The dockyard defences were designed like the layers of an onion – if the enemy got past one, they would find another, then another.
First was a large open area, where attacking soldiers could easily be spotted. This was followed by earth and rubble banks, leading to a moat. In some places there were triangular islands in the moat. Beyond the moat was a massive stone wall. This had high walkways, patrolled by guards, along the top. Inside the walls were spaces for cannons to fire out across the moat.
Looking across the site of Victoria Park towards the walls. On the right, you can see a low bridge crossing the moat, about where Alfred Road turns into Queen Street today.
Looking in the same direction, from a higher vantage point. This shows all the rings of defence around the dockyard.