Speed through water – the missing piece of the vessel performance puzzle?

Speed through water – the missing piece of the vessel performance puzzle?

The fuel efficiency and performance of a vessel depends on a multitude of factors, but according to Andreas Brekke, CEO of Norwegian technology company Miros, there is one vital piece missing from the performance optimisation puzzle.

Accurate speed through water measurement is essential in order to gain a true understanding of vessel performance and the role different fuel-saving methods and technologies have upon a vessel, says Mr Brekke. In its simplest form, understanding the actual performance of a vessel compared to its design specifications is almost impossible without accurate measurements of speed through water.  To verify the incremental impact of fuel saving technologies is equally difficult without the same measurements, and this is only exacerbated further by the lack of a properly documented baseline.

Traditional speed logs exist to determine speed through water, but according to Mr Brekke, these struggle to provide relevant accuracy over time. Acoustic speed logs that operate below the surface of the water are standard practise, but systematic errors and data noise due to air bubbles, turbulence, inadequate calibration are just some of the problems faced. In addition, the high installation and maintenance costs associated with submerged instrumentation only add to the challenge.

Measuring true speed through water

Realising the challenges faced by the industry, Miros identified the need for a tool to accurately measure speed though water and, for the last three years, they have been working on exactly this, launching the new application in June this year. Miros’ Speed Through Water by Wavex is a dry, radar-based sensor that uses X-band navigation radar technology to measure surface currents and waves in real time, eliminating the need for submerged instrumentation.

“Miros Speed Through Water is a kind of virtual sensor,” Mr Brekke tells us. “We use a standard navigation radar, which is on every ship already. We then take the signals from that and put our algorithms on it and provide 25 sea state parameters.”

The tool is typically integrated into a vessel performance system that is already onboard a ship. An owner’s current system, such as for AIS or weather forecast can also be integrated with Miros’ Cloud-based system.

“We can either provide a simple platform in the Cloud for them, or we can integrate to existing systems. The owner can choose to have a monitor on the bridge, or have the data delivered locally into their bridge systems – we do this a lot on hull stress monitoring systems. Otherwise, we can just push it straight to the Cloud.”

The Cloud option means that shipowners and operators can access their data without the need for elaborate and expensive ship performance systems.

Miros Speed Through Water claims to be significantly more accurate than traditional speed logs, measuring with a variance of 5cm/s, compared to speed log variances that can range from 10cm/s to several m/s. Pilot projects suggest the tool has the potential to cut fuel consumption by 7-10 per cent.

The idea behind the technology is that if you can measure current accurately, you can measure accurate speed through water and “suddenly you have the missing piece of vessel optimisation,” he says. “In its most basic form, vessel optimisation is fuel consumption versus speed curve, and you’re trying to optimise this. As of today, you only have an estimation of speed – speed over ground – from GPS. True speed through water is essential for looking at your speed fuel curve with new accuracy,” he explains.

Andreas Brekke, CEO of Miros

Accurate speed through water measurements help to identify the true effect other performance optimisation tools or techniques have on a vessel’s fuel consumption. Hefty investments are made by shipping companies in a bid to maximise the performance of their vessels, including applying expensive hull coatings or carrying out regular propeller maintenance, but without an understanding of the sea state that the vessel is operating in, the actual impact of performance tools and methods on vessel performance is unclear.

For instance, hull cleaning is a common performance management practise used to eliminate fouling that exacerbates fuel inefficiency. Many vendors have developed analytical tools to monitor the effects of fouling on vessel performance to help operators identify the optimal time to clean the hull before rapid performance deterioration occurs. However, according to Mr Brekke, the scatter plots and data generated to identify deteriorating hull performance can have huge variants because of sea state, meaning it can be difficult to understand exactly why the performance is deteriorating. “You tend to only see very broad trend data from the majority of solutions.” Adding sea state to this data can dramatically tighten the scatter and provide much better data on the performance of the hull. “This delivers higher quality information for decision making on the optimal time to clean the hull,” Mr Brekke explains.

