Everything Welders Need to Know About Underwater Welding

Underwater welding is among the one of the highest paying welding job. It is a specialized technique used to join metal components in underwater environments. It is primarily used to construct, repair, and maintain marine structures.

Underwater welding is crucial in assembling and maintaining large structures without needing dry docks or expensive lifting operations. This capability is particularly significant for offshore oil platforms, where on-site welding repairs can be conducted.

Moreover, underwater welding is essential for constructing and repairing ship hulls, ensuring the structural integrity and safe operation of vessels. It is also employed in installing and maintaining underwater pipelines, which are critical for oil and gas transportation.

Underwater Welding Types & Techniques

There are two main types of underwater welding:

Wet Welding

This involves welding directly in the water. The welder uses special waterproof equipment and works while wholly submerged. A common technique for wet welding is Shielded Metal Arc Welding (SMAW). One advantage of wet welding is that it’s cost-effective since the equipment is portable. However, a downside is that the weld quality can be lower because the water cools the metal quickly. It’s also hard to see clearly underwater.

Hyperbaric (Dry) Welding

The welding happens inside a special sealed chamber or enclosure filled with gas to keep the water out. This means the welding environment is dry. Gas Tungsten Arc Welding (GTAW) and Flux Cored Arc Welding (FCAW) are techniques used for dry welding. The big plus is that the weld quality is much better than wet welding since visibility is improved and the conditions are safer. However, setting up a dry welding system is more expensive and complicated than damp welding. It’s also less mobile or portable.

Diver’s Essential Gears for Underwater Welding

Underwater welding is a hazardous job that requires specialized gear for the diver’s survival and safety. Here are the essential pieces of equipment:

Diving Suits: Underwater welders wear specialized diving suits based on the depth and water temperature. Wetsuits made of neoprene allow some water in and are used for shallow, warm water dives up to 60 feet deep. For deep, cold water saturation dives over 300 feet down, thick rubber or nylon drysuits seal out water to keep the diver dry.

Breathing Apparatus: Scuba (Self-Contained Underwater Breathing Apparatus) air tanks carried by the diver provide mobility but only 30-60 minutes of air. Surface-supplied air systems use a long hose to pipe unlimited air down from the surface but restrict the diver’s mobility.  

Communication Tools: Underwater telephones and speakers allow voice communication to the surface crew. When voice communication fails, hand signals convey essential messages like “low air” or “emergency.

Electrodes and Filler Metals: Special waterproof electrodes and filler wire designed for wet welding processes are used to minimize porosity and other issues.

Cutting Torches: Plasma arc cutting, where the plasma transfers through water to cut metal, is sometimes used instead of oxy-fuel torches.

Safety Equipment: Electrical grounding systems safely direct current away from the diver. Arc shields protect the welder’s face from flashes. Emergency breathing backup is critical if the air supply fails.

Applications of Underwater Welding: Where Does it Come In?

Underwater welding has many applications in the marine construction and repair industry. One primary application is in shipbuilding and repair, where underwater welders perform crucial tasks such as hull maintenance and propeller shaft repairs. This allows ships to undergo repairs without needing expensive dry docking facilities.

Another significant application is in offshore oil and gas exploration. Underwater welders play a vital role in constructing and maintaining offshore oil rigs and pipelines. They are responsible for welding pipelines on the seafloor and repairing any damage or leaks that may occur.

Underwater welding is also crucial in the maintenance of bridges and piers. Welders are responsible for repairing support structures and pilings, which are essential for the safety and longevity of these structures.

In the case of dams and levees, underwater welders are often called upon to inspect and repair any leaks or damage. This is particularly important in areas prone to flooding, where the integrity of these structures is critical.

Furthermore, underwater welders are vital in emergency response and rescue operations. During salvage operations or disaster recovery efforts, they may be required to cut through submerged structures or repair damaged vessels to aid in the rescue process.

Challenges and Risks: The Dangers of the Deep

Limited Visibility: Poor underwater visibility due to murky waters and strong currents makes it extremely difficult and dangerous for welders to work accurately. In the Gulf of Mexico, visibility can be as low as 1-2 feet during rough conditions.

Pressure Effects: At depths over 100 feet, divers risk nitrogen narcosis, which causes dizziness and impaired judgment. Below 300 feet, decompression sickness or “the bends” is a significant hazard that can lead to paralysis or death if not treated properly.

Related: Underwater Welding Death Rate

Temperature Variations: In cold Arctic waters around 30°F, rapid heat loss from the welding arc can make welds brittle and prone to cracking. In tropical waters over 90°F, welders face heat exhaustion risks.

Electric Shock Risk: With electricity conducted through water, even a tiny leak in welding equipment can deliver a potentially lethal shock. Proper grounding and waterproofing is critical.

Explosion Hazards: Flammable gases like methane around offshore oil rigs create an ever-present explosion risk if not properly vented away from the welding arc.

The Future of Underwater Welding

Remotely Operated Vehicles (ROVs) for Deep-Sea Operations

As technology advances, Remotely Operated Vehicles (ROVs) are becoming increasingly prevalent in deep-sea operations, including underwater welding. These uncrewed vehicles can perform welding tasks in harsh environments. ROVs are equipped with specialized tools that allow surface operators to control and monitor the welding process remotely.

Automated Welding Systems

In addition to ROVs, automated welding systems significantly increase efficiency and safety in underwater welding. Computerized systems can operate in environments where human divers struggle, such as areas with high currents or limited visibility. These systems can perform repetitive welding tasks with precision and consistency.

Hyperbaric Welding Habitat Development

More Comfortable and Spacious Environments for Divers: Traditionally, underwater welding has been performed in challenging and confined spaces, which can add to the physical and mental strain on divers. However, developing hyperbaric welding habitats aims to provide welders with more comfortable and spacious living quarters during extended underwater operations. Modern habitats offer 600+ sq ft living areas with temperature/humidity control for diver comfort during multi-week “saturation” dives.

Advanced Life Support Systems: Besides improved living quarters, hyperbaric welding habitats incorporate advanced life support systems designed to sustain divers for extended periods underwater. These systems ensure constant breathable air, temperature control, and adequate nutrition and hydration. Habitats supply divers with oxygen, heat, and water and can sustain teams for over a month at depths over 1,000 feet if needed.

Takeaway

Underwater welding is a specialty requiring extensive skill, training, and perseverance. It allows critical construction and repair work on submerged marine structures and vessels that would otherwise be inaccessible.

Looking ahead, the future of underwater welding is bright. Technological innovations like remotely operated vehicle (ROV) welding systems may help make the job safer by keeping human welders out of the riskiest environments. Ongoing research and development of new techniques and equipment will continue to evolve in the field.