The sinking of the Titanic resulted in the Radio Act of 1912 that required 24-hour radio watches.
The disaster also led to clocks in the newer radio rooms featuring three-minute periods marked in red. That three minutes
provided a silent period when only emergency radio messages could be transmitted.
Since 1912 these clocks were used in shipboard radio shacks. See the below diagram
from the Chelsea Clock Company (USA) Special Radio Room Clock.
The US Government mil-specifications for the Chelsea clock, notes "the dial has accurate 4 second
marks in red around the outside edge, over which the sweep seconds hand passes, enabling the radio operator to accurately
transmit the 4 second alarm signal provided by the International Telecommunication Convention and the International Conference
on Safety of Life at Sea." And later, it indicates that, "also marked in red on the dial, clearly and forcibly calling attention
to the radio operator thereto, are the two 3 minute silent periods which must be observed by all radio stations at 15 and
45 minutes past each hour." Thus, the red marks on the dial edge are for the seconds alarm, and the red sector triangles for
3 minute radio silent periods on the 500 kcs. distress frequency. Later models featured additional green sectors at the top
of each hour and 30 minutes past each hour for the monitoring of the 2182 kcs. distress frequency.
For further information contact info@landandseacollection.com
Chelsea U.S. Maritime Commission
Ca 1940, 8 Day Movement
6 inch dial, Forged Bronze Case SN 293013
Original Near new condition
SOLD, THANK YOU!
Price $775.00 plus $20.00 for shipping to 48 States Stand included
CLICK ON PICTURES FOR DETAILS
Chelsea Radio Room Clock, Two Time Zones
WW II 2182 MHz Silent Periods
Currently for Sale, See Ships Clocks Page
SOLD, THANK YOU!
German Chronoquartz Radio Poom Clock
Post WW II German - English Colors
Ca 1968
SOLD, THANK YOU!
Post WW II Schatz electronic quartz radio room clock
SOLD, THANK YOU!
Seth Thomas, Ca 1938, Radio Room Clock, Two Time Zones
WW II 2182 MHz Silent Periods
Currently for Sale, See Ship's Clock Page
SOLD, THANK YOU!
Ca 1930 Chelsea USCG Radio Room Clock
SOLD, THANK YOU!
Chelsea U.S. Army Message Center Clock, Two Time Zones
Currently for Sale, See Ships Clocks Page
SOLD, THANK YOU!
1912 to pre WW II Sewill of Liverpool radio room clock
Both lower clocks from the Land and Sea Collection
of rare radio room clocks
