Page 8
THE WAYNESVIL.E MOUNTAIN EER
THURSDAY, MARCH 3
Charts Of Sea, And Not Compass, Listed
As Navigator's Important Instrument
All Instruments Are Interde
pendent In Navigating: Ship,
Says Harry Hall
The instruments used by navigators
to enable them to determine the posi
tion of a ship at sea, or along a coast
line, and to carry on a
r"""f Si vyaPe from port to
jv ait; aj unci ucpcnu-
ent that it is hard to
select the one outstand
ing aid to the success
I WJW I Iul accompnsnmem 01
J VTVi I sucn an adventure.
VIBaaJ Personally. I should be
H. M. Hall inclined to select the
chart as the most nec
pwuirv sinele aid to navigation, for
upon it must be plotted the result of
all other acts of position-finding, and
from it must be taken the courses
and distances between ports. All oth
er navigational calculations are made
in order that this track may be made
good. The chart is therefore basic in
every navigational endeavor.
It is true that without the compass,
th lead, the log, the sextant and the
chronometer, or their present day sub
stitutions, the charts, for all the good
they would be, might as well be where
mine are, thumb tacked to a wall in
latitude 35 degrees 29 minutes N. and
longitude 82 degress 59 minute W.,
2721 feet above the level of salt water.
Without the chart the navigator
would be as was Columbus, not know
ing where he was going, but neverthe
less, on his way. No one can help but
bump into land, or ice, if they make
enough knots in even an approximate
ly one direction.
With all the improvements and add
ed data found upon them, the charts
of today are fundamentally the same
as were the first hand drawn ones.
They are a map of the sea, showing;
not only the extent of the waters
themselves, but much that is hidden
beneath the surface, the islands that
rise above the surface, and the lands
surrounded by the seas. Few other
forms of maps present such a com
plete picture of every necessary ob
ject and condition as are those found
upon navigational charts, and these
aids are the results of years of marine
surveys, constantly checked and kept
up to date by reference reports pub
lished by the governments of the
world. Any changes in buoys or
lights, any new obstructions to chan
nels, sunken wrecks, or Other alter
ations in charts that might be a cause
of ship damage, arc published in the
daily papers, or broadcast over ma
rine radio.
There arc several forms, or pro
jections, upon which charts arc
drawn,. "each-type-beinf? designed to
meet a specific need of the mariner
The charts most generally used by
navigators of the sea are drawn upon
what is known as the Mercatar's pro
jection. Roughly speaking, this pro
jector assumes the imaginary theory
that the earth is cylindencal. There
fore the meridians of longitude, which
in a sphere came together at the pole.-?,
are opened out and appear on the chart
as straight, parallel lines. This
compels the stretching out in width
of everything shown in high latitudes.
In order that this east and west dis
tortion may not effect the general out
line of the charted sea too greatly the
length is also stretched proportionate
ly, so that although everything in the
higher latitudes appears on too large
a scale as compared with places in
lower latitudes, the courses and dis
tances measured on this chart pro
jection are correct even though the
courses are represented as straight t seen
lines, whereas on the eurved surface
of the earth the courses would also
be curved. This is a very great ad
vantage in course and position plot
ting. In polar regions, because of this
distortion, these charts are useless,
because, for instance, you can not
steer for the north pole on a chart
with the meridians never coming to
gether atiany pole, but are perpet
ually prolonged parallel lines. Also
bearings taken of distant objects are
seldom quite correct when laid down
as straight lines. But in spite of these
high latitude draws back the Merca
tor's projection is the one best adapt-;
ed for the average use of the naviga-1
tors. In the polar region, where the
Mercator's chart can not be used, those
drawn the Gnononic projection are
consulted. On this type of chart a
straight line between any two
points represents the arc of a
great circle, and therefore the
shortest distance between these
two points. Gnomonic charts
are also used in the form of naviga
tion known as Great Circle Sailing.
Now let us look at a Mercator's
chart and see just what a wealth of
information one of them places at out
command.
In the first place, unless otherwise
stated the top of the chart is north,
to the right is east, left is west and
the bottom is south. The meridians
are straight parallel lines extending
north and south, true. The parallels
of latitudes extend across the chart
true east and west. In several ad
vantageous positions on the chart a
compass diagram, or "rose" is placed
with the north, or zero degree point
to the top, and a meridian of longi
tude forms the line from this north
point to the south, or 180 degree
point. The edge of this compass dia
agram is divided into 360 divisions or
degrees, and numbered as on the face
of watch, around to the right. On
coastwise and harbor charts another
diagram is placed inside of the de
gree one and is divided into the quar
ter points of the compass. The north
end of this "rose" points to the mag'
netic north at that point. Dotted
variation between the true and mag
netic north at that point. Dottend
irregular lines cross the chart shoW'
ing lines of equal variation, together
with the year the lines were establish
ed and the amount of annual increase
or decrease in the variation for that
line.
