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Maritime Construction - Canstrut Underwater Pipe Grab System

LOCATION: New Caledonia


CLIENT: Maritime Construction / Canstruct


System was designed to be operated with the Aquane barge + winch system that Torque Industries installed in January 2015 and controlled by a Kato 150 ton crane. The Grab was designed to collect cut sections of pipe under the water up to a range of 60 mt's. The grab also needed to be able to remove the cavalier blocks from the pipeline. The grab function are hydraulically controlled by hoses running down to the grab via a festoon loops and a remote console mounted at the crane. The console also controls tension winch which keeps tension on the grab when the crane moves up and down.


Job started on concept design stage. The concept design included the grab + a Cutting / shear function to cut the pipe under the water. The shear section of the job was removed due to the cost and time frame. After the conceptual drawings and the customer liked the design we completed the solid works drawings and costings for the customer approvals. When the customer approved the job we had 20 days to complete the manufacturing and testing of the grab. This included the below sections.

  • Stress analysis
  • Cylinder locking capacity
  • Wire rope selection for the tension winch
  • Fabrication / manufacturing
  • Welding certification testing
  • Hydraulic system operation
  • Cavalier block lifting system
  • Proof Load testing
  • Safety factor load testing
  • Festoon Testing
  • Winch and console testing
  • Under water testing with lights and camera connecting for live feed video.


All functions of the grab worked and past the testing procedure. Grab was sent to New Caledonia for installation. Torque Industries installed and functionally tested the unit in New Caledonia. Customer and operators were very happy with the complete project.

FEATURES: (key features of job listed in dot points)

  • Enabled the customer to retrieve the lengths of pipe safely and faster than with using divers.
  • Reduced the cost of the operation and the workforce required.


Hello All,

Just an email to advise everyone at Torques of the success we had in New Caledonia with the hydraulic grab.

The grab performed extremely well on site and we were able to achieve very good production removing the pipeline using the grab. On a good day we were able to consistently remove 20-30 sections of pipe in a 12 hr shift. Less of course during night works due mainly to visibility issues but still very productive. The actual process of lowering the grab, clamping the pipe and recovering it back to the surface could often be performed in as little as 10 minutes. There were of course issues along the way but nothing more than expected and nothing that wasn't able to be fixed, repaired or modified on site to continue working. The grab avoided the use of divers entirely for the pipeline removal which saved the Client huge amount of money.

Once again, thanks for your help in achieving the tight time-frame and the quality of the finished product.


Matthew Haskett