Under cranes and canvas

'Come on, girls, pick up the pace. I want to be home in time for dinner." It's not every day that you wake to the sound of a man screaming into a megaphone just metres from your bed but today is no ordinary day. I'm not in my bed, for starters; I'm camping on the kind of waterfront land many Sydneysiders would do anything to get their hands on.

I pull back the flap on my heavy canvas tent to see the day's first rays hitting the harbour. Skimming along its dawn-calm surface are four muscle-bound men in a sleek sculling boat. Hot on their oars is a tinny piloted by Mr Megaphone. Later I meet a man who jokes that these regular early-morning training sessions on the harbour put the cox into Cockatoo Island.

Over the next few days, ferries, cruise vessels, party boats, fishing boats, kayaks and even a sole windsurfer pass near my campsite. Then there are the helicopter flyovers, as well as a queue of jumbos overhead on their way to land at Sydney Airport. This is, after all, the largest island in Australia's biggest city; secluded holiday isle it ain't. Its shores crowded with old shipyards, cranes and workshops, Cockatoo Island rises from the swirling harbour waters at the junction of the Parramatta and Lane Cove rivers. To the west, you can just make out the curve of the Gladesville Bridge; the Coathanger dominates the horizon to the east. To the north are the leafy slopes of Woolwich, to the south the peninsulas of Birchgrove and Balmain. It is the very definition of absolute harbour frontage in a city obsessed with such things.

The UNESCO World Heritage-listed island has served many roles for the past two centuries - convict jail, industrial school, even a girls' reformatory. Later, it was one of Australia's biggest shipyards, with up to 4000 people employed to build, repair and refit ships during both world wars. They could not have imagined that this 18-hectare industrial monolith would one day be the site of one of the world's great camping grounds.

I first stayed at Cockatoo in 2008, shortly after the Sydney Harbour Federation Trust opened the island to campers. Back then, a few tents were pitched between the water and an old cannon, former air-raid shelter and large metal "sculptures" preserved from the shipyard. These days the island's much busier, with word getting out that an overnight stay is both affordable and unmissable. Camping on the edge of one of the world's finest working waterways is a unique experience. To do so in a place so rich in historical significance is a privilege.

With 125 campsites on a patch of ground not much bigger than a football field, it can get crowded. Yet when we make our midweek visit, there are only about 20 campers plus the usual influx of day trippers arriving by ferry. Visitors usually head straight for the old slipways, wharves, workshops, cranes and dry docks on the southern shore, accessible by two tunnels that slice through the island's sandstone heart.

The plateau above has hosted convicts, soldiers, shipwrights, draftsmen and managers over the years. The people are long gone but many buildings remain, including a former prison barracks, military guardhouse, polishing and pattern shops and a timber store. Some stately island residences have been restored to become holiday homes and apartments for rent and there's a grass tennis court for hire.

The gnarled roots of great Moreton Bay figs cover scars on the plateau's cliffs where rock was blasted away to create an extra five hectares of land on the island's northern shore. Grass now grows where the steel for ships' hulls was once cut and shaped, the machines of industry replaced by an amenities block, communal kitchen and rows of tents. What the island's previous generations of inhabitants would make of it all is anyone's guess - especially of the "glamping" package we go for on this visit. The package provides you with a pre-erected heavy-duty dome tent, camp beds, sheets and blankets, towels, sun lounges, a lantern and a clever little side table that doubles as a portable cooler (ice is available from the office). It's a step up from the regular camping package of a smaller tent, thin sleeping mats, two chairs and a light. You can also hire a campsite and bring your own gear.