U.S.NAVY UNDERWATER SHIP HUSBANDRY MANUAL

CHAPTER-7

NON-DESTRUCTIVE TESTING

SECTION 1 - INTRODUCTION7-1.1 PURPOSE7-1.2 SCOPE7-1.3 APPLICABILITY7-1.4 NONDESTRUCTIVE TESTING METHODS7-1.4.1 PRELIMINARY EFFORT7-1.4.2 UNDERWATER VISUAL TESTING (UWVT)7-1.4.2.1 UWVT Applications7-1.4.2.2 UWVT Limitations7-1.4.2.3 UWVT Equipment7-1.4.3 UNDERWATER MAGNETIC PARTICLE TESTING (UWMT)7-1.4.3.1 UWMT Applications7-1.4.3.2 UWMT Limitations7-1.4.3.3 UWMT Equipment7-1.4.4 UNDERWATER ULTRASONIC THICKNESS GAUGING (UWUTG)7-1.4.4.1 UWUTG Applications7-1.4.4.2 UWUTG Limitations7-1.4.4.3 UWUTG Equipment

SECTION 2 - PLANNING AND PREPARATION7-2.1 REFERENCE DOCUMENTS7-2.1.1 U.S. NAVY DIVING MANUAL7-2.1.2 NAVAL SHIPS' TECHNICAL MANUAL (NSTM)7-2.1.3 SHIP DRAWINGS7-2.1.3.1 Docking Plans7-2.1.3.2 Shell Plate Expansion7-2.1.3.3 Shafting Arrangement Drawing7-2.1.3.4 Component-Level Drawing 7-2.1.3.5 General Outboard Profile7-2.1.4 MILITARY STANDARDS7-2.1.4.1 Fabrication, Welding and Inspection of Ships Structure7-2.1.4.2 Requirements for Nondestructive Testing Methods7-2.1.4.3 Nondestructive Testing Acceptance Criteria7-2.1.5 NAVY EQUIPMENT AUTHORIZED FOR NAVY USE (ANU)7-2.2 PLANNING7-2.2.1 OPERATIONAL PLAN7-2.2.2 REFERENCE DOCUMENTS7-2.2.3 EQUIPMENT, TOOLS AND MATERIALS7-2.2.4 DETAILED PROCEDURES7-2.2.5 QUALITY ASSURANCE PACKAGE7-2.2.6 POST-OPERATIONAL PROCEDURES7-2.2.7 SAFETY PRECAUTIONS7-2.2.8 CERTIFICATION REQUIREMENTS FOR UWVT7-2.2.8.1 Fleet Examiners7-2.2.8.2 Fleet Inspectors (Divers)7-2.2.8.3 Non-fleet Personnel7-2.2.9 CERTIFICATION REQUIREMENTS FOR UWMT7-2.2.9.1 Fleet Examiners7-2.2.9.2 Fleet Inspectors (Divers)7-2.2.9.3 Non-fleet Personnel7-2.2.10 CERTIFICATION REQUIREMENTS FOR UWUTG7-2.2.10.1 Fleet Examiners7-2.2.10.2 Fleet Inspectors7-2.2.10.3 Non-fleet Personnel7-2.2.11 SCHEDULING7-2.3 PREPARATION7-2.3.1 EQUIPMENT, TOOLS AND MATERIALS7-2.3.2 PROTECTIVE EQUIPMENT7-2.3.3 DIVER STAGING EQUIPMENT7-2.3.4 SURFACE PREPARATION AND RESTORATION EQUIPMENT7-2.4 SPECIFIC PREPARATION REQUIREMENTS FOR UWVT

TABLE OF CONTENTS

7-2.4.1 UWVT EQUIPMENT7-2.5 SPECIFIC PREPARATION REQUIREMENTS FOR UWMT7-2.5.1 UWMT EQUIPMENT7-2.6 SPECIFIC PREPARATION REQUIREMENTS FOR UWUTG7-2.6.1 UWUTG EQUIPMENT7-2.7 RECORDING EQUIPMENT

SECTION 3 - NONDESTRUCTIVE TESTING PROCEDURES7-3.1 INTRODUCTION7-3.2 UNDERWATER VISUAL TESTING (UWVT)7-3.2.1 HULL SURFACE PREPARATION7-3.2.2 UWVT PROCESS7-3.3 UNDERWATER MAGNETIC PARTICLE TESTING (UWMT)7-3.3.1 HULL SURFACE PREPARATION7-3.3.2 UWVT PROCESS7-3.4 UNDERWATER ULTRASONIC THICKNESS GAUGING (UWUTG)7-3.4.1 HULL SURFACE PREPARATION7-3.4.2 UWVT PROCESS

LIST OF APPENDICESA-1 SAMPLE QUALITY ASSURANCE PACKAGE FOR UNDERWATER

MAGNETIC PARTICLE TESTING AND UNDERWATER VISUAL TESTINGB-1 SAMPLE QUALITY ASSURANCE PACKAGE FOR UNDERWATER

ULTRASONIC THICKNESS GAUGINGC-1 SAMPLE PROCEDURE UWVTD-1 SAMPLE PROCEDURE UWMT

LIST OF ILLUSTRATIONS7-2-1 Hydraulic or Pneumatic Hand-Held Grinder With Abrasive Disk7-2-2 High-Pressure Water Jet7-2-3 Two-Conductor Power Cable With Braided External Ground and Neoprene Jacket7-2-4 Ground Fault Interrupter7-2-5 Electromagnetic Yoke7-2-6 Magnetic Field Indicator7-3-1 Area Prepared for Magnetic Particle Inspection7-3-2 Placement of the Electromagnetic Yoke7-3-3 Placement of Magnetic Field Indicator7-3-4 Application of Magnetic Particles7-3-5 Positive Indication by Magnetic Field Indicator7-3-6 Positioning of Electromagnetic Yoke7-3-7 Use of Arrow Punch to Mark the Ends of a Suspected Discontinuity

LIST OF TABLES7-1-1 Abnormal Conditions7-2-1 Equipment and Materials Required for Visual Inspection7-2-2 Equipment and Materials Required for Magnetic Particle Inspection7-2-3 Equipment and Materials Required for Underwater Ultrasonic Thickness Gauging

CHAPTER 7

NON DESTRUCTIVE TESTING

SECTION 1 - INTRODUCTION

7-1.1 PURPOSE

The purpose of this chapter is to describe methods for conducting nondestructive testing (NDT) underwater and to provide general procedures and requirements for accomplishing each method. The NDT methods discussed include underwater visual testing (UWVT), underwater magnetic particle testing (UWMT) and underwater ultrasonic thickness gauging (UWUTG). Understanding the information in this chapter will facilitate effective planning and execution of underwater NDT tasks and will ensure timely return of the ship to operational readiness. This chapter is not intended to serve as a training document used to certify underwater NDT inspectors.

7-1.2 SCOPE

This chapter describes standard NDT methods that have been adapted to underwater use. The chapter addresses why and when each method is used. For each method, the chapter also discusses planning and preparation requirements, general procedures and expected results. The general procedures provided can be used to develop specific procedures for the NDT task at hand. This chapter does not replace or supersede existing technical documents that pertain to NDT, nor does it provide information on general operational and safety procedures for performing underwater ship husbandry. Definitions for words and phrases applicable to NDT can be found in MIL-STD-271 and MIL-STD-2035.

7-1.3 APPLICABILITY

The information in this chapter can be used by anyone involved in planning and executing underwater NDT efforts. Divers can use the information for instruction in applying the various NDT methods and for recognizing equipment required by each method. Divingsupervisors and NDT inspectors can use this chapter for guidance in developing an operational plan, for coordinating personnel and for monitoring underwater work for quality assurance.

7-1.4 NONDESTRUCTIVE TESTING METHODS

NDT may be accomplished underwater using UWVT, UWMT, UWUTG or a combination of these methods. Underwater Visual Testing (UWVT) is used to verify dimensional requirements associated with underwater welding, to ensure that welds are free of various detrimental conditions and to ensure that inspection surfaces are suitable for other NDT methods. All of these uses of UWVT are more exacting than the underwater visual inspections described in NSTM Chapter 081, related to underwater fouling. Underwater Magnetic Particle Testing (UWMT) is generally used to discover or document surface breaking cracks in ferrous metal structures and, along with UWVT, is an integral part of underwater welding quality assurance. Underwater Ultrasonic Thickness Gauging (UWUTG) is generally used to discover or document the deterioration of hull plating, as part of the pre-overhaul test and inspection program.

7-1.4.1 PRELIMINARY EFFORT. The decision to conduct UWVT, UWMT or UWUTG inspections often results from a visual examination. Visual examinations range in scope from simple appraisals to determine the extent and type of marine growth found on a ship's hull, to more detailed assessments of the material condition of specific areas. Because the results obtained from a visual examination can be instrumental in determining the need for NDT and the method of NDT to be used, divers must be able to relay visual examination results to NDT inspectors, diving supervisors and repair personnel. To relay results, divers must be familiar with ship hull configurations, openings, appendages and propulsion assemblies. They must also be familiar with the abnormal conditions (table 7-1-1) which indicate that NDT may be necessary to determine the extent of damage. Divers may use underwater video cameras, still cameras, stereo cameras and various measuring devices to record the results of a visual examination.

