Page 175 - Theory and Design of Air Cushion Craft

158 Stability

Craft weight: W
Fan characteristics: A = 631
B = -1.80
C = -0.187
C 1 f\ "» A 2
Principal dimensions and parameters of the craft:
= 3.5 m
B c
B^ = 0.13m
B swb = 0.06 m (width of the sidewall at bow)
HW - 0.43 m (height of the sidewall)
= 70° (deadrise of sidewall at bow)
a b
a = 60° (deadrise of the sidewall amidships)
S a = 14 m (frontal area of the superstructure)
= 9.23° (inclination between the stern plate and base-line)
a s
= -0.20 m (aft amidships)
x g
~KG = 1.22m
= 0.50 m (height of thrust for water jet propulsion over base-line)
H s
2. SES type 717C (Table 4.6):
Craft weight: W = 156 kN
Fan characteristics: A =631
B = -I.80
C = -0.187
= 0.24m 2
S t

Table 4.5 The calculation of running attitude of the SES type 717A at various speeds
Item Symbol Units
Craft speed V km/h 30.67 42.90 51.08
Cushion pressure p e N/m 2 2690 2716 2763
Flow rate Q mVs 23.65 23.55 23.38
Outer draft at stern T so m 0.402 0.386 0.356
Inner draft at stern T sl m 0.0389 0.0399 0.0517
Outer draft at bow r bo m 0.1535 0.1385 0.111
Inner draft at bow T bl m 0.1535 0.1385 0.111

Table 4.6 The calculation results of running attitude of SES 717C at various speeds
Item Symbol Units
Craft speed V km/h 26.5 33.1 44.2 55.2
Cushion pressure p c N/m 2 2813 2789 2776 2787
Flow rate Q m /s 5.115 5.115 5.165 5.15
Outer draft at stern r so m 0.5254 0.5823 0.5952 0.5599
Inner draft at stern r si m 0.2066 0.2008 0.1986 0.2006
Outer draft at bow T bo m 0.086 0.0858 0.0868 0.089
Inner draft at bow T bt m 0.086 0.0866 0.0868 0.089