Evening star., 1939-11-26

eight-tenths of a mile per second,
the distance can then be computed
very easily.
Next, the survey moves his vessel
along prescribed course and takes
soundings with an instrument known
as fathometer every minute and
enters these in book containing
sounding records. He may take
such soundings for a day, a month
or even year.
"The fathometer, in case you're
not familiar with it, works on the
echo-sounding principle-sends out
a series of sharp, rapping noises
from the ships bottom, catches the
rap echo which resounds from the
ocean bottom and instantly reports
the exact depth of the water under
the ship at the moment.
ut works at high speed, reporting
the depths as frequently as 20 times
q second, even while the vessel on
which it is mounted steams along
at full speed. Which means that if
the ship is going 10 knots, sound
ing is obtained once every 10 inches!
Fifteen minutes after firing the
first bomb, the ocean surveyor drops
another into the water and may
follow the same procedure at such
intervals for a day or more.
"The reason he needs S.-R. B. in
connection with the soundings taken
by the fathometer is that the latter
device (also developed by mel tells
you the depth, but not the location"
Has Practical Value.
Thus, explains the inventor, the
sono-radio buoy is put to tremend-
GUS practical use every time depth
bomb is fired. Some 20 SIR. BIS
are today in actual use by the
Survey. These are all homemade, :"
constructed on the Survey vessels
whenever they are needed for
sounding work. A buoy can be made
in three days to a week by three
radio operators.
Each buoy is crystal-controlled-
and, incidentally, just as a labor of
love, DR.. Dorsey grinds each in
dividual crystal himself in his
laboratory.
When not in actual use, the buoys
are kept on the deck of the SURVEY
ship. The entire buoy equipment
ready for lowering into the sea is
about 80 feet long. Five to six men
are needed to lower the apparatus
with the aid of a winch, boom and
block-and-tackle. 1t takes only S
to 10 minutes to put a buoy in
proper position in the water.
The drums, or barrels, containing
the radio equipment weigh around
so pounds apiece and are standard
sized steel drums. Including the
batteries, the radio equipment
weighs about 80 pounds. When
placed in proper position for its i'm
portant job of undersea broadcast
ing, the buoy is fastened to an
anchor which is usually made from
three old railroad couplings.
In effect, the apparatus is high
quality radio transmitter Of low
power about six watts, Its equip
ment includes an A, B and c battery
and six tubes of two-volt filament,
types 30, 80 and 33.
Is the buoy durable? Well, DR.
Dorsey points out that three sono-
radio buoys were caught in the full
force of the hurricane that swept
Long Island Sound some weeks ago
While the storm blew superstruc-
lures off the buoys and forced them
to drag anchor, the equipment in
each unit remained in perfect work.
| ing order.
Last 50 Days.
Under fairly favorable weather
conditions, the batteries and tubes
will last about so days without re-
pair or adjustment, DR.. Dorsey says
Whereupon, they are taken aboard
ship and renewed. In general, Sc
days is long enough for most of the
Coast and Geodetic Surveys sound
| Ing pIOJ6CCS. cdCil vi ulil COIlVdnlAIAs
the equipment is entirely air and
water tight, and usually is unaffect-
ed by the terrific battering of vino
and water it is forced to take.
Within the next few years it Il
expected that the sono-radio buoy
will eliminate the need for shore
stations of the Survey. These sta.
tions, utilized for position locating
consist of a tiny hut containing
radio receiving and sending appara.
tus somewhat similar to that on the
radio buoy. A radio operator has
to be on the job "a hours day
during a project.
Equipment for these shore sta.
tions generally has to be carried
through the surf, often in heavy
seas and along a rockbound coast
a procedure which is very dangerous
The sono-radio buoys cost only
about $4OO to make, and the upkeer