7-1.4.2 UNDERWATER VISUAL TESTING (UWVT). Underwater visual testing (UWVT) is a nondestructive method for locating and defining surface discontinuities underwater. It is most often applied to welds, to assess their condition and conformance with dimensional requirements. UWVT must be performed with measuring devices or comparators when quantitative restrictions apply and the diver must be properly trained in the use of such devices. The diver must also be trained to recognize detrimental features associated with welding processes, as well as environmental conditions, such as limited visibility or improper lighting, that would affect the validity of the inspection.

7-1.4.2.1 UWVT Applications. Underwater visual testing is used for three distinct purposes. The first is in the underwater welding process, to verify dimensional requirements such as fit-up and that welds meet the requirements for fillet size, allowable undercut, etc.

The second is to ensure that welds are free of cracks, incomplete fusion, arc strikes and other fabrication scars as specified by the controlling document. The third is to ensure the suitability of underwater surfaces for other underwater NDT methods, where improper surface conditions may cause false indications to mask relevant indications.

7-1.4.2.2 UWVT Limitations. UWVT shares the same limitations as conventional (topside) VT, but is generally more difficult to apply. The minimum size indication detectable may be larger underwater, despite the magnification inherently obtained when viewing objects in an underwater environment. Limited visibility, distortion caused by the diver's faceplate or thermal gradients and fogging of the faceplate are some of the factors that may reduce the inspection sensitivity. Limited mobility or access restricted by thermal protection or life support equipment may also reduce inspection sensitivity. The availability and quality of communications, video and photographic equipment may limit the eventual quality of records and reports.

7-1.4.2.3 UWVT Equipment. The full range of visual testing tools, including weld profile gauges, joint angle measuring devices, surface comparators, etc., must be available to the diver and used when appropriate. Tools which are adversely affected by use underwater should be considered expendable. In addition, an appropriate white light source and ground fault interrupter, such as specified in NAVSEA drawing number 6653063, shall be available.

7-1.4.3 UNDERWATER MAGNETIC PARTICLE TESTING (UWMT). Underwater magnetic particle testing (UWMT) is a nondestructive method for locating and defining surface discontinuities in magnetic materials underwater. Its principles are the same as its topside (i.e., conventional) counterpart, that is, magnetic particles are attracted to flux leakages at the surface of magnetized materials and form indications of discontinuities located either at or just below the surface.

In operation, the magnetic material or item of interest is magnetized using an electromagnetic yoke specially designed for underwateruse. Wherever surface discontinuities exist within the yoke's field of influence, magnetic flux will "leak" from the surface of the part. A slurry of magnetic particles are attracted to and aligned with, the leaking magnetic flux. The particles are brightly colored and form a visible indication corresponding to the location of discontinuities at or very near the part's surface.

7-1.4.3.1 UWMT Applications. Underwater magnetic particle testing is used primarily as a quality assurance tool to support underwater welding on ship structures. It can be used as well to inspect hulls or other magnetic components for surface discontinuities such as cracks and lack of fusion. UWMT may also be used to define the true length (and locate the true ends) of discontinuities detected visually and to help determine where corrective measures (e.g., stop drilling) should be applied.

7-1.4.3.2 UWMT Limitations. As with any inspection method, UWMT has some limitations. These include:

a. Underwater magnetic particle testing has limited sub-surface capability. For use on U.S. Navy applications, it is considered to be strictly a method for detecting and measuring surface discontinuities. It is not an approved method for detection of sub-surface discontinuities.

b. The adequacy of inspection with UWMT (as with most nondestructive test methods) is largely a function of the operator's knowledge and skill. Inspections with UWMT are to be performed only by personnel trained and certified specifically in UWMT. (See Section 7-2.2.9 for certification requirements).

c. UWMT is limited to ferromagnetic materials, which include most steels. For most applications, a simple check with a magnet is sufficient to determine suitability for UWMT.

7-1.4.3.3 UWMT Equipment. For fleet users, the equipment for UWMT is specified in NAVSEA drawing number 6653063. This equipment meets the requirements of MIL-STD-271. Only this equipment may be used. Major components of the UWMT system include:

1. Underwater magnetic yoke with articulated legs

2. White light source

3. Underwater magnetic particles

4. Ground fault interrupter

5. Magnetic field indicator

6. Flaw size sensitivity plate.

For non-fleet users, the UWMT equipment shall meet the requirements of MIL-STD-271.

7-1.4.4 UNDERWATER ULTRASONIC THICKNESS GAUGING (UWUTG). Underwater ultrasonic thickness gauging (UWUTG) is a nondestructive method for measuring the thickness of ships' hulls. Its principles are the same as its topside (i.e., conventional) counterpart - the time of travel of ultrasonic emissions from a hand-held ultrasonic transducer are measured and converted to thickness based on the (known) velocity of sound in the material being tested. In UWUTG, the ultrasonic instrument is located topside and is monitored by a certified ultrasonic test inspector, while the transducer is manipulated along the hull by a diver working under the direction of the inspector. For fleet users, a computer data acquisition system is used, which permits area scanning and rapid data collection and which prints out minimum, maximum and average thicknesses measured.

7-1.4.4.1 UWUTG Applications. The UWUTG technique is suitable for measuring thicknesses of approximately 1/4 inch to 2 inches in steel and ultrasonically comparable materials. It works best on surfaces which are approximately parallel but can be used on surfaces which are corroded or pitted on one or both sides.

7-1.4.4.2 UWUTG Limitations. As with conventional ultrasonic techniques, the degree of difficulty in obtaining accurate readings increases with the degree of surface roughness. Ideal conditions are smooth front and back surfaces; worst-case conditions are very rough or pitted front and back surfaces. In the latter case, the scanning speed may need to be reduced significantly in order to obtain accurate readings. Under conditions of extreme pitting on both surfaces, UWUTG may be unable to provide accurate readings.

7-1.4.4.3 UWUTG Equipment. For fleet users, the equipment for UWUTG is specified in NAVSEA drawing number 6653028. This equipment meets the requirements of MIL-STD-271. Major components of the UWUTG system include:

1. Ultrasonic test instrument

2. Transducer

3. Computer

4. Ground fault interrupter

5. Hogging lines

6. Software

7. Step block

8. Waterproof cables

For fleet users, only this equipment may be used, with the following exceptions:

a. Rigging lines: The UWUTG system includes a set of rigging lines for positioning the diver. These rigging lines are designed to meet most applications but can be modified (or another location system can be used) if desired to better suit the particular user or application. Any changes must be reviewed and accepted by the Level II Inspector.

b. Calibration blocks: The UWUTG system includes two calibration blocks and the software will default to those step block settings if they are not otherwise defined. However, if an activity desires to use different calibration blocks with UWUTG, such use is permitted provided the blocks used meet the requirements of MIL-STD-271.

For non-fleet users, UWUTG equipment shall meet the requirements of MIL-STD-271.

SECTION 2 - PLANNING AND PREPARATION

7-2.1 REFERENCE DOCUMENTS

Planning for nondestructive testing (NDT) requires an in-depth review of various source documents, such as previous inspection reports, hull cleaning reports and engineering drawings that identify the materials used and the construction criteria of the specific area of inspection. Each document has a unique purpose; therefore, all available references must be consulted before and during each task. This section identifies important source documents and the information relevant to NDT that each document provides. For direction on obtaining and using reference materials, refer to Chapter 2 of this manual, General Information and Safety Precautions.

7-2.1.1 U.S. NAVY DIVING MANUAL. NAVSEA 0994-LP-001-9010, U.S. NAVY DIVING MANUAL, Volume 1, Air Diving, provides guidance, instructions and safety precautions for diving operations.

7-2.1.2 NAVAL SHIPS' TECHNICAL MANUAL (NSTM). The purpose of S9086-00-STM-000, Naval Ships' Technical Manual (NSTM), is to provide technical information to personnel engaged in the supervision, operation or maintenance of U.S. Navy Ships. The various chapters and volumes of the NSTM contain detailed administrative and technical instructions that amplify U.S. Navy Regulations and other authoritative documents. These instructions are designed to assist personnel, afloat and ashore, in satisfactorily managing the operation and maintenance of ships and shipboard machinery and equipment. The NSTM chapters listed below contain information of special interest to NDT planners. While the NSTM chapters described below contain a wide range of information, the following descriptions are limited to information relevant to NDT.

050 Readiness and Care of Inactive Ships. This chapter discusses preservation and routine inspection programs for inactive ships' hulls.

