The document discusses the scantling, or dimensions, of structural components for a ship building project. It outlines three common framing systems - transverse, longitudinal and combined - and notes this ship will use a combined system with longitudinal framing on the bottom and deck and transverse framing on the side shells. Dimensions are then calculated based on governing rules for various structures like the bottom shell plating, side plates, bilge, keel, web frames, stringers, longitudinals and deck beams. A summary table is also included listing the structural components, their sections and plate thicknesses.

1. Scantling Of Ship
Bangladesh University of Engineering and Technology
[Year]
Ashifur Rahaman Roll:1312029

2. Scantling means dimension of ship building materials in framing system of
structure.Three types of framing systems are considered in ship building.
1. Transverse framing system
2. Longitudinal Framing system
3. Combined framingSystem
We adopt longitudinalframingin the bottom and deck and transverse framing system in the
side shells . So we adopt the combined framing system.
Here for the purpose of better cargocapacity we adopt single bottom construction.
The calculation based on GL Rule Book for determination of dimensions of differentstructural
components is shown below:
Bottom Shell Plating
Length coefficient = 1 for L ≥ 90 m
Service coefficient ,CRW = 1 for unlimited service range
Distribution factor , CF = 1 for midship
Wave coefficient, Co = Wave Coefficient
=













 

5.1
100
300
75.10
L
CRW
=













 

5.1
100
88.127300
75.10 x 1
= 8.49
nf = 0.83 for longitudinal framing
Probability factor, f = 1 for plate panels of the outer hull (shell plating, weather decks)
Po = Basic external dynamic load
= 2.1(CB+0.7) Co × CL× f
= 2.1(0.8+0.7) × 8.49 × 1 × 1
= 26.74 KN/m2
PB = Load at bottom
= 10T + Po × CF
= 10 × 8.2 + 26.74 × 1
= 108.74 KN/m2
Corrosion addition tk = 1.5 mm for thickness < 10 mm
pl =  22
3 Lperm   --.89  LB = 171.01 N/mm2
perm =230/ k =230/0.72=319.44
 LB= 120/k =166.77
tB1= 18.3x nf x a x
pl
BP

+ tk = 18.3 x 0.83 x 0.92 x
01.171
74.108
+ (0.1*t/  K +0.5)=12.96 mm
tB2 =1.21 x a x ).( KPB + tK = 11.35 mm
Minimum bottom plate thickness =  KL. ≈ 10 mm
So, we accept the bottom plate thickness = 13 mm

3. Side Plate thickness
Side Plate thickness = T +
2
Co
= 8.2 +
2
49.8
= 12.445 13 mm
Bilge thickness
Bilge thickness = Bottom plate thickness = 13 mm
Flat Keel Plate
The thickness of flat plate keel should not be less than
tFK = tB+2.0
=13.0+2.0
=15 mm
So we take the thickness of our flat plate keel as tFK=15 mm The width of flat plate keel is not to be less than :
B= 800+5L (mm)
=800+5*127.88= 1439.44 mm=1.44 m
Web frame and Side Stringers‫׃‬
P=Ps=Load on ship side
= 10(T-Z) +Po × CF (1+
T
Z
)
= 10(8.2-5.995) +26.74×1× (1+
.
2.8
955.5
)
= 68.209 KN/m2
where,
Z = vertical distance of the structure’s load centre above base line [m]
= 0.5(depth- double bottom depth)+ double bottom depth
= 0.5(10.76- 1.23) +1.23 = 5.995 m
T = Draft = 8.2 m
CF = distribution factor=1
Co= WaveCoefficient
=













 

5.1
100
300
75.10
L
CRW
=













 

5.1
100
88.127300
75.10 x 1
= 8.49
where,
CRW = service range coefficient
= 1 for unlimited service range
Po = Basic external dynamic load
= 2.1(CB+0.7) Co × CL× f
= 2.1(0.8+0.7) × 8.49 × 1 × 0.6
= 16.05 KN/m2
where,


4. CL = Length coefficient
f = Probability factor = 0.6 for girders and girder systems of the outer hull (web frames, stringers, grillage systems)
Web frame spacing,e = 1.92 m
l = Length of unsupported span
= 2.24 m
Section modulus, W = 0.55 × e × l2 × P × nc × K
= 0.55 × 1.92 × 2.242 × 68.209× 1 × 0.72
= 260.21 cm3 ≈261 cm3
where,
nc = Reduction coefficient
K = Material factor
Dimension ‫׃‬ T- 219×6+100×9
Bottom structure (Keelson):
Depth, h = 350 + 45×B
= 350 + (45×19.50)
= 1227.5
≈1230 mm
Thickness, t =
ha
h
(
100
h
+ 1) × K
= 1 (
100
1230
+ 1) × 72.0
= 11.29 ≈ 12 mm
Face platewidth ≈12 x 10 = 120 mm
Dimension‫׃‬ T- 1230 × 12
Deck Web and Deck Girder:
Po = Basic external dynamic load
= 2.1(CB+0.7) Co × CL× f
= 2.1(0.8+0.7) × 8.49 × 1 × 1
= 26.74 KN/m2
where, f = Probability factor = 1 for plate panels of the outer hull (shell plating, weather decks)
P = PD = Pressure on ship’s deck
= Po ×
HTZ
T
)10(
20

