Model and Full Scale Evaluation of a 'Propeller Boss Cap Fins' Device Fitted to an Aframax Tanker

Teekay Corporation started a technology development programme in 2006. The programme consisted of a number of projects aimed at improving the efficiency of both existing and new build vessels. This paper gives details of one of these projects, consisting of a comprehensive investigation of alternative fuel saving devices suitable for retrofitting to existing ships. A number of devices were evaluated theoretically and the most promising tested at model scale. The PBCF device was one of the devices tested at model scale. The test programme included normal and inverse open water propeller tests at a range of Reynolds numbers to investigate opens efficiency and scale effects. Resistance and propulsion tests were also conducted to establish power savings. The results showed that propulsive gains were to be expected and that the investment payback period would be short. Full scale trials were then conducted on an Aframax tanker. These were performed before and after the PBCF was fitted afloat, the trials being conducted within 4 days of each other. The good trial conditions and the care taken during the trials have resulted in unusually good trial measurements. The results confirmed the model test predictions and showed that the PBCF device offers a useful reduction in shaft power and hence fuel efficiency.