Beneath the Surface. Why Underwater Sculpture Trails Are Good for the Sea, and Why We Want to Build One
On the synergy between art, marine ecology, and the story of a harbour pilot who walked into the sea.
When the Worser Bay Boating Club and Boat & Beach Wise Trust submitted their proposal for a community marine reserve, one line in it caught our attention: a snorkel trail featuring underwater artworks that serve as habitat. We have been thinking about little else since.
We are Unfound, a sculpture and fabrication studio based in Christchurch. We work primarily in low-carbon GRC concrete. And we think underwater sculpture might be one of the more quietly important ideas in contemporary public art.
Here is why.
Art that works while nobody is watching
The case for underwater sculpture trails is not purely aesthetic. It is ecological.
Sculptor Jason deCaires Taylor has been making the case with his hands since 2006, when he placed the first modern reef sculpture in Grenada to help restore a damaged marine ecosystem. His Museum of Underwater Art at John Brewer Reef off Townsville, the largest underwater sculpture installation in the world, has produced measurable results. Before installation in 2018, surveys recorded 12 fish species and 65 individuals at the site. By 2022 that had grown to 46 species and 365 individuals. Coral transplanted onto the sculptures in 2020 achieved a 91.6% survival rate after one year, above the typical 80% benchmark for shallow water projects.
The sculptures are not decorative additions to a healthy reef. They are structure, physical complexity added to a simplified environment, and marine life responds to structure the way it always has. Small fish find shelter in cavities. Invertebrates colonise textured surfaces. Larger species follow the food chain up. A placed object becomes, over years, a node in a living system.
There is a second benefit that is harder to quantify but no less real: pressure relief. Popular natural reefs carry the burden of every snorkeller, diver, and curious visitor who wants to see them. An underwater sculpture trail gives people somewhere specific to go, a destination with its own draw, that sits alongside the reef rather than on top of it. The people who would otherwise concentrate on the most fragile sections of a natural environment are distributed. The reef gets a rest.
Taylor’s visitors in the Whitsundays rated the beauty of the underwater sculptures above that of the natural reefs nearby. That is a remarkable finding. It suggests that people are not choosing between nature and art. They are finding that art, placed thoughtfully in nature, makes the whole experience richer.
Why GRC is the right material
GRC, glass fibre reinforced concrete, is our primary medium, and with the right mix specification it is well suited to permanent underwater installation.
For marine use we specify a modified approach. The outer shell is cast in GRC with reduced polymer content and a blended low Portland binder incorporating pozzolanic materials. This reduces the free lime that standard concrete leaches, lowers the cured pH closer to neutral, and preserves the micro surface texture that marine organisms need to establish a foothold. Standard polymer modified GRC fills that micro porosity, which is ideal above ground but counterproductive underwater. We leave the surface open to the sea.
The sculptural shell is part filled with a GGBS heavy aggregate concrete, again low in Portland cement, which continues the pozzolanic reaction over months and years, progressively reducing residual alkalinity through the full depth of the piece. All works are cured for a minimum of 28 days before marine placement.
GRC’s inherent strength as a shell material means the upper form can remain hollow, something a traditional solid concrete pour cannot achieve at this scale without significant structural compromise. That hollow interior becomes habitat, a sheltered cavity for small reef fish and invertebrates enclosed within the sculpture itself. The lower section is filled with a dense blended concrete base, providing sufficient mass to anchor the sculpture to the sand substrate without mechanical fixing to the seabed, while keeping the overall weight manageable for transport and placement by a small dive team.
The Standing Pilot
Our concept for the Worser Bay trail centres on James Heberley, the harbour pilot the bay is named after. He came to Wellington in 1839, guided the first ships through the harbour entrance, married into Ngāti Ira, and lived at the bay until old age. He died in September 1899, found floating upright in Picton Harbour, his carved walking stick still in his hand.
The sculpture proposes a single abstract standing figure in black GRC, approximately 1.8 metres, feet buried in the sand of the Worser Bay seafloor. No face. No portrait detail. Only the essential silhouette of a person standing upright in the water, stick in hand, which is exactly how he was found, and exactly where he spent his life.
This is what underwater sculpture can do that a plaque or a memorial bench cannot. It places a story back in the environment that formed it. A snorkeller hovering above the figure, watching caustic light move across the black concrete shoulders, is not reading history. They are inside it.
We are actively seeking engagement with the Boat & Beach Wise Trust, the Worser Bay Boating Club, and the project’s iwi and community partners. We have also reached out directly to James Heberley’s family, whose blessing we consider essential before this concept goes any further.
Where else this could go
Worser Bay is one bay. New Zealand has a coastline of extraordinary length, enormous ecological diversity, and a culture of water, diving, snorkelling, freediving, spearfishing, that runs deep in both Māori and Pākehā traditions.
The Abel Tasman is an obvious next conversation. It is one of New Zealand’s most visited coastlines, with snorkelling already central to the visitor experience. The pressure on its marine environment is real and growing. A thoughtfully designed underwater trail, sculptures that tell the stories of the coast, provide habitat, and give visitors a destination, would do what Taylor’s work has demonstrated is possible: make the experience richer while making the reef stronger.
We are a small studio. We do not have the capacity to propose every trail or pitch every council. But we have the material, the fabrication capability, and the conviction that this is worth doing well. If you are working on a coastal project, a reserve, a trail, a community marine initiative, we would like to hear from you.
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