area propellers pursuing the improvement of the efficiency, furthermore it has been devised for the improvement of anti-cavitative characteristics. Such a fact will be evident also from the comparison by Photograph 5. As explained, PAI propeller is the propeller made suitable for smaller blade area ratio promoting the improvement of efficiency, by applying the improvements in accordance with the pressure distribution preferable. From such a background of the propeller, it is named PAI (Pressure-Accorded Improvement) propeller.

Fig.4　Pressure distributions over the blade surface obtained by calculations

Table 1 shows the comparison of the performance between conventional MAU propeller and PAI propeller for a 120,000 DWT bulk carrier. The efficiency is improved by 5% compared on basis of the same propeller diameter and developed area ratio. The efficiency will be improved by about 6% with PAI propeller's optimum propeller diameter being adopted, while the PAI propeller diameter should be larger by about 5% over the MAU propeller's.

Table 1　Comparision of performance between "PAI" and "MAU" propellers

BACK　　　CONTENTS　　　NEXT