Results P-type bulbous bow optimization
As presented in the previous sustainability report, the bulbous bow of our P8- and P14-type vessels was redesigned to meet the lower draft and speed profile the vessels are operated on. The smaller and flatter bulb was designed to reduce the calm water resistance at lower speeds and to reduce the added resistance due to waves.
As we have been sailing the Pauwgracht with this modified bow for over a year and a half now, all the while gathering data from the performance monitoring system installed on all P8- and P14-type vessels, we have been able to study the in-service performance of the modified bow in more detail. Although the monitoring time seems long, the very diversified use of the vessels still makes comparison difficult. A voyage via the Northern Sea Route is very different from a voyage in the Mediterranean which again differs from a westerly Cape Horn voyage. The general conclusion is that the modification performs as expected. In calm waters at lower speeds the modified bulb performs better. In less moderate weather, for example during an ocean crossing, the modified bulb shows a saving in required power. In this graph the relative fuel consumption on longer voyages is presented as a function of the speed.
Looking at the total fuel consumption over one year, the numbers of the Pauwgracht also look favorable. However, the wide variation in sailing routes and in different seasons has a large influence on this comparison. More data needs to be measured and analyzed to come to a final judgement on the overall performance improvement.