Page 48: of Offshore Engineer Magazine (Jul/Aug 2023)

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TECH FILE SUBSEA PILE PROTECTION

Scour Pneumonia

HexDefence – Installation

Can you discuss a bit more about the materi- What is the process to install HexDefense and als that are used for HexDefence? How long are how does it save time or money in terms of al- they designed to last, and what, if any, specifc ternative methods of protection?

We’ve had discussions with developers and installers to or special maintenance do they require?

really hone in on a installation process that works for them.

Right now we are looking at a couple of different op- tions. Both have different ways of manufacturer, also have We've come up with some basic strategies, and the idea is different advantages. One is a GRP or an epoxy-based it's sleeved over a monopile structure, and that's utilizing system, designed to be used in a seawater environment the same vessel, the same lift vessels that we would use for for 30 years plus. We're also looking at other materials, let's say the transition pieces which have to also get ftted. things like concrete and items like that, which again, That's one scenario. There are obviously different scenarios have a different cost structure but also have a different within the, or different installation strategies that account advantage as well. Things like ballast, weight mass, which happen for different felds. But one scenario would be that.

The idea here really is the total cost of ownership. It's about also helps with the product and making it more stable saying, "We'll put HexDefense on and we are able to reduce when it's around a monopile.

the level of rock dumping." So that eliminates the need for a number of vessels. It's also saying we are able to bury our

Does HexDefence come from the oil and gas sector?

cable much closer to the monopile, therefore it's to have

Its inception came from oil and gas, but to be hon- est, they're all marine engineering in my opinion. If you reduced dynamic length and making the load cases much have something in the water column used in oil and gas, easier to contain on things like cables. Again, we're thinking maybe the risk profles are slightly different. However, longevity. We're thinking what can we do for the total cost the importance of something being used subsea for 30 of ownership of the feld. And we see a lot of the time sav- years, whether it's oil and gas, whether it's renewables, ing, a lot of OpEx cost being saved and really improving the really the thought process, the technology, all should be lifespan of cables, improving the lifespan of not having to go and redo a rock dumping operation after the fact.

very similar.

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