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,,i iTG MARINE NA~rlGATION
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i"- UNtfED STATES COAST GUARD
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UNITED STATES COAST GUARD
Revised June 1 949
GOVERNMENT PRINTING OFFICE
WASHINGTON : 1949
AIDS TO MARINE NAVIGATION
OF THE UNITED STATES
Digitized by the Internet Archive
in 2012 with funding from
University of Florida, George A. Smathers Libraries with support from LYRASIS and the Sloan Foundation
Foreword,--_- ...______ _
Purpose of aids to navigation_ __ _
Range Lights _
Electronic aids to navigation
Symbols employed upon charts
Light lists_______ ______
ENytice to Marianes __
TEaly history_-_-_- -_-_--
Related nautical publications --
The purpose of this publication is to acquaint those who are inter-
ested in the study of the science of navigation with the basic prin-
ciples underlying the marking of coasts and waterways of the United
States and its possessions with lighthouses, lightships, fog signals,
radiobeacons, 10ran, and buoys. I~t explains briefly thne significance
of the various colors of lighthouses and buoys, of the wide variety of
light and fog signal characteristics, and of the system of electronic
aids to navigation. It states in simple terms the mnanner in which the
information provided by these aids is applied in actual navigation.
The text treats primarily with the manner in which the physical
characteristics of the various aids to navigation serve the mariner.
Engineering problems connected with the construction and mainte-
nance of the aids to navigation are not discussed, nor is the publication
intended to replace the Light Lists, Coast Pilots, and other Govern-
ment publications which should be at hand during actual navigation.
T'he expression "Aids to Navigation" as used herein, includes light-
houses, lightships, radiobeacons, loran, fog signals, buoys, minor lights,
THE PURPOSE OF AIDS TO NAVIGATION
Aids to navigation are placed at various points along the Nation's
coasts and navigable waterways as markers and guides to enable myari-
ners to determine at all times their exact position with relation to the
land and to hidden dangers. Within the bounds of actual necessity
and reasonable cost, each and every aid is designed to be seen or heard
over the greatest practicable area.
Aids to navigation assist mariners in making landfalls when ap-
proaching from overseas, mark isolated dangers, make it possible for
vessels to follow the natural and improved channels, and provide a con-
tinuous chain of charted marks for coast piloting.
As all aids to navigation serve the same general purpose, such
structural differences as those between an unlighted buoy and a light-
ship, or a lighthouse and a radiobeacon, are solely for the purpose of
meeting the conditions and requirements of the particular location at
which the aid is to be established.
Lighthouses are found upon all coasts of the United States, upon
the Great L~akes, and along some of the interior waterways rfI the
country. Such structures are so well known as to require little
description. Ligihthouses are placed where they will be of most
use, on prominent headlanmds, at entrances, on isolated dangers, or
at other points where it is necessary that mariners be wsarned or
guided. Their principal purpose is to support a light at a consid-
erable height above thze water. TIhe same structure may also house a
fog signal and radiobeacon equipment, and also contain quarters for
the keepers. ]However, in thne majority of instances, the fog signal,
the radiobeacon. equipment, and the operating personnel are housed
in separate buildings grouped around the tower. Such a group of
buildings constitutes a light station.
CYUINDRICAL TOWER SQUARE
HOUSE ON CYUINDRICAL BASE
SKELETON IRON STRUCTURE
CYUINDRICAL CAISSON STRUCTURE
2 AIDS TO MARINE NAVIGATION OF THIE UNITED STATES
TYP ICAL LIGHT STRU CTUR ES
AIDS TO MARINE NAVIIGATION OF THE UNITED STATES 3
The location of a lighthouse, wFchether in. the water or on shore,
the importance of the light, the kind of soil upon which it is to
be built, and the prevalence of violent storms, have a direct bearing
upon the type of structure erectedl and on the materials of which it
wrill be built. Enlgineering problems will hot be entered into here,
but it is important to note thatt the materials used and types of con-
str~uctio ni differenitiate one lighithlouse! from another and hence aid in
Ligh~thouses vary markedly in their outwazrd appearance because
of the points already mentioned and also because of the grea;t, dif-
fere~nce in. the di anc~re s to wochich their lights should be seen. Where
the need for a powerful light is great and the importance and densityv
of traffic warrants, a tall tower withn a light of high candlepow~er is
erected. Conversely, at points intermediate to the major lights, where
the traffic is light, and where long range is not so necessary, a less
expensive structure of more modest dimnensions suffices.
The terms, secondary lights, minor lights, andi automatic lights
indicate in a general way a wide variety of lights, each class shading
imperceptibly into the next. These lights may be displayed from
towers re~sembling the important seacoast lighthouses, or may be
shown from almost any type of inexpensive structure. The essen-
tials of a light structure where keepers are not in residence as for
all lights, are: best possible location. dependent on, physical conditions
of the site, sufficient height for the location, a rugged support for the
lantern, anld a, housing for the tanks of compressed gas or electric
batteries from which the light is operated. Meeting these ess;entials~
are many types of structures--small tank houses surmounted by a
short skeleton tower, a cluster of piles supporting a battery box and
the lens, and countless other forms.
At the present time many of the lighthouses which were originally cared for
by resident keepers are operated automatically, because of the availability of
commercial electric current. There are also now a great many automatic lights
on inexpensive structures, cared for through periodic visits of Coast Guard cutters
or of attendants placed in charge of a group of such aids.
The recent introduction of much nrew automatic apparatus means that the
relative importanoce of lights cannot be judged on the basis of whether or not
they have resident keepers,c1. for a number of powerful lights in, towers of great
height are now operated without continuous attention.
COLORING OF STRUCTURES
Color is applied to lighthouses and automatic, light structures for
the purpose of making them readily distinguishable from the backi-
grounrd against which they are seen, and to distinguish one structure
4 AIDS TO MARINE NAVIGATION OF THIE UNITED) STATES
COLORING oc ~TYDICAL LISHTHOUSES
ST. AUGUSTINE FLA.
CAPE HENRY, VA.
AIDS TO IMARINEi NAVIGATION OF TH3E UNITED STATES
from others in the same general vicinity. Solid colors, bands of color,
and various other patterns are applied for these purposes.
Minor light structures are sometimes painted black or red, to indi-
cate the sides of the channel which they mark, following the same
lateral system used in. the coloring of buoys. When so painted, red
structures mark the right side of the channel, and black structures the
left side of the channel, entering from seaward.
Lights are given distinctive characteristics so that one light may
be distinguished from another, or as a means of conveying certain
definite information. This distinctiveness is obtained by employing
lights of various colors, by having lights that burn. steadily, and
others that flash at intervals of great variety. Th`]e principal "Lcharac-
teristics" employed for aids to navigation are shown on page 6i.
T1he three standard light colors used for lighted aids to navigation
are white, red, and green.
LENGTH OF LIGHT PERIODS
By varying the length of the periods of light and darknness of any
of the flashing or occulting characteristics, a great variety of charac-
teristics may be obtained. Advantage is taken of this to secure the
necessary distinctiveness between aids of a given area.
IDENTIFICATION OF LIGHTS
When making a landfall, the charts and the light lists should be
consulted to learn the exact characteristics of the light or lights
wPhich it is expected wcPill be first seen. When a light is observed, its
color is noted and, by means of a watch or clock with a second hand,
a note is made of the time required for the light to perform its fwul
cycle of changes. If color, cycle, and number of flashes per cycle
agree with the information in the light list, correct identification has
been made. The light list should be examined to ascertain if any
other light in the general locality- might be seen and mistaken for
the desired light. If there is doubt, a careful timing of the length
of all flashes and dark intervals, for comparison with the light list,
is usually conclusive.
6 AIDS TO MARINE NAVIGATION OF THE UNITED STATES
CHARACTERISTIC LIGHT PHASES
Symbols and meaning
Illustration Lgtwhh Lgtshih Phase description
do not change show solor
ii Ir~ I11I Cr n
rm Illllrlrlrlll IIIII11IIIIIIII
mill -r 11111 ~a IIILlrsl
U III I
I .II I ~~ I I ill
rr I I 1~1 111
I~ mf m mI I I
Light colors used and abbreviations: W= white, R= red, G= green.
| F.= Fixed.....
aie a .
Fl. = Flashing.
tp FI .=
A ltr F. t gl I
Alt. Op. Fl.=
Acontinuous steady light.
