December 2014 - Marine Technology Reporter

Nortek, Imbros Help Keep the Tasman Bridge Safe

Posted by Irina Tabakina

Today, a driver over the 1.4 km long Tasman Bridge, in Hobart, Tasmania, inspires marvel at how the Derwent River gently flows past the bridge. Few today recall how this peaceful scenery was once a disaster scene, when on the evening of January 5, 1975, a bulk ore carrier vessel collided with the bridge causing two pylons to fall and a 127m section of the road to collapse onto the ship and into the water.
A total of twelve lives were lost in the disaster and the Hobart region was severed in half for over two years. Although human error played a key role in the accident, the strong tidal currents at the site were to have its share of the blame To help improve vessel traffic safety around the Tasman Bridge, the Tasmanian Ports Corporation (Tasports) teamed up with Nortek and Imbros (Nortek Representative for Australia), and since 2007 the three have been working closely to provide the most accurate current data possible for safe navigation through the bridge. Tasports have two Nortek 600KHz Aquadopp Profilers deployed, one to the south of the bridge and one to the North.
They are housed in a seafloor mounted frame designed by Imbros that allows for easy deployment and hassle-free compass calibration, with the ability to make small adjustments to ensure a correctly oriented instrument.
Both are powered via cable, utilizing the Nortek 48/15V DC-DC converter, regulating voltage input over long distances. Communications are via the same cable, using an RS-422 wiring harness feeding into a radio transmitter. Data is then transmitted back to the Tasports port tower for analyzes through their server and software solution, allowing the ship pilots to view a summary page of live current speeds and direction. The Nortek 600KHz Aquadopp measure the water column to give an accurate reading of current speed and direction at one meter cells, every minute. This allows the pilot to consider up-to-date and accurate current data at the depths that may affect their particular vessel.

(As published in the November/December 2014 edition of Marine Technology Reporter -

Other stories from December 2014 issue


Marine Technology

Marine Technology Reporter is the world's largest audited subsea industry publication serving the offshore energy, subsea defense and scientific communities.