Construction

Construction began with demolition teams flattening the island in 1839 . And by 1842 the island was ready to receive her guns.

However Barney was replaced by Lieutenant-Colonel Gordon who drew up extensive plans for fortifying the island including the building of a Martello Tower.

George Barney journeyed to England but returned to Australia in 1849, though he was no longer with the Royal Engineers. The project was postponed until the end of the Crimean War (1853-1856). With the installation of the forts name-sake Governor Denison in 1855 Barney was able to start the project again. The ferrying of the thousand tonnes of rock needed from nearby Neutral Bay began and the Fort soon began to take place. The fortification as we know it today was completed in 1862 with twelve 32-pounder cannons installed.

 Sadly by the time this vital fortification of Sydney was finished it had become obsolete. The cannons it had been designed to hold were no longer effective against the modern ships, most with some kind of steel hull.