Tasmania Gordon River cruise: Australia's convict 'hell on Earth' is now more like a paradise

Hell on earth isn't such a bad place. A harbour six times the size of Sydney's surrounds it, and it's just a handful of kilometres to the immaculate rainforest reflections of the Gordon River, which are like etchings on the water. It feels more like an original paradise than damnation. When convicts named Hells Gates, however, all they saw was a wild channel of water at the entrance to Tasmania's Macquarie Harbour. It was a notorious wrecker of ships, and the convicts' gateway to Sarah Island, imprisonment and a life of hell.

But as the Spirit of the Wild catamaran idles outside of Hells Gates, the sea is in a good mood. In winter, the average wave height here is five metres, but this summer day the Southern Ocean rolls beneath the boat like small corrugations.Twin lighthouses sit at the harbour entrance, blinking their warnings each night, and if you head west from here it's 15,000 kilometres to the next landfall, which is Argentina. The Spirit of the Wild, however, is heading east, squeezing through Hells Gates and into Macquarie Harbour.

Spirit of the Wild is Gordon River Cruises' new 33.8-metre vessel. Launched last June, and carrying up to 190 passengers, it's fitted with both diesel engines and electric motors. The diesel engines propel us across Macquarie Harbour, but as we slip past Sarah Island and into the mouth of the Gordon River, the quieter electric motors take over.

A hush falls over the World Heritage-listed river and landscape, and we seem to skate over the water that's darkened with the tannins that pour down the river. It's the classic colour of Tasmanian river water, as though the island floats in a giant keg of beer.

In the early morning, the Gordon River is a breathless place, creating reflections so perfect they turn the world on its head. At this lower end, the river runs wide and shallow, but as we head upstream, entering First Gorge, it narrows, deepens and rainforest pours down the slopes. The forest is a snarl of myrtle beech, sassafras, celery-top pine and Huon pines angling out over the river.

We glide upstream to a pier at Heritage Landing, the furthest point up the river at which tourist boats can travel, where a 400-metre-long boardwalk circuits through the rainforest. Halfway around, the walk breaks into a clearing where a 2000-year-old Huon pine crashed down, flattening the forest around it. From the landing, it's a quick cruise back to Sarah Island. Afloat near the mouth of the Gordon River, it's a tiny island with a huge reputation for brutality. The great white mass of Frenchmans Cap rises in the distance, and a pair of actors from Strahan's Round Earth Company await the boat's arrival, ready to guide us around the island and its strange rags-to-riches convict story.

Up to 380 convicts at a time were held on this glorified rock between 1821 and 1833, and the half-metre-thick walls of the British Empire's first solitary confinement cells still stand among its other ruins. The authorities' plan for Sarah Island was to have convicts fell Huon pines upriver, float them to the island and ship them to Hobart. The fierce seas of Tasmania's west coast proved too formidable, however, so convicts built Huon pine ships on the island instead. It became the most productive shipyard in Australia, launching 131 ships in 12 years.