Houlder’s pile gripper ring integrates into a jacket structure and hydraulically engages with pre-installed or stabbed piles using high pressure cylinders. It grips the pile maintaining stability for subsequent installation operations such as grouting, temporary works, completions and removals. This allows an offshore jacket structure to be temporarily gripped to gain an increase in stability.

Benefits of the Houlder pile gripper ring include;

• Structures can be safely maintained in position over extended periods including bad weather
• Provides a gripping force of up to 1500t ensuring on-bottom stability to even the largest of jackets up to 25,000t
• Requires minimal modification to existing jacket structure designs
• Protects jackets and piles from excessive temporary load cases
• Integrated power supply provides redundancy
• Cylinders can be optimised to provide the required gripping force for jacket design
• Can include a hinged system to open and close around the pile
• Available with local or wireless remote control

The pile gripper tool will comply with the following codes & standards:

• DNVGL-SE-0080 ed. 2015-12, Noble Denton marine services – marine warranty survey
• DNVGL-CG-0127 ed. 2015-10, Finite Element Analysis
• 0001/ND rev.1 2015, General Guidelines for Marine Projects
• 0027/ND rev.6 2015, Guidelines for Marine Lifting and Lowering Operations
• 0030/ND rev.6 2015, Guidelines for Marine Transportations

System Specification

• The pile gripper ring can be easily integrated into the structure of an existing jacket or substructure pile sleeve design
• The ring incorporates high pressure hydraulic cylinders to exert the required gripping force on the pile
• The ring has a system of pile deflector shims to ensure the cylinders are not damaged when engaging with a pile
• The gripping action can be activated using an umbilical from a deck-mounted HPU, via remote control or via an ROV hot stab. Once activated, an isolation valve disconnects from the HPU
• The ring ensures the jacket pile sleeve and pile structures are not overstressed by temporary excessive load cases
• The ring provides operator confirmation that the cylinders have engaged to the maximum force and that the isolation valve is safe to engage
• Cylinder pressure gain is staged to ensure all cylinders apply equal force up to the maximum.
• The ring can remain gripped for extended periods. This allows for construction vessels to stand off from the installation operation through bad weather
• The integrated power supply and contains a secondary means of operation should the primary controls and or power system fail