Evening star., 1936-11-29
GHOST LIGHTSHIPS

astonishing way II all is we'll. this
mechanical ear will permit the radio
beacon to sound the full so seconds of
each minute. But, if the fog signal
noes not sound. the microphone shuts
off the radio-beacon for five seconds
of every minute. Thus the shore op-
orator definitely knows whether or not
the fog horn is sounding. If it is not.
he simply turns on the second one by
pushing the second button as was ex-
planned earlier.
ENGINEERS of the Lighthouse Bu-
reau state that the automatic fea-
lures on the lightship are almost
thinking in the way they operate to
safeguard the equipment and the sig
mails. For instance. to guard against
interference in the shore control radio
receiving set from other signals. static
or similar disturbances, small So
called reed" in the receiver keeps out
all signals except those desired from
the ship. Radio conversations are car.
ried on constantly between other light
house keepers on identically the sam
frequency employed by the st. Clair
shore operator, but, strangely enougS
the reed" effectively screens out
signals except those from the boat.
actually selects only the radio signsa
and permits no others to interfere.
Lighthouse engineers in Washington
state that the st. Clair is the forerun-
ner of system of remote control light
ships up and down Americas entire
coastal length. After five full years of
constant and painstaking research,
they are confident of success for the
plan. The problems of maintaining
the necessary complicated equipment
aboard small floating structure have
been conquered, and they point out
that this new system permits the
placing of lightships in actual posi-
tions of danger, rather than erecting
lighthouse on shore, which definitely
lowers the hazards Of marine naviga-
ton as we'll as that in the Great Lakes.
The radio-controlled lighthouse in
Green Bay, Lake Michigan. is similar
to the set-up on the st. Clair. A dup
licate system of radio trarsmitters and
tone generators on shore at Sherwood
Point, miles distant, controls two
independent fog signals and radio
beacons at the lighthouse on Peshtigo
Reef.
The difference in this arrangement
from that of the ST. Clair is that a
radio-telephone at the lighthouse is
automatically placed in operation
when the fog signal is started, and the
shore operator has q radio receiver
which permits him to hear the fog
signal as well as the clicking Of the
gears and wheels of other machinery
in the lighthouse. Thus he knows If
everything Is as it should be. This
system may also be used for human
communication, for the radio-control
transmitter at Sherwood Point can be
used for conversation as we'll, and is
frequently thus used when a crew OF
men is servicing the lighthouse.
A MOTHER recent engineering
marvel developed by the Bureau
Of Lighthouses is the system for syn
chronizing the fog horn and radio
signal to determine distance between
a vessel and light-station (not to be
confused with the radio-beacon which
Is a directional signal only.
Previous to this invention in times
Of fog, ship had no way Of telling
accurately how far it was from light
house when hearing the fog signal
The wall of the horn was heard but
the mariner could only roughly guess
by its intensity how far he was from I
the reef or dangerous shoal on which ,
the lighthouse was situated. Wind. fog
and atmospheric pressure play tricks
with sound.