The best subsea markers for the North West Shelf region

The North West Shelf of Western Australia is gas and oil well central, packed with a multitude of production areas, pipelines and support facilities.

And where there are subsea facilities, you know there are going to be a lot of subsea markers. But what are the best subsea markers for the North West Shelf region?

Is Aquasign up to the job of keeping ID markers clear of biofouling in these tropical waters?


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What’s biofouling like in the North West Shelf region?

Factors that affect rates of marine growth are:

  • Season
  • Sunlight
  • Temperature
  • Flow Rates
  • Salinity
  • Water Depth

Australia’s North West Shelf region is a tropical area, which means it ‘enjoys’ consistent rates of fouling all year round. It’s fair to say that there’s plenty of sunlight there too, so that’s another plus for marine growth. 🏝

Water in the NWS region averages 21- 22ºC all year round, kept warm by its location and the Leeuwin current, which flows southwards through the area. Nutrient and flow rates are also consistently high. Salinity in the zone averages 35-37ppt, which is at the higher end of normal range.

In terms of depth, it’s generally the rule that you get more bio-fouling in shallower waters, which means that man-made structures are a perfect site for marine growth to flourish.


Want to learn more about biofouling in Australian waters?
Contact us for a copy of our independent report.


How do the usual anti-fouling markers stack up?

So some of the typical subsea marker methods are:

  • Biocidal paint
  • Silicone paint
  • Cupro-nickel markers
  • Plastic

Let’s take a quick look at how they match up to Aquasign’s smart-silicone markers.

Biocidal paint

First of all, the clue’s in the name – the paint is biocidal, which isn’t great news for the marine environment and the organisms that live in it.

And while you might not have much sympathy with barnacles, kelp and algal spores, it’s worth considering your Corporate Social Responsibility agenda. Does it reflect well on your business to be placing biocides in the ocean?

Best subsea markers for NWS region - quote image - square


In the grand scheme of things, it may not be an issue. But then consider these factors:

  • Biocide legality: Many biocidal paints are banned for use in Australian waters following studies that showed significant contamination in the coastal sediment.
  • Biocide effectiveness: the biocide used may not be particularly effective at combating a specific region’s marine growth profile
  • Biocide release rate: biocidal paint has a short life-span and will need to be repainted. It releases biocide rapidly at first, then more slowly as the amount of biocide remaining decreases.
  • Biocidal paint: may be effective over the short-term, decreases in effectiveness over time, toxic to marine life.
  • Aquasign: completely non-toxic and third-party-verified and approved for use within Australian waters.


🚢 Silicone paint

Designed for coating the hulls of sea-going vessels with a speed of at least 15 knots, silicone paints are environmentally-friendly and great for reducing weight and hydrodynamic loading on ships.

So far, so good. But man-made structures like oil and gas wells don’t travel at 15 knots. Without that movement, silicone paint can develop a slimy film of bacteria and proteins – not ideal for subsea markers.

Silicone paint is also easily damaged, not great when it’s used at remote intervention interfaces: ROVs aren’t the gentlest or most graceful of technology, and once they’ve damaged the silicone paint, hard fouling organisms will take the opportunity to flourish.

  • Silicone paint: environmentally friendly, not ideal for stationary structures, low damage tolerance.
  • Aquasign: environmentally friendly, proven effective on stationary structures, higher damage tolerance – third-party tested.


Cupro-nickel markers

Copper-based subsea markers prevent fouling by forming a resistant cuprous-oxide film. But, over time, the film itself oxidises to form a cupric-hydroxychloride film, which offers no resistance to marine growth whatsoever.

Copper-resistant bacteria (bacterial growth being the primary type of bio-fouling) can also colonise on the surface of cupro-nickel markers, causing layers of corrosion that entraps biological matter and silt.

The results? Well, they’re not great.


  • Cupro-nickel markers: environmentally unfriendly, can be effective over the short-term
  • Aquasign: environmentally friendly, guaranteed to remain in place and clear of biofouling for 60 years.

Plastic, Vinyl or Metal Nameplates

We debated as to whether to include plastic subsea markers in this list because…well, they’re just not effective. But, it’s surprising how many operators still massively underestimate the problem marine fouling can cause, particularly in tropical areas like Australia’s North West Shelf.

Using marking materials with zero anti-fouling properties is really common. And we think a picture is worth 1,000 words when it comes to the results:


  • Plastic markers: Useless as a subsea marker in almost every way. 👎🏼
    Aquasign: Non-toxic smart silicone anti-fouling marker, proven and guaranteed for 60 years. 🤩

And the best subsea marker for the North West Shelf is…

In news that will surprise absolutely no one, the award for best anti-fouling subsea marker for use in Australia goes to Aquasign 🏆

  • Environmentally friendly
  • Guaranteed to stay in place for 60 years
  • Guaranteed to remain visible for 60 years
  • Range of powerful and simple installation methods
  • Attached easily pre-deployment
  • Easy to retrofit by diver or ROV

Aquasign won’t need to be replaced for 60 years, saving you time, money and hassle. Our hydrophobic, smart silicone markers are easy to install and guaranteed to perform – even in the most tropical of tropical waters!

Aquasign’s been tested extensively and proven effective in the North West Shelf region (and other parts of the oceans off Australia).

So if you’ve got a project coming up down under, we’d recommend you give Aquasign a try – our markers can be tailored to every application and substrate.

Call us today, or send us an email, to discuss your requirements. We’re happy to help.

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➡️Related content: read our guide to the different Aquasign installation methods or review our smart silicone marker’s key features for your next project.

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