MATERIAL CONDITIONS OF READINESS
There are three material conditions of readiness.
Those conditions are named XRAY, YOKE, and
ZEBRA. When set, each condition affords the ship with
a level of protection, with XRAY being the least and
ZEBRA the most. Some fittings or closures on a ship
may not be classified although the majority of them are
classified. They are identified by a classification plate
affixed to the closure or fitting, or sometimes the
classification is painted on the bulkhead next to the item.
Ships instructions (and Navy instructions) specify
what type of classification an item should hold, how it
will be marked, and when that condition should be set.
The commanding officer of the ship is authorized by
instruction to alter this to a small extent if he/she desires
but basically this system is standard Navywide.
XRAY. Provides the least watertight integrity and
the greatest ease of access throughout the ship. It is set
when the threat to the ship is minimal. Condition XRAY
is set during working hours when the ship is in port,
when there is no danger of attack, and when there is no
threat from bad weather. All fittings marked with a
black X and circle X are closed when condition XRAY
YOKE. Provides a greater degree of watertight
integrity than condition XRAY but to a lesser degree
than the maximum condition. YOKE is normally set at
sea and in port during wartime. All fittings marked with
Xs and Ys, Circle X, and Circle Y are closed when
condition YOKE is set.
ZEBRA . Provides the greatest degree of
subdivision and watertight integrity to the ship. It is the
maximum state of readiness for the ships survivability
system. Condition ZEBRA is set when the following
1. Immediately when GQ is sounded
2. When entering or leaving port in wartime
3. To localize damage and control fire and flooding
when the crew is not at GQ
4. At any time the CO deems the maximum
condition of survivability should be set
All fittings marked with X or Y, Circle X, Circle Y,
Z, Circle Z, and DOG Zs are closed when condition
ZEBRA is set.
The setting of material conditions is normally
carried out by the division or department responsible for
the compartment and is accomplished by using the
compartment checkoff lists (CCOLs). In an emergency
the repair party personnel responding to the casualty
assisted by those Sailors in the area will set the required
condition to restrict the spread of damage. CCOLs are a
tool used by repair party personnel to find the damage
control fittings and closures in each compartment. The
fittings and closures are identified by name (type) and a
number that represent the location of the fitting by deck,
the frame it is located at, and the side of the space similar
to the compartment identification process. The CCOL
list is posted in each space near the entrance and should
be kept up to date by the division who owns the space.
An example of a CCOL is shown in (fig. 12-2).
The normal setting of a material condition should
be logged in the Damage Control Closure Log by each
division or repair party completing the setting. Any
exceptions to the setting should also be noted in the log
so DCC/OOD are aware of the reduction in the ships
ability to restrict the spread of potential damage. This
log and the Inoperative Fitting Log are maintained in
either DCC or on the quarterdeck by the OOD. If you
have a need to break (open) a fitting that should be
normally set in a specific condition, you must first
request it open and then log it in before opening the
fitting. If you dont do this, you are in violation of the
setting and have jeopardized your shipmates survival.
When you have completed work in a space that you
needed a fitting/closure open, close it first, then log it
closed. Now those who maintain the log will have a
clear picture of what is open and closed in a given area
of the ship. In addition to the closure log, a log for
inoperative fittings and closures exists. As its name
implies, this log lists all DC-related fittings and closures
on the ship that dont work properly. It becomes a
tracking tool for future maintenance.
A modified condition YOKE or modified condition
ZEBRA is sometimes set, rather than the normal setting
of XRAY, YOKE, or ZEBRA. These are settings of
convenience at the discretion of the CO.