Underwater welding, also known as hyperbaric welding, is a fascinating and challenging profession that involves welding in an aquatic environment. It is a specialized skill that requires extensive training, knowledge, and expertise. In this blog article, we will explore the intricate details of how underwater welding works, its techniques, equipment, and the risks associated with this underwater profession.
First and foremost, let’s understand the two main types of underwater welding: wet welding and dry welding. Wet welding, as the name suggests, is performed directly in the water, while dry welding involves creating a dry environment around the welding area. Both methods have their own advantages and limitations, and the choice depends on various factors such as the depth of the water, the duration of the welding project, and the conditions of the underwater environment.
Wet Welding
Wet welding is the most commonly used method in underwater welding. This technique allows welders to work directly in the water, eliminating the need for complex dry environments. To perform wet welding, a welder must be a certified commercial diver with expertise in both welding and diving techniques.
Equipment for Wet Welding
Wet welding requires specialized equipment to ensure the safety and efficiency of the welder. One of the crucial tools is the welding machine, which is designed to operate underwater. These machines are typically powered by electricity and are specially insulated to prevent electrical shocks. The electrodes used in wet welding are also specifically designed for underwater use, with a waterproof coating to ensure proper arc ignition and stability.
In addition to the welding machine and electrodes, wet welding also requires diving gear to provide the welder with the necessary life support and mobility. This includes a diving mask, breathing apparatus, and a drysuit or wet suit to protect against cold temperatures and water pressure. The welder must also have diving tools such as a cutting torch and underwater welding electrodes readily available.
Techniques in Wet Welding
Wet welding techniques involve a combination of manual dexterity, welding expertise, and proper positioning in the water. One of the commonly used techniques in wet welding is shielded metal arc welding (SMAW), also known as stick welding. SMAW involves striking an electric arc between the electrode and the workpiece, creating a molten pool that fuses the two materials together.
Another technique used in wet welding is flux-cored arc welding (FCAW). FCAW utilizes a tubular electrode filled with a flux material that not only shields the weld from contaminants but also provides a source of additional alloying elements to enhance the weld’s strength and corrosion resistance. This technique is often preferred in underwater welding due to its ease of use and the ability to produce high-quality welds even in challenging conditions.
Challenges in Wet Welding
Wet welding presents several challenges that require welders to adapt and employ specific techniques to overcome them. One of the primary challenges is poor visibility, which can be caused by sediment, algae, or darkness in deep water. Welders must rely on their training and experience to ensure accurate positioning and proper alignment of the welding electrode with the workpiece.
Another challenge in wet welding is the presence of water currents, which can affect the stability of the welding arc and the overall control of the weld pool. Welders must constantly adjust their body position and manipulate the electrode to compensate for these currents and maintain a stable arc and weld pool.
Furthermore, the corrosive nature of seawater poses a significant challenge in wet welding. Seawater contains high levels of salt, which can lead to accelerated corrosion of the weld and surrounding metal. To combat this, welders must carefully select the appropriate welding electrodes and apply corrosion-resistant coatings or protective measures, such as cathodic protection, to ensure the longevity and integrity of the weld.
Dry Welding
Dry welding, also known as habitat welding, involves creating a dry environment around the welding area to carry out the welding process. This method is typically used for projects that require extended durations or when the water depth exceeds the capabilities of wet welding. Dry welding offers better control over the welding environment, reducing the impact of variables such as water currents and visibility.
Methods for Creating a Dry Environment
There are several methods used to create a dry environment for underwater welding. One commonly used method is the cofferdam, which is a temporary enclosure built around the welding area. The cofferdam is typically constructed using flexible materials such as rubber or plastic, and it is filled with compressed air to displace the water and create a dry space for welding.
Another method used in dry welding is the habitat system. A habitat is a more permanent structure that provides a controlled environment for the welder to work in. It consists of a rigid chamber, often made of steel, that is sealed off from the surrounding water. The habitat is pressurized with a mixture of gases, such as helium and oxygen, to ensure a breathable atmosphere for the welder.
Advantages and Limitations of Dry Welding
Dry welding offers several advantages over wet welding, particularly in terms of control, visibility, and access. The dry environment allows for better control of variables such as temperature, humidity, and contaminants, resulting in higher quality and more consistent welds. Additionally, the absence of water currents and sediment improves visibility, enabling the welder to have a clear view of the welding process.
