Evening star., 1928-11-20

are sent out from a station on shore,
and are picked up on shipboard in such
a way that their exact direction Is mani
tested When the mariner thus receives
waves from two such shore stations
whose localities are charted, 1t Is a SIM
pie matter of triangulation to discover
his own exact position at sea. vessels
have thus been located more than 200
miles from the sending stations.
A later device is known as radio
synchronization, which is useful for
sounding the depths Of the sea. and
also for locating and measuring the dis
tance of a vessel from the ightship
sending out the waves.
The radio wave travels with the speed
of light-1S6,000 miles second; the
time required, therefore. for such fash
to register upon receiver 10 or 80 or
so miles away is such an inflnite5lrnal
part of a second that It Is neglible In
this test But the speed Of an actual
sound-as the stroke Of mighty ham,
mer or the explosion of bomb under
Water-is about eight-tenths of mile
per second, or. measured in feet, from
4,80O to 1900 feet per second. Sounds
can be heard through the ocean water
distance of so miles or more, but to
travel so miles at the rate OF 4.S00 feet
per second requires IS seconds. The
receiving officer with ,stopwatch IN
hand notes the difference between the
radio and the sound, just as one may
note the difference between a flash of
lightning and the peal of thunder
which difference indicates the distance
Of the storm.
This method enables the mariner to
determine from a. single operation.
without triangulation, the location of
his ship from the charted source of the
sound Usually the same button OF the
sender which gives the radio flash also
operates a great hammer under water.
which makes the required sound: or an
oscillator or a bomb for the same pur-
nose Sound travels through water
much farther than through air. and
such sounds can be registered Under
water a distance of nearly 10 miles.
For measuring the depth and chartins
the ocean bed. the apparatus gives %
signals per second. the depth being
known by the length of time required
for the sound wave to-. descend from
the ship. strike the bottom and echo
up to the ship. as measured by the
known average speed of sound through
water-4,800 feet per second. The Le-
viathan has been equipped within the
last few weeks with the device, the en-
tire COSb Oh WHICH, ID OllAJ 0OsuON'
X \
Three years ago the Navy lost sew
eral destroyer vessels because the COM
mander became confused and DOUBTED
the accuracy of his radio compass. but
il he had had this new radio-syncnro-
nizing device it would have told him OF
the dangerously shallow depths he was
sailing, and the fleet would not nave
rushed blindly to its destruction on
Honda Point. 1t is more servlceaole
than a bow wstchman equipped with
powerful glasses. depending on vision.
and the radio device is as good IN tog as
in clearest day.
Light vessels for sending out the sig
nails to passing ships are stationed at
strategic points along shore. and prac-
tically ali light vessels in the world
now are equipped to send submarine
signals and radio beacons. In place
of a bell now, there is substituted an
apparatus called an "oscillator," which
being dropped into the ocean causes
an explosion which can be heard many
miles farther than any bell. the average
range being about 40 miles. but the
extreme audibility being 20 miles.
Scientific development Of this device
must be credited to the work of the
Bureau of Standards and the United
States Coast and Geodetic Survey, but
European coasts are today better pro-
tected with 1t than Is America. the
first use of the idea was made in 1911
by Admiral Winterhalter of the United
States Navy, with radio, steam
whistle and submarine bell. In 1917.
Comdr. Hooper of the Coast and
using a submarine bell. But during
the World War the Fessenden sub
marine oscillator was invented. which
produces underwater sounds of enor-
nous intensity and carrying power. "
was only since the war that the metho1
has been put to general use-in fact
only within the last Ave years.
Another device of recent origin but
which applies to the guidance of ship
mechanically in place of by steersms,1
at the wheel. Is the gyro-compass, or
Iron Mike" the seaman calls II. When
this IS used, as upon the Leviathan. tn
ships course. once determined, Is kept
absolutely without deviation, by ths
electric Iron Mike"-far more accu-
rstely than possible by hand steering,
no matter how the winds and waves
may buffet.
So with all the devices of safety on
board a modern ship. it is accepted pol
icy based upon the idea that the best
way to save lives Is to save the ship,
rather than to abandon ship prema-
turely and trust to RATS or lifeboats
and life-preservers In the teInpestuous
sea. Waves as high as six-story house
make short work Of little lfeboats, toss
ing them topsy-turvy.
" y X
In 1913, there was an international
conference in London upon safety Of
ocean travel and elaborate plans were
recommended to increase safety This
conference report was adopted by the
United States Senate, but with so many
executions and reservations that 1t was
practically rejected. Now similar
conference is called TO be held in Lon
don next April IT has not yet been
determined whether the United States
will participate.