Ar engTur l tervl y y
flash of greater brilli
Ardegldrli er vared bat
groups of 2 or more
flashes of greater brilli-
Sho ung ai si gle fash t
duration of light al-
ways being less than
the duration of datrk-
ness. Shows not more
than 30 flashes per
Showing at regular in-
tervals groups of 2 or
Shnos enoterless n an 60
Shobs quick oflasde sfo
lowed by a dark period
of about 4 seconds.
Sabobuta0.4 con ff h
lowed by a long flash
of 4 times that dura-
A light totally eclipsed
at regular intervals, the
duration of light always
equal to or greater than
the! duration of darkess.
A21ight ih a gousp
Alt. Oce.= Al-
AIDS TCO MARINE NAVIGATION OF TH-E 'UNIITED STATES
HOW FLASHES ARE PRODUCED
The flashinlg lights of lighthouses and minor lights are produced in several ways.
Iln some of the larger lights the flashles result from thie rotation of the lenses
in which various flash panels are incorporated. Th~e use of elec~tricity as the
illumtinant has also made it possible to procdnlee flashes by metans of timing devices
which interrupt the flow of current or conceal the light source at definite
In those minor lights where acety~lene gas is used, the flashes are produced
by interrupting the flow of gas by means of a bellows-like device, each small
charge of gas being ignited at the burner by a constantly burning nonluminous
]Electricity is the illuminant now used in most of the larger lighthouses,
electric incandescent lamps placed inside the larger sizes of lenses producing
beams of as much as 5,000,000 candlepower where such, brilliance is required.
Lenses, which are aggregates of highly polished glass prisms, are assembled in a
variety of types to produce the characteristics desired.
VISIBILITY OF LIGHTS
The theoretical visibility of a light in clear wea~ther depends upon
two factors, the height of thne light above water, and its intensity or
brilliance. TPhe height controls what is known. as the geographic
range, wrihile the intensity controls what is kInown as thne luminous
Als a rule, for the principal lights the luminous range is greater
than the geographic, and the distance from. which such lights are
visible is limited by the earth's curvature only. Under some atmos-
pheric conditions the glare or loom of these lights, and occasionally
the light itself, may be visible far beyond the computed geographic
range. On the other hand, and unfortunately more frequently, these
distances may be lessened by fog, rain, snow, hase, or smoke.
Lights on inside wa~~ters, where their radius of usefulness is not
great, are frequently of insufficient intensity to reach to the full limit
of their geographic range.
Sectors of colored glass are placed in the lanterns of certain light-
houses to mark shoals or to warn mariners off the nearby land. Lights
so equipped show one color from most directions and a different
color or colors over definite arcs of the horizon indicated in the light
lists and upon the charts. ALS sector changes the color of a light,
when vFiewved from certain directions, but not the charancter~istic. For
example, a flashing white light having a red sector, when viewed from
within. the sector, will appear flashing red.
g AIDS TO MARINE NAVIGATION OF THE UNTITIED STATES
Sectors may be but a few degrees in width, marking an isolated
rock or shoal, or of such width as to extend from the direction of the
deep water toward shore. Bearings referring to sectors are expressed
in degrees as observed from a vessel toward the light.
In the majority of cases, water areas covered by red sectors should
be avoided, the exact extent of the danger being determined from
an, examination of the charts. In some cases a narrow sector may
mark: the best water across a shoal. A narrow sector mnay also mark
a turning point in a channel.
These signals form an important part of the equipment of mnany
lighthouses situated in sections of the country where fog or low
visibility is prevalent. Identification is made inl the same manner
as wlith lights. ]Each fog signal station is assigned a signal consisting
of a definite number of blasts recurring at stated intervals. The
sound or tone of the signal varying with the type of mechanism
employed, also assists in identification. Fog signals are treated in
greater detail on page 10.
Two lights, located some distance apart, visible usually in. one
direction only, are known as range lights. They are so located that
the mariner by bringing his ship into line with them, when, they
will appear one over the other, places his ship on the axis of the
channel. If he steers his ship so that the lights remain continuously
in line, he will remain within the confines of the cha~nnel. Entrance
channels are frequently marked by range lights. The Delaware River
and the St. Johns RCiver on the Atlantic coast, and the Columbia
River on thne Pacific coast are examples of successive straight reaches
marked in this manner.
TIhe lights of ranges may be any of the three standard colors, and
may also be fixed, flashing, or occulting, the principal requirement
being that they stand out distinctly from. their surroundings. Most
range lights lose brilliance rapidly as a ship diverges from the range
line. Ranges should be used only after a careful examination of the
charts, and it is particularly important to determine for what dis-
tance the range line can be safely followed, this information not
being obtainable from the lights themselves in all cases.
AIDS TO MARINE NAVIGATION OF THE UNITED STATES
Lightships serve the same pur11pose as lighthouses, being equipped
with lights, fog signals, and radiobeacons. They take the form of
ships only because they are placed at points where it w-ould be im-
practicable to build lighthouses. Lightshhips mark the entrances to
important harbors or estuaries, dangerous shoals lying in much fre-
quented waters, and also serve as leading marks for both tranlsocean~ic
and coastwise traffic.
COLOR OF LIGHTSHIPS
All lightships in United States waters, except Lake Huron Liglht-
ship, are painted red with the name of the station in white on both
sides. Lake H~uron Lightship is painted black with the name of the
station painted in white on both sides. Superstructures are white;
masts, lantern galleries, ventilators, and stacks are painted buff. Re-
lief lightships are painted the same color as the regular station ships,
w1ith the word "RELIIE]F" in, white letters on thne sides.
These may be placed at any of the lightship stations, and, when
practicable, will exhibit lights and sound signals having the char-
acteristics of the station. Relief ships may differ in outward ap-
pearance from the regular station ships in certain minor details.
T'he masthead lights, the fog signals, and the radiobeacon sigEnals
of lightships all have definite chnaracteristi<;s, so that each lightship
may be distinguished from others and also from nearby lighthouses.
As with lighthouses, details regarding these signals are shown briefly
on charts and more completely in the light lists.
A lightship under way or off station will fly the International
Code signal flags "LPC" signifying lightship is not at anchor on her
station. It will not show or sound any of the signals of a lightship,
but will display the lights prescribed by the International or Inland
Rules for a vessel of its class. While on station a lightship shows only
the mnasthead light and a less brilliant light on the forestay, the latter
serving to indicate the direction in which the ship is heading. ]By
day the! lightship wvPill display the International Code signal of the
station, whenever it appears that an approaching vessel does not
recognize the lightship or requests the information. As lightships
ride to a single anchor, the light on the forestay also indicates the
direction of the current.
10 AIDS TO MARINE NAVIGATION OF THE `UNITED STATES
United States lightships are self-propelled vessels capable of pro-
ceeding to and from their stat ions under their own power. By this
means they also work back to their stations if driven off by storms,
and also use their engines to relieve the strain on their moorings in
severe weather. A number of lightships are Diesel propelled, somne
direct connected, others with geared drive, and still others with an
electric motor connected to the propeller shaft and served by D~iesel
electric generating sets. Several ships still employ reciprocating
steam engines, usually with oil-fired boilers.
Most lightships, when on station, derive power for the operation
of their signals from Diesel driven auxiliaries. In the Diesel-electric
ships, one or more generating sets are used for auxiliary purposes in
accordance with the demand for power.
The names appearing on the sides of lightships are the names of the stations
which the ships occupy at the time. Individual ships of the service are identified
by permanent numbers. During a lifetime of 40 or 50 years a lightship may
occupy a half-dozen stations, having the namle of each in turn painted upon it.
~Any sound-producing instrument operated in time of fog from a
definite point shown on the charts, such as a lighthouse, lightship, or
buoy, serves as a useful fog signal. T'o be effective as an aid to naviga-
tion, a mariner must be able to identify it and to know from what point
it is sounded. Tlihe simpler fog signals are bells and whistles on buoys,
and bells struck by hand generally at lighthouses. As such signals on
buoys which are operated by the action of the sea do not produce
sounds on a regular time schedule, positive identification is not always
At most lighnthouses and lightships, fog signals are operated by
mechanical means and are sounded on definite time schedules, pro-
viding th~e desirable feature of positive identification.
TIhe various types of apparatus employed for sounding fog signals
are of interest to the mariner principally because each type produces
distinctive sounds, familiarity with which assists in identification.
