In brief: In February 2020 MontiPower® presented a DNV offshore hydro unit: a hydraulic power unit that can drive up to five Subsea Bristle Blaster® tools at the same time. Besides the Subsea Bristle Blaster®, it can also feed a Caviblast, a drill or a grinder, making it a single power source for offshore structural repair and maintenance work.
This news item from February 2020 introduces the DNV offshore hydro unit for the Bristle Blaster® Subsea. Below you will find what the unit does, how it fits with the water-driven Subsea Bristle Blaster®, and why one power source for several underwater tools matters for offshore repair and maintenance crews.
The announcement
This is a DNV offshore hydro unit for powering up to five Subsea Bristle Blaster® tools simultaneously. The possibility of feeding the MontiPower® Subsea Bristle Blaster®, a Caviblast, a drill or a grinder makes this unit a complete kit for offshore structural repair and maintenance.
What the Subsea Bristle Blaster® is
The Bristle Blaster® Subsea is MontiPower's hydraulic underwater surface preparation tool with a water drive. It is connected to a power unit via a single, neutrally buoyant high-pressure hose, and its torque and speed are adjusted at the high-pressure unit. Like the topside Bristle Blaster® tools, it removes corrosion, coatings, scale and adhesive residue and leaves a profiled surface for the mechanical bonding of protective materials. MontiPower specifies the result as a surface preparation grade comparable to ISO 8501-1 Sa 2½ or Sa 3, with an anchor profile of 65–85 µm Rz on standard steel in documented tests; results vary with steel grade, rust grade, belt and technique.
Because it uses no loose abrasive, there is no blast media to contain or recover below the waterline. Typical applications are pipeline composite reinforcements, preparation for subsea welding on ships, port infrastructure and subsea pipelines. More background is on our subsea surface preparation page.
Why a multi-tool hydro unit matters offshore
Offshore repair and maintenance campaigns are constrained by deck space, lifting capacity, diver time and logistics. A single hydraulic power unit that can run up to five Subsea Bristle Blaster® tools at once, or switch to other hydraulic tools such as a drill or grinder, reduces the amount of separate equipment that has to be mobilised to a vessel or platform. It also lets several divers prepare surfaces in parallel from one power source.
For asset owners, the point of underwater surface preparation is what follows it: repair coatings, composite wraps and other protective materials only perform when they are applied to a clean, profiled substrate. The tool is part of that chain, and the result is still verified against the project specification.
Background and research
The Subsea Bristle Blaster® builds on research into bristle blasting below the waterline. A 2016 German study examined bristle blasting as surface preparation for underwater corrosion protection; see the summary of bristle blasting for underwater corrosion protection. Independent work at Fraunhofer IGP has since tested a robot-guided Subsea Bristle Blaster® for underwater coating repair, described in robots below the waterline.
Earlier news on the subsea line: the new hydraulic underwater device (September 2019) and the first series of Subsea units leaving the factory (December 2019).
Where to learn more
For the full range of offshore applications, see marine and offshore surface preparation. Subsea surface preparation and diving equipment can also be rented; see tool rental. For project-specific configurations of the hydro unit and Subsea tools, contact the MontiPower® team.
Frequently asked questions
How many Subsea Bristle Blaster® tools can the DNV offshore hydro unit power?
The DNV offshore hydro unit presented in February 2020 can power up to five Subsea Bristle Blaster® tools simultaneously. That allows several divers to prepare surfaces in parallel from one hydraulic power source instead of mobilising a separate unit for each tool.
Which other tools can the hydro unit drive?
Besides the MontiPower® Subsea Bristle Blaster®, the unit can feed a Caviblast, a drill or a grinder. This makes it a single power source for a range of offshore structural repair and maintenance tasks rather than a dedicated unit for one tool.
What surface does the Subsea Bristle Blaster® produce?
MontiPower specifies a cleanliness comparable to ISO 8501-1 Sa 2½ or Sa 3 and a profiled surface suited to mechanical bonding of protective materials, with 65–85 µm Rz on standard steel in documented tests. Results vary with steel grade, rust grade, belt and technique, so the result is verified on the job.
