3-2. Performance of astern operation

Table of comparison for vessel speed between "full-ahead" and "full-astern" shown on Fig. -10. It is necessary to rotate propeller to the anti-direction f operating vessel to astern on normal ship. Efficiency of propeller is lower in this condition. In case of Z-peller vessel, it is a high performance of operating astern, controlling the direction of propeller thrust not changing the direction rotation for propeller, keeping same propeller efficiency.

Comparision table of vessel speed

(Full-ahead and full astern)

Fig. -10

3-3. Emergency operation

Table of comparison for required time of changing "ahead" to "astern" on Fig.-11 and for required distance of running the vessel on Fig. -12 at the same condition of Fig.-11. It is clear that operation of Z-peller vessel has high performance of emergency control.

Required time for Full-ahead ⇔ Full-astern

Fig. -11

Required running distance and time (mean) for emergency stop

(from order to vessel stop)

Fig. -12

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