Port Taranaki is partnering in world-first technology that aims to give a better understanding of the waves in the harbour so that more vessels can stay in port during disruptive weather events.
Port Taranaki and New Zealand ocean science company Oceanum have joined forces in the design and testing of technology that captures live continuous data of the height, length and gradient of the waves at individual berths in the port. This will help determine which vessels, on which berths, will be affected most by a long period wave (LPW) event.
“Strong winds and LPWs are a key risk factor for us. They can cause mooring lines to break which puts staff, customers and vessels at risk,” Port Taranaki head of operations Captain Ashley McDonald explains.
“To manage this risk, we deploy additional ship’s lines and a dynamic mooring system known as ShoreTension. In more serious events it is necessary to send vessels out of the port.”
Currently, the height measurement of waves is taken from only one point in the harbour which, crucially, doesn’t give the port an understanding of the gradient of the waves at the berths.
“It is the gradient of the water at the berth that causes the ship to surge back and forth, which can cause the mooring lines to break,” says Ashley.
“We know that wave conditions at each berth are different, and the way each vessel responds is different. For example, we’ve seen a vessel break lines during a 10cm wave, but a vessel on another berth handle a 19cm wave – almost twice the limit.
“Therefore we want to get more data so we can make better decisions regarding LPWs and be able to increase the frequency of safely keeping vessels at the berth.”
Oceanum managing director and physical oceanographer Dr Peter McComb, who has spent many years investigating and collecting wave data at Port Taranaki, including making the world’s first LPW forecast, was approached to help find a solution.
Firstly, a prototype sensor was designed and installed in the water off Moturoa Wharf.
With that successful, now the work is being scaled up to a trial of six sensors placed in the water, 80m apart, along Blyde Wharf.
Powered by solar panels on the wharf, the sensors will collect data on the height of the wave at each set point and talk to each other wirelessly, forming a sensor mesh.
One of the sensor units will collect all the information and transmit it to a central computer, where a live picture of the wave at the berth will be formed, showing its height, length and gradient. Port staff will be able to access this data in real time.
“Monitoring the wave-by-wave LPW in real time is a new development, along with connecting sensors into a data mesh to capture a live two-dimensional picture of how the harbour is behaving,” Ashley says. “It’s a world first and exciting for us.”
It is hoped the technology will also, eventually, be installed along Moturoa Wharf and the Newton King Tanker Terminal.
In the longer term, the goal is for the technology to use the large amount of data obtained to begin to predict what the gradient of the wave will be on each of the berths for a given swell forecast.
“With 10-20 sensors across the harbour collecting data, we can bring the data together and ultimately run machine learning algorithms across this combined data set to produce a much better predictive capability,” Peter says.
Ashley says this will help the port better plan, ahead of an LPW event, whether or not ShoreTension is needed for a particular vessel, and whether a vessel on a particular berth can stay in port.
Peter says the rewards could be significant.
“Hundreds of ports around the world have similar problems, so we’re keen to work with Port Taranaki to create a solution and then collaboratively export that to the world.”