Decom Engineering Launches Ultra-Light Chopsaw for Subsea Ops

June 18, 2025

Northern Ireland-based subsea technology specialist Decom Engineering has developed and deployed a new ultra-light Chopsaw for subsea cutting operations.

The C1-16UL Chopsaw represents the most significant advancement in Aberdeen-based Decom's Chopsaw range, specifically engineered for cutting flexible risers and mooring chains under tension, riser turret moorings and deepwater tensioned moorings.

The C1-16ULChopsaw (Credit: Decom Engineering)
The C1-16ULChopsaw (Credit: Decom Engineering)
The C1-16ULChopsaw (Credit: Decom Engineering)
The C1-16ULChopsaw (Credit: Decom Engineering)

The standout feature of the C1-16UL is its weight characteristics - weighing approximately 270 kg in air but just 30 kg in seawater. The weigh reduction offers increased maneuverability with ROVs while maintaining its cutting capabilities inherent in all Decom Chopsaws.

"We've fundamentally rewritten the chopsaw rulebook. Where traditional subsea cutting relied on heavier, rigid steel frames, we've created a tool that delivers superior performance while being light enough for smaller ROVs to deploy effectively. This eliminates the need for cranes and enables access to challenging locations previously considered inaccessible,” said Nick McNally, Decom Engineering Commercial Director.

Following extensive testing and trials, the C1-16UL has been deployed offshore on international projects, leading to Decom investing in three additional units which are currently engaged in chain cutting and flexible riser cutting operations.

The C1-16UL incorporates several innovations, including a subsea-grade aluminium frame replacing traditional steel construction and a high-torque direct-drive hydraulic motor which has eliminated the need for a gearbox without sacrificing performance.

It also employs a single-clamp system that provides equivalent stability while reducing weight and complexity and modular buoyancy system that allows fine-tuning for different operational environments, ensuring optimal stability and control across varying deployment conditions.

According to Decom Engineering, the C1-16UL addresses critical limitations in existing subsea cutting technology, where weight and size constraints made traditional tools less suited for deployment in confined subsea environments or attached to an ROV.

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