A standard XBT/XSV system
consists of an expendable probe, a
data processing/recording system, and
a launcher. An electrical connection
between the probe and the processor/
recorder is made when the canister
containing the probe is placed within the
launcher and the launcher breech door
is closed. Following launch, wire dereels
from the probe as it descends vertically
through the water. Simultaneously,
wire dereels from a spool within the
probe canister, compensating for any
movement of the ship and allowing the
probe to freefall from the sea surface
unaffected by ship motion or sea state.