Dredging prepares for autonomous vessels

Arzana dredge tracking. Royal IHC
Arzana dredge tracking. Royal IHC

Until recently, the maritime industry, like others, was limited in the scope and efficiency of its operations, which would either benefit from an abundance of local computing power or suffer from a lack thereof. However, just as a business’ earning potential improves with its supply chains, productivity has bumped up a gear as the net gets wider in terms of sourcing computing power to apply to operations. Today, there are better ways of improving productivity than acquiring the necessary servers and processors oneself. For example, if a port needs processing power, this can be provided over the internet, with sourcing of hardware and technology left to those companies that do it for a living.

This leaves many companies with an effectively unlimited reservoir of data collection and optimisation capability at their fingertips – provided, of course, that they can afford it. Ports are busily applying this technology to their operations, given there are many improvements to be made to a system with so many moving parts.

At the Port of Hamburg, which was recently given the opportunity to eliminate its other main limiting factor – depth (see DPC March 2019 for more on this) – is now performing tests with 5G, the next highest band of over-the-air data exchange with as much as 10 times the speed of its predecessor 4G – potentially as much as 10 gigabits per second – as part of an EU initiative.

Strong connection
Under project Mobile Network Architecture, a 5G transmitter is being fitted to Hamburg’s nearby and famous TV tower, with an operational radius covering the entire port. The project will examine the various logistical applications of the technology. With the help from 5G, the port’s various machines will tighten up the way they interact with one another, ratcheting up performance and reducing waiting times for ships, trucks, and trains.

This can be done, Hamburg says, because more than mere throughput, 5G offers a level of reliability unseen thus far in mobile networks.
Companies are now coming to grips with the benefits that this connectivity will bring. As with high-throughput-satellite (HTS) broadband a few years ago, prices will be high to start with; but over time, the cost will decrease, along with a consummate increase in the understanding of the technology and its benefits.

With a never-before-seen capacity for connectivity on the horizon, it is likely that operations typically thought of as separate will become better integrated with operations in ports themselves – in fact, will come to be seen as just another element. One example is dredging, where large amounts of data processing capability have been used for many years to great effect. However, it is only recently that the possibilities of exchanging streams of high-fidelity data with shore have opened up new avenues for operational excellence.

The pathfinder
Recently in China, controversial new cutter suction dredger Tian Kun Hao conducted its second batch of sea trials amid concerns that the vessel would be used to provide raw material for new military island bases in disputed territories in the South China Sea. During the trials, operator Tianjin Dredging, a subsidiary of China Communication Construction, claimed that the 6,000 m3/hour dredger was able to conduct dredging operations, for a time, without intervention from its human crew. Dredging may be an extremely complex and sensitive operation, but regardless, this claim might not be so far-fetched as it sounds.

In 2017, Royal IHC’s Kinderdijk shipyard in The Netherlands completed construction of Arzana, a new state-of-the-art trailing suction hopper dredger (TSHD). Delivered to Abu Dhabi’s National Marine Dredging Company, the vessel was the first of its kind to be specifically designed for the shallow waters and hot climate of the Middle East, and like Tian Kun Hao, is capable of shifting 6,000 m³/per hour. However, it also featured an integrated forward-looking system, combining various sensory components with edge computing.

A study associated with the launch chronicles the progress made in general with Big Data, relating it specifically to Arzana, along with a previous IHC vessel, trailing hopper dredger Amsterdam built in 1996. The whitepaper cited IHC Connect, IHC’s vastly improved internet architecture, as pivotal in the technology of today’s dredging. A safe internet connection, secured through WiFi, 3G, 4G, 5G, or high-throughput satellite, keeps the data flowing.

This data is in large part generated by Arzana’s multibeam echo sounder (MBES), used to create a 3D image of the seabed in an arrangement of wide fan-shaped directional sonar. The whitepaper points out that in so-doing, this massive input of sounding data can operate in concert with Arzana’s navigation systems, including dynamic position and dynamic tracking systems.
Data is exchanged with shore via IHC Connect, which uses 4G and satellite data. Later, 5G infrastructure will be used where possible. The study’s authors anticipate that this technology will be used to pilot IHC dredgers remotely from shore. With an extremely accurate 3D image, assembled using the MBES, the dredger can consider the composition of the dredging surface, optimising its speed and reducing overall fuel consumption. However, it can also effectively navigate by itself. Seabed features are mapped in such a way that the system can build up a highly sensitive 3D representation, from which the vessel’s navigation system can manoeuvre along designated dredge tracks, effectively eliminating the need for human intervention in specific phases of the operation.

