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Professional Diploma in Underwater Welding

This professional diploma prepares you for a specialised field of the maritime industry. You will learn wet and dry underwater welding techniques and how materials behave in these conditions. The programme is theory-based: diver and welder certifications are not included and are issued only by the bodies authorised in each country.

100% online800 hours8 modulesTaught in EnglishEnrol any time

What is this programme?

This professional diploma prepares you for a specialised, high-demand field of the maritime industry. It teaches welding techniques, from SMAW to GTAW, adapted to the underwater environment, and covers the inspection and repair of structures such as oil platforms, pipelines and ship hulls. The programme is theory-based: it gives you the technical knowledge behind the discipline, while diver and welder certifications are not included and are issued only by the bodies authorised in each country.

Its strengths are comprehensive knowledge, from diving physics to occupational safety and emergency procedures; coverage of wet and dry hyperbaric welding, underwater cutting and non-destructive inspection; and a final integrated project in which you plan an underwater repair from start to finish.

Programme highlights

  • Advanced techniques: current methods and technologies in hyperbaric and underwater welding.
  • Safety and regulation: demanding safety protocols and the regulations in force for safe, efficient operations.
  • Inspection and quality: non-destructive testing of underwater welds and the related standards.
  • Career boost: high-level training in a growing sector.

Study plan

01Fundamentals of Commercial Diving, Hyperbaric Physiology and the Underwater Environment100 h
History and fields of application of commercial diving and underwater welding, and the profile of the diver-welder. Physics of gases under water (Dalton's, Henry's and Boyle-Mariotte's laws), decompression sickness and nitrogen narcosis. Surface-supplied diving equipment: helmets, umbilicals, gas panels, suits and communications. International standards (IMCA, ADCI, OSHA). Dive planning, decompression tables, gas mixtures (air, nitrox, heliox) and hyperbaric chambers. Risk management: zero visibility, currents, entrapment, hypothermia, suction zones and emergencies. Technical terminology in English and Spanish, diver-to-surface communications and underwater video.
02Principles of Marine Metallurgy, Welding Processes and the AWS D3.6M Code100 h
Metallurgy of steel in water: severe cooling, hydrogen embrittlement, cold cracking and martensite in the heat-affected zone. Classes of underwater welds under AWS D3.6M (A, B, C and O). Mechanical properties of joints: tensile strength, ductility, hardness and toughness. Physics of the electric arc under water, straight and reverse polarity, and ionisation. Consumables for wet welding: waterproofed electrodes and diameter selection. Electrical equipment: DC generators, knife switches, marine cables and watertight electrode holders. Electrical safety: preventing electrocution, earthing and open-circuit voltage. Certification of underwater welders.
03Wet Underwater Welding Techniques100 h
Joint preparation and surface cleaning (biofouling, rust, paint) with hand, hydraulic and pneumatic tools. Welding positions: flat, horizontal, vertical and overhead. Electrode manipulation: drag technique, angles, arc length and deposition rate in reduced visibility. Fillet and bevel welds, tacking, root and fill passes. Controlling the gas bubble and slag between passes. Applications on offshore structures and hulls: crack repair, watertight patches and pile reinforcement. Common defects (porosity, lack of penetration, undercut, inclusions, hydrogen cracking) and their prevention. Qualification of the wet welding procedure.
04Dry Hyperbaric Underwater Welding100 h
Principles of submerged dry habitats: pressure chambers, water evacuation with gas and environmental conditioning. TIG, SMAW, GMAW and FCAW processes adapted to high pressure. Effects of pressure on the arc: constriction, metal transfer and changes in the shielding gas. Life support and ventilation: fume extraction, control of oxygen, carbon monoxide and temperature. Alignment and preparation of high-pressure pipes. Qualification of hyperbaric procedures (WPS/PQR) to AWS D3.6M Class A for subsea oil and gas pipelines. Real-time inspection and control from the surface with HD cameras and welding engineer supervision. Repair welding on ship hulls.
05Underwater Cutting and Demolition: Broco Exothermic Cutting and Thermic Lance100 h
Fundamentals of exothermic cutting (Broco system): thermochemical reaction, exothermic rods, high-purity oxygen and electric ignition. Equipment: insulated torches, reactive rods, high-flow regulators and 12 V batteries. Cutting techniques on steel, alloys and concrete. Oxy-arc cutting with tubular electrodes. Safety against hydrogen and oxygen pockets, explosions and purging of cavities. Dismantling and demolition: pile cutting, wreck salvage, obstruction removal and controlled blasting. Auxiliary hydraulic and pneumatic tools (chainsaws, shears, grinders and diamond discs). Abrasive waterjet cutting.
06Underwater Non-Destructive Testing (NDT) and Quality Control100 h
Roles of the underwater NDT inspector and the rules of classification societies. Visual inspection: weld profiles, undercut measurement, photographic records and condition reports. Underwater magnetic particle inspection with marine yokes, fluorescent particles and UV light. Ultrasonics: plate thickness, probe calibration and detection of internal discontinuities. Alternating current field measurement (ACFM) to detect cracks through paint. Cathodic protection monitoring with reference electrodes. Digital documentation, defect mapping and repair recommendations. Certification routes for underwater inspectors.
07Operational Safety, Emergency Procedures and Equipment Maintenance100 h
Risk prevention in underwater welding and cutting: electrocution, explosion of gas mixtures, umbilical entrapment and burns. Isolation and lockout of systems during the intervention (propellers, sea inlets, valves). Equipment maintenance: torch watertightness, cable insulation, gauge calibration and connectors. Contingencies: loss of communication, interruption of breathing gas, generator failure and umbilical rupture. First aid: rescuing an unconscious diver, recovery, oxygen therapy and treatment of burns and electric shocks. Emergency plans and drills on board with the support vessel, supervisors and hyperbaric medical staff. Managing decompression after long work periods.
08Integrated Project: Planning, Execution and Certification of an Underwater Repair100 h
Selecting a case study: a hull crack, reinforcement of a quay pile or a pipe joint on a platform. Diving and welding operations plan, with risk assessment, breathing mixtures, decompression tables and logistics. Welding procedure specification: parameters, electrode, joint preparation and acceptance criteria. Simulated execution of preparation, tacking and welding or cutting passes. Post-weld non-destructive testing plan. Calculation of costs, resources and bottom time. Technical report and class certificate. Final defence before a panel of supervisors, welding engineers and NDT auditors.