However, dry welding also has its limitations. The construction and maintenance of habitats or cofferdams can be time-consuming and costly. Moreover, the use of habitats requires specialized training and equipment, making dry welding less accessible for certain projects or locations. It is essential to carefully assess the specific requirements and constraints of each underwater welding project before deciding whether wet or dry welding is the most suitable approach.
Equipment Used in Underwater Welding
Underwater welding requires specialized equipment to ensure the safety and efficiency of the welder. These tools are designed to withstand the unique challenges of working in an aquatic environment and provide the necessary control, protection, and accessibility for successful welding.
Welding Machines
Welding machines used in underwater welding are specially designed to operate in wet or dry conditions. They are typically powered by electricity and equipped with features that ensure safety and performance underwater. These machines often have additional insulation to prevent electrical shocks and short circuits that can occur due to the presence of water.
In wet welding, the welding machine must be waterproof and capable of functioning in high humidity and variable depths. It should have controls and displays that are easily readable underwater, allowing the welder to adjust settings and monitor the welding process effectively.
In dry welding, the welding machine is typically placed outside the habitat or cofferdam to prevent any potential hazards associated with operating electrical equipment inside the sealed environment. The machine is connected to the welding electrode and power supply through waterproof cables or connectors.
Electrodes
Underwater welding electrodes are specially designed for use in wet or dry environments. These electrodes have specific coatings that provide protection against moisture and ensure proper arc ignition and stability. The coatings also contain alloying elements that enhance the weld’s mechanical properties and corrosion resistance.
In wet welding, the electrodes are typically consumable and made of materials such as mild steel or stainless steel. These electrodes are designed to function in wet conditions, allowing the welder to create strong and durable welds underwater. The selection of the electrode depends on the specific requirements of the project, including the type of base metal, welding technique, and environmental factors such as salinity and temperature.
In dry welding, the electrodes may vary depending on the specific welding process used. For example, shielded metal arc welding (SMAW) typically uses coated electrodes similar to those used in wet welding. On the other hand, processes like gas tungsten arc welding (GTAW) or gas metal arc welding (GMAW) may require different types of electrodes, such as tungsten electrodes or solid wire electrodes, respectively.
Diving Gear
Underwater welding requires the welder to be a certified commercial diver, equipped with the necessary diving gear to ensure safety and mobility. Diving gear typically includes a diving mask or helmet, breathing apparatus, buoyancy control device (BCD), and exposure suit.
The diving mask or helmet provides a clear field of vision and protects the welder’s face from water pressure and potential hazards. The breathing apparatus, such as a demand valve regulator or a continuous flow system, supplies the welder with a mixture of gases suitable for the depth and duration of the dive, ensuring proper respiration throughout the welding process.
The exposure suit, either a drysuit or a wetsuit, protects the welder from the cold temperatures and provides insulation against the water pressure. The choice between a drysuit and a wetsuit depends on factors such as water temperature, duration of the dive, and personal preference.
In addition to these essential diving gear components, the welder may also require additional tools such as a cutting torch, underwater welding electrodes, and inspection equipment to assess the quality of the welds. These tools are typically attached to the welder’s diving harness or carried in specialized pockets or containers.
Techniques in Underwater Welding
Underwater welding techniques are specialized methods that allow welders to create strong and durable welds in challenging aquatic environments. These techniques require a combinationof manual dexterity, welding expertise, and adaptability to the unique conditions encountered underwater. Different techniques may be employed depending on factors such as the type of welding required, the depth of the water, and the specific project requirements.
Shielded Metal Arc Welding (SMAW)
Shielded Metal Arc Welding (SMAW), also known as stick welding, is one of the most commonly used techniques in underwater welding. It involves creating an electric arc between a consumable electrode and the workpiece, which melts the electrode and forms a weld pool. As the weld pool cools, it solidifies, creating a strong bond between the base metals.
In underwater SMAW, the electrode is coated with a flux material that provides a shielding gas, slag formation, and alloying elements. The flux coating melts and forms a protective gas shield around the weld pool, preventing contamination from the surrounding water and ensuring the integrity of the weld. The slag formed during the welding process acts as a protective layer, shielding the weld from potential corrosion and improving its mechanical properties.
