He devised an ambitious plan to fortify the whole inner harbour of the Derwent River with a network of heavily armed and fortified batteries located at Macquarie Point, Battery Point and Bellerive Bluff on the eastern shore. He envisaged the forts all having an interlocking firing arc, which would cover the entire approach to Sullivans Cove, making it impossible for ships to enter the docks or attack the town unchallenged.
By 1855, the colony of Van Diemens Land was granted responsible self-government by the colonial Office, and renamed Tasmania. The Colonial Office began to pressure the newly formed local government to take more responsibility for the self-defence of the colony.
The arrival of three Imperial Russian Navy warships, the Africa, Plastun, and Vestnik in 1872 caused a great deal of alarm in the colony. Britain and its empire had only been fighting the Crimean war with the Russians 16 years previously. The colony was virtually defenceless, and had the Russians had hostile intent, would probably have easily fallen. Luckily the Russians were on a good will mission, however, it cause a great deal of debate about the state of the colonies defences.
A triangle of fortresses with the Queens Battery at the Apex, and two new Batteries, the Alexandra Battery, named for Princess Alexandra, the Princess of Wales, and the Kangaroo Battery on the eastern shore would be adequate for the task. Construction began on the new fortifications in 1880, and at the same time, a new permanent field artillery unit, the Southern Tasmanian Volunteer Artillery equipped with two breech-loading 12 pound howitzers and two 32 pounder guns on field carriages, was raised.
Following the dismantling of the Battery Point batteries, much of the stonework was relocated to the site of the Alexandra Battery. The site of the Alexandra Battery is now a public park with commanding views of the river, and much of the original construction is still accessible.