These are composed of blasts and silent periods. A definite time is
required for each signal to perform a complete cycle of changes.
This time, stated in the light list is one of the means of identification.
W"Chere the nlumlber of blasts and the total time for a signal to complete
a cycle is not sufficient for positive identification, reference may be
AIDS TO MARINE NAVIGATION OF` THE UNITED STATES
made to details in the light list regarding the exact length of each
blast and silent interval.
TIhe various types of fog signals differ in tone, and this facilitates
the recognition of the respective stations. T'he type of fog signal
apparatus for each station is stated in the light lists.
Diaphones produce sound by means of a slotted reciprocating
piston actuated by compressed air. Blasts may consist of two tones
of diffekrentt pitch, in which. case the first part of the blast is high
and the last of a low pitch. These alternate-pitch signals are called
Diaphragmn horns produce sound by mneans of a disc diaphnragmn
v-ibrated by compressed' air, steam, or electricity. Duplex: or triplex
horn. units of differing pitch produce a chime signal.
Reed horns produce sound by- means of a steel reed vibrated by comn-
Sirens produce sound by means of either a dise or a cup-shaped
rotor actuated by compressed air, steam, or electricity.
Whistles produce sound by compressed air or steam emitted
through a circumferential slot into a cylindrical bell cham~ber.
Bells are sounded by means of a hammner actuated by hand, by a
descending weight, compressed gas, or electricity.
ELECTRONIC AIDS TO NAVIGATION
The marine radiobeacon system, effective for distances up to 200
miles and more, is an electronic system by means of which a navigator
can determine position or lines of position quickly in practically any
kind of weather. It makes use of radio transmitting stations (radio-
beacons) and specially designed radio receivers equipped with a rotat-
ing coil antenna (radio direction finders).
Marine radiobealcons, installed at lighthouses, on lightships, and
other charted locations, operate separately or as part of a group of
two or three radiobeacons. Any one or all of a group of radiobeacons
can be used by the navigator in determining position or lines of
Marine radiobeacons transmit radio signals on preselected fre-
quencies of from 285 to 315 kilocycles which radiate in all directions.
The signals are emitted as groups of dots and dashes or a series of
short dashes. The arrangement of the groups of dots and dashes is
selected to permit identification of individual radiobeacons trans-
mitting signals on the same radio frequency.
12 AIDS TO MARINE NAVIGATION OF 'THIE UNITED STATES
The majority of Coast Guard radiobeacons transmit signals for 1
minute every 3 minutes during one or two 10-minute periods out of
each hour in clear weather and for 1 minute every 3 minutes during
periods of fog or low visibility. Some Coast Guard radiobeacons
transmit signals 24 hours daily, for 1 minute every 3 minutes 24 hours
daily, or for about 15 seconds twice every minute 24 hours daily.
In t~he radiobeacon system, a navigator uses the radio direction-
~finder to determine the direction or bearing of thre signal transmitted
from a radiobeacon. The general problems and practice of navigation
when using radiobeacon bearings are the same as when using visual
bearings on lighthouses or other charted objects. While both radio-
beacon and visual bearings are available in clear weather, the former
have the added important advantage of being available at greater
distances and under all conditions of visibility.
The signal emitted by a radiobeacon follows a great circle course.
When the distance to a radiobeaconl is short, the bearing is plotted in
the same manner as a bearing on a visual charted object. When the
distance is greater than 50 miles, a correction usually must be applied
to the radiobeacon bearing before plotting on a mercator chart. TIhese
corrections are found in Radio Bearing Conversion tables published in
United States Nav~y H~ydrographic Office publication. H3. O. 205 titled
"LRadio Navigational Atids."~
While marine radiobeacons are specifically provided for the purpose
of navigation, it should be noted that radio bearings for navigation can
be obtained from any radio station which transmits identifying radio
signals within the frequency range of the radio direction-finder and
whose charted location is known or can be plotted.
IMany Coast Guard radiobeacons are synchronized with sound fog
signals at the station for distance finding. During fog, a group of two
radio dashes, 1. second and from 3 to 5 seconds in length, are trans-
mitted every 3 minutes coincident with sound signal blasts of corres-
ponding lengthy. When within audible range of the sound signal,
distance from the station can be determined with any radio receiver
capable of receiving radiobeacon signals by observing the time elapsed
between hearing the radiobeacon and corresponding synchronized
sound signal. The elapsed time in seconds divided by 5 for statute
miles or 5.5 for nautical miles will give the distance from the station.
The error of such observations should not exrceed _10 percent.
The Coast Guard maintains and operates all marine radiobeacon
stations along the coasts of the ~United States, its territories and pos-
sessions (185 in 1949). Complete information regarding these ra-
diobeacons is given in the Coast Guard light list and United States
Navy Hydrographlic Office publication. H. O. 205 titled "'Radio Navi-
AIDS TO MARINE NAVIGATION OF THE: UNITED STATES 12!
Section of Page of Radiobeaconr Characteristics
StafdoD Si--i-- lBgnal characteristic
Latitude N. L~ongitude W. cycles Power 5
E~ST QOODD. 11EAD LIGHT STATION, MAINE..
44 48.9 66 57. 1
MOUNT DESERT LIGHT STATION, MAINE......
43 58. 1 68 07.7
MATINICUS ROCK LIGHT STATron, MbINE.....
43 47.0 68 51.3
MANANA IsLAwN FOG SIGNAL STATION, MAINE.
43 45.8 69 19.7
HALFWAY Rocx LIGHTSTATION, MAINE......
43 39.4 70 02.2
PORITLANqf LIGHTSHIP, nlAINE...........----
43 31.6 70 05.5
EASTERN PomaT LIGRT STATION, NAss.......
42 34.8 70 39.9
Boston LIGHTSHIP, MAss..................
42 20.4 70 45.5
CANAL aEAKWA~TER LIGHT STATzon, MAss.
4.1 46.5 70 29.8
CAPE COD LIGHT STATIon, MIAss?..........
42 02.4 70 03.6
POLLOCK RIP LIGHTSHIP, MASS.............
41 36. 1 69 51.1
NANTUCKET SHBOALS LIGHTSHIP, MASS........
Mag* gs gg
* ug il
am as gu
DISTANCE FINDING STATIONS
SYNCHRONIZED RADIOBEACON. AND SOUND SIGNALS
302 A su s s
314 A la* u
314 A se usemsm
starson, mREausucy in c AND
CHARACTERISTIC OF RADIDBEACON SIGNAL
PARTRIDGSE 10., CAN. In' ai,
WEST QUODDY HEAD
MATINICUS ROCK r
300 K.C. asu rn
HAFHAY ROCK Ioonr~aew#N swLEar.
AIDS TO MARINE NAVIGATION OF THE: UNITED STATES
national Aids." Radiobeacon system charts showing the general
locations and operating characteristics of Coast Guard radiobeacons,
suitable for ready reference by posting near radio direction-finders,
are available from the Coast Guard. Three charts are! issued, one each
for the Atlantic and Gulf, the Pacific, and the Great Lakes areas. A
detail treatise on the radiobeacon system is contained in a separate
Coast Guard publication on "'Electronic Aids to Navigation."
TIhe term 10ran is derived b~y comnbining thne first letters of LOng
Range Aid to Navigation. The loran system, effective for distances up
to 750 miles by day and 1,400 miles by night, is an electronic system
by means of which a navigator can determine position or a line of
position accurately and quickly in practically any kind of weather. It
makes use of special radio transmitting stations on shore (loran trans-
mitting stations), specially designed radio receivers with an electronic
time-measuring device (10ran receiver-indicator) and special charts
or tables (10ran charts or tables).
Loran transmitting stations, strategically located on, shore, operate
in pairs as part of a group of three or more 10ran transmitting stations
separated at distances of from 200 to 600 miles. WIhen the number of
stations in a group exceeds two, the intermediate stations are paired
with both adjacent stations. Any pair or all pairs of stations in a
group of 10ran transmitting stations can be used by the navigator in
determining position or lines of positions.
Loran. transmitting stations transmit radio signals on preselected
frequencies of 1750, 1850, 1900, or 1950 kilocycles which radiate in
all directions. T'he signals are transmitted 24 hours daily. They are
emitted as a series of pulses or short bursts of radio energy recurring
at selected regular intervals of time. Th'le use of pulse transmission of
signals permits the identification of individual pulses on the same radio
frequency and the measuring of time difference between reception of
pulses from each station in a pair of loran transmitting stations.