Underwater SMAW requires careful control of the welding parameters, such as the arc length, travel speed, and electrode angle. The welder must maintain a stable arc and ensure proper penetration and fusion of the base metals. Adequate training and experience are essential to master the techniques and produce high-quality welds underwater.
Flux-Cored Arc Welding (FCAW)
Flux-Cored Arc Welding (FCAW) is another commonly used technique in underwater welding. It is similar to SMAW but utilizes a tubular electrode filled with a flux material. The flux not only provides shielding gas but also contains alloying elements that enhance the mechanical properties of the weld.
Underwater FCAW offers several advantages over SMAW, including higher deposition rates, increased efficiency, and the ability to weld thicker materials. The tubular electrode allows for the use of a continuous wire feed, reducing the need for frequent electrode changes and resulting in a faster welding process. The flux material within the electrode provides additional protection against contamination and improves the weld’s mechanical properties.
Similar to SMAW, proper control of welding parameters is crucial in underwater FCAW. The welder must adjust the wire feed speed, voltage, and travel speed to ensure proper penetration, fusion, and deposition rate. The choice between SMAW and FCAW depends on factors such as the specific project requirements, the type of materials being welded, and the skill level and preference of the welder.
Gas Tungsten Arc Welding (GTAW)
Gas Tungsten Arc Welding (GTAW), also known as Tungsten Inert Gas (TIG) welding, is a precise and versatile welding technique commonly used in both wet and dry underwater welding applications. GTAW utilizes a non-consumable tungsten electrode to create an electric arc, which melts the base metals and forms a weld pool.
Underwater GTAW offers several advantages, including excellent control over the welding process, high-quality welds, and the ability to weld a wide range of materials, including aluminum and stainless steel. The non-consumable tungsten electrode does not require a flux coating, resulting in cleaner welds with minimal spatter and slag formation.
Underwater GTAW requires the use of a shielding gas, typically argon or a mixture of argon and helium, to protect the weld pool from contamination. The welder must maintain a steady hand and precise control of the torch position, filler metal feed, and welding parameters to achieve the desired results. GTAW is often used for critical welds requiring high aesthetic appeal, such as in the construction of underwater structures or pipelines.
Gas Metal Arc Welding (GMAW)
Gas Metal Arc Welding (GMAW), also known as Metal Inert Gas (MIG) welding, is a widely used technique in various welding applications, including underwater welding. GMAW involves the use of a consumable electrode wire that continuously feeds through the welding gun, creating an electric arc with the workpiece.
Underwater GMAW offers several advantages, such as high deposition rates, ease of use, and the ability to weld a wide range of materials. The continuous wire feed allows for efficient and faster welding, making it suitable for projects with time constraints. GMAW also offers better control over the welding parameters, resulting in consistent and high-quality welds.
Underwater GMAW requires the use of a shielding gas, typically a mixture of argon and carbon dioxide or argon and oxygen, to protect the weld pool from contamination. The welder must control the wire feed speed, voltage, and travel speed to achieve proper penetration, fusion, and deposition rate. GMAW is commonly employed in underwater welding projects where high productivity is essential, such as in large-scale construction or repair projects.
Friction Welding
Friction welding is a solid-state welding technique that can be employed in certain underwater welding applications. It involves the generation of heat through mechanical friction between two workpieces, causing them to soften and fuse together. Friction welding can be performed in various forms, such as rotary friction welding, linear friction welding, or friction stir welding.
Underwater friction welding offers unique advantages, including high joint strength, minimal heat-affected zone, and the ability to join dissimilar materials. The absence of an external heat source reduces the risk of distortion or warping of the workpieces and allows for precise control over the welding process.
Underwater friction welding requires specialized equipment, such as a friction welding machine or tool, that can operate effectively in a submerged environment. The welder must carefully position the workpieces and apply the appropriate pressure and rotational speed to generate the required friction and achieve a successful weld.
Safety Precautions for Underwater Welding
Underwater welding poses numerous risks and hazards to the welders due to the unique environment they work in. It is essential to implement strict safety protocols and precautions to ensure the well-being of the welder and the integrity of the welding operation.
Diver Training and Qualifications
One of the critical safety measures in underwater welding is ensuring that the welder is a certified commercial diver with proper training and qualifications. Commercial dive training programs provide divers with the necessary skills and knowledge to perform underwater welding safely. These programs typically include training in diving techniques, equipment operation, emergency procedures, and welding procedures.
