# ps1_soln - 1 A survey vessel has a 10 ft diameter B 5-90...

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1. A survey vessel has a 10 ft diameter, B 5-90 propeller with a pitch of 10 ft. The propeller speed is 200 rpm, the boat speed is 20 knots, and the thrust reduction factor (t) is 0.12, wake fraction (w) is 0.18, and the relative rotational efficiency η R is 1.0. The propeller operates as indicated by the Wageningen (Troost) Series B propeller charts. Determine: a. Thrust b. Shaft torque c. EHP of the boat d. The propeller shaft power (delivered power) P D e. The (Quasi) PC or η D The propeller is also tested at zero ship speed (bollard pull) and it is found that the engine limits the torque to 50,000 lbf ft. Determine: f. the propeller rpm and thrust at this condition a. Prop. Thrust . p_over_d p d := Given variables V s 20knot := d1 0 f t := f := p1 0 t n_rpm 200 := ρ 1.9905lb sec 2 ft 4 := η R 1 := t. 1 2 := w. 1 8 := V A V s 1w () := V A 8.437 m s = Velocity of Approach J 1 V A nd := n n_rpm 60 sec := n 3.333 1 s = Advance Ratio J 1 0.83 = Use the B 5-90 prop curve to determine K T and K Q K T .12 := K Q .023 := Thrust K T ρ n 2 d 4 := Thrust 2.654 10 4 × lb = b. Shaft Torque Torque K Q ρ n 2 d 5 := Torque 5.087 10 4 × lb ft = PD 2 π n Torque 550 lb ft sec hp := c. Shaft powerr delivered PD 1.937 10 3 × hp =

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ps1_soln - 1 A survey vessel has a 10 ft diameter B 5-90...

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