074 Volume 1, Welding and Allied Processes; and Volume 2, Nondestructive Testing of Metals-Qualification and Certification Requirements for Naval Personnel. This chapter provides the minimum mandatory requirements and guidance for welding, brazing, NDT and safety used for ship maintenance. Volume 1 is useful in identifying improper welds and familiarizing personnel with welding terminology. Volume 2 addresses NDT qualification and certification of naval personnel.

080 Publications and Drawings. This chapter discusses the various systems used to store information, the particular information each system contains and the requisitioning of information.

081 Waterborne Underwater Hull Cleaning of Navy Ships. This chapter provides guidance on criteria for evaluating fouling severity and antifouling and anticorrosive paint condition; determining intervals of cleaning; and selecting cleaning methods and equipment to be used.

090 Inspections, Tests, Records and Reports. This chapter discusses types of corrosion and their causes and identifies critical inspection areas.

091 Submarine Hull Inspection. This chapter furnishes submarine hull integrity inspection, repair and reporting requirements.

100 Hull Structures. This chapter discusses inspection and repair requirements for ships' hulls and superstructures.

631 Preservation of Ships in Service (Surface Preparation and Painting). This chapter provides precautions the diver must take when removing organotin paints from ships' hulls. It also discusses safety precautions for topside operation of hydroblasting equipment.

633 Cathodic Protection. This chapter provides information on the equipment, design, installation, operation and maintenance of cathodic protection systems used on active Navy ships, submarines, boats and craft. It discusses the requirement for periodic diver inspections to: detect abnormal hull conditions, ensure adequate cathodic protection system operation and assess the cathodic protection system performance.

9430 Shafting, Bearings and Seals. This chapter furnishes descriptive visual evidence of and repair requirements for deterioration, physical damage, lack of adhesion and other discontinuities to rubber and fiberglass covered shafts.

7-2.1.3 SHIP DRAWINGS. Ship drawings are the primary source of engineering data required for underwater ship husbandry (UWSH). Ship drawings define the configuration, arrangement and dimensions of a ship's structure and its components. They provide UWSH personnel with the locations, dimensions and interfaces of all underwater components such as hull plating, structural members,

propulsion gear, rudders, hull appendages and hull openings. Ship drawings also specify types of material used and list materials and parts for each ship system. The ship drawings listed below are pertinent to NDT.

7-2.1.3.1 Docking Plans. The ship docking plan provides an underwater profile of the ship, the plan view of its bottom and the exact locations of all underwater appendages with reference points and measurements. The docking plan also provides vertical measurements taken from the main deck and from the baseline.

7-2.1.3.2 Shell Plate Expansion. Shell plate expansions provide detailed information on individual hull plate locations, materials used, construction details, and design plating thickness. Inspectors and diving supervisors can use the information to develop specific procedures for the area being inspected.

7-2.1.3.3 Shafting Arrangement Drawing. The shafting arrangement drawing shows the locations of all the propulsion shafting components from the propeller to the reduction gear connection. The drawing also gives shaft measurements and clearances around shafting components.

7-2.1.3.4 Component-Level Drawing. Drawings of a component being inspected or of components in an inspection area will specify construction conditions such as dimensions, base material and surface finishes of the component or components.

7-2.1.3.5 General Outboard Profile. The General Outboard Profile provides visual landmarks between the water line and the 01 deck that can be used to locate specific frame numbers. The diving supervisor can direct hogging line placement or position the dive boat with respect to these above-water features.

7-2.1.4 MILITARY STANDARDS. Military standards contain minimum requirements for performing various activities. Those which are most often used in the inspection and repair of ships are listed below.

7-2.1.4.1 Fabrication, Welding and Inspection of Ships Structure. MIL-STD-1689 contains minimum requirements for the fabrication and inspection of the hull and associated structures of combatant surface ships. This includes requirements for shipbuilding, materials, welding, welding design, mechanical fasteners, workmanship and inspection.

7-2.1.4.2 Requirements for Nondestructive Testing Methods. MIL-STD-271 discusses how to determine the presence of surface and internal discontinuities in metals. It also contains the minimum requirements necessary to qualify NDT procedures, equipment and civilian personnel.

7-2.1.4.3 Nondestructive Testing Acceptance Criteria. MIL-STD-2035 contains acceptance criteria for determining the acceptability of nondestructive test discontinuities in materials and components used by the Naval Sea Systems Command (NAVSEA) and tested in accordance with the methods described in MIL-STD-271.

7-2.1.5 DIVING EQUIPMENT AUTHORIZED FOR NAVY USE (ANU). NAVSEAINST 10560.2, ANU, denotes selected commercially available diving equipment, tools, accessories and hyperbaric system components which have undergone design safety reviews, test and evaluation or both, to ensure diver safety.

7-2.2 PLANNING

Chapter 2 of this manual, General Information and Safety Precautions, contains general planning guidelines. This chapter discusses general planning requirements that include personnel, equipment, procedures and quality assurance (QA) for developing an operational plan to conduct underwater NDT. This chapter also contains planning requirements specific to underwater visual testing (UWVT), underwater magnetic particle testing (UWMT) and underwater ultrasonic thickness gauging (UWUTG).

7-2.2.1 OPERATIONAL PLAN. Before undertaking any NDT operation, the NDT inspector, diving supervisor and repair officer should develop a comprehensive, written operational plan that includes detailed procedures for the NDT tasks involved. The plan should include:

a. Documents pertinent to planning the operation, including identification of the area(s) to be inspected and, for UWUTG, the size of the inspection grid.

b. Personnel training and certification requirements

c. Responsibility assignments for all involved activities

d. Required tools, equipment and expendable materials

e. Detailed step-by-step procedures for performing NDT underwater

f. QA package with specific inspection and verification (I&V) points

g. Post-operational procedures

h. Safety precautions.

7-2.2.2 REFERENCE DOCUMENTS. For information on identifying NDT reference documents needed for planning, see paragraph 7-2.1.4. See Chapter 2 of this manual for information on obtaining and using reference documents.

7-2.2.3 EQUIPMENT, TOOLS and MATERIALS. The equipment, tools and materials needed to accomplish NDT can be determined from the information provided in this chapter. When special equipment, tools and materials are needed, procurement or fabrication arrangements should be developed and the sources and lead times should be incorporated into the operational plan. NDT equipment and materials must meet the requirements set forth in MIL-STD-271 and this document.

7-2.2.4 DETAILED PROCEDURES. A NAVSEA approved procedure is required before performing UWVT, UWMT or UWUTG. In the case of UWVT and UWMT, sample procedures are provided as Appendix C and D of this document. These samples have NAVSEA approval. If desired, the activity performing UWVT or UWMT may elect to utilize either (or both) of these procedures (unaltered) by including it with the appropriate signed cover sheet. Otherwise, the activity must establish its own procedure and submit it for NAVSEA approval.

7-2.2.5 QUALITY ASSURANCE PACKAGE. QA requirements for NDT must be determined before beginning the task. Local regulations should specify a format for preparing a QA package or one may be developed for the particular underwater NDT operation. The QA package developed for each NDT operation will be specific to that operation and can range from a separate QA plan to a QA checklist or worksheet incorporated into the operational plan. The package should include a set of designated inspection and verification (I&V) points and provide space for personnel to document that QA standards have been met before proceeding from one step to the next in the NDT procedures. Appendixes A and B provide the minimum information requirements for QA forms with designated I&V points for UWVT/UWMT and UWUTG. I&V points ensure that all work is properly performed, that measurements and dimensions are accurately taken and recorded and that all specifications set forth in the drawings and manuals are met.

7-2.2.6 POST-OPERATIONAL PROCEDURES. The operational plan must include post-operational procedures for removing and re-storing equipment, returning personnel to their duty stations and submitting all necessary reports. The NDT inspector assigned to the particular task is responsible for timely submission of all NDT inspection reports.

7-2.2.7 SAFETY PRECAUTIONS. Every NDT task performed underwater will present unique circumstances that can be potentially hazardous to personnel. Each procedural section of this chapter provides specific safety precautions applicable to the task addressed. For direction on general safety precautions refer to Chapter 2 of this manual.

7-2.2.8 CERTIFICATION REQUIREMENTS FOR UWVT. Personnel performing UWVT require certification in UWVT. Certification can only be obtained by training and examination.

7-2.2.8.1 Fleet Examiners. Fleet Examiners certified in conventional VT in accordance with NAVSEA S9086-CH-STM-020 Chapter 074 Volume 2 do not require special certification in underwater visual testing (UWVT) since topside inspection tools, methods and criteria are applied directly to underwater visual inspections. The Fleet Examiner must become familiar with limitations associated with UWVT and conduct training and testing of Fleet Inspectors that addresses these limitations.

7-2.2.8.2 Fleet Inspectors (Divers). Divers will be trained for UWVT by a conventionally certified VT Examiner or Inspector. Training will include all aspects of visual inspection normally required for weld inspection and VT performed in conjunction with MT and UT. This training will include underwater inspections on well characterized test pieces, using VT tools as appropriate. Divers will be certified as Level II Limited Visual Inspectors by the cognizant VT Examiner, based on successful completion of training and both written and practical examinations. Certification will be limited to UWVT performed in accordance with a procedure approved by the cognizant Examiner. Certification will be valid for three years. However, if the technique is not used for a period of six months, proficiency must be demonstrated to the Examiner by successfully inspecting a test piece prior to performing any inspections for acceptance or rejection.

