Professional underwater welding services restore vessel integrity and maintain operational readiness
Reliable underwater diving services play a vital role in maintaining the operational efficiency and safety of state and commercial vessels. A recent underwater intervention demonstrates how experienced commercial divers can quickly resolve critical structural hull issues afloat and prevent costly dry-docking downtime.
Following an urgent request a specialized three-diver team from NSD | Nick Segredakis Diving Ltd. was mobilized at Piraeus port. The operation was initiated alongside to repair a hull hole located on the starboard side of the vessel’s grey water tank. The works were completed swiftly in a single day under good weather and underwater visibility conditions.
Initial underwater inspection
Upon arrival at 09:00, the diving supervisor and the team executed immediate safety checklists and initiated a detailed dual-aspect inspection. The supervisor inspected the affected area from the inside of the grey water tank, while the commercial divers descended to a draft of approximately 3.0 meters to assess the damage from the outside.
The initial inspection revealed the following:
- The hull damage had been temporarily sealed using a wooden wedge covered with epoxy putty.
- The temporary plug was holding, but required complete removal and preparation to facilitate a certified, permanent afloat weld repair.
Initial diving status: Divers confirmed that the starboard hull of the patrol vessel suffered localized damage. The temporary plug needed immediate extraction to allow for high-quality, class-approved wet welding to restore watertight integrity.
Specialized underwater diving services in action
Performing permanent hull repairs afloat requires high-precision techniques, specialized tools, and strict adherence to commercial diving safety standards. The NSD technical team carried out the repair utilizing the following systematic procedure:
- Surface Preparation: Divers carefully cut away the temporary wooden wedge from the outside of the hull. Using hydraulic grinding disks, they ground the surrounding paint and marine growth away until the plating was brought to bare metal.
- U/W Plate Fabrication & Welding: A steel plate measuring 200X150X6mm was precision-formed to match the curvature of the vessel’s hull shell. The plate was held in place with “screw dogs” and welded underwater using specialized wet-welding electrodes approved by the classification society Bureau Veritas (BV).
- Internal Inspection & Reinforcement: Once the exterior plate was fully welded, the team removed the remaining internal wood from inside the tank to re-inspect the shell. The hole was found to be the result of local pitting, while the surrounding hull plate was verified to be in intact, healthy condition.
- Internal Build-Up Welding: To ensure maximum structural reinforcement, our welder-divers performed internal build-up welding over the pitted area using high-strength E7018 electrodes.
- Corrosion Protection: To finalize the repair, the divers applied a protective layer of epoxy putty over all newly exposed bare metal surfaces on the exterior hull to prevent future corrosion.
Rapid same-day diving operation
Due to the critical operational nature, minimizing downtime was of utmost priority. Working in close coordination with the vessel’s Chief Engineer and the Bureau Veritas Surveyor, the team operated continuously.
The entire operation, which lasted merely 5 hours, began at 09:00 and was successfully completed by 14:00 the very same day, with the team packing up and departing by 14:30.
Why afloat underwater services are essential
Unplanned hull damage can disrupt patrol schedules and commercial operations. Opting for certified afloat repairs provides vessel operators with major advantages:
- Elimination of Dry-Docking Costs: Avoiding shipyard blockings saves substantial capital and keeps the vessel in its operating region.
- Rapid Turnaround: Completing critical class-approved structural repairs in under 5 hours ensures the vessel remains active with almost zero schedule disruption.
- Class-Certified Quality: Repairs are executed to international standards using class-qualified welders and approved procedures.
Project summary
The successful afloat repair of the Coast Guard vessel highlights NSD | Nick Segredakis Diving ltd’s capability to deliver rapid, permanent, and certified underwater engineering solutions under tight deadlines. Using surface-supplied diving equipment and Bureau Veritas-approved procedures, our team successfully restored the hull’s integrity.
Final diving status: The starboard grey water tank hole was completely repaired with a custom welded steel plate. The welds were approved by the Bureau Veritas Surveyor, the hull’s watertight integrity was fully restored, and the vessel was immediately cleared to resume its duties.
