We apply new Z-peller as standard of direction of rotation for propeller as "inner-rotation" on shown Fig. -13. The direction of "inner-rotation" makes to be low vibration for ship constructure, and to be higher efficiency of propulsion.
Fig.-13 Direction of propeller rotation
(View from stern side)
3-5. Examination Subject
We have carried out the following tests to develope new Z-peller ZP-21.
(1) Static Load Test
According to the static load test for the main structure (lower gearcase, kort nozzle and installation bed), we had confirmed that measurement result of stress and strain was satisfied with designed level.
(2) Measurement of Noise Level
Fig. -14 shows the measurement result of noise level of original Z-peller and new Z-peller ZP-21 during operating with no load at rated input speed. Noise level of new Z-peller was improved by approx. 10dB on each frequency, because we used the high accuracy HPG bevel gear unit.
(3) Measurement of Transmission Loss
Fig. -15 shows the transmission loss at 40｡? temp. of lub. oil with no load running.