Digital integration
Dredging is not the only arena in which intricate 3D modelling, informed by a high-throughput data exchange, could be used to improve performance; it is one of the most successful. Elsewhere, the transition into such technology has not been as smooth as anticipated five years ago. DNV GL has espoused digital twin technology for some time, creating a 3D model of a vessel, and then updating it from continuous streams of sensor data in much the same fashion as IHC.

“First, you need to have a unique physical copy, to be able to identify the IMO number, vessel name, and piece of equipment,” Christian Cabos, head of Information Management Technologies at DNV GL – Maritime, told DPC. “But then you have to collect information from real life, documenting what’s happening with the physical twin. The third element is that you’re doing this for a purpose, so you need to have some predictive capability at the shore end that gives some value. Once you have that, you can act on the physical copy.”

However, the implementation of this third element has been patchy. Without the injection of up-to-the-minute data, there is only so much prediction that can be done, Cabos explained, and harvesting it is a major job. “There is no full digital twin, I haven’t seen that anywhere. But you can maintain a digital twin without a daily data input.

“We are working on integrating survey data with digital twins. At the moment, what we do with surveys is we define whether the function of the piece of equipment is there. We do not record everything that is working fine.”

For the time being, this remains a barrier to the full potential of big data, which could be used to monitor the performance of components being used over time, and predict when it will need to be replaced. The so called TIMON concept has been proven in principle. DNV GL is already using it to circumvent the need for tail shaft surveys, which prevents unnecessary damage to the sealed stern tube. “We have that regular data stream; measures like oil sampling. If you have this sensor package installed on the tail shaft, based on the readings from these sensors you don’t require a survey,” Cabos said. “As a result, you avoid damage from having to open up, and instigate a survey.”

TIMON is already providing major cost savings on surveys, but it is only one data-stream out of thousands. To instigate this condition-monitoring on an entire ship would entail far better systems integration than exists today, Cabos added.

“That would be much more work to do. We are not recording data from all equipment. Certainly, there are more steps to go. What we need to do is integrate these inputs with records you get from shipowners themselves.”

Improved connection
In early March, DNV GL entered talks with a major dredging company, to implement the digital twin on some of its vessels, however, it will be a big task. Thus far, DNV GL has concentrated on hull management; thanks to OEMs, covering machinery can be a much more complicated enterprise, because different manufacturers are administering their own proprietary digital twins, rather than the holistic one envisioned by DNV GL. In the future, Cabos believes, this will change. “We need to integrate information we see on components, which typically will be collected by the companies who installed these components,” he said. “Part of the information from the components will be delivered by the system integrator, and part will be delivered by the OEM.
“For the machinery, OEMs work more with behavioural models – the relationship between what goes into a pump and what comes out, say. The type of data you are collecting is different for each system – vibration measurement and oil measurement. You might even get two different signals from the same component. But the industry is calling for standardisation. We are slowly going to bring together all these different inputs.”

With so many niche elements, the notion of bringing together a holistic digital twin, tracking all inputs, may be far-fetched for the time being. Fortunately, there are already use-cases for DNV GL’s technology which are bringing value to customers. One of these is digital commissioning, using software modelling to get disparate systems on a newbuild to play nice with one another. “If you talk to shipyards, things typically go wrong; connections go wrong, in particular the integration of the control software goes wrong, and the system does not work as a result.

“Today, our 3D modelling might come from construction of the vessel; we model the behaviour of components but also integrate them. In a virtual commissioning case, we use this to build a control system, referring to use cases and operational planning. So, suppose you have a ship with a crane, and you want to use the crane in a different operational strategy than the manufacturer anticipated; we are building systems, which will allow owners to do this.”

Part of this is to do with simulation, a key element, also, in IHC’s dredging route planning. With DNV GL’s OpenSimulation platform, vessels will be able to benefit from operational data passed to shore. “We are building the infrastructure to simulate the behaviour of complex vessels,” Cabos said. With better inputs of vessel operating data as sensors improve, combined with the heightened connectivity capabilities of 5G, risk can be effectively exported to the digital twin, making it possible to experiment with different use case scenarios and yield operational improvements over time.