THE DEVELOPMENT OF THE GEOMETRY OF UNIKL MIMET FP PROPELLER SERIES – A MODERATE SKEW FIXED-PITCH PROPELLER SERIES FOR MEDIUM-SPEED VESSELS

Abstract

The need for new propeller series is required for a new generation of medium-speed vessel ranging from 18 to 30 knots. Currently a naval architect and boat designers are still depending on old propeller series such as Wageningen B series, KCA series, Newton Rader series, but most of this propeller series are either suited for low speed vessels or high speed vessels. Therefore, there is a requirement for a propeller series for medium-speed vessels. The existing propeller series as mentioned above i.e. B series, KCA series, and Gawn series are already outdated and need some improvement to be suited to a modern medium speed hull form. These old propeller series are not efficient as what a modern propeller required. Nowadays, more ships are using the state-of-the-art propeller, therefore a new modern propeller series is needed for modern medium speed vessel with moderate to a high skew for less noise and vibration. This is the main reason on why we need for our own new up to date propeller series with a high skew blade profile. This propeller are fixed-pitch propellers which have a moderate blade skew and camber. The aim for this project is to develop the 3D model and the CAD drawing for 4, 5, 6 and 7 bladed propellers with blade area ratio from 0.4 to 0.758. The series have a range of pitch diameter ratio from 0.40 to 1.2. Before any modelling can be done in PropCAD, the blade thickness of the propeller need to be defined earlier. This estimation of the blade thickness was based on Bureau Veritas Class rules on Propeller, NR 467 (Bureau Veritas, 2020). The blade thickness calculations were done in Matlab. Once, the blade thickness was defined using the BV rules, the modelling of the FP series propeller was done in PropCAD. The FP series propeller which consisted of 62 propellers then were varied in its pitch diameter ratio, expanded area ratio, skew tip angle and rake angle. The 3D model in PropCAD were enhanced in Rhinoceros in order to make the propeller as in a solid form. In the PropCAD, the offset tables and the 2D CAD drawings were produced and printed out. Once the solid propeller modelling was completed, the 3D printing of a sample of propeller was printed. A sample of 6 bladed propellers was 3D printed using PLA or Polylactic Acid plastic material. The sample is 250 mm in diameter. Overall there were 62 propellers were modelled in Rhinoceros where all the 62 propellers were varied in its expanded area ratio and its pitch diameter ratio.