In the loran system, the time difference of reception of signal pulses
from a pair of loran transmitting stations is measured electronically
and not th~e individual distances themselves. This measurement is
known as a loran reading. There are many points at which the same
loran reading is obtained but all these points fall along a smooth curve
which is known as a loran line. Loran readings are sho-win as lines
(10ran lines) having geographic position on Joran charts or a series
of loran readings can be transposed to construct lines having geo-
graphic position by the use of 10ran tables.
AIDS TO MARINE NAVIGATION OF THKE UNITED STATES
SDETERM INULN EDO
Navigator aboard loran-equipped ship at "8" establishes "fix" by determining two lines
of position, "A" and "B" by loran measurements.
Line of position "A" is found by measuring the time difference between signals received
from transmitting stations Al and Az.
Line of position "B" is found by measuring the time difference between signals received
from transmitting stations B1 and B,.
The navigators fix is established at the point of intersection of the two lines of position.
The latitude and longitude of the navigator's position is determined from the loran data
by using either the loran charts or loran tables.
The principle of the loran system differs from that of the radio-
beacon system in that it is based on the difference in time of arrival
of radio signals rather than the direction of arrival of radio signals
as in the radiobeacon. system~. It is not necessary to know7P the charted
locations of loran transmitting stations to use the loran system.
In the loran system a navigator uses the 10ran receiver indicator to
obtain a loran reading and from it determine a line of geographic
position between a pair of loran transmitting stations. The general
problems and practice of navigation when using loran readings is the
same as when using other means to determine lines of position. W~Chile
lines of position obtained by loran readings or other means produce the
16 AIDS TO ~MARINE NAVIGCATION OF THZE UN~ITIED STATES
same general results, 10ran readings, obtainable in effective areas cov-
ered by the loran system, can be obtained with great accuracy and
quickly day or night during all kinds of weather. Calculations by
the navigator in using the loran system for position finding or deter-
mining lines of position are practically nil.
TPhe diagram of figure 1 illustrates the basic principles of the deter-
mination of position. byT means of loran.
The Coast G-uard maintains and operates 31 of the 37 10ran trans-
mitting stations now (1949) available for the navigation of all vessels
and aircraft of the wForld. Coast Guard loran transmitting stations
are located in the United States, Alaska, Hawaii, Greenland, Labrador,
~Newfoundland, Mariannas Islands, Marshall Islands, Iwo Jima, Oki-
na~wa, Japan, and the Philippine Islands.
Loran charts and tables for the individual areas nlow served by
the loran system are obtainable for sale from the United States Navy
Hydrographic Office WCashington, D. C. A detail treatise on the loran
system is contained in a separate Coast Guard publication on Elec-
tronic Aids to Na~vigation.
THE SIGNIFICANCE OF BUOYS
The primary function of buoys is to warn the mnariner of some
danger, some obstruction, or change in the contours of the sea bottom,
and to delineate the channels leading to various points, so that he
may avoid the dangers and continue his course safely. The utmost
advantage is obtained from buoys when they are considered as mark-
ing definitely identified spots, for if a mariner knows his precise loca-
tion at the moment and is properly equipped with charts, he can plot
a safe course on which to proceed. Such features as size, shape,
coloring, numbering, and signaling equipment of buoys, are but means
to these ends of wFParning, guiding, and. orienting the navigator.
THE LATERAL SYSTEM
The waters of thle United States are marked for safe navigationl by
the lateral system of buoyage. This system employs a simple arrange-
ment of colors, shapes, numbers, and light characteristics to show the
side on which a buoy should be passed wchen proceeding in a given
direction. The characteristics are determined by the position of the
buoy with respect to the navigable channels as the channels are entered
from seawPard toward the head of navigation. As all channels do
not lead from, seawPard, arbitrary assumptions must at times be made
in order that the system may be consistently applied. The characteris-
UNITED STATES COAST GUARD
BUOYAGE OF THE UNJITED STATES
Significncme of Shapes, Coloring, Numbering. and Light Characteristica
SymboLs shown adjaesnt to Buoore ar those usd on Chuart to indicate suh Aide
PORT HIDE BrCHNEL8ARBOARD SIDE
(an sman Ir.. e.w. (an.= sun e... e....auIn Brd
Yu,,,g==,****-=.-= Color BLACE ANID WBT V ~CAIlg18 a uau e ofd o chanesL
on~ rbr hada MB sl Numbrng: NONE. Yb1Marb etrd ml otm rctlons whlah mut be
c.I.. arACE Simpe: NO SHAPB eaIGNICANCB o emban RQ
No DDu~m Bh Iappy at Lihw Yhdrl N~m VN (Dratppl
Was CAN. (Ilhandbunama ou BHORTIDNG FIASHING Shape:NUN. (Lihaul boops. ond
ta. ad.p hoaw n~so bo. ad p bar have n
Color of Irst: WHITB OR GREEN Color of ILht WHTIT OR RAD
UhPhasChametristim* se~ I6ht PhaQseCratristim: (on
OCCULTING Lh OCCULTING)
QUICK ~FIAHING QUICK FLASHING
m0 *s 0
Can Spar Nun
(Kntering Ium Seward)
Marks junctio nsad obstrciaos which ay bel paedo
either side. PfeReda channel s Indicated by color of
a Colon RED AND BLACK HORIEONTAL BANDS
Numbrkrns: NONE Ma b Lettered $
Lighted SM~:CAN OR NUN ACCORDING TO COMIR OF TDP Lieae
IAght PhasChtarmbatistim:dbassd p b
A INTERRUPTED QUICK FLASHING
Can SparSa u
en* sat whsep..ere whea poawlan channel. BALL
Unlighted Bell thea tued is BlAK Lth outC M sRE nlighted Bell
Unlighted Wit Can Spar Spar N Unl~ghted Whistle
BUOTS HAVING NO LATERAL SIGNIFICANCE
c.I.. As anowN. N~mbcrYIng ND 1 ay ha Leaed. Mis Phas Chametertatie: Colar or ~a b: ANY EECEI~' RED OR GEREN
FIXED FIASHING OCCULTING
AIDS TO MARINE NAVIGATION OF TH-E UNITED STATES
ties of buoys are~ based on the aIssump-tion. that pr~ocecling~ in. a south-
erly direction along the: Atlantic coast, in a northerly and westerly
direction along the Gulf coast, in a northerly direction. on. the PIacific
coast, and in a northerly and westerly directioon on. t-he G~reat Luke~s
is proceeding from seaward. On the Int meanl,; st; a Wa;te~rwa.y pro-
ceeding in. a general sou~therlly direction along the Atlant~ic coast, and
in a general westerly direction along the Gul~f coaLst is conisidel.red~ as
proceeding from seaward. On the Misiss~ippi and Ohio Rivers and
their tributaries the aids to navrigationl chararcter~i-f ies are de~te~lrm-inedc'
as proceeding from sea towards the head of naviglt ion althoughil local
terminology describes "~left bank" and "right bank" as pr'c~eedlig Irwith
the ~flow of the river.
SPECIAL PURPOSE BUOYS
In addition to the lateral system of buoyage, several special purpose
buoyage characteristics, which have no ]lateratl sign ~i fi ennee.(, are utilized
to mark dredging areas, quarantine areas, fish net areas, anchorages,
race courses, experiments or tests, etc.
TYPE OF BUOYS
Tlhe buoyage system adopted for the waters of the United States
consists of several different types of buoys, each kind designed to serve
under definite conditions. Broadly speaklling~, all buoys serve as day-
marks, those having lights are also available for navigation by night,
and those having sound signals are also more readily located in time
of fog as well as by night. The following are the principal general
SP~AR BUrOYs.-L--arge logs, trimmed, shaped, and appropriantelyr
painted. Buoys of the same spar shape are also constructed of steel
CAN AND NUN BUOYS.--Buoys built up of steel plates having the
distinctive shapes designated by these names.
BEI~L BU~OYS.-Steel floats surmounted b~y short skeleton towers in
which the bells are fixed. Most bell buoys are sounded by the motion
of the buoy in the sea. In a few buoys the bells are struck by com-
pressed gas or electrically operated hammers.
GONG BUrOYs.--Sim~ilar in construction to bell buoys, but sounding
a. distinctive note because of the use of sets of gongs each gong of
wc~hich has a different tone.
