Irish Sea Contractors has developed AERSUB™, a globally patented subsea cable repair system engineered to international standards including DNV, IMCA and NORSOK requirements for diving, subsea equipment and offshore operations.
AERSUB enables a fundamentally different approach to power cable repair—performing the entire jointing process on the seabed, without recovering the cable to the deck of a vessel.
How it works
Guided by our ethos—anything you can do on land, we can do under the sea—AERSUB removes the need for cable lifting and deck-based repair operations. Instead, the system creates a stable, dry working environment around the cable at depth, allowing subsea jointers to perform controlled jointing operations on the seabed.
BENEFITS OF AERSUB
While operational data continues to be gathered, early testing and demonstrations indicate that AERSUB has the potential to deliver significant benefits over traditional “lift-to-repair” methods:
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Substantial reduction in vessel time and total repair cost
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Lower carbon emissions due to reduced reliance on large vessels
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Rapid response capability thanks to a deployable system that can operate in challenging conditions
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Enhanced safety by avoiding heavy-lift operations and complex deck handling
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Operational flexibility, enabling repairs in weather windows that would halt traditional methods
These benefits position AERSUB as an important advancement for offshore wind, interconnectors, and subsea power infrastructure.
AERSUB Development Journey
IDEATION & CONCEPT DEVELOPMENT
The idea for AERSUB emerged from extensive engagement with subsea cable owners, insurers and offshore wind stakeholders, where a common challenge was repeatedly highlighted: the excessive cost and complexity of subsea power cable repair. This insight initiated the development of AERSUB.
ENGINEERING & PROTOTYPE DEVELOPMENT
A multidisciplinary design team—naval architects, certification specialists, marine consultants and boatbuilders—collaborated to transform the concept into an engineered system. A full-scale AERSUB prototype was constructed and tested within Irish Sea Contractors’ Subsea Innovation Facility, where feasibility studies and joint testing were carried out using certified components.
These early trials were independently reviewed with DNV, who issued a Statement of Feasibility, confirming the technology was suitable for further development and qualification.
SKILLS & CAPABILITY BUILDING
To support future operations, Irish Sea Contractors established a dedicated Subsea Cable Training Academy, delivering advanced jointing and subsea skills programmes. Training continues in partnership with OEMs to ensure operational teams maintain the highest level of technical capability.
INDEPENDENT VALIDATION & INVESTMENT
Following feasibility success, DNV issued an Endorsement of Technology Qualification Plan, outlining the path to full certification.
Irish Sea Contractors also secured significant external support, including innovation funding from Enterprise Ireland—recognised globally for its leadership in venture-backed technology investment.
AERSUB has undergone extensive testing, analysis and procedure refinement, supported by continuous engagement with DNV.
Both European and US patents for AERSUB have now been granted, strengthening the technology’s international protection and commercial readiness.
FINAL QUALIFICATION PHASE
AERSUB is now in its final qualification and certification phase with DNV, supported by ongoing wet testing, procedural verification, and engineering optimisation ahead of commercial deployment.
TESTING, CERTIFICATION & PATENT ACHIEVMENTS
WHAT'S NEXT
AERSUB is progressing through the final steps toward market introduction.
Irish Sea Contractors is engaging with select operators, utilities and cable owners to prepare for commercial readiness.
How AERSUB works
AERSUB
Repair demonstration of prototype
AERSUB’s commercial prototype was deployed offshore Ireland to complete a full subsea repair demonstration on a 3-core power cable.
The operation was carried out in challenging conditions—including strong winds and 1.5 m swell—conditions that would typically halt a traditional lift-to-repair approach.
During the demonstration, AERSUB subsea jointers successfully installed:
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four complete joints
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twelve fibre optic joints
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a steel jointing case filled with resin
The works were completed safely within 12 hours, showing the potential for significantly faster and more predictable repair operations.
Insights from this demonstration were incorporated into subsequent refinements of the system.