Offshore Decommissioning

Underwater Cutting Solutions

Abrasive waterjet cutting

Complete Calder/ANT underwater cutting system.

Why Water Abrasive Suspension?

The unique ANT Water Abrasive Suspension (WAS) system is the latest in waterjet cutting technology. Through innovative design, waterjet cutting is now more efficient and safe, with lower water flow, greatly reduced abrasive/garnet consumption, minimization of equipment downtime, and efficiencies of operation.

Ultra high pressure waterjet cutting has become a recognised method for the cutting of many materials. The ANT Water Abrasive Suspension system ensures a constant flow of abrasive is delivered through the nozzle, allowing uninterrupted flow, maximising cutting time and accuracy. Through the Abrasive Mixing Unit (AMU) the abrasive is added to the water in a vessel pressurized at up to 2,500 bar. The pressure ensures that the abrasive remains in a state of suspension in the water and eliminates blockages, allowing the abrasive mixture to flow freely to the cutting head.

The Water Jet - The water/abrasive mixture is delivered to the cutting piece through a ≥0.6mm nozzle. The abrasive particles pass through the nozzle virtually in single file, thus creating a saw effect and providing a high quality, cold, precision cut.

Why Calder/ANT?

Calder and ANT joined forces to provide the complete equipment package for offshore caisson, pipe, and tube cutting in hazardous area environments.

Calder’s experience and reputation as a leading supplier of hazardous area, high pressure pump packages and ANT’s knowledge and experience of abrasive cutting technology makes for a great team. Together, we provide a full cutting system with expertise in all the relevant technologies.

As ANT’s partner in the UK offshore sector, Calder provide full service and spares support for all components of the system.

The Water Jet

Water abrasive suspension for subsea cold cutting


  • Treatment Fluids
  • Up to 2,500 bar cutting pressure
  • Operate down to a water depth of 600 metres
  • Low abrasive consumption
  • 0.6mm nozzle for precision cutting
  • High cutting speed
  • Reduced kerf width
  • Rated for hazardous area use
  • Cut through multiple layers of steel and concrete

  • Cut through multiple layers of steel and concrete
  • Cut metal up to 500 mm thick
  • Cut concrete up to 1,500 mm thick
  • Use potable or sea water
  • Low flow through precision nozzles
  • Cutting manipulators available for ≥2” pipe
  • Twin option for continuous operation
  • Cold cutting

The Complete System

Calder supply the full WAS cutting system - abrasive mixing unit, high pressure pump, cutting devices, winch, abrasive storage, compressor, control station, manipulation systems, and accessories.

The Process:

  1. The high pressure pump creates water pressure up to 2,500 bar
  2. That water is piped to the abrasive mixing unit (AMU)
  3. The AMU introduces the abrasive into the water

  1. The AMU maintains the abrasive at high pressure in suspension
  2. The water/abrasive suspension is pumped to
  3. the cutting head
  4. Cutting commences

High Pressure Pumping & Vacuum

The Offshore LITE range of vacuum and waterjet units address the issue of reduced crane capacity during offshore platform decommissioning operations.

Vacuum unit for offshore decommissioning

Electric-drive vacuum unit

Jetting machine for subsea decommissioning

Modular, lightweight, hazardous area pump units

Lightweight jetter for oil and gas decommissioning

Integral control panel

Whether your requirement is for high flow water, high pressure water, or vacuum, our OffshoreLITE hazardous area containerised units weigh a maximum of 4,500 kg and our modular crash frame packages can weigh as little as 1,500 kg per lift. All units provide substantial space saving advantages over traditional offshore pump units.

With self-contained diesel powered units, and electric units designed to operate from a standard 63 amp 3-phase socket, these lightweight jetting and vacuum packages offer real versatility to the offshore decommissioning and asset management sectors. See full details of the OffshoreLITE range here.

Calder Hot Wash

Water Abrasive Suspension (7505)

View PDF

Calder Hot Wash

Calder Offshore Lite (7201)

View PDF