Revealing performance loss due to fouling at anchorage

For us humans, lying in the sun relaxing can be a great way to regain our energy and prepare for upcoming challenges. For ships however, this is not the case since these are the conditions where risk of fouling is at its highest.

But how can you tell if there has been significant accumulation of fouling? The way we like to do it is to collect quality data from onboard sensors and compare to a reference model, a sort of a “digital twin”, describing the performance of the vessel when it is clean. If we see increasing deviation between our reference and the measurements, this is a good indication of development of fouling.

Recent example from our client’s vessel equipped with our system shows very clearly how good sensor data can bring performance issues into light at a very early stage. Below chart shows the operation of the vessel, a bulk carrier. The coloured lines in the chart correspond to periods the vessel was at anchorage. Notice that in in April and May there is a long idling time of about 6 weeks in warm waters.

In the days following departure beginning of June we begin to see a large increase in the deviation between the expected and actual propulsion power. Below figure shows the deviation in the weeks before and after the idling period. The mean deviation is clearly shifted about 12% indicating the power needed to achieve the measured speed has increased by this amount on average. The speed drop calculated by similar means is about 4.7%.

Armed with this information our client could take further actions and plan his maintenance in more sensible data-driven way, ultimately saving fuel and cutting costs.

Contact the Marorka team for more information and to see how we can help you improve your performance.