| Artist's rendering of the original rocky island feature |
This work was undertaken with convict labour without Imperial authorisation, which caused further angst.
The Crimean War of 1854 and the threat to the colony posed by the strong Russian Pacific Fleet reinvigorated the project, and the new Governor of NSW Sir William Denison added his enthusiasm. The Martello tower with its distinctive circular fortification was completed in 1857.
| Fort Denison pre-1885 loop-hole flank defences and seawall work |
Commencing in 1906, one of the Fort's gun was fired (without shot!) at 1.00 pm each day as the Sydney Observatory time ball was seen to drop. This was the signal which navigators used to synchronise their chronometers. This practice continues to today and if you go out to the island, they let someone from the crowd fire the gun - my Father in law did it on the day we visited because it was his birthday.
It has the distinction of having come under attack from U.S. friendly fire in 1942 when the tower was damaged by the heavy cruiser USS Chicago, as she opened fire on Japanese submarines at night during the Battle of Sydney.
Another interesting anecdote (from Wikipedia): In October 1900, as the Boer war raged in Africa, the White Star Line ship SS Medic sailed into Sydney Harbour and dropped anchor in Neutral Bay. One night, the fourth officer, Charles Lightoller and two shipmates rowed to Fort Denison and climbed the tower with a plan to fool locals into believing a Boer raiding party was attacking Sydney. They hoisted a makeshift Boer flag on the lightning conductor and fired a harmless wad of cotton waste from one of the 8-inch cannons.[5][6] The blast shattered a few of the fort's windows but caused no other damage.
Charles Lightoller was never apprehended but confessed to his company's superiors and related the whole story in an autobiography. He was transferred to the Atlantic route and went on to be the second officer of the RMS Titanic and the most senior officer to survive the sinking of the ship. He was a key witness at both the British and American inquiries into the disaster.