What is a fuel table – and why do you need it so badly?
A new built vessel comes out of the yard with a certain fuel oil consumption for propulsion. The consumption is as a new vessel with a clean hull and propeller and the speed / consumption relation is established at the delivery sea trials.
When the vessel starts trading, the speed and consumption is influenced by the environment the vessel is sailing in. Wind, waves, sea water temperature and currents have an effect as does the operations with regards to draught, trim and rudder cycling when sailing.
Over time the vessel will experience fouling on the hull and the propeller, and this will create an added resistance on the vessel which will lead to a speed loss and a higher consumption.
The vessel will further meet wear and tear on the main engine and maintenance routines have a large impact on the engine performance and therefore also the fuel oil consumption.
Therefore, a lot of factors influence the daily fuel oil consumption, and it can be tricky to give a good estimation of the actual value. How much is coming from the different factors above and can some of it be reduced by the proper maintenance schedule either a hull/propeller cleaning to get rid of the fouling effect or an overhaul on the main engine.
To be able to take the right decisions on this, a performance analysis for the vessel can be utilized, where data logged on the vessel is used in a performance software system. The system includes all the fuel consumers and a base line model of each. The model will set a benchmark towards the new vessel and when actual data are fed into the system, the difference between the actual and the new vessel can be established. For the propulsion part, it is an advantage to include a model for the hull/propeller and for the main engine. Then the fouling effect can be separated from the main engine performance and therefore help making decision on which actions to take to lower the consumption.
The performance system should then be able to produce an actual fuel consumption at any given speed and draught. The values will give an overview of the actual state of the vessel and used when decision needs to be taken for maintenance schedules, cleaning of hull and propeller and when entering new charter party agreements.
Further, if the performance software is fed with live sensor data, any effect on the fuel oil consumption can be registered almost immediately e.g., any fouling issues after an idling period or if any technical issues in the main engine and equipment.
In the VesOPS system we operate with three performance KPIs for the above.
- X-Power – indicates the percentage added power used to maintain service speed
- X-SFOC – indicates the performance of the main engine
- X-Consumption – indicates the extra fuel oil consumption used to maintain the service speed.
The performance KPIs are updated continuously with sensor data, they are trended over time and events that affect the KPIs are logged to the system. To identify the best/worst performers, each vessel is benchmarked towards the rest of the fleet. Fuel tables are available for each vessel at any time.
If you want to know more about vessel performance and how you can start monitoring the vessels in your fleet, do not hesitate to contact us at VesOPS. We are the performance experts and can offer you advice and solutions that will meet your needs.
Phone: +45 2939 2960