WHIISTLE BUrO~s.--These buoys provide a sound signal which is
useful at night and also during fog and low visibility. As the whistle
mechanism is operated by the motion of the buoy in the sea, these
buoys are used principally in exposed locations.
AIDS TO MARINE: NAVIGATION OF THIE UNITED STATES
A type of sound buoy is also in use in which a HoRN is sounded at
regular intervals by mechanical means.
LIGHrTED BUOYS.---A- metal float on which is mounted a short skeleton
tower at the top of ~which the lantern is placed. Tanks of compressed
acetylene gas, or electric batteries, on which the light is operated, are
placed in the body of the buoy below the water level.
CO1MBINATION BUOYs.-TrChese are buoys in which a light and a sound
signal are combined, such as a lighted bell buoy, lighted gong buoy,
lighted whistle buoy, or lighted horn buoy.
COLORING OF BUOYS
All buoys are painted distinctive colors to indicate their purpose or,
in the lateral system, the side on which they should be passed. The
meaning of lateral system buoys, when proceeding from seaward (s~e
Laterazl Syrstemn) is indicated by their colors as followCs:
BLACK BUOYs maark the port (left) sides of channels, or the loca-
tion of wrecks or obstructions which must be passed by keeping
the buoy on. the port (left) hand.
RED BUSOYs mark the starboard (right) sides of channels, or the
location of wrecks or obstructions wI~hich must be passed by kreep-
ing the buoy on the starboard righth) hand.
RED AND BLACK HIORIZONT`ALLY ]BANDED BUOYS mark junctions in
the channel, or wrecks or obstructions -which may be passed on
either side. If the topmost hand is black, the preferred chan-
nel will be followed by keeping the buoy on the port (left)
hand. If the topmost band is red, the preferred channel will
be followed by keeping the Buioy on the starboard (rigIht) hand.
(NOTE.--When proceeding toward seaward, it mnay not be pos-
sible to pass on either side of these buoys, and the chart should
always be consulted.)
BLACK AND VHITE VEiRTICALLY STRIPED BUOYS mark the fairway
or midchannel and should be passed close to, on either side.
The meaning of special-purpose buoys is indicated by their colors
as f 0110ws:
White buoys mark anchorage areas.
'Yellow buoys mark quarantine anchorage areas.
White buoys with green tops are used in connection with dredging
and survey operations.
White and black alternate horizontally banded buoys mark fish
AIDS TO MARINE NAVIGATION OF TIHE ITNITED STATES
WShite and international orange buoys alternately banded, either
horizontally or vertically, aire for special purposes to which
neither the lateral-system colors nor the other special-purpose
Yellow and black vertically striped buoys are usedi for seadrome
markings and have no marine significance.
NUMBERING OF BUOYS
Most buoys are given numbers, letters, or c.ombllinations of numbers
and letters which are painted conspicuously upon themY. These mnark-
ings facilitate identification and location of the buoys on the charts.
All solid-colored red or black buoys, except those in the Mississippi
River aids to navigation system, are given numbers or combinations of
numbers and letters. Other colored buoys may be given. letters.
Numbers increase from seaward and are kept in approximate sequence
on both sides of a channel by omitting numbers where required. Odd
numbers are used only on solid-black buoys. Even numbers are used
only on solid-red buoys. Numbers followed by letters are used on.
solid-colored red or black: buoys when a letter is required so as not to
disturb the sequence of numbering or on important buoys, particularly
those marking isolated offshore dangers. An example of the latter
case would be a buoy marked "~1DIR" which in this instance the number
hias the usual significance, while the letters "DR"' indicate the place as
Duxbury Reef. Letters without numbers are applied in some cases
to black and white vertically striped buoys, red and black horizontally
banded buoys, solid-yellow buoys, and other buoys not solid colored
red or black.
In the Mississippi River system, unlighted buoys are not numbered,
while the numbers on lighted buoys have no lateral significance but in-
dicate the number of miles from a designated point.
SHAPES OF BUOYS
In order to provide ready identification, certain unlighted buoys
are differentiated by shape.
RED BUOYS, OR RED AND BLACK HORIZONTALLY BANTDED BUOYS with
the topmost band red are conical shaped and called nun buoys.
BLACK; BUOYS, OR RED AND BLACK HORIZONTALLY BANDED BUOYPS
with the topmost band black: are cylindrical shaped and called can
BLACK AND HIITE VERTICALLY STRIPED BUOYS may be either nun or
can buoys. The shape has no significance in this case.
20 AIDS TO MARINE NAVIGATION OF THE UNITED STATES
Full reliance should not be placed on the shape of an unlighted buoy
alone. Chnarts and light lists should be consulted to ascertain the sig-
nificance of unlighted buoys as determined by their colors.
-IGHTED BUSOYS, SOUND BUOYS, AND SPAR BUOYS are not differen-
tiated by shape to indicate the side on which they should be passed.
Since no special significance is attached to t~he shapes of these buoys,
their purpose is indicated by the coloring, numbering, or light
COLOR OF LIGHTS
Red lights on buoys are used only on red buoys or red and black
horizontally banded buoys with thne topm~ost hand red. Green lights
on buoys are used only on black buoys or red and black horizontally
banded buoys with the topmost band black. White lights on buoys
are used on any color buoy. No special significance is attached to a
white light on a buoy, the purpose of the buoy being indicated by its
color, number, or its light phase characteristic.
M~any unlighted buoys are fitted with reflectors. These greatly
facilitate the locating of the buoys at night by means of a searchlight.
Reflectors may be white, red, or green, and have the same significance!
as lights of these colors.
LIGHT PHASE CHARACTERISTICS
]FLASHINGI LIGHTs (flashing at regular intervals and at the rate of
not more than 30 flashes per minute) are placed only on black buoys,
red buoys, or special purpose buoys.
Quicxr FLASHING LlourTs (not less than 60 flashes per minute) are
placed only on. blackI buoys and on red buoys, at points where it is
desired to indicate that special caution is required, as at sharp turns
or sudden constrictions, or where used to mark wrecks or dangerous
obstructions which must be passed only on one side.
INTERRUPTED QUICK FLASHING ;IGH-TS (the groups consisting of a
series of quick flashes, with dark intervals of about 4 seconds between
groups) are placed only on buoys painted with red and black hori-
zontal bands, at points where it is desired to indicate junctions in
channels, or wrecks or obstructions which may be passed on, either side.
Snona-L;oNo FLASHING LIGHTs (groups consisting of a short flash
and a long flash, the flashes recurring at the rate of about eight per
minute) are placed only on buoys painted in black and white vertical
stripes, at points where it is desired to indicate fairways or mnidchanr-
AIDS TO MARINE NAVIGATION OF THE: UNITED STATES
nels and should be passed close to, on either side. The lights are
The lights of buoys are operated by means of acetylene gas supplied from cylinders stored
in the body of the buoyg and piped to a flashing mechanism in the base of the lantern, or by
means of electricity supplied from batteries storedl in the buoy body in the same manner as
the acetylene cylinders.
In order that lighlrte buoys may function for a reasonably long period of time without
requiring a replenishment of the gas supply or a rep~lacemnent of the batteries, the length
of the light ~flashes as compared with the interven~inr: periods of darkness is mad~e quite
short. Buoys at isolated points frequently function for 6 months or more without
There are many aids to navigation, which are not lighlted~. Struc-
tures (not buoys) of this type are called dalybeacons. They vary
greatly in design and construction,' depending upon their location,
and the distance to which they must be seen. A daybeacon may consist
of a single pile with a daymark at thle top, a spar with a cask at the
top, a slatted tower, or a structure of matsonry. D~aybeacons are
colored, as are lighthouses, to distinguish them from. their surround-
ings and to provide a means of identification. Daybeacons marking
the sides of channels are colored and numbered in the same manner as
buoys and minor light structures; red indicating the right side enter-
ingT, and black the left side entering. Many daybeacons are also fitted
with reflectors to facilitate locating them at night by means of a search-
The Intracoastal Waterway, to which, is applied the system of
marking about to be described, is that comparatively shallowri channel
lying parallel to and extending along the Atlantic and Gulf coasts
from. Chesapeake Bay to the Mexican border. The special marking is
applied to the so-called "Linside route" proper and to those portions of
all connecting waterways wrihich must be crossed or followed in order
to make a continuous passage.
All buoys, day~beacons, and light structures marking the Inta-
coastal Waterway have some portion of them painted yello~w. This
8A constant effort is being made to standardize daybeacon maaring~s which have become
established by custom over many years.