7-2.2.8.3 Non-Fleet Personnel. Employees of the Department of Defense (DoD) seeking certification in UWVT shall adhere to the same requirements as outlined for Fleet personnel, above. Non-DoD activities desiring to utilize UWVT must establish a program similar to that described above, which meets the requirements of MIL-STD-271 for training and certification of inspection personnel.

7-2.2.9 CERTIFICATION REQUIREMENTS FOR UWMT. Personnel performing UWMT require certification in UWMT. Certification can only be obtained by training and examination.

7-2.2.9.1 Fleet Examiners. Examiner candidates for UWMT must hold prior certification as Examiners in conventional MT in accordance with NAVSEA S9086-CH-STM-020 Chapter 074 Volume 2. Training will be provided either at a facility designated by NAVSEA's agent or at the candidate's activity, utilizing divers as part of the training program and including hands-on training with topside tanks. Certification of Examiners in UWMT will be confirmed by notifying the NAVSEA Certification Agency (NDT programcoordinator) upon satisfactory completion of an examination administered by NAVSEA's agent. Certification shall be valid for a period of five years, provided that the individual maintains Examiner certification in conventional MT. Recertification shall be accomplished by repeating the requirements for original certification.

7-2.2.9.2 Fleet Inspectors (Divers). Divers may be trained either by a certified UWMT Examiner or by NAVSEA's agent. Training may be accomplished at either the diver's activity or at the agent's facility, as determined by NAVSEA. Regardless of where training was administered and by whom, certification will be by the cognizant UWMT Examiner based on satisfactory completion of both practical and written examinations. Certification will be limited to UWMT using equipment provided by NAVSEA and a procedure approved by NAVSEA. Certification will be valid for three years. However, if the individual does not perform UWMT for a period of six months or more, proficiency must be demonstrated to the cognizant UWMT Examiner by successfully inspecting a test plate prior to performing any inspections for acceptance or rejection.

7-2.2.9.3 Non-fleet Personnel. Employees of the Department of Defense (DoD) seeking certification in UWMT shall adhere to the same requirements as outlined for Fleet personnel above. Non-DoD activities desiring to utilize UWMT must establish a program similar to that described above which meets the requirements of MIL-STD-271 for training and certification of inspection personnel. This program requires NAVSEA approval.

7-2.2.10 CERTIFICATION REQUIREMENTS FOR UWUTG. Personnel performing UWUTG require certification in UWUTG. Certification can only be obtained by training and examination.

7-2.2.10.1 Fleet Examiners. Examiners certified in conventional UT in accordance with NAVSEA S9086-CH-STM-020 Chapter 074 Volume 2 will not require a specific certification in UWUTG, but will be trained in the overall capabilities, limitations and operation of the system and in the use of the available instructional materials. Training will be provided at a facility designated by NAVSEA's agent. Training of Examiners in UWUTG shall be confirmed by notifying the NAVSEA Certification Agency (NDT program coordinator) upon satisfactory completion of the training.

7-2.2.10.2 Fleet Inspectors. Inspector candidates for UWUTG must hold prior certification as Inspectors in conventional ultrasonic thickness testing in accordance with NAVSEA S9086-CH-STM-020 Chapter 074 Volume 2. Training may be administered by NAVSEA's authorized agent or by another person or activity approved by NAVSEA. The training shall consist of a minimum of 40 hours of instruction, using the Inspector's Lecture Guide LG-UWSH-UWUT(I)-1, Diver's Lecture Guide LG-UWSH-UWUT(D)-1 and User's Guide UG-UWSH-UWUT-1 supplied with the Navy UWUTG system. Training will be provided either at a facility designated by NAVSEA's agent or at the candidate's activity, utilizing divers as part of the training program and including hands-on training with topside tanks. In all cases, certification will be by examination (written and practical) and will be issued by the activity's ultrasonic test examiner.

7-2.2.10.3 Non-fleet Personnel. Employees of the Department of Defense (DoD) seeking certification in UWUTG shall adhere to the same requirements as outlined for Fleet personnel above. Non-DoD activities desiring to utilize UWUTG must establish a program similar to that described above which meets the requirements of MIL-STD-271 for training and certification of inspection personnel. This program requires NAVSEA approval.

7-2.2.11 SCHEDULING. Whenever possible, underwater NDT should be scheduled to follow hull cleaning operations to eliminate the time needed by the diver to clean the inspection site(s). This particularly applies to UWUTG because of the large number of individual scanning sites involved.

7-2.3 PREPARATION

Chapter 2 of this manual, General Information and Safety Precautions, contains guidelines for preparing for underwater ship husbandry (UWSH) tasks. General preparation requirements for NDT methods are discussed below. Section 3 contains specific requirements for UWVT, UWMT and UWUTG.

7-2.3.1 EQUIPMENT, TOOLS and MATERIALS. The following paragraphs describe the equipment, tools and materials that need to be assembled at the site to perform NDT surface preparation, inspection and recording tasks. While most surface preparation and recording equipment is common to all NDT methods, inspection equipment varies with each method. Inspection equipment specific to each NDT method is discussed under the separate method heads and listed along with general preparation and recording equipment in the tables. Equipment, tools and materials required for specific tasks may vary depending on the area being inspected and its condition.

7-2.3.2 PROTECTIVE EQUIPMENT. During surface preparation where the removal of organotin anti-fouling paints may be necessary, all areas of skin subject to water exposure must be protected. For protection, divers should wear a dry suit with full helmet. If this is not possible, divers should wear a wet suit, full face mask, hood, gloves and bootees. All areas of skin subject to water encroachment must be coated with a water-insoluble cream before donning wet suits, full face masks, hoods, gloves and bootees. Federal Specification PS-411 type III protective cream is recommended. This cream is available under NSN 6850-00-244-4892 in 1-pound jars.

7-2.3.3 DIVER STAGING EQUIPMENT. A staging device, rigged into position directly below the area to be inspected is recommended for use by the diver to remain stable while conducting UWVT and UWMT in specific locations.

7-2.3.4 SURFACE PREPARATION AND RESTORATION EQUIPMENT. NDT operations require inspection surfaces to be prepared by using one or more of the following types of equipment: pneumatic or hydraulic hand-held grinder with abrasive disk or wire brush; high-pressure water jet; or hand-held brushes, pads (greenies) and scrapers. An informative assessment of the material condition of a ship's hull cannot be made if the hull is even moderately fouled. Functional descriptions of surface preparation equipment are provided below:

Hydraulic or Pneumatic Hand-Held Grinder: Divers use the hydraulic or pneumatic hand-held grinder with an abrasive disk or wire brush attachment (figure 7-2-1) to remove marine growth, scale or paint from the surface of the area to be inspected. A small grinder, commonly called a peanut grinder, can be used to remove corrosion prior to inspection or to even the surface area where light surface pitting is found. When removing fouling from painted surfaces, the use of brushes as described in NSTM Chapter 081 is recommended. The grinder requires two-handed operation.

High-Pressure Water Jet: Divers use the water jet (figure 7-2-2) to remove marine growth, scale and paint from the surface of the area to be inspected. It requires two-handed operation. The water jet is best suited for cleaning the rough irregular surfaces of weldments. Divers should not use the jet on painted surfaces that do not require paint removal.

Hand-Held Brushes, Pads (Greenies) and Scrapers: Divers use hand-held cleaning devices during inspection to remove localized marine growth and surface corrosion that can mask surface discontinuities or interfere with UWUTG scanning or UWMT yoke placement. Certain geometric hull configurations, because of restricted access or radical curvature, make proper surface preparation difficult using power tools. When divers cannot use power tools, they must use hand-held cleaning devices.

Anticorrosion Coating: UWMT operations require the diver to apply a suitable underwater coating to the bare metal areas exposed during surface preparation to prevent corrosion. An underwater epoxy approved by NAVSEA 00C5 is required.

7-2.4 SPECIFIC PREPARATION REQUIREMENTS FOR UWVT

Preparation for conducting UWVT entails assembling all necessary material and personnel required to safely satisfy the plan requirements. Divers must determine that the underwater visibility is adequate for the performance of the inspection. The following paragraphs describe inspection equipment required to conduct UWVT by fleet personnel. Table 7-2-1 lists all inspection equipmentspecific to UWVT, along with general surface preparation and recording equipment. Non-fleet users require similar equipment, but need not comply with the NAVSEAINST 10560.2 listing.

7-2.4.1 UWVT EQUIPMENT. Power Cable: A two-conductor power cable with a braided external ground and a protective jacket (figure 7-2-3), listed in NAVSEAINST 10560.2, delivers power to the white light source. Typical cables are 250 feet long to permit operation in the majority of locations accessible by a surface-supported diver. The external ground braid generates a ground fault whenever the cable is cut; the power conductors cannot be reached except by first penetrating the ground braid.

