Caisson Lifting Tool

STATS provide a range of caisson handling equipment for safely securing and recovering damaged or redundant caissons. Internal and External Lifting Tools cover a range of sizes to allow for safe and controlled caisson removal.


Due to their harsh environment, caissons can experience severe external corrosion at the waterline and galvanic corrosion / erosion at the pump string location. This can result in a lack of integrity, and occasionally result in part, or all, of the caisson becoming detached and lost to the seabed. Should a caisson become detached this would pose a serious safety concern for a platform and risk damage to subsea pipelines and equipment, impacting on production and reputation.


Internal and External Lifting Tools (ILT / ELT) are used to safely secure damaged or corroded caissons in position, until a planned retrieval back to the platform can be performed using the same tool. The compact size of the ELT and modular design of the ILT allows caissons to be recovered where space is limited. Caissons are securely lifted and cut into manageable sections before being safely removed from the platform.


Lifting Tool Locking Features

ILT and ELT taper-locks are hydraulically actuated applying vertical load to the locks set against the caisson. The taper-lock design provides a fail-safe locking system independent of hydraulic pressure, once pre-tension is applied to the lifting tool the hydraulic actuation circuit becomes redundant. The lock engagement range allows lifting tools to be simply modified for use with a range of caisson sizes. 

To provide technical assurance, all lifting and securing tools undergo a client or third party witnessed factory acceptance test (FAT). The purpose of the FAT is to prove the functionality, serviceability, integrity and safe working load (SWL) of each ILT / ELT prior to mobilisation. In addition, all STATS mechanical lifting tools are design in accordance with the DNV Standard for Certification of Lifting Appliances DNV 378 (Lifting Beam).

External lifting tool caisson handling

External Lifting Tool

External Lifting Tools (ELT) are mounted to the outside of the caisson to provide secure lifting when internal access is obstructed or restricted due to pump strings or liners. The split section design allows easy installation, particularly in areas with restricted access or height. External gripping locks are hydraulically activated applying vertical load to the ELT which is set against the caisson.


Internal Lifting Tools

Internal Lifting Tools (ILT) feature a twin module design, with each module containing its own set of independently controlled locks allowing operation in caissons with varying wall thicknesses. The taper-lock design provides a fail-safe locking system independent of hydraulic pressure, both locks provide axial and lateral stabilisation within the caisson. The modular design of the ILT allows the length between lock modules to be configured to client requirements, this also allows for easy installation particularly in areas of restricted access.



24” to 48”

Safe Working Load

up to 55 tonnes

  • Lifting tools retain caissons securely until planned repair or replacement
  • Safe and controlled system for removing damaged or redundant caissons
  • No production shutdown required during the removal operation
  • Designed and tested in accordance with DNV 378 (Lifting Beam)
  • Once pre-tension is applied to support rigging, hydraulic actuation circuit is redundant
  • Hydraulically actuated taper-locks grip wall of caisson
  • Taper-lock design provides a fail-safe locking system independent of hydraulic pressure
  • Tension cable supplies self-energisation effect when pre-tension is applied
  • Tool removed by releasing tension and hydraulically de-activating locks

Related Resources

Safely Securing and Recovering Caissons

Safely Securing and Recovering Caissons

Examples of internal and external lifting tools used to prevent dropped object threat from damaged caissons
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Caisson Securing & Recovery, North Sea, UK

Caisson Securing & Recovery, North Sea, UK

As assets remain in service beyond their planned operational lifespan, caissons will inevitably experience severe external and internal corrosion due to their harsh ...
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Caisson Securing & Recovery | Internal and External Lifting Tools

Caisson Securing & Recovery | Internal and External Lifting Tools

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24” Caisson Liner 95m Long | Piper Bravo, North Sea, UK

24” Caisson Liner 95m Long | Piper Bravo, North Sea, UK

Caisson Liner during factory acceptance testing and offshore installation
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