Lesson 1Welding processes for ship repairs: SMAW, GMAW/MIG, FCAW, and submerged arc—process selectionReviews main welding processes used in ship repair, comparing SMAW, GMAW, FCAW, and SAW for productivity, access, position capability, and quality, and guiding process selection for typical structural repairs.
SMAW setup and shipyard applicationsGMAW and MIG variants in repairsFCAW self-shielded and gas-shieldedSubmerged arc for panel renewalsProcess selection decision factorsDistortion and heat input controlLesson 2Corrosion repair for bottom shell plating: local renewals, patch plating, and double-skin/trim patch solutionsExplains corrosion damage mechanisms in bottom shell plating and guides selection of local renewals, patches, and double-skin solutions, with emphasis on class rules, load paths, drainage, and long-term corrosion protection.
Corrosion types in bottom shell regionsCriteria for local plate renewalsDesign of insert and patch platesDouble-skin and trim patch conceptsScantling checks and class approvalCoating, anodes, and sealing detailsLesson 3Use of advanced materials and consumables: higher-strength steels, corrosion-resistant alloys, and consumable selectionExamines selection and use of higher-strength steels, corrosion-resistant alloys, and welding consumables, focusing on matching strength, toughness, corrosion behaviour, and weldability in typical ship repair scenarios.
Grades of higher-strength ship steelsCorrosion-resistant alloys in repairsMatching and overmatching consumablesHydrogen-controlled consumable typesStorage and handling of electrodesDissimilar metal joint strategiesLesson 4Cutting and removal: oxy-fuel, plasma, and CNC/high-precision thermal cuttingExplains safe and accurate removal of damaged structure using oxy-fuel, plasma, and CNC thermal cutting, addressing equipment setup, cut quality, heat-affected zones, and minimising distortion and rework.
Selection of cutting process by taskOxy-fuel cutting setup and safetyManual and mechanized plasma cuttingCNC and template-guided cuttingControl of HAZ and edge qualityDistortion control during removalLesson 5Prefabrication and modular panel replacement: templates, edge preparation and tolerancesCovers planning and fabrication of modular replacement panels, including measurement methods, template creation, edge preparation, tolerances, and alignment to minimise onboard fitting time and welding distortion.
Damage survey and panel mappingTemplate methods and digital scanningShop fabrication and fit-up checksEdge preparation and root gapsDimensional tolerances and fairnessLifting, handling, and positioningLesson 6Weld quality control: welders qualification, NDT acceptance criteria, and repair limitsCovers weld quality control in ship repair, including welder qualification, WPS compliance, NDT methods, acceptance criteria, and repair limits, ensuring structural integrity and regulatory conformity.
Welder qualification and continuityVisual inspection and weld gaugesUltrasonic and radiographic testingMagnetic particle and dye penetrantAcceptance criteria and defect limitsRepair welding and reinspection stepsLesson 7Damage assessment to repair decision framework and scope definitionProvides a structured framework from initial damage assessment to repair decision and scope definition, integrating class requirements, risk, cost, downtime, and long-term structural performance.
Initial inspection and data collectionUse of NDT and thickness measurementsResidual strength and buckling checksTemporary versus permanent repairsRepair scope and work package definitionCoordination with class and ownerLesson 8Welding procedure specifications (WPS), preheat/postheat, PWHT considerations for common ship steelsDescribes development and qualification of WPS for ship steels, including preheat and interpass control, postheat, and PWHT decisions, with attention to hydrogen cracking, hardness limits, and class documentation.
Essential WPS variables and rangesPreheat and interpass temperature controlPostheat for hydrogen diffusionPWHT need, methods, and limitsHardness and microstructure controlWPS qualification and recordsLesson 9Joint design improvements to reduce stress concentrations and extend fatigue lifeFocuses on joint design improvements to reduce stress concentrations and extend fatigue life, covering geometry changes, soft transitions, backing details, weld profiles, and alignment to optimise load transfer.
Assessment of existing joint detailsNotch effects and stress raisersSmooth transitions and tapersBacking bars and run-on tabsOptimized weld profiles and toesAlignment and fit-up tolerancesLesson 10Fatigue crack repair strategies: stop-holes, full-penetration welds, splice plates, doublers and redesign of detailsDetails fatigue crack mechanisms and repair options, including stop-holes, weld removal, full-penetration welds, splice plates, doublers, and redesign of details to improve fatigue life and comply with class guidance.
Identification of fatigue-prone detailsCrack sizing and monitoring methodsStop-holes and crack arrest drillingFull-penetration weld repair stepsUse of splice plates and doublersDetail redesign to reduce hotspots