Appropriate Weld Inspection Gages and Measuring Tools: The tools required will vary with the nature of the inspection (i.e. fit-up, final, damage assessment, etc.).

Ground Fault Interrupter (GFI): The diver's primary protection from electric shock is an approved isolation transformer/GFI device (figure 7-2-4), listed in NAVSEAINST 10560.2. The GFI interrupts power when it senses a drop in the resistance between the isolated system power leg and the power supply ground.

White Light Source: The primary illumination source is a Remote Ocean Systems model TUBE-LIGHT, listed in NAVSEAINST 10560.2.

7-2.5 SPECIFIC PREPARATION REQUIREMENTS FOR UWMT

Preparation for conducting UWMT entails assembling all necessary material and personnel required to safely satisfy the plan requirements. Divers must determine that the water current will not affect the application of magnetic particles where UWMT is to be conducted. Water currents greater than one knot make it difficult to perform UWMT. Divers must also determine that the underwater visibility is adequate for the interpretation of the test results. The following paragraphs describe inspection equipment required to conduct UWMT by fleet personnel. Table 7-2-2 lists all inspection equipment specific to UWMT, along with general surface preparation and recording equipment. Non-fleet users require similar equipment, but need not comply with the NAVSEAINST 10560.2 listing.

7-2.5.1 UWMT EQUIPMENT. Electromagnetic Yoke: An electromagnetic yoke (figure 7-2-5), which meets the specifications of MIL-STD-271 and is listed in NAVSEAINST 10560.2, is used to induce a magnetic field in the material. The articulation of the yoke's legs allow any pole spacing between 2 inches and 8 inches and the yoke can accommodate plate offsets of up to 6 inches and joint angles from about 45 degrees to 270 degrees. To minimize the risk of electric shock, there are no controls on the yoke. A topside operator energizes the yoke.

Power Cable: A two-conductor power cable with a braided external ground and a protective jacket (see figure 7-2-3), listed in NAVSEAINST 10560.2, delivers power to the electromagnetic yoke. Typical cables are 250 feet long to permit operation in the majority of locations accessible by a surface-supported diver. The external ground braid generates a ground fault whenever the cable is cut; the power conductors cannot be reached except by first penetrating the ground braid.

Ground Fault Interrupter (GFI): The diver's primary protection from electric shock is an approved isolation transformer/GFI device (see figure 7-2-4), listed in NAVSEAINST 10560.2. The GFI interrupts power when it senses current leakage between the isolated system power leg and the power supply ground.

White Light Source: The primary illumination source is a Remote Ocean Systems model TUBE-LIGHT, listed in NAVSEAINST 10560.2.

Magnetic Particles: Magnetic particles are finely divided ferromagnetic particles having a low magnetic retentivity and a high permeability. The magnetic particles used for UWMT must meet the specifications of MIL-STD-271. They are dyed pink to be visible under normal lighting. The particles are mixed with wetting agents and corrosion inhibitors to enhance their underwater performance.

Magnetic Particle Applicator: The magnetic particle applicator is a reservoir of magnetic particles and water that the diver uses to deliver magnetic particles to the surface of the inspection area. A simple and effective magnetic particle applicator is a plastic squeeze bottle that contains a marble-sized object to aid in mixing.

Magnetic Field Indicator: The magnetic field indicator is a small device with crack-like discontinuities on its face. The indicator is used to determine if the inspection site has adequate magnetic flux. The diver places the indicator at the inspection site, topside energizes the yoke and the diver delivers the particles. A clearly visible accumulation of particles (indications) should then form along the crack-like discontinuities on the pie-shaped magnetic field indicator (figure 7-2-6). In the pie-shaped gauge, the crack-like discontinuities are furnace-brazed joints between adjacent steel wedges. Though a simple test to measure the magnetic field strength inside the material being inspected is unknown, it is assumed that an adequate field just outside the material signifies an adequate field inside as well.

7-2.6 SPECIFIC PREPARATION REQUIREMENTS FOR UWUTG

Preparation for conducting UWUTG entails assembling all necessary materials, equipment and personnel required to safely satisfy the plan requirements, including arranging for any required training for the dive team. The following paragraphs describe the inspection equipment required to conduct UWUTG by fleet personnel. Non-fleet users will require similar equipment, but specific item descriptions may be different and computer-related data acquisition equipment may not be required. Table 7-2-3 lists the inspection equipment specific to UWUTG, along with general surface preparation materials and equipment for recording inspection results.

7-2.6.1 UWUTG EQUIPMENT. Ultrasonic Transducer: The transducer used in UWUTG is a commercially available immersion transducer with a frequency of 1 to 10 megahertz, that is highly damped and designed for high resolution. It has a diameter of approximately 1/2 inch and is about 2 inches long.

Underwater Transducer Housing: The housing for the transducer consists of a machined plastic body with a stainless steel base plate and a stainless steel acoustic mirror. The housing unit protects the transducer from abuse and provides a constant standoff distance between the transducer and the surface of the material being inspected. The housing is about 8 inches by 2 inches.

Calibration Block: The system calibration block is a five-stepped block of material that is acoustically similar to the material of the hulls being tested. The minimum step is approximately 0.15 inches thick and the maximum step is approximately 1 inch thick.

Transducer Cable: The transducer cable is a C-N-4 coax cable, usually 250 feet long. One end has a BNC connector and the other has a waterproof UHF connector that mates with the transducer.

Desktop Computer: The desktop computer is an IBM PC-compatible microcomputer with an analog-to-digital converter installed. The computer collects data, correlates data points, stores pertinent information and provides a printed record of all data.

Ground Fault Interrupter (GFI): The diver's primary protection from electric shock is an approved isolation transformer/GFI device (see figure 7-2-4), listed in NAVSEAINST 10560.2. The GFI interrupts power when it senses current leakage between the isolated system power leg and the power supply ground.

Ultrasonic Instrument: The ultrasonic instrument is a pulse echo device capable of detecting flaws and measuring wall thickness in a variety of materials. The instrument has a CRT and digital readout. The instrument meets the specifications of MIL-STD-271. It is also specially modified by the manufacturer to facilitate communication with the computer.

Premarked Hogging Lines: The hogging lines are marked at regular intervals to provide a location reference. The hogging lines can be two equal lengths that can be connected at the keel or a single length that spans the hull from port to starboard.

7-2.7 RECORDING EQUIPMENT

The following paragraphs describe equipment useful for recording NDT results. The determination as to whether or not any of this equipment is required for a particular operation is left to the on-site NDT inspector.

Stereo Camera: Stereophotography produces three-dimensional images by using two photographs of the same object taken from two distinct camera positions while lighting and object distance are held constant. Stereo photographs can be used to estimate the depth of corrosion pits, the depth and type of marine growth and depth and width of some surface cracks. Some stereophotographic systems include video cameras operated by topside personnel who view the inspection area through a video monitor and select stereophotos to be taken.

Still Camera: Still photography produces photographs or slides of specific areas, openings and appendages on ships' hulls. The still camera is an individually controlled instrument and requires an experienced photographer to produce quality photographs. Close-up photography is mandatory for documentation and interpretation of indications and damage. Photo documentation is an excellent method of presenting inspection results to a topside NDT inspector for review. Photographs can document work performed during UWMT.

Video System: Video systems include a video camera with enough cable to reach the area to be inspected, a monitor for topside viewing and a recording device. Because a topside NDT inspector can monitor a task in progress on a video system, it is an excellent quality assurance tool. When used in conjunction with a video recorder, it can often serve as a documentation tool.Verbal communications between topside and divers can be recorded with many underwater video systems (i.e., DUCTS) and provide an excellent source of inspection documentation.

Grease Pencil: Standard, highly visible, grease pencils can be used to mark areas with abnormal conditions that may require more detailed inspection.

Measuring Tape: Measuring tapes, preferably cloth with a magnet attached to one end, can be used to record the size and location of abnormalities found during an inspection.

Writing Slate: Tablet-sized plexiglas sheets can be used to record locations and measurements of specific areas. Verbal communications with topside are frequently used instead of writing on an underwater slate.

SECTION 3 - NONDESTRUCTIVE TESTING PROCEDURES

7-3.1 INTRODUCTION

This section contains general procedures and techniques for three underwater NDT methods: underwater visual testing (UWVT), underwater magnetic particle testing (UWMT) and underwater ultrasonic thickness gauging (UWUTG). The general procedures and techniques apply to these NDT methods and equipment and may be adapted for a specific hull area or appendage. In most cases, underwater NDT requires that locations be determined fairly accurately. Hogging lines are often used to provide the diver with a reference location. In many cases, hogging lines or other reference markers may already be in place in association with some other underwater activity. Since each siutation is different, it will be necessary to determine if location acceptance is required for a specific NDT operation. This section also includes surface preparation requirements that are unique to each method.