Duration and format

800hours in total
8modules of 100 hours
100%online, at your own pace
Openenrolment all year round

At 10 hours a week you would finish in about 80 weeks; at 20 hours a week, in about 40.

What you will learn

  • Understand how high-quality underwater welds are produced.
  • Inspect and repair submerged structures by welding.
  • Apply cutting and welding techniques in hyperbaric environments.
  • Comply rigorously with safety standards in underwater welding operations.
  • Master communication and coordination in diving and welding teams.
  • Select and maintain specialised underwater welding equipment.

Career outcomes

  • Underwater welder on oil platforms.
  • Underwater welder in shipbuilding.
  • Underwater welder in maritime works (ports, quays and submerged infrastructure).
  • Underwater welding inspector.
  • Underwater maintenance technician.
  • Professional diver specialising in welding.
  • Underwater welding project supervisor.
  • Underwater welding consultant.

Entry requirements

  • Academic or professional profile: approved welder certificate (for example SMAW, GTAW or FCAW) and professional diving certification (class 1, 2 or 3).
  • Physical fitness: medical certificate of fitness for professional diving and physical tests (swimming and endurance).
  • Documentation: up-to-date CV, copies of welding and diving certifications, accident insurance, identity document or passport, and a letter of motivation.
  • Additional requirements: demonstrable experience in welding or diving (desirable) and knowledge of underwater safety regulations. Admission is provisional until the committee validates the documentation.

How to enrol

Enrol online

Complete your enrolment on this page, or apply through admissions if you prefer to talk to us first.

Receive your access

We send you the details to enter the virtual campus and start the programme.

Study at your pace

Work through the modules when it suits you and complete the programme from anywhere in the world.

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