In the case
of other types of ships, the speed at which visibility of the wake becomes of
paramount importance is not known.
Discussion
of Measure 1.
The Dark Gray System of Measure 1 is the system which
appears to offer the best compromise color for low visibility under various
conditions of weather and illumination. This came about in the following
way:
In the experiments of Reference
1, ships painted
Light Gray, Ocean Gray, Dark Green and Black were observed, the results being
summarized in Table 1. In view of the fact that a black color increased
the visibility of the ship as an object to a surface observer, although it possessed
desirable features of a low visibility to aerial observers and of range and
course deception, Reference 1 suggested that the Dark Gray 5-D might be the
best compromise low visibility color for combat ships.
Further experiments during Fleet Problem Twenty-One
with destroyers painted Light Gray and Black, described in Reference
2,
verified a number of the conclusions of Table 1 and recommended that all
destroyers attached to Destroyers, Battle Force, be painted Dark Gray.
This Dark Gray System, Measure 1, which is the most
important measure of Chapter 2 is a system which has never been tested.
It must be kept in mind that THE EFFECTIVENESS OF THE DARK GRAY SYSTEM IS NOT
KNOWN.
Reference 1 states, "Laboratory tests show the
in the dark under searchlight illumination the Dark Gray color is distinctly
more visible than black, but whether the difference is important can only be
determined by tests at sea."
It is important to remark that a pure intense blue
color possesses desirable low visibility features perhaps to a greater extant
than those of Dark Gray. The reasons for the low visibility of a vivid
blue color are fully described in Reference 1. However, attempts to
prepare a stable ultramarine blue paint which does not fade have been
unsuccessful, and, therefore, tests of the color on a ship have not been made.
Discussion
of Measures 2, 3 and 4.
By consulting References 1 and 2 and
Table 1, it will
be found that the Graded System, the Light Gray System and the Black System of
Measures 2, 3 and 4, Chapter 2, respectively, have been tested.
Therefore, the effectiveness of these measures can be said to be known from
direct experiment.
Discussion
of Measure 5.
As described in a reference cited in Reference1 the
painted bow wave of Measure 5, Chapter 2, was tested only once on a destroyer
in 1935. The bow wave designs of Plates 4,
5, 6,
7 and 8
have not been
tested and their effectiveness is not known.
Table
1
Color for Low Visibility
Position of
Observer |
Conditions |
Color for Lowest
Visibility |
Day |
Night |
Weather, Illumination, etc. |
Vertical
Surfaces |
Horizontal
Surfaces |
On Surface |
Day |
|
Clear sky, sunny, no haze. |
Ocean Gray |
Usually not seen |
|
Day |
|
Cloudy sky, no sun, no haze. |
Light Gray |
|
|
Day |
|
Haze or fog. |
Light Gray |
|
|
Day |
|
Black smoke screen. |
Dark Colors |
|
|
Day |
|
White smoke screen. |
Light Colors |
|
|
|
Night |
Natural illumination, stars or clounds,
no moon. |
Black |
|
|
|
Night |
Clear sky, moon behind observer. |
Black |
|
|
|
Night |
Moonlight diffused through clouds |
Ocean Gray |
|
|
|
Night |
Searchlight illumination from observing
ship, or from behind observer. |
Black |
|
|
|
Night |
Far side of target from observer illuminated
by searchlight, flare, or star shell. |
Target in silhouette
all colors alike. |
|
In the Air |
Day |
|
All conditions of weather and illumination. |
Black |
Black |
|
|
Night |
All conditions of weather and illumination. |
Black |
Black |
Notes on Table 1
Note 1. |
In silhouette against the sun,
moon, searchlight or other source of light all colors look alike and
camouflage is of no effect. |
Note 2. |
No color affects appreciably the
accuracy of stereo-ranges. |
Note 3. |
Gloss is objectionable in any
color. It is most apparent on stacks and gunshields. |
Note 4. |
Dark Green is almost the same as
Black but not quite as satisfactory. |
Note 5. |
In the daytime black ships are
visible at long ranges as objects but target angles and ranges,
because of indistinctness of shadows, are much more difficult to
determine than with lighter paints. |
Note
6. |
When observed from the air at
distances 1 to 8 miles, altitudes 1000 to 2000 feet, the black ships
of DIVISION FOUR were not visible over two or three miles, while the
Light Gray were visible at all distances. The Black ships were
less visible than the Green. Sun glints and light spots aided in
locating the destroyers. The visibility of the dark ships was
1/3 to 1/4 that of a Light Gray ship. |
Note 7. |
All surfaces visible from the air
should be black or a color approaching black. These include
canvas of all kinds. |
Note 8. |
Exposed life ring buoys should be
the same color as the surrounding surfaces.
|
Note 9. |
Black masts and similar high
structures are very revealing when they alone protrude above the
horizon. The Light Gray color is believed to be the best for
them. |
Note 10. |
At Speeds above 12 knots the white
wake of a destroyer becomes important. At night and from
aircraft at any time when destroyers are making speeds above 20 knots
and above the wakes are so apparent that little advantage can be had
from camouflage. At night under searchlight high speed wake is
clearly visible and readily discloses the presence of a destroyer
regardless of painting. |
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