WARNINGRotation of propellers or operation of underwater electrical equipment while divers are in the vicinity can cause serious injury or death. Ensure that ship's equipment is de-energized and tagged out as required by the U.S. Navy Diving Manual

before beginning underwater operations.

When divers are performing underwater NDT, they should also be observing the general condition of the hull and other components for signs of damage or deterioration. Any such observations should be reported to topside personnel.

WARNINGWhen performing underwater diving operations on surfaces coated with organotin paints or rubber NO-FOUL, use a dry suit with full helmet, for example, USN MK 21. If this is not

possible, use a wet suit, full face mask, hood, gloves and bootees. However, coat all areas of skin subject to water

encroachment with a water-insoluble cream before donning wet suits, full face masks, hoods, gloves and bootees. PS-411 type III protective cream is recommended. This cream is available

under NSN 6850-00-244-4892 in one-pound jars.

7-3.2 UNDERWATER VISUAL TESTING (UWVT)

This section provides general recommendations for performing UWVT. It can be used as a guide for the preparation of the written procedure required by MIL-STD-271 (see 7-2.2.4). A check-list of inspection and verification (I&V) points should be developed from the procedure for each job.

7-3.2.1 HULL SURFACE PREPARATION. Hull surface preparation for UWVT will generally be controlled by the associated welding or inspection procedure. For example, when UWVT is used to determine the suitability of a surface for UWMT, the surface must be bare metal in an area which includes the suspect region or weld and an area 1/2" on all sides around this region. When UWVT is used to determine the suitability of a surface for UWUTG, it is only necessary to remove marine growth; paint may be left intact. For close visual inspection to discover such discontinuities as cracking or undercut, all marine growth, paint and oxidation products must be removed. It is the inspector's responsibility to ensure that relevant indications will not be masked by inadequate surface preparation.

7-3.2.2 UWVT PROCESS.

7-3.2.2.1 Before starting the underwater visual inspection, the diver must be briefed on specific inspection tasks to be accomplished, the frequency of measurements to be taken, recording and reporting requirements, etc. All tools should be checked for the visibility of markings, the diver's faceplate checked for clarity and cleanliness and the proper functioning of communications verified.

7-3.2.2.2 Upon arrival at the inspection site, the diver should check lighting and other environmental conditions to ensure that reliable results can be achieved.

7-3.2.2.3 Visual inspection should proceed according to a written plan, with inspection and verification (I&V) points noted topside. Communications between the diver and topside should be used freely to step the diver through required observations and measurements. Where video documentation is used, a running commentary should be logged describing the area being inspection and its condition.

7-3.2.2.4 Upon completion of each UWVT dive, all measurement tools should be cleaned and protected against corrosion.

7-3.2.2.5 If bare metal was exposed as part of the inspection procedure, it must be recoated. Prepare the epoxy anticorrosion coating topside for application to the bare metal area. Use a hand-held wire brush to roughen the painted area surrounding the bare metal area for a distance of three to five inches. Apply the epoxy coating to cover the bare metal and the roughened paint edges, tapering the edges to blend smoothly into the paint (I&V).

NOTEEpoxy anticorrosion coating must be applied within ten minutes of surface preparation or biological fouling will prevent proper

adhesion of the epoxy.

7-3.2.2.6 Inspection reports should contain, as a minimum, the entire QA package, as well as the sizes and locations of all indications detected, including any sketches, photographs or video-tapes produced during the inspection. If repairs to discontinuities were performed, the reinspection data associated with the repairs should also be included.

7-3.3 UNDERWATER MAGNETIC PARTICLE TESTING (UWMT)

This section provides general recommendations for performing UWMT. The section can be used as a guide for the preparation of the written procedure required by MIL-STD-271 (see 7-2.2.4). Some of the steps in the following paragraphs are designated as I&V points that should appear in the UWMT QA Package developed for each UWMT operation (appendix A). The equipment described in Table 7-2-2 should be assembled at the UWMT site.

7-3.3.1 HULL SURFACE PREPARATION

7-3.3.1.1 Position a diving stage immediately below the area to be inspected. Secure the diving stage allowing enough distance from the surface of the area to be inspected for the diver to work comfortably. Because of the amount of equipment the diver must handle simultaneously (i.e., yoke, particle bottle, pie gauge, light) a stage is strongly recommended. This allows the diver to concentrate on the inspection details.

7-3.3.1.2 Remove all marine growth, corrosion and paint from the surface of the area to be inspected (figure 7-3-1) (I&V).

NOTEMarine growth and corrosion must be removed from an area

approximately 5 to 6 inches around the inspection area to provide an adequate surface for yoke placement. Paint must be

removed only from an area of 1/2 inch on all sides of the suspected damage.

NOTEIf using a pneumatic or hydraulic grinder with an abrasive disk

or wire brush, the bare metal area should appear bright and shiny. If a water jet is used, the bare metal area should appear

dull gray.

7-3.3.1.3 Visually inspect the bare metal area for any residual marine growth, corrosion or paint which, if not removed, can result in false indications of discontinuities (I&V).

7-3.3.2 UWMT PROCESS

7-3.3.2.1 Transfer the electromagnetic yoke, the particle applicator containing the particle slurry and the magnetic field indicator to the diver.

WARNINGUngrounded equipment can cause electric shock. To avoid

shock hazard do not use the electromagnetic yoke without the GFI and do not attempt to set up or operate electrical systems in

adverse environmental conditions.

7-3.3.2.2 Position the electromagnetic yoke against the surface of the area to be inspected. Ensure that the legs of the yoke straddle the area to be inspected and that the base of the legs have full contact with the cleaned area of the hull surface (figure 7-3-2) (I&V). Also ensure that the legs spacing does not exceed eight inches. Energize the yoke.

NOTEA topside operator energizes the yoke. There is no power

control on the yoke itself.

7-3.3.2.3 Place a magnetic field indicator against the inspection surface between the legs of the yoke (figure 7-3-3). Squeeze a slurry of magnetic particles into the area between the legs of the magnetic yoke (figure 7-3-4).

NOTEThe applicator should be shaken prior to each application to

ensure proper agitation.

7-3.3.2.4 Observe the field indicator's response. A positive indication (accumulation of particles) should be seen along the crack-like discontinuities (figure 7-3-5) (I&V). This indicates that the UWMT system is operating properly.

NOTEThe lack of an indication signifies that either the magnetic field is too weak or that an insufficient amount of particles is being applied-possibly due to insufficient particle concentration. The

NDT Inspector is responsible for testing the equipment to determine the cause of the problem and for taking corrective

action.

7-3.3.2.5 Remove the field indicator from the inspection surface.

7-3.3.2.6 Brush gently by hand to remove any residual particles from the inspection area. Apply a fresh slurry of particles into the area between the legs of the yoke. Without rubbing the surface, gently fan away, by hand, any residual particles from the surface area between the yoke legs and visually inspect the area for particle accumulations (indications).

7-3.3.2.7 If no indications are found, brush gently by hand to remove any residual particles from the inspection area, move the yoke to the next inspection position (figure 7-3-6) and reapply fresh slurry.

NOTEComplete UWMT inspection requires that each area be inspected with the yoke at two perpendicular directions.

7-3.3.2.8 If an indication is detected, keep the yoke positioned at 90 degrees (perpendicular) to the indication and continue moving the yoke and retesting until the ends of the suspected discontinuity are located.

NOTEMagnetic particles tend to follow the magnetic field created by the yoke. Movement of the yoke while energized may result in

the loss of particles that form the indication.

Record the position and length of the indication by any suitable means (sketch, video camera, still camera, etc.) (I&V). Permanently mark the ends of the indication using an arrow punch or similar device (figure 7-3-7).

NOTEBased upon the diver's records and observations, the topside NDT Inspector and maintenance personnel will determine if

remedial action should be taken, such as drilling arresting holes or repair welding. If repairs are determined to be necessary, the

repairs must be reinspected.

7-3.3.2.9 Validate the UWMT inspections by using the magnetic field indicator to confirm the system operation as described in 7-3.3.2.3 and 7-3.3.2.4.

7-3.3.2.10 Prepare the epoxy anticorrosion coating topside for application to the bare metal area. Use a hand-held wire brush to remove all residual magnetic particles from the bare metal surface and to roughen the painted area surrounding the bare metal area for a distance of three to five inches. Apply the epoxy coating to cover the bare metal and the roughened paint edges, tapering the edges to blend smoothly into the paint (I&V).

NOTEEpoxy anticorrosion coating must be applied within ten minutes of surface preparation or biological fouling will prevent proper

adhesion of the epoxy.

7-3.3.2.11 Inspection reports should contain, as a minimum, the entire QA package, as well as the sizes and locations of all indications detected, including any sketches, photographs or videotapes produced during the inspection. If repairs to discontinuities were performed, the reinspection data associated with the repairs should also be included.