 ×CD
= 26.74 ×
76.10)2.8995.510(
2.820

 ×1 = 52.28 KN/m2
where,
CD = distribution factor = 1
H = Depth = 10.76 m
Section Modulus, W = c × e × l2 × P × K
= 0.75 × 1.92× 2.752 × 52.28 × 0.72
= 409.92 cm3
where,
l = Length of unsupported span = 2.75 m
c = 0.75 for beams, girders and transverses which are simply supported on one or both ends
Dimension‫׃‬ T- 287×6+120×9

5. Bottom Longitudinal:
Po = Basic external dynamic load
= 2.1(CB+0.7) Co × CL× f
= 2.1(0.8+0.7) × 8.49 × 1 ×0 .75
= 20.06 KN/m2
f = Probability factor = 0.75 for secondary stiffening members
P = PB = Load at bottom
= 10T + Po × CF
= 10 × 8.2+20.06 × 1
= 102.06 KN/m2
ma = 0.204 ×
l
a
[4– (
l
a
)2] = 0.204 ×
75.2
92.0
[4– (
75.2
92.0
)2] = 0.265 ; a = frame spacing
mk = 1 –(lki+lkj)/10³/l= 1- (0.2+0.2)/10³/2..75= 0.99
m = mk
2 – ma
2 = 0.91
σpr =
K
150
= 208.33
Sectional modulus, W =
pr
3.83
× m × a × l2 × P =
33.208
3.83
× 0.91× 0.92 × 2.752 × 102.06 =258.37≈260 cm3
Dimension‫׃‬ L – 160×80×14
Side Longitudinal:
Ps = Load on side
= 10(T-Z) + Po × CF (1 +
T
Z
)
= 10(8.2-5.995) + 16.05 x 1 x (1 +
2.8
995.5
)
= 49.83 KN/m2
Section Modulus, W =
pr
3.83 × m × a × l2 × Ps =
33.208
3.83
×0 .91×0.92×2.242 × 49..83
= 83.70 cm3 ≈ 84 cm3
Dimension‫׃‬ L – 100 × 75 × 9
Deck Longitudinal:
P = PD = Pressure on ship’s deck
= Po ×
HTZ
T
)10(
20

 ×CD
= 26.74 ×
76.10)2.8995.510(
2.820

 × 1
= 52.28KN/m2
W =
pr
3.83 × m × a × l2 × PD =
33.208
3.83
× 0.91 ×0.92 ×2.752 × 52.28= 132.35≈133 cm3
Dimension =L-130×75×10
Deck Beam:
P = PD = Pressure on ship’s deck
= Po ×
HTZ
T
)10(
20

 ×CD = 52.28 KN/m2
c = 0.75 for beam & girders
Sectional modulus, Wd = c × a × l2 × K × P = 196.42=197 cm3

6. Dimension‫׃‬ L- 160 × 80× 10
Superstructure:
Side plate
1.21*a * √(P.K)+tk
=1.21*.92*√(52.28*.72)+1.5
=6.8+1.5=8.3
Deck Plate
t = (5.5 + 0.02 L ) √k
= 6.837 mm
Scantlings :
WD= C *a * l^2 * k
= 0.75*.92*52.28*2.24^2*0.72
=130 cm^3
Dimension : 180 × 12
Girders
W= C × e × l2 × p × k
=271.97 cm3
Dimension : 220 × 17
Bulkheadplating
t = 6,0√ f
= 6×√0.67= 4.88 mm
f =235/ReH
= 0.67
ReH = minimum nominal upper yield point(N/mm)
Summary Table
WEB FRAME
Items Section
Center Girder T T- 1230 × 12
Side Stringer T T-
219×6+100×9
WEB FRAME T T-
219×6+100×9
Deck Girder T T-
287×6+120×9
Deck Web T T-
287×6+120×9

7. LONGITUDINAL Section
Items L
Deck L L-130×75×10
Side L L – 100 × 75 ×
9
Inner Bottom L L – 160×80×6
Bottom L L – 160×80×6
Super Structure
Girder 150×100×10
Longitudinal 287×6+180×6
Plate Thickness
Botom 13mm
Flat keel 15mm
Bilge 13mm
Side Shell 13mm
Deck 10mm
SuperSt deck 6.8mm
SuperSt side 8.23mm