The Hobart Coastal Defences are a network of now defunct coastal batteries, some of which are inter-linked with tunnels, that were designed and built by British colonial authorities in the nineteenth century to protect the city of Hobart, Tasmania, from attack by enemy warships. During the nineteenth century, the port of Hobart Town was a vital re-supply stop for international shipping and trade, and therefore a major freight hub for the British Empire. As such, it was considered vital that the colony be protected. In all, between 1804 and 1942 there were 12 permanent defensive positions constructed in the Hobart region.
When Governor Lachlan Macquarie toured the Hobart Town settlement in 1811, he was alarmed at the poor state of the defences and the general disorganisation of the colony. Along with planning for a new grid pattern of streets to be laid out, and new administrative and other buildings to be built, he commissioned the building of Anglesea Barracks, which opened in 1814, and is now the oldest continually occupied barracks in Australia. Macquarie also suggested the construction of more permanent fortifications.
The Kangaroo Bluff Battery was built to support the Queens Battery (located at the Domain in Hobart) and the Battery Point battery. It was developed to stop any enemy vessels from shelling Hobart Town from just outside the range of the Domain and Battery Point batteries. Although the proposal was mentioned in the early days of settlement, procrastination was the order of the day. It is thought that the appearance in the River Derwent of two Russian warships in 1873 prompted plans for the construction of the Kangaroo Bluff Battery. The Kangaroo Bluff Battery was manned by the Tasmanian Artillery Company volunteers until its closure in the 1920s, though a shot was never fired in anger.
The presence of the Russian warships in the Derwent River, and the condemning of the Battery Point batteries in 1878 had expedited the development of the Alexandra and Kangaroo Batteries.
The design of the fort was a pentagon shape that fitted conveniently into the point of the bluff above the cliff. The ditch, tunnels and underground chambers had to be cut out of solid stone and faced with masonry. Several loopholes and firing ports were fitted into the stone encasements to allow rifle fire from every aspect of the fort. In case of an attempted infantry assault, caponiers faced both landward sides of the fort, with firing positions facing each direction. This meant that the only position to safely assault the fort with infantry was up the sheer cliffs of Kangaroo Bluff.
Access to the caponiers was through iron hatchways that opened into open passageways three metres deep. These in turn led to tunnels accessing underground magazines, stores, a lamp room, well and the loading galleries. The loading galleries were ingenious and allowed the guns to be muzzle loaded with shells dragged along a conveyor belt directly to the muzzle of the gun, when it was in a downward tilted position.
Construction of the Kangaroo Battery was begun when excavations began to be dug in September 1880, according to the plans of Colonel P.H. Scratchley, a Royal Engineer who had been placed in charge of overseeing construction of defences for all of the Australian colonies.
Work was intermittent and beset by funding problems and delays, but in May 1883, Patrick Cronly was placed in charge of the construction on behalf of the Public Works Department, and under the supervision of Staff Officer Boddam, work was completed the following year with the arrival of two massive 14 tonne eight-inch (203 mm) cannons from England. The construction had cost £8,150 (A$16,300) at a time when labourers earned an average wage of about 4 shillings (50c) per day. The guns fired shells weighing 81.7 kg, and thanks to the barreled rifling, had excellent range and accuracy. In 1888, two smaller QF 6 pounder Nordenfelt guns were added. Although the projectiles were only 2.7 kg, they also had excellent accuracy and range. The same year, a Nordenfelt machine gun was mounted facing the entrance gate of the fort.
The first shots were fired on 12 February 1885. Later that year, a dry mound, and deepened wet moat were added, as was further coarse-work covered in broken bottle glass set in mortar. Fences were constructed around the moat in November 1885 when a local boy fell into the moat and drowned.
From 1887, both the Alexandra and Kangaroo Batteries were being manned by detachments of the Southern Tasmanian Volunteer Artillery, as well as the Tasmanian Permanent Artillery. In 1901 Tasmania joined the new Federation of Australia, and all of the city's fortifications passed into Commonwealth control. Kangaroo Fort remained operational until the 1920s, but never fired a shot in anger. In 1925, all of the guns were buried as obsolete, and in 1930, the Clarence City Council took over the site for use as a public park. In 1961, the Scenery Preservation Board acquired the site, and in 1970, the site was turned into a historical site, with the guns being dug up and put on display. The site is now operated by Tasmanian National Parks and Wildlife Service and is a major tourist attraction.