Lesson 1Welding processes for ship repairs: SMAW, GMAW/MIG, FCAW, and submerged arc—process selectionExamines primary welding methods in ship repairs, contrasting SMAW, GMAW, FCAW, and submerged arc for efficiency, reach, position options, and standards, guiding choices for standard structural fixes in Namibian shipyards.
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 solutionsDescribes rust damage processes in bottom plating and directs choices for spot replacements, patches, and double-layer fixes, stressing classification rules, load routes, drainage, and lasting rust prevention for Namibian vessels.
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 selectionLooks at choosing and applying stronger steels, rust-proof metals, and welding materials, focusing on matching power, durability, rust resistance, and weld ease in common Namibian ship repair situations.
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 cuttingOutlines safe, precise removal of damaged parts using oxy-fuel, plasma, and computer-controlled thermal cutting, covering tool setup, cut standards, heat zones, and cutting down on bends and extra work in Namibia.
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 tolerancesAddresses planning and making modular replacement panels, including sizing methods, pattern making, edge readying, allowances, and fitting to cut shipboard time and welding bends for Namibian projects.
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 standard checks in ship repairs, including welder training, procedure following, testing methods, approval standards, and fix boundaries, ensuring structure soundness and rule adherence in Namibia.
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 definitionOffers a planned structure from first damage check to repair choice and range setting, combining classification needs, dangers, expenses, delays, and long-run structure performance for Namibian operations.
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 steelsDetails creating and approving welding procedures for ship steels, covering preheating, interval heat, postheat, and heat treatment choices, noting hydrogen cracks, hardness caps, and classification papers in Namibia.
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 lifeConcentrates on joint design upgrades to lessen stress points and lengthen fatigue duration, including shape shifts, smooth joins, support details, weld shapes, and lining up for better load passing in Namibian repairs.
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 detailsOutlines fatigue crack processes and fix choices, such as stop holes, weld clearing, full welds, join plates, extra layers, and detail redesigns to boost fatigue life and meet classification advice in Namibia.
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
