15 Feb '13 The added benefit of data logging for ship energy management
We are often asked: “What are the benefits of data logging over noon reports?” So we thought it might be worth highlighting some obvious benefits here on our blog.
The line charts above show readings during a 4-day voyage for speed, main engine consumption and wind. In the left-hand column the data is plotted at 15-minute intervals while the right-hand column shows daily averages. You can clearly see just how much information is lost when moving from the shorter intervals to the daily averages.
The shipping industry mostly uses noon reports in which the crew documents aggregated and average values for the last 24 hours. These reports are then delivered to the office each day by email or (less frequently) by surface mail at the end of a voyage.
Manual reporting can be a valuable source for energy-related analytics, but it has the following disadvantages:
- Low resolution – It is unrealistic to track energy saving measures which provide an improvement of less than 5% using daily readings.
- Averaging obscurity – Daily average values for speed, wind and shaft power can only be indicative at best.
- Data integrity – Unfortunately the human factor in data logging often increases the margin for error, especially when you have to estimate conditions such as the weather for a 24-hour period.
Benefits of data logging include:
- Consistent and accurate data for analysing energy efficiency.
- High resolution KPI trending for volatile measurements like SFOC and hull/propeller performance.
- Real-time tracking and management of voyage execution. Monitor speed profile, shaft power, trim and other dimensions both on board and ashore.
Having said all that, we are not suggesting that you stop doing noon reports. It is an essential part of our solution and of the overall concept of energy management. The fact of the matter is that meters break and nothing beats the human eye when it comes to identifying errors and evaluating data integrity.
We recommend you watch this video explaining Marorka Express for data logging and have a closer look at our products if you are interested in adding data logging to your energy management arsenal this year.