Welders must also maintain their certifications and undergo regular refresher training to stay updated with the latest industry standards and techniques. Continuous education and professional development are crucial in keeping welders competent and prepared for the challenges they may encounter underwater.
Dive Planning and Risk Assessment
Prior to any underwater welding operation, a comprehensive dive plan must be developed, taking into account the specific project requirements, environmental conditions, and potential risks. The dive plan should include a thorough risk assessment that identifies potential hazards and outlines the necessary safety measures and contingency plans.
Risk assessment factors may include water visibility, currents, temperature, depth, potential underwater hazards (such as marine life or structures), and the presence of hazardous materials. By identifying and mitigating these risks, the dive plan ensures the safety of the welder and the successful completion of the welding project.
Proper Equipment Maintenance
Regular maintenance and inspection of the diving and welding equipment are crucial for ensuring their proper functioning and safety. The diving gear, including the breathing apparatus, exposure suit, and diving tools, should be regularly inspected for any signs of wear, damage, or malfunction. Any faulty equipment should be repaired or replaced before undertaking any underwater welding operations.
The welding equipment, such as the welding machine, electrodes, and cables, should also be inspected and maintained to ensure their safety and performance underwater. Any damaged or worn components should be repaired or replaced by qualified personnel. Regular calibration and testing of the welding machine are essential to ensure accurate welding parameters and proper insulation.
Emergency Procedures and Communication
Underwater welding operations must have well-defined emergency procedures in place to handle any unforeseen circumstances or incidents. This includes procedures for rapid ascent in case of an emergency, communication protocols between the welder and the surface team, and contingency plans for equipment failure or loss of visibility.
Communication systems, such as underwater communication devices or hand signals, should be established to maintain constant contact between the welder and the surface team. These communication channels are vital for conveying important information, providing instructions or assistance, and ensuring the safety of the welder throughout the welding process.
Challenges in Underwater Welding
Underwater welding presents several challenges that require skilled welders to adapt and overcome. These challenges arise from the unique conditions encountered underwater, such as low visibility, extreme temperatures, and the corrosive effects of seawater.
Low Visibility
One of the primary challenges in underwater welding is the reduced visibility caused by factors such as sediment, algae, or darkness in deep water. Limited visibility makes it challenging for welders to accurately position and align the welding electrode with the workpiece, increasing the risk of improper welds or weld defects.
To overcome low visibility, welders must rely on their training and experience to navigate through the welding process. They may use specialized lighting systems, such as underwater welding lamps or strobes, to improve visibility in the immediate vicinity of the weld. Additionally, divers may employ tactile feedback or rely on communication with thesurface team to ensure precise positioning and alignment of the welding electrode.
Extreme Temperatures
Underwater welding often involves working in extreme temperatures, which can pose challenges for both the welder and the welding process. Cold temperatures can cause discomfort, reduced dexterity, and increased fatigue for the welder. It can also affect the performance of the welding equipment and consumables, such as the welding machine, electrodes, and shielding gas.
To mitigate the effects of extreme temperatures, divers may wear insulated exposure suits, such as drysuits or wetsuits, to provide thermal protection. Adequate insulation helps maintain the welder’s body temperature and prevents heat loss. Welding equipment may also be designed with additional insulation or heating elements to ensure optimal performance in cold water conditions.
Corrosion from Seawater
Seawater is highly corrosive due to its high salt content, which can pose a significant challenge for underwater welders. The exposure of the weld and surrounding metal to seawater can lead to accelerated corrosion, compromising the integrity and durability of the weld. Corrosion can weaken the weld and increase the risk of failure, especially in marine environments with high salinity levels.
To combat corrosion, underwater welders employ various techniques and precautions. They may use corrosion-resistant welding electrodes specifically designed for underwater applications, such as stainless steel electrodes. Additionally, welders may apply protective coatings or utilize cathodic protection systems to minimize the contact between the weld and seawater, reducing the risk of corrosion.
Hydrostatic Pressure
Another significant challenge in underwater welding is the hydrostatic pressure exerted by the water at greater depths. As the depth increases, the pressure on the welder and the welding equipment also increases. High hydrostatic pressure can compress air spaces, such as the diving suit or habitat, and affect the performance of the welding equipment.
