The C-Job performance prediction program goes hand in hand with wind-assisted propulsion. For shipowners who have, or are looking into, wind-assisted propulsion, C-Job can calculate how much fuel savings can be made with their (proposed) vessel. Additionally, the program can (further) optimize the use of wind-assisted propulsion on a vessel.

Wind-assisted propulsion is an energy-efficient measure to reduce fossil fuel use in ships. Using Flettner rotors on the deck of the ship will achieve fuel savings between 5 and 20%. Fuel savings can be even more when optimizing ship design and using the performance prediction program developed by C-Job.

The performance prediction program analysis any ship design with wind-assisted propulsion and provides information and optimization. The program works with designs for new build ships or retrofit situations. While originally developed for ship designs featuring Rotor Sails, the modular program easily adapts to ship designs with other types of wind-assisted propulsion.

The performance prediction program analyzes the effect Flettner rotors – for example – will have on a stability and maneuverability of the ship. Furthermore, it calculates the highest attainable fuel savings without exceeding limits for heel angles and rudder angles. Lastly, effects on the propeller and engine efficiency of operating in part-load conditions are also taken into account.

“If you have one Flettner Rotor operating in moderate winds from a favorable direction, you can already achieve a sizeable 25% fuel reduction. Of course, it is important to look at the bigger picture. Conditions are not always favorable, which leads to lower savings in average wind conditions.”
- Robin Berendschot, Junior Naval Architect
C-Job Junior Naval Architect Robin Berendschot black and white

Weather routing

The program does not just calculate fuel savings and optimization for a ship design with wind-assisted propulsion. It can also analyze the expected operational profile of the ship. C-Job worked together with our partner NAPA to look at historic weather data and current weather predictions to accurately predict fuel savings in the future. NAPA’s weather routing software Voyage Optimization combines these prevailing wind patterns with a vessel-specific ship performance model to find the optimum route between two points. This provides the shipowner with the most accurate information while also giving information on how to further optimize both its operational profile and design. Particularly as they provide information to answer the following questions:

  1. What is the optimal position of Flettner rotors on the ship to reduce the occurrence of large rudder angles and the resulting additional resistance?
  2. Do the Flettner rotors consistently provide sufficient thrust, such that the installed main engine power could be reduced?


Benefits for shipowners

  • Calculating fuel savings on an existing route
  • Calculating an optimized route to find the best wind conditions
  • Calculating the impact of ship design modifications on overall vessel performance