20 BAB II PERHITUNGAN RENCANA GARIS (LINES PLAN) A. PERHITUNGAN DASAR A.1 Panjang Garis Air Muat (Lwl) Lwl = Lpp + 2 % x Lpp = 36,00 m + (2 % x 36,00 m) = 36,720 m A.2 Panjang Displacement (L Displ) L Displ = 0,5 x ( Lwl + Lpp ) = 0,5 x (36.720 m + 36,00 m) = 36,36 m A.3 Coefisien Midship (Cm) Formula Arkent Bont Shocker. Cm = 0,90 - (0,1 x Cb) = 0,90 - (0,1 x √0,758) = 0,824 Memenuhi Syarat (0,73 - 0,88) A.4 Coefisien Prismatik (Cp) Formula Troast Cp = Cb / Cm = 0,758 / 0,824 = 0,698 Memenuhi Syarat (0,61 – 0,70) A.5 Coefisien Garis Air (Cw) Formula Troast Cw = √0,758- 0.025 = 0,733 Memenuhi Syarat (0,73 – 0,81) A.6 Luas Garis Air (Awl) Awl = Lwl x B x Cw = 36,720 m x 8,55 m x 0,733 = 230,218 m 2 A.7 Luas Midship (Am)
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PERHITUNGAN RENCANA GARISeprints.undip.ac.id/69251/3/4_BAB_II_RG.pdfC. Rencana bentuk garis air C.1. Perhitungan Besarnya Sudut Masuk (a) Untuk menghitung besarnya sudut masuk garis
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BAB II
PERHITUNGAN RENCANA GARIS
(LINES PLAN)
A. PERHITUNGAN DASAR
A.1 Panjang Garis Air Muat (Lwl)
Lwl = Lpp + 2 % x Lpp
= 36,00 m + (2 % x 36,00 m)
= 36,720 m
A.2 Panjang Displacement (L Displ)
L Displ = 0,5 x ( Lwl + Lpp )
= 0,5 x (36.720 m + 36,00 m)
= 36,36 m
A.3 Coefisien Midship (Cm) Formula Arkent Bont Shocker.
Cm = 0,90 - (0,1 x Cb)
= 0,90 - (0,1 x √0,758)
= 0,824 Memenuhi Syarat (0,73 - 0,88)
A.4 Coefisien Prismatik (Cp) Formula Troast
Cp = Cb / Cm
= 0,758 / 0,824
= 0,698 Memenuhi Syarat (0,61 – 0,70)
A.5 Coefisien Garis Air (Cw) Formula Troast
Cw = √0,758- 0.025
= 0,733 Memenuhi Syarat (0,73 – 0,81)
A.6 Luas Garis Air (Awl)
Awl = Lwl x B x Cw
= 36,720 m x 8,55 m x 0,733
= 230,218 m2
A.7 Luas Midship (Am)
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Am = B x T x Cm
= 8,55 m x 2,44 m x 0,830
= 17,315 m2
A.8 Volume Displacement (V Displ)
V Displ = Lpp x B x T x Cb
= 36,00 m x 8,55 m x 2,44 m x 0,58
= 431,843 m3
A.9 Coefisien Prismatik Displacement (Cp Displ)
Cp Displ = Lpp / L Displ x Cp
= 36,00 m / 36,360 m x 0,698
= 0,670
A.10 Displacement(D)
D = Vol Displ x γ x C
= 431,843 m3 x 1,025 x 1,004
= 444,410 Ton
γ = berat jenis air laut = 1,025 ton/m
C = koefisien berat las = 1,004
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B. MENENTUKAN LETAK TITIK LCB
B.1. Dengan menggunakan Cp Displacement pada grafik NSP pada Cp
Displacement = 0,67 Didapat letak titik LCB (Longitudinal Centre
Bouyancy = 0,20 % x L Displ, dimana L Displ = 42,215 m
Gambar 2.01. Grafik NSP
Cp
Displ = (LPP/L disp) x Cp
= 36,00 / 36,360 x 0.698
= 0.691
B.1.1. Letak LCB Displ menurut grafik NSP
LCB Displ( b ) = 0,75 % x L Displ
= 0,75 % x 36,36m
= 0,273m ( Di belakangmidship Lpp)
B.1.2. Jarak midship () L Displ ke FP
() Displ = 0,5 x L Displ
= 0,5 x 36,360m
= 18,180 m
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B.1.3. Jarak midship () Lpp ke FP
() Lpp = 0,5 x Lpp
= 0,5 x 36,360 m
= 18 m
B.1.4. Jarak antara midship () L Displ dengan midship () Lpp
a = ()Displ - () Lpp
= 18,180 m-18,00m
= 0,18 m
B.1.5. Jarak antara LCB terhadap midship () Lpp
c = b - a
= 0,18 - 0,273
= -0,0927 m ( Di belakang mid Lpp)
Gambar 2.02. Letak LCB Kapal
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B.2. Menurut diagram NSP dengan luas tiap section (Am) = 14,496 m2
No.
