The watertight integrity of a naval ship is
Material Condition YOKE
established when the ship is built.
Condition YOKE provides more protection than
condition XRAY. It is set and maintained at sea during
peacetime and in port during wartime. It is also
maintained in port during peacetime outside of regular
What types of watertight closures are
installed in interior and exterior areas where
rapid access or egress is required?
Material Condition ZEBRA
Lightweight aluminum doors
Condition ZEBRA is set before leaving or entering
Quick-acting watertight scuttle
port during wartime. It is also set immediately, without
Raised watertight hatch with scuttle
further orders, when manning general quarters (GQ)
stations. Also, condition ZEBRA is set to isolate and
Individually dogged watertight doors
control fires and flooding when the ship is not at GQ
A successful chalk test does not guarantee a
closure is watertight, but it does provide a
reasonable assurance of watertight integrity.
CLASSIFICATION OF FITTINGS
All watertight, airtight, fire-tight, and fume-tight
access fittings will be classified. Each classification
applies to a certain group of fittings. Although the
fittings are usually classified by a basic classification, a
select group of closures within each of the three
MATERIAL CONDITIONS OF
material conditions of readiness will be modified. The
purpose of the modified closures is to allow access to a
space that is secured because of the material condition
Learning Objective: Recall the requirements for the
that is set. Once a material condition is set, no fitting
three material conditions of readiness.
within the condition is to be opened, except as noted.
Closures that are not modified require permission of
The term material condition of readiness refers to
the commanding officer to be opened. Permission to
the degree of access and system closure in effect at any
open a closure is obtained through the damage control
given time. The securing of access fittings or systems
central (DCC) watch or the officer of the deck (OOD)
limits the extent of damage that could occur to a ship.
when the ship is not manning the GQ stations. With
approval of the damage control assistant (DCA), repair
MATERIAL CONDITIONS XRAY, YOKE,
party officers control the opening and closing of all
fittings in their assigned areas when the ship is at GQ.
Any change in the status of a fitting must be reported to
For damage control purposes, naval ships have
DCC so the ship's DC closure log may be updated. You
three material conditions of readiness. Each condition
may open a modified closure without any special
represents a different degree of tightness and protetion.
authorization. However, you are not authorized to
These titles have no connection with the phonetic
leave the closure open unattended. Through careful
alphabet. Furthermore, the titles are used in all spoken
attention to these procedures, a ship's watertight
integrity can be maintained at a safe level.
The following discussion will help you understand
that various groups of fittings are assigned different
Material Condition XRAY
classifications. Also, you will know when you may or
may not open a fitting that has a certain classification.
Condition XRAY provides the least amount of
protection. It is set when the ship is in no danger of
attack. Examples are when the ship is at anchor in a
well-protected harbor or when secured at a home base
XRAY fittings are marked with a black X and are
during regular working hours.
s e c u r e d d u r i n g c o n d i t i o n s X R AY, YO K E , a n d