22 AIDs TO MARINE NIAVrIGATIION OF THrE: UNITED STATES
is the distinctive coloring adopted for the WaterwayT. Buoys have a
band of yellow at the top, daybeacons have a band or border of yellow,
and light structures are similarly painted.
The coloring and numbering of buoy~s and daybeacons, and the
color of the lights on buoys and on, light structures is on the sam~e
lateral system as that prevailing in other waterways. The basic rule
is that RED buoys and daybeacons are on the right-hand side of the
channel when proceeding from. Chesapeake Bay towslard Mexico, and
BLACK. buoys and daybeacons are on the left-hand side of the channel
when proceeding in the same direction. This rule is applied in a
unliformn manner from one end of the Intracoastal ~Water~way to the
other, regardless of the widely differing compass headings of the many
sections, and the fact that rivers and other waterways marked on the
seacoast system are sometimes followed.
Numbering of Intracoastal Waterway aids follows t~he basic rule,
numbers increasing from Chesapeake Bay toward Mexico. Aids are
numbered in groups, usually not exceeding 200; numbering begins
again at "1" at certain natural dividing points.
Lights on buoys follow the standard system, of red or white lights
on red buoys, and green or white lights on black buo~ys. The color
of the lights on fixed structures also follow this general rule. Range
lights, not being lateral markers, may be any of the three standard
In order that vessels may readily follow the Intracoastal Wr;ater-
way route where it coincides with another waterway such as an imn-
portant river marked on. the seacoast system, special markings are
employed. These special markings are applied to the buoys or other
aids which mark the river or waterway for other traffic. Thle special
marks consist of a, yellow square and a yellow triangle, painted on a
conspicuous part of the dual-purpose aid. The yellow square, in out-
line similar to a can buoy, indicates that the aid on. which it is
placed should be kept on the left hand when following the Intra-
coastal Waterway from Chesapeake Bay toward Mexico. The yellow
triangle, in outline similar to a nun buoy, indicates that the aid on
which it is placed should be kept on the right hand when following
thne Intracoastal Waterway fromn Chesapeake Bay toward Mexico. By
this marking, the mariner approaching a body of water such as the
Savannah River, and knowing that he must follow it for some distance
before again entering a dredged cut of the Intracoastal Waterway,
knows that his course lies along such buoys or other aids as are
specially marked in yellow. 3He determines the side of his vessel on
WHITE OR GREEN LIGHTS,
FIXED OR FLASHING
SPECIAL RANGESI SPAR DAYBEACONS 3 PILE SLATTED, PILE SKELETON
(8) ROUND, BUOY Pointer Daymarkr DOLPHIN STRUCTURES STRUCTURES
CAN OVAL OR 12nd.-4h DmakohNdotted
BUOY IDIAMONDI Class Supporting Structure may be painted White or Aluminum. added where needed.
Border and number on
Daymark where used.
.C"3 A---AY.S"/7 A"17, A"5"S Fl 2sec "45"| FIG Ssec"17" F "9" FG"15"
PEORT Side of channel (Black with Odd Numbers) entering from north and east and
traversed to south and west respectively.
WHITE OR RED LIGHTS,
FIXED OR FLASHING
SPEQIAL RANGES SPAR DAYBEACONS 3 PILE SLATTED, PILE SKELETON
(S) ROUND. BUOY Pointer Daymaark DOLPHIN STRUCTURES STRUCTURES
NUN OVAL OR 12nd.-4th. Damr oh oted)
BUOY IDIAMONDI Class Supporting Structure may be painted White or Aluminum. added where needed.
Border and number on
Daymarkr where used.
"/2"i "R S4 R 4 A.A.6 FI 2sec"14" FI R 5sec l"12 F "6" FR "12"
SrDA DuAR Side of channel (Red wpith Even Numbers) entering from north and
1 aneeast and traversed to south and west resrnectively.
TH ICW AIDS
ARE CHARACTERIZED BY
THE YELLOW BORDER
TYPES OF AIDS TIO NAVIGATION
ICWC joins another waterway at buoy
No. 8 and is common with it to buoy No. 3.
This section is numbered in the opposite di-
rection to that of the ICW. T'he IC;W numb-
berss and yellow borders are omitted from. the
regular aids but a d or O is shown to desig-
nate the ICW.
- Proceeding south and west
REFECORS on beacons are
RED) on starboard side and
GREEN on port side.
a on RED and O7 on BLACK
for common section
n on BLACK and O on
for common section
ICWV joins another waterway, ~which is
numbered from seaward, at buoy No. 2 and is
common with it to buoy No. 9. ICW number
and yellow borders are omitted in this see-
tion but the n or D] is used on the regular
aids to designate the ICWN.
ILLUSTRATING ~TH[E: S`YST`EM OF DUAL PURPOSE MARIN
WNHERIE THE ICW AND OTHI~ER WATERWAYSS COIN~CIDEi
AIDS TO MARINE NAVIGATION OF THE: UNITED STATES
which these aids should be passed by the shape of the yellow marks,
bearing always in, mind thle basic direction. of his travel..
Where coincidental marking is employed, the mariner following
the Intracoastal Wa~terwaty disregards the color and shape of the aid
on which the mark is pheced, being guidedr solely by the shape of the
yellow mark1. Can buoys of the se~nconslt system may have p~ailte~d
upon them yellow triangles or yellow squares, depending on whethf-er
the w~aterwc7ay which, they markr is followedl in the direction of the
sea or in the direction of its headwaters, as the Inltra;coastal Water-
way is followed in the direction of Mexico. Mariners not traversing
the Intraconstal Waterway~n entirely disregard the special yellow
SYMBOLS EMPLOYED UPON CHARTS
In order that mariners may derive the maximum use from naviga-
tional aids, they are shown upon the various nautical charts. In this
manner, maariners are apprised of the various aids which they may
expect to pass, and may plot any bearings which they may takre for
the purpose of determining their position.
Upon the charts the aids are shown by means of a series of con-
ventional symbols to which are appended various abbreviations giving
condensed information regarding the aids. The principal symbols
and, abbreviations are shown on Plate I, following pag~e 16i. The mean-
ing of the various abbreviations are shown on page 6.
Light lists, describing the aids to marine navigation maintained
by or under thne authority of the United Staes Goverrnllent, are pubu-
lished by the Coast Guard. Revised editions appear each year. The
following volumes are issued:
Light List, Atlantic and Gulf Coasts (St. Croix River, Maine,
to the Rio Grande, including the U. S. West Indian Isllands).
Light List, Great L~akes (United States and Canada).
Light List, Mississippi River (and T'ributaries).
Light List, Pacific Coast (United States; Alaska; Canand a;
Hawaiian and outlying Pacific islands~l).
Light List, Intracoastal War:telrwy.
Light lists are issued to the public on a sales basis. Copies may be
obtained from the Superintendent of Documents, Governmnent Printing
Office, W~ashington, D). C., or from sales agents located in the principal
ports. A list of sales agents is publ:lish~ed~ quarterly in, the W~eekly
Notice to Mllariners.
24 AIDS TO MARINE NAVIGATION OF TH[E UTNITE~D STATES
Light lists are compiled and published to provide mariners with
more complete details regarding aids to navigrat~ion than are to be
found on the charts.
Aids are listed in geographic order and in tabular form. Sea-
coast aids for a given district are listed first. These are followed by
mnain-channel aids in bayrs, harbors, and important ri~vers. Next
a-re listed the aids in the less important tributaries. T1he information
is classified as follows:
Name.--This is the official name of the aid or its station, and is
to be preferred to local names which have become associated with cer-
Location.--The brief description. of the location. enables the mari-
ner to find the aid on the chart, to identify it as it is approached,
and to know in what depth of water it is located if not on land.,
The latitude and longitude of the more important lights is stated
to assist in referring to charts.
Character and per-iod of light.-- Under this heading is stated the
color of all lights, whether they are fixed, flashning, or occulting,
and if flashing or occulting the time required for the mechanism
to perform a complete cycle. Also indicated in this column is th~e
fact that certain lights are unwatched.
Height of flight above water.-FEromn this mariners may calculate
the distance to which a lighthouse will probably be seen in the day-
time. In conjunction with the candlepower, it also indicates thne
approximate range of visibility by night.
