'Somebody else's dream': How it feels to snorkel in an underwater museum

Most of MOUA is 70 kilometres off Townsville at John Brewer Reef, and it takes about two hours to reach the site by catamaran. On the morning I set out, the waters are calm and the journey a pleasure but sometimes, apparently, rougher waves take their toll on passengers with weaker stomachs.

Once we anchor by the reef and I step off the boat and sink flippers-first into the Coral Sea, I flail around stupidly for a bit, looking for The Coral Greenhouse, a 165-tonne structure sunk 16 metres deep to the seabed.

Inside the stainless-steel bones of The Coral Greenhouse is a collection of cement sculptures of children practising coral gardening - but the artwork is designed to be viewed by SCUBA divers, and all I can make out is the building's soaring ribcage and some rising columns of bubbles.

However, before I board the boat, I'm lucky enough to share a beer in Townsville with Jason deCaires Taylor, creator of The Coral Garden and MOUA's most recent installation, Ocean Sentinels.

British-born environmentalist and underwater artist Taylor has been identified by the highly respected Foreign Policy magazine as a "Global Thinker", alongside Barack Obama, Jordan Peterson and, um, Koko the Gorilla. He once worked as a diving instructor on the Great Barrier Reef and his sculptures are designed to create artificial reefs and draw tourists away from over-visited and endangered marine areas: in the process, they become ecosystems themselves, home (or at least, second home) to an amazing variety of marine life.

Taylor shows me a photograph of an object recently spotted on the greenhouse's frame: it looks like a sunken vegetable but is actually an aquatic animal. "That's a big sea cucumber that has crawled up the top, 12 metres high," he says. It seems that this is unusual behaviour for a sea cucumber.

"They've climbed inside - and they've actually climbed down ropes to get down to things," says Taylor. "It's quite amazing."

The SCUBA divers on my catamaran love The Coral Greenhouse. It's a pity I can't fully appreciate it, but the Ocean Sentinels are a different, um, kettle of fish.

A snorkelling trail leads from the boat to the eight Sentinels, which sit at about five metres deep. The statues - most of them modelled on marine conservationists - are half-human/half sea-life, made up of hands and feet and polyps and tentacles, like giant fantasy fish-tank toys. When I swim among them, I feel lost in somebody else's dream. As a museum experience, it is like no other.

SeaLink Ferries operates daytrips to the Great Barrier Reef and MOUA, leaving from Breakwater Marina, Townsville. Adrenalin Snorkel and Dive trips depart at 7am, returning about 4.30pm, Tuesday, Thursday and Sunday. Snorkellers pay from $295/$245 (adults/children). Certified SCUBA divers pay from $390.

The writer was a guest of Townsville Enterprise