A.changes in seawater salinity B.glare on clouds on the horizon C.changes in air temperature D.icebergs
A.can usually be detected by radar in a smooth sea at a range of 4 to 6 kilometers B.are indistinguishable from sea return on the PPI C.are invisible to radar when covered with a thick layer of snow D.are usually seen at night before they are close enough to provide a radar echo
A.one engine ahead and one engine astern,with full rudder B.one engine ahead and one engine astern,with rudders amidships C.both engines ahead,with full rudder D.both engines astern,with full rudder