In [1]:
import math
In [2]:
L = 199.33        # lOA SSV 
V = 8.5           # Speed in Knot
D = 8.5           # Depth
T = 5             # Draft
CB = 0.738        # Breakbulk Vessel
k = 1.2           # Ship withot Bilge keel
g0 = 9.81         # Gaya Gravitasi
B = 42            # Breadth
l = 192.5         # LPP
kr = 0.39 * B     # lihat B400
GM = 0.07 * B     # lihat B400
h = 8.4           # distance in m from the center of mass to the axis of ratoation

\ $C_w = 10.75 - \left[ \frac{300 - L}{100} \right]^{\frac{3}{2}}$ \ \ $C_v = \frac{\sqrt{L}}{50}; \text{maximum 0.2} $\ \ $C_{v1} = \frac{V}{\sqrt{50}}; \text{maximum 0.8} $

In [3]:
Cw = round(10.75 - ((300-L)/100)**(3/2),2)
Cv = math.sqrt(L)/50
Cv1 = V / math.sqrt(L)
print("Cw = ",Cw)

Cw =  9.74
In [4]:
if Cv > 0.2:
    Cv = 0.2
   
if Cv1 > 0.8:
    Cv1 = 0.8

print("Cv =", Cv)
print("Cv1 =", Cv1)

Cv = 0.2
Cv1 = 0.6020500438128915

$a_0 = \frac{3 \cdot C_w}{L}+C_v \cdot C_{v1}$

In [6]:
atas = 3*Cw 
cwl = atas/L
a0 = cwl + Cv * Cv1
print("a0 =",a0)

a0 = 0.2670010888809749

$a_x = 0.2 \cdot g_0 \cdot a_0 \cdot \sqrt{C_B}$

In [8]:
# The surge acceleration is given by:
ax = 0.2*g0*a0*math.sqrt(CB)
print("surge acceleration (ax) =",ax)

surge acceleration (ax) = 0.4500287054191305

$a_y = 0.2 \cdot g_0 \cdot a_0$

In [9]:
# The combined sway/yaw acceleration is given by
ay = 0.3*g0*a0
print("combined sway/yaw acceleration (ay) =",ay)

combined sway/yaw acceleration (ay) = 0.7857842045767092
In [10]:
# The heave acceleration is given by:
az = 0.7*g0*(a0/math.sqrt(CB)) 
print("heave acceleration (az) =",az)

heave acceleration (az) = 2.134282478275009
In [11]:
TR = (2*kr)/math.sqrt(GM)
c = (1.25 - 0.025*TR)*k
print("kr =",kr)
print("GM =",GM)
print("TR =",TR)
print("c =",c)

kr = 16.38
GM = 2.9400000000000004
TR = 19.106019993708784
c = 0.9268194001887364

z = distance from the baseline to the roll axis of rotation¶

$z = \text{terkecil dari }\left[ \frac{D}{4} + \frac{T}{2}\right] \text{dan}\left[ \frac{D}{2} \right]$

In [12]:
z1 = D/4 + T/2
z1
Out[12]:
4.625
In [13]:
z2 = D/2
z2
Out[13]:
4.25
In [14]:
z = min(z1,z2)
z
Out[14]:
4.25
In [15]:
phi = 50*c/B+75
phi = math.radians(phi/math.pi)
print(phi)

0.4227964246044229
In [16]:
RR = h - z
RR
Out[16]:
4.15
In [17]:
ar = phi * ((2*math.pi/TR)**2)*RR
ar
Out[17]:
0.18975738363049244

Pitch angle is given by:¶

$\Theta = 0.25\cdot\frac{a_0}{C_B}$

Period of Pitch:¶

$T_p = 1.8\cdot\sqrt{\frac{L}{g_0}}$

In [18]:
Theta = math.radians(0.25*(a0/CB)/math.pi)
Theta
Out[18]:
0.0005024862407425754
In [19]:
TP = 1.8*math.sqrt(L/g0)
TP
Out[19]:
8.11380067957612
In [20]:
ap = 120*Theta*((l-0.45*L)/L)
ap
Out[20]:
0.031097981805667703
In [25]:
# Combined vertical acceleration: {B600}
arz = 0.0
av1 = math.sqrt(arz**2 + az**2)
av2 = math.sqrt(ap**2 + az**2)
av = max(av1,av2)
av
Out[25]:
2.1366239016428965
In [26]:
# Combined transverse acceleration: {B700}

at = g0 * math.sin(phi) + phi*(2*math.pi/16.7)**2
at
Out[26]:
4.085012237807879
In [27]:
# Combined longitudinal acceleration: {B800}

al = math.sqrt(ax**2 + (g0*math.sin(Theta)+ap)**2)
al
Out[27]:
0.4514685007916476
In [28]:
print ("SUMMARY")
print ("")
print ("ax (long.) = ",round(al/g0,2),"g")
print ("ay (tran.) = ",round(at/g0,2),"g")
print ("az (vert.) = ",round(av/g0,2),"g")

SUMMARY

ax (long.) =  0.05 g
ay (tran.) =  0.42 g
az (vert.) =  0.22 g