What's At The Bottom Of Sydney Harbour

The Ucruise Team are always active on the harbour and of course a common questions by many boat tourists, locals, sail teams, etc, is - I wonder what interesting things lie below the surface and wouldn't it be great flush all the water away for a moment to reveal what's down there.

Well courtesy of the survey team at Sydney Ports we can now view a 3D map of what's below the water. Their report revealed some obvious finds but also some things much less expected including; a sports car, 100 year old shipwrecks and a hole which goes 45 metres deep just west of the Sydney Harbour Bridge.


How The Map Is Created

The team use a “multibeam echo sounder’’ system, which isn't cheap, valued at $750,000 - this generates the detailed 3-D maps of the Harbour floor. This system is installed on-board their Port Explorer motor boat. The system itself emits 512 separate sonar rays to the bottom to build up a digital map.


Four hydrographic surveyors at Sydney Ports have charted the harbour with colours representing the different depths.


The dark blue section depicting a 45-metre deep hole, just west of the Harbour bridge.


The Reason For Doing This

Venessa O’Connell from the Sydney Ports team said, “We are looking for anything that can impact on shipping and shipping schedules. While Sydney Harbour doesn’t really have any problems with filling up with silt, we do find a wide variety of objects that have been dumped or fallen off the back of ships and barges.”


What's Been Discovered

  • Large concrete blocks and steel poles from construction work
  • A variety of furniture items including tables and chairs
  • Dozens of shopping trolleys
  • Small pleasure boats that have broken free from moorings
  • Cars and motorbikes. They have also found what was thought to be
  • A brand new Toyota Landcruiser 4WD which was 50 metres from the wharf at White Bay which "...may have fallen off the back of a ship” according to Andrew Tsaccounis a colleague of Miss O’Connell.
  • Possibly a Porsche or Audi sports car in 6.5m of water just a few metres from the edge of Pier One at Dawes Point, almost under the Harbour Bridge.



Toyota Landcruiser found in White Bay


Sports car found near Dawes Point

The survey also shows the location of historic items including the Harbour’s biggest and most intact wreck, the TSS Currajong, a collier that was sunk just off Bradleys Head, near Mosman, in 1910 after being hit by the SS Wyreema, a 6000-tonne passenger liner.

The Currajong is in a shipping lane, but lies in about 30m of water, one of the deepest parts of the Harbour. “Thousands of people have passed over the Currajong, and have no idea it’s down there,” Ms O’Connell said.


The Currajong Wreck off Bradley’s Head


Wrecks off Balls Head


Other Interesting Highlights

“There is also a 45m deep hole in the Harbour floor just west of the Harbour Bridge, close to Blues Point, that most people have no idea exists.”

The maps also pick up the two straight lines of the Sydney Harbour Tunnels, running just west of the Opera House to Kirribilli. Sydney Ports’ harbour master Philip Holliday said the work of the survey team is critical for the safe navigation of shipping not only in Sydney Harbour, but Port Botany, Yamba and Eden as well.

“It’s all about ensuring our busy working ports remain safe for commercial and recreational traffic,” Captain Holliday said.


Original article written by Jim O'Rourke - The Daily Telegraph