Student's Research Gives New Steer On Tides

Foundation for Research, Science and Technology
For immediate release

STUDENT'S RESEARCH GIVES NEW STEER ON TIDES

Port Otago pilots, and ships' coxwains, will benefit from a university student's research into the tidal jet flow of the harbour's navigation channel, the effects of which mariners have tried to fully understand since the 1820s.

The port company intends to use Chris Old's data to make a real-time computer simulation of the harbour to include water flow for pilot training, company chief executive Renè Bakx says.

Dr Old, who studies marine science at the University of Otago, did his three-year project with the support of Technology New Zealand's Graduates in Industry Fellowship (GRIF).

"I wanted to do more work on coastal fluids because I'd worked on a computer model of the Hauraki Gulf for my MSc [master of science degree]," he says.

His work entailed building a picture of tidal currents in and around the Otago harbour entrance to help the port company develop better ways of dredging. This particularly focused on the incoming sand-laden flood tide, which dumps its load on the entrance bar and in the harbour, and the out-flowing two-knot ebb tidal jet, "which hoses sediment out along the channel", Dr Old says.

The currents demand special skills from pilots and ships' handlers, and coxwains - those who do the steering - because the channel is a narrow waterway between tidal mudflats.

Dr Old was able to improve on data collected since the 1820s because of the advances in acoustics equipment.

"Chris has been able to come up with an understanding of the jet that hasn't been possible before, simply because equipment available did not provide the detail required," university supervisor Ross Vennell says.

"New technology has enabled a more accurate mapping of the harbour tidal currents than in the past."

Port Otago authorities realised that the new information the project revealed would help pilots to model ship-handling techniques in a simulator, particularly since bigger ships are expected to call at the port in the next few years.

"It's been win-win all-round," Mr Bakx says. "We'll be able to try different techniques for our pilots without compromising ships, the marine school's capability has been increased, and it's been useful for Chris to have a meaningful research project."

The project was new to Dr Old in another way. Originally from Tauranga, he had never been to the South Island before. "It's true. I came to Dunedin via Australia."

Under Technology New Zealand's GRIF scheme, students do research projects for their degrees with companies, the aim being to increase their skills and benefit companies, and foster links between universities, research institutes and businesses.

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