Ord %
% Terhadap
Am Fs Hasil Fm Hasil
AP 0.000 0 1 - -10 -
1 0.090 1.558 4 6.234 -9 -56.102
2 0.270 4.675 2 9.350 -8 -74.803
3 0.490 8.485 4 33.938 -7 -237.568
4 0.650 11.255 2 22.510 -6 -135.061
5 0.825 14.285 4 57.141 -5 -285.705
6 0.915 15.844 2 31.687 -4 -126.749
7 0.975 16.883 4 67.530 -3 -202.591
8 0.994 17.212 2 34.423 -2 -68.846
9 1.000 17.315 4 69.262 -1 -69.262
S 2 -1,256.687
10 1.000 17.315 2 34.631 0 -
11 0.997 17.264 4 69.054 1 69.054
12 0.975 16.883 2 33.765 2 67.530
13 0.950 16.450 4 65.799 3 197.396
14 0.915 15.844 2 31.687 4 126.749
15 0.865 14.978 4 59.911 5 299.557
16 0.750 12.987 2 25.973 6 155.839
17 0.550 9.524 4 38.094 7 266.658
18 0.330 5.714 2 11.428 8 91.426
19 0.120 2.078 4 8.311 9 74.803
FP 0.000 0 1 - 10 -
S 1 710.730 S 3 1,349.013
Tabel 2.1. Letak LCB Kapal
B.2.1.h= L Displ / 20
= 6,36 m / 20
= 1,818 m
B.2.2. Volume Displacement
V Displ = 1/3 x h x ∑
= 1/3 x 1,818 m x 710,730 m2
= 307,371m3
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B.2.3. Letak LCB NSP
LCB NSP = 1
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x h
= 581,592
1054,1711035,036 x 1,818
= 0,236 m
B.2.4. Koreksi prosentase penyimpangan LCB
= Displ L
NSP LCB - Displ LCB x 100 %
=
36,16
0,236-0,273 x 100 %
= 0,99% < 0,1 % ( Memenuhi )
B.2.5. Koreksi prosentase penyimpangan untuk volume Displ
= Awal Displ Vol
NSP Displ Vol - Awal Displ Vol x 100 %
= 431,843
430,703- 431,843 x 100 %
= 0,264 % < 0,5 % ( Memenuhi )
B.3. Perhitungan prismatik depan (Qf) dan koefisien prismatik belakang (Qa)
berdasarkan label “Van Lamerent”
Dimana :
Qf = Koefisien prismatik bagian depan midship Lpp
Qa = Koefisien prismatik bagian belakang midship Lpp
e = Perbandingan jarak LCB terhadap Lpp
e = ( LCB Lpp / Lpp ) x 100 %
= ( -0,0927 / 36,00 m ) x 100 %
= -0,0026
Dengan rumus tersebut diatas dapat dihitung harga Qa dan Qf dengan
rumus berikut :
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Qa = Qf = (1,4 + Q) x e
Dimana
Qf = Cp + (1,4 + Cp ) x e
= 0,698 + (1,4 + 0,698) x (0.0026)
= 0,692
Qa = Cp - (1,4 + Cp) x e
= 0,698 - (1,4 + 0,698) x (0.0026)
= 0,67
Tabel CSA lama menurut Van Lamerent, Am =14,496 m2
No. Ord Luas Station Luas Station Terhadap Am
AP 0 0.000
0.25 0.077 1.333
0.50 0.165 2.857
0.75 0.26 4.502
1 0.357 6.182
1.5 0.548 9.489
2 0.715 12.381
2.5 0.845 14.632
3 0.931 16.121
4 0.996 17.246
5 1 17.3155
6 0.994 17.212
7 0.918 15.896
7.5 0.825 14.285
8 0.692 11.982
8.5 0.524 9.073
9 0.339 5.870
9.25 0.245 4.242
9.50 0.156 2.701
9.75 0.071 1.229
FP 0 0.000
∑ 184,548
Tabel 2.2 CSA Lama
P=LCB b =4𝐶𝑃−1
6𝐶𝑃= 0,428
= 0,273 m tb = 7,407
Q = LCB NSP
= 0,236 m
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Perhitungan LCB dan Volume displacement dengan metode van lammerent