The situation
A high-voltage subsea cable represents critical infrastructure and must be repairable in case of failure. Without a suitable solution, repairs would be complex and time-consuming, risking downtime across installations.
The cable’s multi-layer flexible construction makes it particularly challenging to handle. It must be lifted without damage, requiring high precision and control of friction and clamping force.
The project was developed as a contingency solution, ensuring that a verified lifting and repair tool would be available before a critical failure occurred.
The Solution
Concept
IK Subsea developed a friction-based lifting clamp that enables safe handling and lifting of the cable without damaging its multi-layer structure.
Engineering highlights
- Friction-based lifting principle.
- Designed for a 184 mm HVAC cable outside diameter.
- 40-tonne lifting capacity.
- Tool weight of 2.4 tonnes.
- Precise control of clamping force.
- ROV installation using a standard class 4 torque-tool bolt interface.
- Full-scale testing on the actual cable.
- Analysis of creep and material behaviour.
Delivery & execution
- IK Subsea developed and tested the lifting clamp as a contingency solution.
- The customer was NKT.
- Aker BP is the operator, with Equinor and Orlen Upstream Norway as licence partners.
- The solution was developed and tested, but had not been deployed operationally at the time of the case description.
Verification and qualification
- Full-scale testing on the actual cable.
- Verified lifting capacity.
- Controlled material behaviour.
- Documented safe handling without damage.
Key Facts
| IK Group company | IK Subsea |
|---|---|
| Segment | Yggdrasil |
| Location | Snøhvit / Norwegian Continental Shelf |
| Year | 2024 |
| Asset type | High-voltage subsea cable |
| Cable dimension | 184 mm HVAC cable OD |
| Lifting capacity | 40 tonnes |
| Tool weight | 2.4 tonnes |
| Depth / Pressure / Temp | No depth limitations specified |
| Delivery model | Contingency tool for lifting and repair |
| Customer | NKT |
| End customer / operator | Aker BP, with Equinor and Orlen Upstream Norway as licence partners |
| Status | Developed and tested; not deployed operationally |
Challenges
High-voltage subsea cable representing critical infrastructure that must be repairable in case of failure
Flexible cable with a complex multi-layer structure.
Risk of damaging the cable during lifting and repair operations.
Need for precise control of friction and clamping force.
Creep and material deformation in the cable structure.
Need to verify lifting capacity through testing.
Adaptation to a specific cable dimension.
High reliability requirement in contingency scenarios.
ROV installation using a standard class 4 torque-tool bolt interface.
Results
Contingency solution established
The project established a tested contingency solution for handling critical subsea cable infrastructure.
Rapid repair enabled
The lifting clamp enables faster repair preparation in case of cable failure.
Reduced downtime risk
The solution reduces the risk of downtime for installations and field operations.
Development and mobilisation time saved
Having the tool developed and tested in advance can save up to approximately 26 weeks of development and mobilisation time.
Lifting capacity verified
Full-scale testing verified the required lifting capacity.
Cable handled without damage
Testing documented safe handling of the cable without damage.