Adding sea state data also eliminates the huge offsets that occur with speed logs. “We are measuring undisturbed water in front of the ship. While the speed measurements that we compete against are submerged in the water and influenced by the acoustics of the hull, and air bubbles, and everything that makes it difficult to measure something in water.”

Mr Brekke admits that the idea for Miros’ Speed Through Water sprung from several years of “trying to find the killer application for shipping.

“We worked on redoing our algorithms for surface current, doing pilots and lots of testing. Then last year we finally got our verification that the accuracy that we were seeking, we were actually getting. Finally, we were able to measure current with great precision.”

Verifying accuracy

Accuracy of Miros’ Speed Through Water has been verified by testing against other instruments. “We test with instruments on vessels, against speed logs, model data and against weather forecasts. We look at how we perform against these other technologies and how we correlate with underlying models.”

At the present time, Miros is piloting its technology with various shipping companies, one of which is BW Group. The company’s managing director of BW Dry Cargo, Christian Bonfils, has publicly stated that he believes 10 per cent fuel savings can be achieved using Miros’ Speed Through Water technology. “It is really satisfying that BW expects to see these kinds of savings,” says the Miros CEO.

Several other commercial pilot customers are onboard with Miros’ concept, including Höegh LNG. Mr Brekke also assures that other shipping companies that cannot be named presently are also piloting the technology.

“These interactions with customers are very important to further understand the basics of fuel optimisation and how we can help.” Mr Brekke points out. “We want to see now how we can use this to a larger degree and in real time. What if your vessel is estimated to burn 20 tonnes of fuel but it actually burns 25 tonnes and you don’t know why? We want Miros Speed Through Water to be used both in real time and for post journey processing, in order to address the added fuel consumption caused by the difference in speed over ground versus speed through water.”

Challenges and opportunities

One of the challenges for Miros has been to increase awareness around the lack of accurate sea state data. “Traditionally, the industry has adapted to being without reliable sea state data and has tried to be flexible to correct offsets. What we’re saying is don’t spend so much on trying to adjust for this uncertainty. Let’s just get the facts into the model instead and assemble a much more valuable model to truly understand the impact of hull fouling and other parameters and the true efficiency of a vessel.”

Another challenge for Miros is the general move by owners to start optimising what they see as the ‘big things’ first. “It’s the things that they know how to go about optimising that they start with” says Mr Brekke. “Some aren’t always aware of how much local variations and current can affect fuel consumption.”

The traditional wait-and-see approach also means that owners and operators are not always keen to jump onboard with another technology. “Sometimes it’s challenging in this market because owners can feel like it’s just another technology that they’re being sold without understanding the benefits behind it. A lot of companies believe that because of their speed log, they already have the speed through water measurement. Our challenge is to show that true speed through water data can affect vessel performance and efficiency quite significantly.”

For Miros, its long-term plans include getting its tool type approved as a speed log. “This is one direction to go in, but there are so many regulatory challenges. One of the requirements of a speed log is that it has to be an autonomous system, but ours relies on input from the navigation radar, input from gyrocompass and input from GPS. We’re breaking new ground, and that means we don’t necessarily fit into the existing framework,” he says.

In the meantime, Miros plans to continue working with large shipping companies to document explicit savings and to expand their understanding of how to target more specific applications for the data that they are providing. “At the moment we are a sensor company that provides some neat data in a way that hasn’t been done before. Our learning curve is about understanding relevant applications for that data and the more we learn about that the more we can tune our technology to meet the needs for our customers. We need to understand more about how our customers use the data – this is a big learning curve for us and our focus for the future,” he confirms.

Read more about Miros’ Speed Through Water technology.

Andreas Brekke is speaking at VPO’s forum in Copenhagen tomorrow. Find out more here.