To counteract the effects of hydrostatic pressure, divers must undergo proper training and acclimatization to work at various depths. Diving suits and habitats are designed to withstand the pressure and maintain a safe environment for the welder. The welding equipment, such as the welding machine and electrodes, is also specially designed to operate under high-pressure conditions to ensure safety and performance.
Applications of Underwater Welding
Underwater welding finds numerous applications in various industries that require maintenance, repair, or construction work in aquatic environments. The versatility of underwater welding allows for the completion of critical projects that would otherwise be challenging or impossible to achieve without the expertise of underwater welders.
Offshore Oil and Gas Industry
The offshore oil and gas industry heavily relies on underwater welding for various maintenance and repair tasks. Underwater welders play a crucial role in the construction and maintenance of offshore platforms, pipelines, and underwater structures. They are responsible for welding and repairing the structural components, ensuring the integrity and safety of these vital offshore installations.
Underwater welding is also utilized in the installation and repair of underwater pipelines, including those used for oil and gas transportation. Welders are tasked with joining sections of the pipeline, repairing damaged sections, and ensuring the watertight integrity of the welds. Their expertise is essential in maintaining the efficiency and safety of the pipeline infrastructure.
Marine Salvage and Ship Repair
Underwater welding plays a significant role in marine salvage operations and ship repair. When vessels experience damage or structural failures, underwater welders are called upon to repair or reinforce the affected areas. They are skilled in working with various materials, including steel, aluminum, and composite materials, to restore the structural integrity of the vessel.
Additionally, underwater welders are involved in the installation and repair of ship hulls, propellers, and other underwater components. Their expertise ensures the seaworthiness and operational efficiency of the vessel. Underwater welding is particularly critical in naval and military applications, where the maintenance and repair of submarines and other submerged structures are essential.
Hydropower and Renewable Energy
Underwater welding is integral to the construction and maintenance of hydropower plants and renewable energy infrastructure. It is used in the installation and repair of underwater turbines, dams, and other components of hydropower systems. The welders ensure the watertight integrity of the structures and the efficient operation of the power generation equipment.
In the renewable energy sector, underwater welding is employed in the installation and maintenance of offshore wind farms. Welders are responsible for constructing the foundations and supporting structures for wind turbines, as well as repairing any damage or corrosion that may occur over time. Their expertise ensures the longevity and reliability of the renewable energy infrastructure.
Advancements in Underwater Welding Technology
Over the years, advancements in technology have revolutionized the field of underwater welding, improving efficiency, safety, and the overall quality of the welds. These advancements have enhanced the capabilities and productivity of underwater welders, allowing them to tackle more complex projects and work in challenging underwater environments.
Improved Welding Equipment
Technological advancements have led to the development of more advanced and specialized welding equipment for underwater welding. Welding machines are now designed to withstand the harsh underwater conditions, with improved insulation, corrosion resistance, and enhanced control features. These machines provide accurate control over welding parameters, ensuring optimal performance and weld quality.
The electrodes used in underwater welding have also undergone significant improvements. Manufacturers have developed specialized coatings and alloys that provide better protection against corrosion, improved arc stability, and enhanced mechanical properties of the welds. These advancements have resulted in higher-quality welds and increased durability in underwater applications.
Remote Welding Systems
Remote welding systems have emerged as a significant advancement in underwater welding technology. These systems allow for remote-controlled or automated welding operations, reducing the need for direct human intervention in hazardous underwater environments. Remote welding systems can be operated from the surface or from remote control stations, providing enhanced safety and precision in the welding process.
Remote welding systems utilize advanced sensors, cameras, and robotics to perform welding tasks with high accuracy and efficiency. They can navigate through challenging underwater conditions, maintain stable arcs, and adjust welding parameters in real-time. These systems are particularly useful in deep-sea welding projects or in situations where human access is limited or unsafe.
Improved Underwater Communication
Effective communication is crucial for the safety and success of underwater welding operations. Technological advancements have led to the development of improved underwater communication systems, allowing for clear and reliable communication between the welder and the surface team.
Underwater communication systems utilize technologies such as acoustic signaling, voice transmission through water, and wireless communication devices. These systems enable welders to convey important information, receive instructions, and alert the surface team in case of emergencies or contingencies. Improved communication enhances the coordination and efficiency of underwater welding projects, ensuring the safety and productivity of the welders.
