Why noon-reports alone do not work for the assessment of fuel-efficiency

Any commercial ship uses noon-reports.

It comes in all forms, but in fact, it is a data sheet prepared by the ship’s chief engineer on a daily basis. The report provides data such as the vessel’s position and other relevant data and is often used to assess the performance of the ship based on its speed and environmental forces, including weather conditions.

Noon-reports are the most used form of monitoring by charterers. They use it to assess the difference in the performance against the Charter Party and to detect underperformance or possible issues.

Why noon-reports alone do not work for assessment of performance

As said, noon-reports include data, such as weather (wind direction, wind force, sea and swell condition) and average speed over the last 24 hours. They are general values, taken at the time of report preparation.

As we all know, the weather can change significantly per hour. An average value of wind speed at noontime might vary significantly from windspeed at night. Also, average speed does not say much, only if the speed is constant for 24 hours, which it (almost) never is.

Another major issue is that we often see an extremely stable consumption being reported, such as shown below.  This reported value is very stable for 19 days in a row, which makes it clear that it is of limited use for the assessment on performance and fuel-efficiency.

Noon reported bunker consumption
Noon reported main engine consumption

If you plot the reported consumption against reported speed, you often get something like below. It is quite clear that the data cannot be used for performance assessments.

Speed vs. Consumption plot

We need something better.

So, with all available data around us, why not upgrade from using noon-reporting as the basis of performance monitoring, and start monitoring in real-time? Often because it requires capital investments in sensors, cables and installation. And for charterers, it simply isn't possible to install anything on board, as they are not the owner.

A new approach: The Digital Twin

As a radical new approach to efficiency monitoring for ships, We4Sea has developed and validated a Digital Twin concept. A Digital Twin is designed as a “living” digital simulation model that updates and changes as its physical counterpart (your ship) changes.

The Digital Twin combines vessel specifications, such as hull shape, engine- and propellors, sensor-data and remote-sensed data such as AIS and environmental data (wind, waves, currents). The Digital Twin incorporates algorithms developed by We4Sea's experts and validated in various projects.

Using these tools, we have analysed the difference between reported fuel consumption (from noon-reports) and Digital Twin calculated fuel consumption, based on the vessels specs, motions, speed, and weather data. Please note that the Digital Twin represents a clean and efficient vessel.

In below picture, the Digital Twin-based fuel consumption over the noon reported interval (blue line) is plotted against reported fuel consumption (dotted green line).

Benchmarked bunker consumption data

It clearly shows the power of data-driven benchmarking: it significantly increases insight.

The overall discrepancy between reported and calculated consumption was, was 28% for this complete voyage. As the model is matched with sea trial data, the difference are a result of inefficiencies such as aging and marine growth. Based on this insight, a hull inspection was performed, which showed significant fouling.

What about the weather?

In a noon reports, also weather is mentioned. But what you are really interested in is the effect of weather on speed and consumption.

Using our Digital Twin, we can also calculate the added resistance from different factors, such as wind, waves, currents and shallow water effects. If we combine weather data with the model, for example wind force and wind direction on the vessel's location, we can calculate the added resistance as a result of wind impact. Same goes for currents, waves and shallow water effects.

Visualisation of weather effects

Better decisions without capital investments

A Digital Twin concept support better, data-driven business decisions. It comes at low cost, requires no capital investments in hardware to be installed on-board.

We4Sea data and models have been verified against real-world ship performance data collected by customers' on-board vessel performance monitoring systems, and accuracy was found to be over 97%, depending on ship-type. This high level of accuracy will support owners, operators and charterers to have new insights into fleet efficiency and make informed decisions on the improvement of fuel efficiency.

Interested to start? Drop us an e-mail at support@we4sea.com