YELLOW OR ALTERNATING WHITE AND YELLOW 
-Proceed with caution.
-Range operations are in progress but no torpedoes or testing is occurring.
-Be prepared to shutdown engines when lights change to red. Red or alternating white and red
-Range operations are in progress and submarine torpedo  and/or sound testing are occurring.
-Stop engines until red beacons have been shut off, showing test is completed.
-Follow the advice of Naval Guard Boats when in or near the range area.


OPERATIONAL PERIODS
-Typically, boat passage is permitted between tests when the yellow beacons are operating.
-Normally, tests and torpedo runs are confined to periods of less than 30 minute durations.
-Submarine operations can occur for longer periods.