Miles seez.--Indicaltes the distance to which a light may be ex-
pected to be seen under normal conditions, the height of the light
and its candlepower having been taken into consideration. Th~le
figures used are based upon the observer's eyes being 15 feet above
sea level. Visibility for other heights may be computed with. the
aid of a supplementary table published in the front of each light list.
C~a~ndlepDouter.- This serves as a rough. gage of the distance to which
a light may be seen, and indicates the relative brilliance of lights in
the same general locality. In the case of a light of alternating
colors it indicates the relative distances to which each color will be
Apparatus and illuminant.-Of use primarily to maintenance per-
sonnel of the Coast Guard.
Ea~~ n >;d~
gea FJ (YLdd
aO' U) OQ)
a S c~
OIC $ u
Q~ ~~ t- i"co
~1 a ~cxj %8yj
C3 ~QI XU3 UCV3
u m O c~
k ci c,
~5 d d~
U o o
st "S O 8
M X 80;
4 E 5: 01,
~d cr vr ., ~gt~r-o
Pda p:d .~P (O00
p: O~ ~Y~~O
~8 o~r d
4, dl(p R~i~cj o, ~X
TC O WY ID a 1
Y~ .O,a ir m o ~d % ~
4;=jr w C3a~ i: c
*io~s~ PIIEj"~a~-. U o
Bsoan 40ma~ v U
C) u v
AIDS TO MARINE NAVIGATION OF THE: UNITED STATES
26 AIDS CTO MARINE: NAVIGATION OF THE UNITED STATES
Light characteristics.-Additional details giving the exact length
of all periods of light and darkness. Information regarding colored
sectors is noted here.
Fog signatl.--Includes details regarding the type and characteristics
of fog signals. Radiobeacon operating characteristics are also stated
in brief under this heading, more complete details being given in a
table in another part of the list.
Structure, sessel, or buoy.--These brief descriptions of the shape
and coloring of the various aids assist in location and identification.
Established, rebuilt.-T-ihese dates serve as an indication of any
recent change in the outward appearance of an aid.
Top of lantern above ground.-This information. is provided to
enable a mariner to compute a vertical danger angle. With a sextant,
the angle subtended by the top of the lantern and the base of the
tower is measured. Knowing this angle, and the height, which be-
comes one side of a triangle, th~e length of another side of a triangle
can be computed. The length of this second side is the distance be-
tween the observer and the lighthouse.
NOTICE TO MARINERS
The Coast Guard disseminates information concerning establish-
ments, changes, and discontinuances of aids to navigation in the U7nited
States, its territories, and possessions by means of Notices to Mariners.
Reports of channel conditions, obstructions, menaces to navigation,
danger areas, etc., are also included in Notices to Mariners. TLhese no-
tices are essential to all navigators for the purpose of keeping their
Light Lists, nautical charts, Coast Pilots, and other nautical publi-
cations currently corrected.
]LOCAL NOTICES TO MARINERS arT issued by each district commander.
They include changes and deficiencies in aids to navigation within the
area of each Coast Guard district. These notices are published as
required, which in most districts is daily. If only local information
is required, the notices issued by the various district commanders will
serve the needs of local navigators. They mzay be obtained, free of
charge, by making application to the appropriate district
WEEKLY NOTICES TO MARINERS (ZNORTHI AMIERICAN-CARIBBEAN
EurrION) are prepared jointly by the Coast Guard and the Navy
Hydrographic Office, and published weekly by the Navy Hydro-
graphic Office. They include changes in aids to navigation in as-
sembled form for all Coast Guard districts, except the Ninth Coast
Guard District (Great Lakes), and the Second Coast Guard District
(Mississippi River system). Foreign marine information in the
AIDS TO0 MARINE: NAVIGATION OF THrE 'UNITED STATES
Section of Page of NOTICE TO MARINERS
(2716) NORTH CAROL;INA--Cape Fear River--Light establishdd.--ram
Tree Point Light 56G, showing floawlry r'ed every 4 seconds, flash 0.1, second, eclipse
3.6 seconds, of 11 candlepower, has been established 95i0 yards 330030' from the
westernmost tank south of Dram Tree Point. T~he light is exhibited 16 feet
above water on a red slatted pile structure.
Approx. position: 34"11'50" N, 77"57'25"' W.
(N. M. 21, May 21, 10949)
(N. M. 77, C. G., Norf olk, May 3, 1949.)
TJ. 8. Coast Survey Chart 425.
U., S. Light List, Atlantic Coast, 1948, No. 2816.5.
U. S. Coast Pilot, Section D, 1948, page 188.
(2621) CA~LIFORNIA--Los Angeles-Long Beach Harbors--Light and fog
signal discontinued--Light, fog signal and radiobeacon established.-1l. Long
Beach Entrance W'est Light and the fog signal have been discontinued.
Approx: position: 33"43'23" N., 118*11'10" W.
2. Long Beach Harbor Light, showing flashing schite every 5 seconds, flash 1
second, eclipse 4 seconds, of 140,000 candlepower, has been established on the
east end of the Middle Breakwater. The light is exhibited 50 feet above water
on a white rectangular tower on a white concrete building.
A fog signal consisting of a diaphragm horn sounding 1 blast every 20 seconds,
blast 3 seconds, silent 17 seconds, has been established at the light.
A radiobeacon (Class D) has been installed on the light structure, and trans-
utits on 296 kes a group of 0.5 second dashes for 13.5 seconds, silent 1.5 seconds.
The radiobeacon operates continuously only when the fog signal is in operation.
(Supersedes N. M. 8 (974) of 1949.)
(N. M. 20, May 14, 1949.)
(N. M. 17, C. G., Long Beach, Apr. 22, 1949.)
H. O. Charts Anch. N, 5196, 5760.
U. 8. Coast Survey Charts 5147, 5148, 5143, 5101, 5020, 5002, 9000.
U. S. Light List, Pacific Coast, 1949, No. 124 and page 13.
U. S. Coast Pilot, Pacific Coast, 1942, page 66.
H. O. Pub. 205, 1947, No. 2157.5.
Nluorth American-Caribbean area is also included in these notices.
TPhese notices are intended for ma79rinerls and others who have a definite
need for them in connection with extdende seagoing activities or
those operating in several Coast Guard districts. These notices may
f28 AIDs TO MARINE NAVIGATION OF THE UNITED STATES
be obtained, free of cha~brge, by making application to Commandant
(OAN), UT. S. Coast Guard, Washington, D). C.
WEEKLY NOTICES TO0 MARINERS OF THIE GREAT LAKES are prepared
jointly by the Coast Guard and the Navy Hydrographic Office, and
published weekly at the Navy Branch H~ydrog~raphnic Office, Cleve-
land, Ohio. These notices maly be obtained, free of charge, by making
application to the Navy Branch Hydrographic Office, Clev~eland,
WEEKLY NOTICES TO ]MARINERS ( ORLD EDITION) are published
weekly by the NavyT Hydrographic Office. These notices contain all
the information published in. the North Amnericant~' Caribbean Edition
and also similar information collected from other maritime countries.
Requests for these notices should be addressed to the Navy H~ydro-
graphic Office, Depar~1tment of the Navy, Washington 25, D. C.
MARINE BROADCAST NOTICES TO MARINERS are made by the Coast
Guard through ;Coast Guard or Nav~al radio stations to report de-
~ficiencies and changes in aids to navigation of importance. Radio
stations broadcasting marine information are listed in "Radio Aids
to Navigation (HO0-205) and "CHydrogrraphic B3ulletins" published
by the Navy H-y~drographic Office.
Single copies of Notices to ~Mariners mnay be obtained or consulted
at the offices of the United States Coast Guard district commanders,
the Coast and Geodetic Survey district offices, the Navy branch hydro-
graphic offices, or other agencies distributing marine information.
The manintenanllce of aids to marine navigation is one of the oldest
Federal functions, the workr of erecting and maintaining lighthouses
being provided for at the first session of Congress by act of ~August
7, 1789 (the ninth law enacted by Congress). Twelve lighthouses
which had previously been built by the Colonies were ceded to the
new Federal Government, and became the nucleus of a system of
aids to navigation which over a period of 160 years has been increased
to a present total of over 36,000.
Federal maintenance of aids to navigation was first carried on under
the direct supervision of th-e Secretary of the Treasury. Somewhat
later, when the duties of the Secretary of the Treasury had grea:tlyT
increased, adm-iniste~ntion of the aids to navigation was delegated to
the Commissioner of the Revenue. In. 1820, the superintendence of
the lighthouse establishment was assigned to thne fifth auditor of thre
Treasury, and in 1845 again transferred, this time to the Revenue
Marine Bureau, an organization which later became the Coast Guard.
