We drip back aboard the Lady Franklin and negotiate the notoriously narrow and treacherous entry into Macquarie Harbour, which the convicts dubbed Hell's Gate. Then, from the drama of the Southern Ocean, we sail up through the Edenic serenity of the Gordon river.
Today, 160-odd years after the end of transportation and the name change from Van Diemen's Land to Tasmania, Sarah Island is part of a Wilderness World Heritage Area, and its convict sites form one of Tasmania's biggest visitor attractions.
A scenic flight by seaplane is de rigueur to appreciate the scale of the landscape - from the little fishing town of Strahan to the sweep of Macquarie Harbour, the immensity of the rainforest backdrop and the vast contortions of the rivers that carve through this landscape. Flying is also the only way to reach Sir John Falls, a magical spot where a limpid waterfall cascades into a pool tinged a vivid orange by the peaty ground. Dappled light filters through trees jacketed in brilliant moss.
We bid farewell to Strahan, and drive along country roads to Cradle Mountain-Lake St Clair National Park, in the Central Highlands, for walks over button-grass plains and wildlife encounters, dining on marinated wallaby and sleeping in comfortable wooden cabins perched above gurgling creeks.
When not served up on a plate, wallabies hop through the undergrowth, and furry wombats - the principal diet of the park's founder, Gustav Weindorfer - display more circumspection, dashing down burrows at human approach.
Tasmanian devils provide evening entertainment at a local sanctuary set up to safeguard these endemic creatures from the facial tumour disease that is ravaging their numbers. A little devil called Windermere is summoned blinking to meet us, her apparently cuddly demeanour belying a carnivorous bite force of 550kg - shown to good effect at feeding time with her screeching, squabbling siblings. Sarcophilus satanicus, they used to be called, giving rise to an exaggerated reputation for ferocity: when not feeding, they are really rather sweet.
We follow old Aboriginal trails over ridges strewn with ancient flints and middens of oyster shells, emerging in bays of heart-stopping loveliness. I learn that I can nibble "sea spinach", a seaweed known as "sea lettuce" and the base of snake grass (tastes like peas) for sustenance - not that it was necessary. Dinners at the Friendly Beaches Lodge, a simple but comfortable wooden construction concealed behind coastal wattle on a deserted stretch of beach, are convivial feasts of locally sourced produce.
But I cannot pretend. After this three-day burst of exertion, it is with relief that I fall into Saffire on Coles Bay, a heavenly hotel that, along with the eccentric and provocative Museum of Old and New Art in Hobart (which also offers sophisticated accommodation in its eight art-themed "pavilions"), has given a fillip to Tasmania's reputation, introducing new standards of contemporary chic to an island that still rejoices in place names like Bust-Me-Gall Hill and Stinking Creek.
On Saffire's powerful launch, we ride the waves along the peninsula to the former sites of whaling stations and past a quarry that provided granite for the Empire State Building. White-bellied sea eagles soar and swoop to emerge clutching fish, careful lest they wet their feathers. Dolphins dance around us while, on the orange lichen-stained cliffs of Schouten Island, Australian fur seals announce their presence with their unmistakable fishy breath. We moored upwind, and toasted a solitary fairy penguin with a bottle of local wine.
I spent two weeks in Tasmania, and it was not enough. This island the size of Ireland is so diverse, so blessed with the freshest, succulent produce, so far removed from the headlong rush of our century, that I was loath to leave. My final memory is of powering south along the cliffs of the Tasman Peninsula - granite mountains here replaced by theatrical mudstone arches and sea caves, and sheer, dark Jurassic dolerite sculpted into organ pipes and elephant skin by the waves.
Albatross follow our wake to the end of the land, marked by the crashing sea and a solitary lighthouse high on a cliff. For romance and elemental appeal, it is a peerless spot.
Next landfall, Antarctica.
CHECKLIST
Top tips
• The weather in Tasmania fluctuates from the wet west coast to the dry east coast, and it is not uncommon to experience "four seasons in one day".
• To avoid the crowds, go on the shoulders of high season - in spring (October-November) or autumn (March-April).
• Public transport facilities in Tasmania are poor, but it is easy to self-drive. Cars may be hired at airports from around $345 a week. Book at Rental Cars - 0800 368 3001.
Getting there: Qantas flies daily from Auckland, via Sydney and Melbourne.
Further information: See discovertasmania.com.au and parks.tas.gov.au.
