An offshore drilling vessel operating in the Eastern Mediterranean required the installation of a new hydrophone pipe system to support subsea monitoring and operational requirements. The vessel remained afloat and alongside anchorage during the project, necessitating a fully underwater installation approach. Subsea Global Solutions was engaged to provide commercial diving, underwater welding, and structural installation services to complete the work safely and efficiently without interrupting the vessel’s operational schedule.

The Challenge

The project involved installing a hydrophone pipe casing on the vessel’s hull in a precise, predefined location, requiring accurate alignment, certified underwater welding, and structural reinforcement. All work had to be conducted in moderate currents and offshore conditions while adhering to port authority restrictions that prohibited diving while the vessel was docked. Additional challenges included coordinating work around vessel movements, crew changes, and crane availability, as well as ensuring all welding met strict procedural and inspection requirements. The installation also required templating and fabrication underwater to accommodate actual hull geometry and pipe positioning.

Scope of Work & Solution

Subsea Global Solutions deployed an experienced dive team supported by a dedicated dive support vessel to execute the underwater installation. After completing vessel inductions and pre-job planning with the ship’s engineering team, divers cleaned and prepared all designated hull locations by removing coatings and marine growth. Positioning padeyes were installed, and the hydrophone pipe was lowered into place using the vessel’s crane. Subsea Global’s divers performed underwater welding of support brackets and fabricated and installed two pipe braces, ensuring precise fit-up through underwater templating. All welding was completed in accordance with approved welding procedures, followed by magnetic particle inspection (MPI) to verify weld integrity. Once testing was successfully completed, epoxy splash-zone coating was applied to all exposed welds to provide long-term corrosion protection. Throughout the project, Subsea Global Solutions maintained close coordination with vessel personnel, documented all work photographically, and adjusted execution sequencing to accommodate operational constraints.

Conclusion

The hydrophone pipe installation was completed successfully, meeting all technical, safety, and quality requirements while the vessel remained afloat. Subsea Global Solutions delivered a fully compliant underwater installation solution that minimized operational disruption and ensured long-term structural integrity. The project demonstrated Subsea Global Solutions' capability to perform complex underwater welding and structural installations in offshore environments under demanding logistical and operational conditions.

Underwater Welding with Subsea Global Solutions

Subsea Global Solutions provides specialized underwater welding and structural installation services for offshore vessels, drilling units, and marine assets, including hull-mounted piping, structural reinforcements, and subsea support systems—all performed without the need for drydocking. Our certified commercial dive teams execute precision welding, fabrication, inspection, and corrosion protection in accordance with approved procedures and class requirements, helping operators maintain critical systems while reducing downtime. Learn more about our underwater welding and structural installation capabilities here.