Underwater Maintenance and Operation

Underwater Maintenance by Divers

Divers perform preventive and corrective maintenance tasks on submerged structures and equipment. Some common tasks include:

1. Hull Cleaning & Propeller Maintenance

• Removal of marine growth (algae, barnacles) from ship hulls and propellers.

• Reduces drag, improves fuel efficiency, and extends life of coatings.
  
  

2. Underwater Welding and Cutting

• For repairing pipelines, offshore platforms, and ship structures.

• Often uses techniques like wet welding or hyperbaric welding.
  
  

3. Cathodic Protection Maintenance

• Inspection and replacement of sacrificial anodes to prevent corrosion.

• Common on ship hulls, offshore rigs, and submerged pipelines.
  
  

4. Pipeline and Cable Maintenance

• Cleaning, coating, and fixing damaged sections.

• Often done with ROV support in deep waters, but divers are essential in shallow to moderate depths.
  
  

5. Intake & Outfall Systems

• Cleaning and desilting of water intake systems for power plants and desalination units.

• Involves use of suction tools and inspection cameras.
  
  

 Underwater Inspection by Divers

Inspection ensures structural integrity, identifies defects, and guides maintenance actions.

1. Visual and Video Inspection

• High-resolution underwater cameras mounted on diver helmets or handheld.

• Video recording and live feed for real-time assessment by engineers on the surface.
  
  

2. Non-Destructive Testing (NDT)

• Techniques like:

  • Ultrasonic Thickness Gauging (UTG) – checks metal thickness.

  • Magnetic Particle Testing – detects surface cracks.

  • Cathodic Protection Readings – measures corrosion protection effectiveness.
    
    

3. Structure Inspection

• Piers, bridge foundations, jetties, and underwater tunnels.

• Divers check for erosion, scouring, cracks, biological growth, and joint conditions.
  
  

4. Mooring & Anchor Chain Inspection

• Inspection of mooring lines, anchors, and chain wear.

• Important for floating platforms, ships at anchorage, and buoys.
  
  

  Documentation & Reporting

    After the operation:

• Divers prepare detailed inspection reports with photos/videos.

• Maintenance logs are updated.

• Recommendations for repairs or follow-up inspections are made.
  
  

Safety and Equipment

• Use of Surface Supplied Air Diving (SSAD) or Scuba depending on depth.

• Divers follow strict dive tables and safety protocols.

• Emergency rescue systems and standby divers are always on alert.