The Subsea Challenge
Recently, TMT has supported multiple clients with the cutting of large studded and studless anchor chain, with chain sizes ranging from 85 mm to 112 mm.
These projects presented a range of technical challenges, including cutting chain in a vertical configuration while under tension, as well as horizontal cutting operations following deployment into a subsea chain table.
In both cases, our clients approached TMT due to our proven track record in the design, supply and deployment of specialised subsea cutting solutions for previous anchor chain cutting campaigns.
Precision Engineering for Dual Configurations
Following a detailed engineering assessment, including evaluation of cutting methods and controlled test cuts at TMT’s dedicated cutting facilities, the optimum solutions were identified. A diamond wire saw (DWS) was selected for the horizontal cutting application, while a hydraulic chopsaw was selected for the vertical cutting operation.
Both cutting systems were engineered for remote operation via ROV, with each tools configuration tailored specifically to the operational requirements.
DWS Deployment for Subsea Table Integrity
For the horizontal cutting application, TMT designed and manufactured a custom clamping system to secure the diamond wire saw to both the chain and subsea table. The design incorporated protective guards to prevent damage to adjacent chain links, allowing the remaining chain to be reused.
ROV-Operated Chopsaw and Blade Optimisation
The vertical cutting operation presented additional challenges, requiring the ROV to free-fly the saw into position, clamp securely onto the chain, complete the cut, and remain attached to the chain following separation. A hydraulic chopsaw configuration was developed to meet these requirements.
A comprehensive blade selection process was undertaken, including trials of multiple blade types, test cuts, and hardness testing of the chain material. Once the optimum blade and saw combination was identified, further testing was completed to establish the required operating parameters, including blade motor flow rates and pressure and feed rates and pressures.
The final tool configurations were then equipped with dedicated hydraulic control circuits, enabling the ROV to hot stab directly into the cutting tools and remotely control the cutting operation subsea.
Offshore Execution and Rapid Redeployment
Following successful factory acceptance testing, the cutting systems were packaged, mobilised and deployed offshore. Both cutting campaigns were completed successfully, meeting the required operational schedules.
DWS cutting the anchor chain subsea
The success of the horizontal cutting solution also led to a further chain cutting requirement from the same client. TMT was able to rapidly redeploy the existing diamond wire saw, incorporating minor modifications to configure the system for the smaller chain size, demonstrating the flexibility and adaptability of the tooling solution.
Whether the requirement is cutting large anchor chain or developing a bespoke subsea cutting solution, TMT brings together ROV experience, specialised tooling, engineering capability, and offshore experience to support complex subsea operations.
If you have an anchor chain cutting challenge, contact us. Our team has the equipment and experience to engineer a solution suited to your project requirements.