Principles of naval engineering - Historic Naval Ships Association

Chapter 4- PREVENTIVE AND CORRECTIVE DAMAGE CONTROLofficer who is qualified in damage control andwho is capable of taking over the supervisionof the repair party.Many repair stations have unit patrol stationsat key locations in their assigned areas tosupplement the repair station. Operating instructionsshould be posted at each repair station.In general, instructions should include thepurpose of the repair station; the specific assignmentsof space for which that station isresponsible; instructions for assigning and stationingpersonnel; methods and procedures fordamage control communications; instructionsfor handling machinery and equipment locatedin the area; procedures for nuclear, biological,and chemical (NBC) defense; sequence and procedurefor passing control from one station toanother; a list of current damage control bills;and a list of all damage control equipment andgear provided for the repair station.MATERIAL CONDITIONS OF READINESSMaterial conditions of readiness refers tothe degree of access and system closure tolimit the extent of damage totheship. Maximumclosure is not maintained at all times becauseit would interfere with the normal operation ofthe ship. For damage control purposes, navalships have three material conditions of readiness,each condition representing a differentdegree of tightness and protection. The threematerial conditions of readiness are calledX-RAY, YOKE, and ZEBRA. These titles, whichhave no connection with the phonetic alphabet,are used in all spoken and written communicationsconcerning material conditions.Condition X-RAY, which provides the leastprotection, is set when the ship is in no dangerfrom attack, such as when it is at anchor in awell protected harbor or secured at a home baseduring regular working hours.Condition YOKE, which provides somewhatmore protection than condition X-RAY, is setand maintained at sea. It is also maintained inport during wartime and at other times in portoutside of regular working hours.Condition ZEBRA is set before going to seaor entering port, during wartime. It is also setimmediately, without further orders, whenmanning general quarters stations. ConditionZEBRA is also set to localize and control fireand flooding when not at general quarters stations.The closures involved in setting the materialconditions of readiness are labeled as follows:X-RAY, marked with a black X. These closuresare secured during conditions X-RAY,YOKE, and ZEBRA.YOKE, marked with a black Y. These closuresare secured during conditions YOKE andZEBRA.ZEBRA, marked with a red Z. These closuresare secured during condition ZEBRA,Once the material condition is set, no fittingmarked with a black X, a black Y, or a red Zmay be opened without permission of the commandingofficer (through the damage controlassistant or the officer of the deck.) The repairparty officer controls the opening andclosing of all fittings in his assigned area duringgeneral quarters.Additional fitting markings for specific purposesare modifications of the three basic conditions,as follows:CIRCLE X-RAY fittings, marked with a blackX in a black circle, are secured during conditionsX-RAY, YOKE, and ZEBRA. CIRCLEYOKE fittings, marked with a black Y ina blackcircle, are secured during conditions YOKE andZEBRA. Both CIRCLE X-RAY and CIRCLEYOKE fittings may be opened without specialauthority when going to or securing from generalquarters, when transferring ammunition,or when operating vital systems during generalquarters; but the fittings must be secured whennot in use.CIRCLE ZEBRA fittings, marked with a redZ in a red circle, are secured during conditionZEBRA. CIRCLE ZEBRA fittings may be openedduring prolonged periods of general quarters,when the condition may be modified. Openingthese fittings enables personnel to prepare anddistribute battle rations, open limited sanitaryfacilities, ventilate battle stations, and provideaccess from ready rooms to flight deck. Whenopen, CIRCLE ZEBRA fittings must be guardedfor immediate closure if necessary.DOG ZEBRA fittings, marked with a red Zin a black D, are secured during conditionZEBRA and during darken ship condition. TheDOG ZEBRA classification applies to weatheraccesses not equipped with light switches orlight traps.WILLIAM fittings, marked with a black W,are kept open during all material conditions.This classification applies to vital sea suctionvalves supplying main and auxiliary condensers,fire pumps, and spaces that are manned during63