~AIDS> ii MARINE NAVIGATION OF THE UNITED STATES
'Tlhe collectors of customs through all this period served as local
superintendents of lighthouses.
A Lighthouse B'oard was crleatedl in 1852, to admin~ister the con-
stantly expanding service, being composed of officers of the Army
and the ~Navy, and of civilian. sc~ientists. In 1903 the Lighnthouse
establishm-ent was tranlsferred from the T~real~lSur Deprl'tmen~lt to the
newly created Deptirtnient of Commerce and Labor and in 19)10, the
Lighthouse Board was superseded by the Bureau of Lighthouses in
the Depar~tment of C'ommerce. On July 1, 1!,30., the Lighthouse
Service wans consolidated with the Unitedi States Coast. Guard.
The United Stat'es Coast Guard today maintains over 36i,000 aids
to marine natvigattion. The great~~er number of these are ligihthouse~s,
automatic lights, and buoys. There are also about 185 radiobeacons,
28 lightship stations, and about 2,100 fog signals, incllcuding those on
BRIEF HISTORY OF BUOYAGE
Buoyage of natvigalble walterwa~y s in this country was undertaken at
least as early as 1767, when, according to available records, buoys w-ere
in. use in the D~elaware R~iver. The earliest types wercle simply solid
wooden spars or wFPere built up of staves, similar to a barrel. This
stave construction was employed in. small buoys used~ near Boston
about 1808, but these gave way to spar buoys about 1820,, supplemen~lted
byT iron buoys in 1850. A ~marked improvement was effected in 1900
when. tall can and nun buoys were introduced. In 1881, the first
lighted buoy7, burning oil gas, was put into service outside New York
Harbor. 1Electricity was employed from 1888 to 1903 in the Gedney
Channel in New YTork lower bay. Current for these buoys w-as
supplied through cables from shore, but this systei'cl proved imprac-
tical. Buoys lighted by comprfielle acetylene gas stored in tanks
within the buoy itself, the type of lighlted buoy in general use today,
were introduced in 1910. Bell buoys, in which the bell is struck by
clappers aIctualted by the rolling of the buoy in the seal, have been
in service since 1885; and now buoys are also in service in. which. the
bell is struck at regular intervls\il by a mechanism opej~ntrate by com-
pressed gas. Whiistle buoys, the whistle sounded through motion
of the buoy in the sea, have been employed since 1876g. Similar buoys
are now? available in which a horn is soundedrt by electrical means.
Tests have also been made of buoys fitted with automaatic radiobeacons.
The maintenance of aids to marine navigation is a function of the
United States Coast Guard, having been placed under that o~ganliza-
30 AIDS TO MARINE NAVIGATION OF THE UNIITED STATES
tion on July 1, 1939, and consists of the maintenance of lighthouses,
lightships, radiobeacons, 10ran, fog signals, buoys, and daybeacons
upon all navigable waters of the United States and its possessions;
including Atlantic and Pacific coasts of continental Ujnited States, the
Great L~akes, the Mississippi River and its tributaries, Puerto Ri~co,
the approaches to the Panama Canal, the Hawaiian Islands, Alaska,
and such other places where aids to navigation are required to serve
the needs of the earned forces.
The chief administrative officer is the Comnmandant of the Coast
Guard, with headquarters at Washington, D. C. Under his direction
the functions of establishment, construction, maintenance, and opera-
tion of aids to navigation are carried on through administrative and
engineering divisions in Washington. Because of the wide geo-
graphic distribution of aids to navigation on the sea coasts, the Great
Lakies and navigable rivers of the United States, with an aggregate
coast line of over 40,000 miles, the field work of the service is car-
ried on, by district organizations. There are 12 Coast Guard dis-
tricts, carrying on lighthouse work, as well as other functions of the
Coast Guard. Each district is under the supervision of a com-
mander, assisted by a suitable engineering and administrative force,
and equipped with the necessary supply and buoy depots, and with
suitable vessels for thne maintenance of the aids to navigfation~.
RELATED NAUTICAL PUBLICATIONS
NOTICE TO MARINERS (see page 26 for details)
Areas within Coast Guard district limits:
Issued by each Coast Guard district commander.
F'ree of charge from commander of Coast Guard district concerned.
North American-Caribbean weekly edition:
PrepaLred jointly by Coast Guard, Treasury Departmaent, and Navy Hydro-
graphic Office, Navy Department, and published by Navy Hydrographic
Firee of charge from Commandant (OAN), United States Coast Guard, Wash-
ington, D. C.
World weekly edition:
Published by Navy H~ydrographie Office, Navy Department.
F'ree of charge from Navy Hydrographic Office, WFSashington, D. C.
Great Lakes weekly edition:
Prepared jointly by Coast Guard, Tr~easury Department, and Navy Department,
and published by Navy branch hydrographic office.
Free of charge from Navy Branch Hydrographic Offce, Cleveland, Ohio.
AIDS TO MARINE NASVIG~ATION OF THE UNITED STATES 31
LIGHT LISTS (see page 23 for details)
Coasts of the United States, Territories, and possessions:
Published by Coast Guard, Treasury Department.
For sale by Superintendent of Documents, Government Printing Office, Wash-
ington, D. C., and sales agents
Published by Navy Hydrographic Office, Navy D~epartmlent.
For sale by Navy Hydrographic Office, Washington, D. C., and sales agents
RADIOBEACONS AND LORAN (see page 11 for details)
Charts of radiobeacon system, Atlantic and Gulf coasts, Pacific coast, and Great Lakes:
Published by Coast Guard,-Treasury Department.
Free to vessels equipped with radio direction finders from Commandant (OAN)
UInited States Coast Guard, WC1ashington, D. C.
Radio Navigational Aids (H. O. Pub. No. 205h:
Published by Navy H-ydrographic Office, Navy Department.
For sale by Navy H~ydrographic Office, Washington, D. C., and sales agents.2.
Loran charts and tables:
Published by Navy Hydrographic Office, Navy Department.
For sale by NavyV Bydrographic Office, Washington, D. C.
Coasts of: the United States, Territories, possessions, and Philippine Islands:
Issued by Coast and Geodetic Survey, Commerce Department.
For sale by Coast and Geodetic Survey, Washington, D. C., and sales agents.'
Mississippi River from the Head of Passes to Cairo:
Issued and for sale by the M~ississippi River Commaission, Department of the
Army, Vicksburg, Mliss.
Illinois Waterway System:
Issued and for sale by the Corps of Engineers, Department of the Army, Chi-
Issued and for sale by the Corps of Engineers, Department of the Army, Cin-
Great Lakes, Lake Champlain, New York State Canals, and the St. Lawrence River, St. Regis
to Cornwall, Canada:
Issued anld for sale by the U. 8. Lakre Survey Office, Department of the A8rmy,
New York State Canal System:
Issued and for sale by the Superintendent of Public Works, State of New York,
A8lbany, N. YJ.
1A list of sales agents for charts and publications is published quarterly in the Weekly
Notice to Mariners.
For sale by the Superintendent of Documents, U. S. Government Printing Ofthe
Washington25, D. C. Price 25cents
AIDS TO MARINE NAVIGATION OF THE UNITED STATES
Issued by Navy Hydrographic Office.
F~or sale by Navy Hydrographic Office, Navy Department, WTCashington, D. C.,
and sales agents
Coasts of the United States, Territories, possessions, and Philippine Islands:
Published by Coast and Geodetic Survey, Commerce Department.
For sale by Coast and Geodetic Survey, Washington, D. C., and sales agents
Published by Navy Hydrographic Office, Navy Department.
For sale by Navy H-ydrographic Office, Washington, D. C., and sales agents
Atlantic Ocean, and Pacific and Indian Oceans:
Published by Coast and Geodetic Survey, Commerce D~epartment.
For sale by Coast and Geodetic Survey, Washington, D. C., and sales agents.'
Atlantic Coast, North America, and Pacific Coast, North America, and Philippine Islands:
Published by Coast and Geodetic Survey, Commerce Department.
For sale by Coast and Geodetic Survey, Washington, D. C., and sales agents
1A list of sales agents for charts and publications is published quarterly in the WCeekly
Notice to M~ariners.
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