7-3.4 UNDERWATER ULTRASONIC THICKNESS GAUGING (UWUTG)

This section provides general recommendations for performing UWUTG. The section can be used as a guide for the preparation of the written procedure required by MIL-STD-271 (see 7-2.2.4). Some of the steps in the following paragraphs are designated as I&V points that should appear in the UWUTG QA package developed for each UWUTG operation (appendix B). The equipment described in Table 7-2-3 should be assembled at the UWUTG site.

7-3.4.1 HULL SURFACE PREPARATION Since UWUTG is conducted over such a large expanse of the hull, the surface preparation steps have been incorporated into the actual UWUTG operation, as described in the following paragraphs.

7-3.4.2 UWUTG PROCESS

7-3.4.2.1 The topside NDT Inspector and the diver who will be manipulating the underwater transducer ensure that the UWUTG system is properly calibrated.

7-3.4.2.2 Topside personnel and diver determine need for positioning equipment (such as hogging lines) and install if necessary.

NOTETopside personnel must ensure that the port and starboard frame numbers or location reference points designated for

hogging line placement are identical.

7-3.4.2.3 Diver locates the predetermined inspection starting point and visually inspects the surface area for marine growth. If necessary, diver removes marine growth with hand-held scraper to expose an area large enough to perform the required inspection scan.

NOTEThroughout the inspection, the diver(s) involved in the

UWUTG shall note and report to the topside NDT Inspector any observed adverse hull conditions such as pitting, coating

damage, scaling, corrosion, etc.

7-3.4.2.4 Diver places the ultrasonic transducer against the surface of the area to be inspected and scans the area as directed by the topside NDT Inspector.

NOTEDuring the scanning process, the diver must position himself in such a manner that the exhaust air from the diving helmet flows away from the work area. This precaution is necessary because

an air pocket between the ultrasonic transducer and the inspection surface can produce false measurements.

NOTEBecause the topside NDT Inspector interprets inspection results during the operation, the diver and the inspector must maintain

constant communication during UWUTG.

7-3.4.2.5 Diver continues to move hogging lines (if required) and perform UWUTG to cover all areas specified in the operational plan.

7-3.4.2.6 The topside NDT Inspector and the diver ensure that the UWUTG system is still properly calibrated.

7-3.4.2.7 Inspection reports should contain, as a minimum, the entire QA package; a summary report listing any thin areas detected, including their location and surrounding hull condition; and the computer generated raw data.

APPENDIX A

SAMPLE QUALITY ASSURANCE PACKAGE FOR UNDERWATER MAGNETIC PARTICLE TESTING AND UNDERWATER VISUAL TESTING

L

APPENDIX B

SAMPLE QUALITY ASSURANCE PACKAGE FOR UNDERWATER ULTRASONIC THICKNESS GAUGING

APPENDIX C

SAMPLE PROCEDURE INSPECTION AND EVALUATION OF MATERIALS AND WELDS USING UNDERWATER VISUAL TESTING (UWVT)

1.0 SCOPE

1.1 This procedure provides instructions for locating and documenting surface discontinuities in materials and welds using the underwater visual testing (UWVT) technique.

1.2 This procedure meets the requirements of S0600-AA-PRO-070 for underwater visual testing.

2.0 PERSONNEL

2.1 Personnel performing inspections to this procedure must hold a certification specific to underwater visual testing (limited certification is acceptable) as specified in S0600-AA-PRO-070.

3.0 DEFINITIONS

3.1 For the purpose of this procedure, the following definitions (extracted from ASTM E1316) shall apply:

3.1.1 Discontinuity - An interruption, which may be either intentional or unintentional, in the physical structure or configuration of a part.

3.1.2 Evaluation - A review, following interpretation of the indications noted, to determine whether they meet specified acceptance criteria.

3.1.3 Indication - Evidence of a discontinuity that requires interpretation to determine its significance.

3.1.4 Nonrelevant Indication - An indication that is caused by a condition or type of discontinuity that is not rejectable. False indications are nonrelevant.

3.1.5 Relevant Indication - An NDT indication that is caused by a condition or type of discontinuity that requires evaluation.

4.0 EQUIPMENT

4.1 Only the relevant equipment itemized on NAVSEA Drawing Number 6653063 shall be used to carry out this procedure. The equipment components are summarized as follows:

4.1.1 White light source, Remote Ocean Systems model TUBELIGHT.

4.1.2 Ground fault interrupter. Western Instruments model 1.0KVA-D (as listed in NAVSEAINST 10560.2, Diving Equipment Authorized for Navy Use).

4.2 Measure Equipment. Dimensional equipment as required for the particular inspection shall be acquired. Examples include thickness gauges, weld contour gauges, undercut gauges, fillet weld gauges, 6-inch machinists rule, bevel protractor, dial vernier calipers, and surface roughness scales.

5.0 APPLICABILITY

5.1 General. Underwater components (plates, shafts, and other structural shapes) may be tested by this procedure. Welds joining such components may also be tested by this procedure. Surfaces to be tested must be free of irregularities which would interfere with the interpretation of test results.

6.0 TECHNIQUE

6.1 Equipment Set-up

CAUTIONElectrical shock hazard potential exists with equipment used to perform magnetic particle inspections underwater. All electrical

circuits associated with underwater magnetic particle inspection, either topside or circuits leading directly

underwater, SHALL be protected with ground fault interrupter (GFI) circuits.

CAUTIONPrior to performing any interface connections of electrical

components, ensure that their power function switches are in the OFF position.

6.1.1 Physical set-up

6.1.1.1 Plug the light into one of the 250’ water proof cable assemblies and secure the connection with the threaded lock.

6.1.2 GFI Electrical Safety Check

6.1.2.1 Plug the GFI unit into the 120 VAC electrical outlet which is to be used during underwater operations, and turn it on by first turning the ON-OFF switch fully counter-clockwise to RESET, then fully clockwise to ON. The green indicator lamp should light.

6.1.2.2 Test actuate the GFI by pressing the red test button located on the front face of the unit; the green indicator lamp should go out.

6.1.2.3 If the GFI shuts off, the unit is acceptable for use; turn the ON-OFF switch fully counterclockwise to reset the unit.

6.1.2.4 In the event the GFI does not interrupt power when test actuated, the unit SHALL NOT be used.

6.1.3 Electrical Connections

6.1.3.1 The light should be plugged in on the right side of the GFI (when facing the unit), since the voltage output from these outlets is variable.

CAUTIONLight may be illuminated topside (i.e., out of the water) for

brief periods of time (1 minute maximum). Additionally, the light may be passed through the air/water interface without

damage to the equipment, keeping in mind the 1 minute maximum top-side illumination limit.

6.2 Underwater Site Preparation

6.2.1 Ensure that the inspection area is suitable for inspection. As welded surfaces, following removal of slag, scale, arc strikes, etc., are suitable for visual inspection without grinding if this condition does not interfere with interpretation of test results.

6.2.2 Ensure that the light source is functional such that the test surface is clearly observable.

6.3 Inspection

6.3.1 Areas of coverage shall be as specified in the document which requires this inspection.

6.3.2 Reporting requirements shall be as specified in the document which requires this inspection.

7.0 ACCEPTANCE CRITERIA

7.1 Acceptance criteria shall be as specified in the document which requires this inspection.

APPENDIX D

SAMPLE PROCEDURE INSPECTION AND EVALUATION OF MATERIALS AND WELDS USING UNDERWATER MAGNETIC PARTICLE TESTING (UWMT)

1.0 SCOPE

1.1 This procedure provides instructions for locating and documenting surface discontinuities in ferromagnetic materials using the underwater magnetic particle testing (UWMT) technique. This procedure is specific to the UWMT technique and shall not be usedfor any other type of testing.

1.2 This procedure meets the requirements of S0600-AA-PRO-070 for magnetic particle testing.

2.0 PERSONNEL

2.1 Personnel performing inspections to this procedure must hold a certification specific to underwater magnetic particle testing (limited certification is acceptable) as specified in S0600-AA-PRO-070.

3.0 DEFINITIONS

3.1 For the purpose of this procedure, the following definitions (extracted from ASTM E1316) shall apply:

3.1.1 Discontinuity - An interruption, which may be either intentional or unintentional, in the physical structure or configuration of a part.

3.1.2 Evaluation - A review, following interpretation of the indications noted, to determine whether they meet specified acceptance criteria.

3.1.3 Field magnetic - The space, within and surrounding a magnetized part or a conductor carrying current, in which the magnetic force is exerted.

3.1.4 Indication - Evidence of a discontinuity that requires interpretation to determine its significance.

3.1.5 Magnetic Particle Examination (MT) - A nondestructive test method utilizing magnetic leakage fields and suitable indicating materials to disclose surface and near-surface discontinuity indications.

3.1.6 Magnetic Particle Field Indicator - An instrument, typically a bi-metal (for example, carbon steel and copper) octagonal disk, containing artificial flaws used to verify the adequacy or direction, or both, of the magnetizing field.

3.1.7 Magnetic Particles - Finely divided ferromagnetic material capable of type of individually magnetized and attracted to distortion in a magnetic field.

