Practical Ship Hydrodynamics

174 Practical Ship Hydrodynamics
C (−)
a s
A (−)
B (−)
3
2
1
2
1
0.5
0.4
0.3
0.2
0.1
25°
20°
15°
10°
5°
0
0
0
A = t a .V/L d = 20° y = 10°
0.1 0.2 0.3 0.4 0.5
Fn (−)
0.1 0.2 0.3 0.4 0.5
Fn (−)
⋅
C = y ⋅L / 57,3 ⋅V
d = 20°
y = 10°
0.1 0.2 0.3 0.4 0.5
Fn (−)
0 0.1 0.2 0.3 0.4 0.5
Fn (−)
B = t s ⋅V/L
d = 20°
y = 10°
a s [°]
d = 20°
y = 10°
Figure 5.8 Non-dimensional data obtained from zigzag model tests (Brix (1993))
A D non-dimensional initial turing times ˇ D B D non-dimensional times to check starboard
yaw C D non-dimensional turning speed to port ˛s starboard overshoot angle
6. Hard rudder test
With the ship on an initially straight course, the rudder is put hard to
35° port. As soon as this rudder angle is reached (i.e. without waiting
for a specific heading or rate of turning), the rudder is reversed to hard
starboard. The time for changing the rudder angle from 35° on one side
to 30° on the other side must not exceed 28 seconds according to IMO