Splash zone inspection without divers

The splash zone is the band of an offshore structure that sits in the reach of the waves and the tide, and it is the hardest part of the asset to inspect. Divers and ROVs both struggle there, because the same wave action that degrades the steel makes the zone dangerous and unstable to work in. Remotely operated robotic tools now do that work without divers, ROVs, or a support vessel. They clean marine growth, take wall thickness and crack detection readings, and carry out repairs and structural modifications, all controlled from the deck. For an operator weighing a life extension case on an ageing platform, this changes the economics of finding out what condition the structure is actually in. OceanTech Innovation, a Norwegian company now with an office in Perth, has built its business on this work, with more than 80 projects across 55 installations.

Why the splash zone is the hardest part of the structure to inspect

The splash zone is where wave action, tidal range, and marine growth combine, and it is where corrosion and fatigue accumulate fastest on a fixed structure. It is also where conventional access is worst. Divers face wave loading and confined access around jacket members and risers, and ROVs lose station keeping in the surface turbulence, so the data either costs a great deal to collect or does not get collected at all.

What a remotely operated tool actually does in the splash zone

OceanTech runs a set of remotely operated access tools that clean, inspect, and modify structures in the splash zone, deployed and controlled from the platform deck. The Clamp Access Tool clamps onto a riser or conductor, cleans it, and carries a robotic arm with inspection probes for wall thickness and crack detection. The Diverless Riser Inspection Tool extends the same idea to flexible risers, reaching the balconies, bellmouths, and bend stiffeners that are otherwise diver-only scope.

What the inspection produces for an integrity decision

The point of the inspection is a defensible integrity decision, not just an image. Eddy current and pulsed eddy current testing detect fatigue cracks and measure wall loss, which lets the engineering team calculate remaining service life and decide whether a member needs a clamp or further monitoring. That is the data a life extension case has to rest on, and it is the data that is hardest to collect in the splash zone by conventional means.

Whether removing divers and ROVs changes the cost

Removing the dive spread changes three cost lines at once. It cuts persons on board, which is a hard constraint on most offshore facilities. It removes the support vessel with its day rate and emissions. And it reduces the weather dependence that drives standby time, because the remote tools capture data in conditions that would stand a dive team down. On one life extension project, ConocoPhillips Skandinavia reported a saving of $1.9 million by using OceanTech's crack detection robot instead of conventional methods.

What modifications can be done without a dive spread

Inspection is only half of a life extension scope. The same remotely operated approach handles structural modification work: anode installations to manage corrosion, fairlead replacements, caisson replacements, and riser protection net replacements. Riser protection nets shield risers from the impact of an errant supply boat, and they degrade over time, so replacing them is a recurring life extension task that would otherwise need divers.

Where this has been done

This is not a trial technology. OceanTech developed an eddy current weld inspection robot with ConocoPhillips for the Ekofisk C jacket and qualified it through a DNV technology qualification process. It has carried out riser protection net and fairlead work for Equinor, riser inspection for Hess on the South Arne field, and it lists Woodside among the operators it has done life extension work for. Across its projects it records 250,000 incident-free work hours.

What this means for a Western Australian operator

The North Sea reached the ageing asset problem first, and the Norwegian continental shelf is full of platforms now operating beyond their original design life. WA's offshore infrastructure is moving the same way, and the inspection and life extension questions are the same. OceanTech has opened an office in Perth, which means a WA operator can scope this work without coordinating a campaign across a 10-hour time difference. The question worth asking on a specific asset is whether the next splash zone inspection has to be a dive campaign at all.

Common Questions

Can you inspect the splash zone without divers?

Yes. Remotely operated tools clean, inspect, and repair structures in the splash zone without divers, ROVs, or a support vessel, controlled from the platform deck. OceanTech records 250,000 incident-free work hours across this kind of work.

What is the splash zone on an offshore platform?

The splash zone is the band of the structure within the reach of waves and tide. It is where marine growth, corrosion, and fatigue accumulate fastest, and where divers and ROVs are hardest to deploy because of wave action.

How does robotic splash zone inspection support platform life extension?

It produces the integrity data a life extension case needs. Eddy current and pulsed eddy current testing detect fatigue cracks and measure wall loss, which lets engineers calculate remaining service life and decide on clamps or further monitoring. OceanTech qualified its eddy current weld inspection robot with ConocoPhillips on the Ekofisk C jacket through a DNV technology qualification process.

How much does removing a dive spread save on splash zone work?

On one life extension project, ConocoPhillips Skandinavia reported a $1.9 million saving using a crack detection robot instead of conventional methods. The saving comes from cutting persons on board, removing the support vessel, and reducing weather standby time.

Which operators have used OceanTech's splash zone robots?

OceanTech lists work for ConocoPhillips, Equinor, Woodside, and Hess. That includes riser protection net and fairlead replacement for Equinor and riser inspection for Hess on the South Arne field.

Does OceanTech operate in Australia?

Yes. OceanTech has opened an office in Perth, Western Australia, which puts support and project coordination in the same region and time zone as WA operators rather than in Norway.

What is a riser protection net and why is it replaced?

A riser protection net shields risers from impact by an errant supply boat. The nets degrade over time, so replacement is a recurring life extension task, and OceanTech replaces them remotely without a dive spread.

Can the splash zone be inspected in bad weather?

The remotely operated tools capture inspection data in conditions that would stand a dive team down, which reduces the weather standby time that drives offshore cost. Eddy current testing works through the surface turbulence that limits diver and ROV access.

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