Scattered all over the chart are
figures in black. Those represent the
depth' of water in fathoms. Close
inshore the figures placed on a shad
ed section represent depths in feet
Along shore at depths up to 100 fath
oms these depths figures are close to
gether. Off Cape Hatteras the hun
dred fathom curve is about thirty
three miles out, and ftt forty-seven
miles a depth of fifteen hundred fath
oms is reached. Ten miles off the
Cape there is no more than ten or
twelve fathoms anywhere.
The type of the bottom is also
marked at frequent intervals. For
instance wc find "gy.-S.-bk.-sp." This
means that the bottom consists of
gray sand with black specks in it.
Putting an armed lead overboard we
find 14 fathoms of water and the bot
torn sample is as above. Consulting
the chart we find where these two
features coinside, and we know very
closely where our ship is.
All light ships are located on the
chart with a description of the type
of light it is, the duration of its
flash, its Color and how far it can be
Light houses are shown with
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Phone 10
descriptions of their lights. All buoys
are located, and by their markings, or
lights, or bells, or whistles, these can
be identified by the navigator. All
fog signals are described and located.
Life saving stations are shown. The
rate of tidal ebb and flow, and current
directions and speed are given.. Every
thing that can be of any aid to the
mariner in locating his position off
shore is printed on the chart.
Harbor charts are on a much larg
er scale and depths of water are
shown in feet. Piers and docks are
shown, and objects ashore from which
ranges and bearings can be taken are
identified. Tidal information and an
chorage ground are given. All chan
nel guides are shown; red buoys with
even numbers are placed on the star
board side, and black buoys with odd
number on the port side coming in
from sea. Buoys with black and
white perpendicular stripes are in
mid-channel and must be passed close
to. Buoys with red and black horizon
tal stripes show obstructions with1
a channel on each side.
There are manv signs on charts to
indicate abstructions, etc., as for in
stance, rocks just under the surface
are indicated by a cross surrounded
by a dotted circle, and rocks above
water by a dotted circle with dots
inside of it. All charts are dated
and mean that they were correct on
this date. As changes occur a notice
of it is issued applying to chart num
ber so and so of a given date.
The instruments used in consult
ing the chart are the parallel rule,
the dividers and the course-protractor.
The parallel rules are made of
ebony or gutta-percha. They consist
of two rules connected by cross-pieces
of brass working on pivots so that
the rules can be spread apart or drawn
together, but always remain parallel
to each other. They are used to de
termine the direction of courses.
The dividers are used to measure
distanPR. Small ohafia ckmu u ci'.li
of nautical miles from which to takej
off the distances. On larger charts i
use the latitude scales on the side, 1
as a minute of latitude is always a:
nautical mile. The course protractor;
is used for shaping long courses and '
consists of a long, single rule upon
which slides a movable compass card.;
Makes $199.90 Profit
From Ten-Cent Deal
Patrolman Fayette Cherry, of May
field, Ky., started trading when he
had a 10-cent pocket knife, and ten
weeks later he had an automobile he
valued at $200.
Net profit claimed, $199.90.
There were at least 100 trades be
tween the pocket knife and the car,
Cherry said.
He doesn't remember them all, but
anion? thinps tnr .
were other knives, cash ,J apfc.
watcnes. w
Cherry, now 67. ha k... .
for 40 years. '
By laying this rule to the course and
moving the north point of the com
pass disk to coincide with a maridian,
the angle of the course is shown at
once.
Now we have the compass, the lead,
the log and the chart, navigational
tools sufficient to take us out of port,
and start us on our voyage. Next
week we will put them to use, take
our departure by bearings, shape our
course, start dead reckoning, check
ourselves in a fog by lines of sound
ings and radio bearings, and get down
to deep watr navigation.
seriously
"It's just mv natm-J i
said, I ve never seen the uL . '
n't get a trade out of . -f
Cherry, for many v,r
a second hand furniturt stol v
wood. La., returning hire fiv
ago still in a swsnni,,,. ' e fa-
There', nothing ,Z 6 " '
trade he has just compk tn 'd
Take, for example, that
years ago, when he start
later, he said he owned a h0Us
Another time, on a "tde j
Cherry swapped all day and J,
himself the dosspsso f . i "l
He had started out with
His Alik;
"I'm surnrisl tVio
mi, juu pft t
Door marks in srwllin
i.wr ii ' .'"sp '"y son
"Well, you see. daH,h, ;. .
fault. The teacher don't sU" :
the. nam as I " r wct,
"OME OUT OF EVERY FIVE IS FREE
To Owners of General Electric
1938 General Electric Refrigerators are equip
ped with the new sensational Quick Freeze
Tray. It freezes faster, removes cubes easily
and keeps ice from melting at the time of cube
removal . . .
Tests indicate that 20 of the ice which has
been frozen is melted in releasing cubes from
their trays and dividers by the now antique
way of holding them under a faucet.
With the Quick Tray this is eliminated . . .
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General Electric owners.
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90 op
15c A Day Buys Some Models
v
Massie Furniture Company
Phone 33
Main Street
You Will Always Be Glad You Bought a General Elect
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