3.1.8 Nonrelevant Indication - An indication that is caused by a condition or type of discontinuity that is not rejectable. False indications are nonrelevant.

3.1.9 Relevant Indication - An NDT indication that is caused by a condition or type of discontinuity that requires evaluation.

4.0 EQUIPMENT

4.1 Only the relevant equipment itemized on NAVSEA Drawing Number 6653063 shall be used to carry out this procedure. The equipment components are summarized as follows:

4.1.1 Underwater magnetic yoke with articulated legs (115 VAC, AC field), Parker Research Corp., Model No. UW-15 Contour Probe altered as reflected in NAVSEA Drawing 6653063.

4.1.2 White light source, Remote Ocean Systems model TUBELIGHT.

4.1.3 Underwater magnetic particles, Circle Chemical Co., MI-GLOW UW#1.

4.1.4 Magnetic powder applicator, plastic squeeze bottle with snap open/shut cover. Bottle will be transparent or semi-transparent and will contain a stainless steel nut or marble to serve as an agitator within the bottle. (Any bottle meeting the description above and shown to be effective for the intended use is acceptable.)

4.1.5 Ground fault interrupter. Western Instruments model 1.0 KVA-D (as listed in NAVSEAINST 10560.2, Diving Equipment Authorized for Navy Use).

4.1.6 Magnetic field indicator segmented type. (Any magnetic field indicator meeting the requirements of MIL-STD-271 is acceptable.)

4.1.7 Sensitivity plate as specified in MIL-STD-271.

5.0 APPLICABILITY

5.1 General. Underwater components (plates, shafts, and other structural shapes) made of ferromagnetic materials may be tested by this procedure. Welds joining such components, and using ferromagnetic filler metal, may also be tested by this procedure.Surfaces to be tested must be free of irregularities which would interfere with the interpretation of test results.

5.2 Welments. For new and repair weldments, prior to UWMT inspection, the weldments must be visually inspected and accepted in accordance with requirements of MIL-STD-271 and MIL-STD-2035.

6.0 TECHNIQUE

6.1 Equipment Set-up

CAUTIONElectrical shock hazard potential exists with equipment used to perform magnetic particle inspections underwater. All electrical

circuits associated with underwater magnetic particle inspection, either topside or circuits leading directly

underwater, SHALL be protected with ground fault interrupter (GFI) circuits.

CAUTIONPrior to performing any interface connections of electrical

components, ensure that their power function switches are in the OFF position.

6.1.1 Physical set-up

6.1.1.1 Plug the light into one of the 250’ water proof cable assemblies and secure the connection with the threaded lock.

6.1.1.2 Plug the electromagnetic yoke into another of the cable assemblies and secure that connection.

6.1.1.3 Attach the Light/Camera Mount Assembly to the body of the electromagnetic yoke. Insert the light and position it to illuminate the area between the yoke’s legs. Tighten all adjustments.

6.1.1.4 Loosely place the strain relief block around the cable, above the connector between the 250’ cable and the yoke’s whip. Snap the strain relief assembly hook into the ring on the yoke leg. Adjust the position of the strain relief assembly so that when the strain relief cable is taut, the electrical cable is still slack. Tighten the bolts on the strain relief block to fix its position on the electrical cable.

6.1.1.5 Prepare the magnetic particle suspension by first filling the applicator bottle 1/2 to 2/3 full of magnetic particles then filling the remainder of it with water (fresh or sea water). Agitate the bottle vigorously to suspend the particles.

6.1.2 GFI Electrical Safety Check

6.1.2.1 Plug the GFI unit into the 120 VAC electrical outlet which is to be used during underwater operations, and turn it on by first turning the ON-OFF switch fully counterclockwise to RESET, then fully clockwise to ON. The green indicator lamp should light.

6.1.2.2 Test actuate the GFI by pressing the red test button located on the front face of the unit; the green indicator lamp should go out.

6.1.2.3 If the GFI shuts off, the unit is acceptable for use; turn the ON-OFF switch fully counterclockwise to reset the unit.

6.1.2.4 In the event the GFI does not interrupt power when test actuated, the unit SHALL NOT be used.

6.1.3 Electrical Connections

6.1.3.1 The electromagnet MUST be plugged into the left side of the GFI (when facing the unit) to ensure that the full AC line voltage is delivered to the electromagnet.

6.1.3.2 The light should be plugged in on the right side of the GFI (when facing the unit), since the voltage output from these outlets is variable.

CAUTIONLight may be illuminated topside (i.e., out of the water) for

brief periods of time (1 minute maximum). Additionally, the light may be passed through the air/water interface without

damage to the equipment, keeping in mind the 1 minute maximum top-side illumination limit.

6.1.4 Performance Check

6.1.4.1 Performance of the UWMT system shall be checked both before and after every set of inspections. Performance checks may be performed in a convenient underwater location, where visibility, lighting, currents, etc. are reasonably similar to the inspection site. Inspection results may be accepted as valid only if the system performs properly at the beginning and end of the inspections. If the system fails to perform properly BEFORE inspecting, corrective action must be taken before proceeding. If the system fails to perform properly AFTER inspecting, none of the data collected since the last performance check can be accepted as valid.

6.1.4.2 Field strength check. This check is intended to verify that the yoke is producing adequate magnetic field strength. With the yoke leg spacing set to the maximum that will be used during the test (8 inches maximum, 2 inches minimum) check the intensity of the magnetic field by placing a “pie gauge” field indicator on the work piece, copper side up, in the area of interest.

6.1.4.3 Sensitivity check. This check is intended to verify that the entire system is performing adequately in the local environment. With the yoke leg spacing set to the maximum that will be used during the test (8 inches maximum, 2 inches minimum), check the sensitivity of the test by testing the sensitivity plate in the local underwater environment. Apply the magnetic particles to the test surface and remove the excess particles. The test sensitivity is adequate if the notch is visible.

Apply the magnetic particles to the test surface and remove the excess particles. The magnetic field is adequate if the lines at 45 and 90 degrees to the applied field are clearly visible.

6.2 Underwater Site Preparation

6.2.1 Ensure that the inspection area is suitable for inspection (i.e. the inspection area and and an adjacent 1/2” wide border must be cleaned to bare metal, and sufficiently smooth to permit evaluation of indications).

6.2.2 With electrical circuit de-energized and at the direction of the diving supervisor, the magnetic yoke may now be lowered to the inspection site. DO NOT ENERGIZE the yoke until the diver indicates ready to begin inspecting.

6.2.3 Lower the magnetic particle suspension and ruler to the diver.

6.2.4 Ensure that the light source is functional such that the test surface is clearly observable.

6.3 Inspection

6.3.1 Beginning at one end of the inspection area or weld, place the yoke across the inspection area or weld (e.g. perpendicular to the weld axis), with the yoke legs set so as to obtain good contact between the magnetic yoke and the test surface. Spacing between the legs of the yoke shall be no greater than 8 inches, no less than 2 inches. Energize the yoke.

6.3.2 Prior to each application of the magnetic particles, shake the applicator bottle vigorously to assure that the particles are adequately suspended. Check the suspension occasionally by spraying solution onto the yoke legs to see if magnetic particles are present and flowing correctly.

6.3.3 Apply particles to the area between the yoke legs. After the particles have settled completely, remove the excess particles, being careful not to disturb any relevant indications by excessive removal of particles.

6.3.4 Inspect the weld and approximately 1/2 inch of base metal on either side of the weld for indications of discontinuities. If necessary, instruct topside personnel to vary the intensity of the light source to obtain maximum contrast and indication definition.

6.3.5 Measure and record (to the nearest 1/16 inch) the position and length of any relevant indications detected. Position should be measured relative to an easily distinguishable feature of the hull. Indications may be recorded by means of an underwater writing slate and grease pencil, by reporting measurements verbally to a designated recorder topside, or by any other method suitable for the conditions at hand (e.g., video, still photographs, or sketches). If required, ends of indications shall be marked with arrow punch.

6.3.6 When all relevant indications have been recorded, remove the yoke from the test surface and remove any magnetic particles remaining on the surface. Move the yoke approximately two inches down the length of the inspection area or weld to begin the next inspection. Ensure that the yoke is properly magnetized.

6.3.7 When the entire length of the weld has been inspected for longitudinal discontinuities, reinspect the inspection area for transverse discontinuities. Each successive yoke placement shall overlap the prior placement by at least 1 inch.

6.3.8 De-energize the yoke as needed to remove excessive particle buildup from the legs or to relocate it.

6.3.9 Continue inspecting until the entire length of the inspection area has been inspected two perpendicular directions and all relevant indications have been recorded.

6.4 Tear-down. When all inspections have been completed, check the particle concentration, and the magnetic field strength (pie gauge) and perform the sensitivity test. De-energize the yoke and remove all equipment from the water.

7.0 ACCEPTANCE CRITERIA

7.1 Acceptance criteria shall be as specified in MIL-STD-1689 and MIL-STD-2035.

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