Certification and Training for Underwater Welders
Becoming an underwater welder requires specialized training, certification, and continuous education to ensure competence and safety in this demanding profession. Proper training programs and certifications are essential to equip welders with the necessary skills, knowledge, and understanding of the unique challenges faced in underwater welding.
Commercial Diving Certification
Underwater welders must obtain commercial diving certification to ensure their competency in diving techniques and safety procedures. Commercial diving certification programs provide comprehensive training in various aspects of diving, such as underwater navigation, decompression procedures, equipment operation, and emergency response.
These programs typically involve both classroom instruction and practical hands-on training in simulated underwater conditions. Divers learn about the potential risks and hazards associated with working underwater and acquire the necessary skills to mitigate these risks. Certification programs may also include specific modules or courses dedicated to underwater welding techniques and procedures.
Underwater Welding Training
In addition to commercial diving certification, underwater welders must undergo specialized training in underwater welding techniques and procedures. These training programs focus on developing the necessary skills, knowledge, and understanding of the welding processes, equipment, and safety protocols specific to underwater environments.
Underwater welding training programs typically involve a combination of theoretical instruction, practical welding exercises in controlled environments, and simulated underwater welding scenarios. Trainees learn about the different welding techniques used in underwater welding, proper equipment usage and maintenance, safety precautions, and emergency procedures.
Continuing Education and Professional Development
Continuous education and professional development are crucial for underwater welders to stay updated with the latest industry standards, technological advancements, and safety protocols. Underwater welding is a dynamic field with evolving techniques and equipment, making ongoing education essential for welders to remain competent and competitive.
Welders can pursue advanced training programs, attend workshops and seminars, and participate in industry conferences to expand their knowledge and skills. Professional organizations and associations dedicated to underwater welding provide resources and opportunities for welders to enhance their expertise and stay connected with the industry.
Environmental Impact of Underwater Welding
Underwater welding can have potential environmental implications due to the release of certain materials and the disturbance caused to underwater ecosystems. It is essential to minimize the environmental impact of underwater welding operations through the implementation of proper practices and adherence to regulations and guidelines.
Use of Environmentally Friendly Materials
One way to reduce the environmental impact of underwater welding is to use environmentally friendly materials and consumables. Manufacturers have developed welding electrodes and coatings that are less harmful to the environment, with reduced levels of toxicmaterials or contaminants. By using these eco-friendly materials, the release of harmful substances into the surrounding water can be minimized, ensuring the preservation of underwater ecosystems.
Adherence to Regulations and Guidelines
Underwater welding operations must comply with environmental regulations and guidelines set by governing bodies and industry organizations. These regulations aim to protect the marine environment and ensure that welding activities are carried out in a sustainable and responsible manner.
Welders and project managers should be familiar with the applicable regulations and guidelines and implement appropriate measures to minimize the environmental impact. This may include obtaining necessary permits, conducting environmental assessments, and implementing best practices in waste management and disposal.
Prevention of Contamination
To prevent contamination of the surrounding water during underwater welding, proper containment and waste management practices should be implemented. Welders must ensure that materials such as welding electrodes, coatings, and debris are properly collected, stored, and disposed of in designated containers or facilities. This prevents the release of potentially harmful substances into the aquatic environment.
Furthermore, divers should avoid conducting welding activities near sensitive marine ecosystems or areas of high biodiversity. By selecting appropriate locations and avoiding environmentally sensitive areas, the potential impact on underwater ecosystems can be minimized.
Environmental Monitoring and Assessment
Regular monitoring and assessment of the environmental impact of underwater welding operations are essential to ensure compliance with regulations and identify any potential issues. Environmental monitoring may involve water sampling and analysis to assess the quality and composition of the surrounding water before, during, and after welding activities.
By monitoring the environmental conditions and conducting regular assessments, any changes or adverse effects can be promptly identified and appropriate actions can be taken to mitigate them. This proactive approach ensures the preservation of underwater ecosystems and the sustainable practice of underwater welding.
In conclusion, underwater welding is a complex and demanding profession that requires specialized skills, equipment, and safety measures. It involves both wet and dry welding techniques, each with its own advantages and limitations. By understanding the intricacies of underwater welding, we can appreciate the expertise and dedication required by the welders who work in this challenging underwater environment.