Calculation (midship) of ship

Department of Naval Architecture & Ocean Engg, IMU , M.Tech(NA&OE), Batch- I

MIDSHIP SECTION INTRODUCTION

Midship section design is in accordance with Part 4, Chapter 9 of “Lloyd’s Register”,

Rules and Regulations for Classification of Ships, which has been revised to include requirements

for Double Hull Oil Tankers. These requirements reflect regulation 13F of Annex I of MARPOL

73/78 with the other features. Fig.1 is a typical midship section of a double skin tanker.

Figure 1 - Typical midship section of a double skin tanker

1.1. Definitions

(1) L : Rule length, in m, is the distance, in meters, on the summer load water line

from the forward side of the stem to the after side of the rudderpost or to

the center of the rudder stock, if there is no rudder post. L is neither to be

less than 96% nor to be greater than 97% of the extreme length on the

summer load water line.

97% of extreme length of LWL = 229.89m

(2) B : Breadth at amidships or greatest breadth, in meters.

B = 42.0 m

(3) D : Depth is measured, in meters, at the middle of the length L, from top of the keel

to top of the deck beam at side on the uppermost continuous deck.

D = 22.0 m

(4) T : T is the summer load draught in m, measured from top of keel.

T = 14 m


(5) LPP : Distance in m on the summer LWL from foreside of the stem to after side

of rudder post, or to the center of the rudder stock, if there is no rudder post.

LPP = 233 m

(6) CB : Moulded block coefficient at draught T corresponding to summer

waterline, based on rule length L and moulded breadth B, as follows:

CB =

(7) B : The width of plating supported by the primary member or secondary

member in m or mm respectively.

(8) be : The effective width, in m, of end brackets.

(9) bI : The minimum distance from side shell to the inner hull or outer

longitudinal bulkhead measured inboard at right angles to the centre line

at summer load water line, in m

(10) le : Effective length, in m, of the primary or secondary member, measured

between effective span points.

(11) ds : The distance, in m, between the cargo tank boundary and the moulded

line of the side shell plating.

(12) h : The load height applied to the item under consideration, in m.

(13) db : The distance, in m, between the bottom of the cargo tanks and the

moulded line of the bottom shell plating measured at right angles to the

bottom shell plating.

(14) kL, k : Higher tensile steel factors. For mild steel, kL, k may be taken as 1.

(15) I : Moment of inertia, in cm3, of the primary or secondary member, in

association with an effective width of attached plating.

(16) s : Spacing of secondary members, in mm.

(17) S : Overall span of frame, in mm

(18) t : Thickness of plating, in mm.

(19) Z : Section modulus, in cm3, of the primary or secondary member, in

association with an effective width of attached plating.

(20) L1 : Length of ship in meters, but need not be greater than 190m.

(21) CW : Wave head, in m.

(22) RB : Bilge radius, in mm.

moulded displacement (m3) at draught T

L.B.T


(23) FD,FB : Local scantling reduction factor above neutral axis and below neutral axis

respectively. FD = 0.67, for plating and 0.75, for longitudinals

FB = 0.67, for plating and 0.75, for longitudinals

(24) O : Specified minimum yield stress, in N/mm2

(25) C : Maximum compressive hull vertical bending stress, in N/mm2

(26) T1 : T but to be taken not less than 0.05L m

= 11.495 m

(27) hT1 : T + CW m but need not be taken greater than 1.36 T

(28) hT2 : T + 0.5CW m but need not be taken greater than 1.2 T

(29) c1 : 60 / (225 – 165 FD) at deck; 1.0 at D/2; 75 / (225 – 150FB) at base ` line

of ship

(30) c2 : 165 / (345 – 180FB) at deck; 1.0 at D/2; 165/(345 – 180FB) at base line of

ship

(31) R : sin, where is the roll angle in degrees

sin = (0.45+0.1 L/B)(0.54 – L/1270)

R =0 .358

(32) D1 : D, in m, but is to be taken not 10 and need not be taken 16

D1 = 16m

sin = (0.45 + 0.1L/B)(0.54 – L / 1270 )

R = 0.358

(33) dDB : Rule depth of center girder, in mm

(34) SS : Span of the vertical web, in m

(35) tW : Thickness of web, in mm

(36) tB : Thickness of end bracket plating, in mm

1.1.2. Class Notation

Vessel is designed to be classed as ‘100 A1 Double Hull Oil Tanker ESP.’ ESP means

Enhanced Survey Program. This is for seagoing tanker having integral cargo tanks for carriage of oil

having flash point > 60o C.

1.1.3. Cargo Tank Boundary Requirements

Minimum double side width (ds) in m


ds = 0.5 + (dwt/20,000) or ds = 2.0 m

whichever is lesser. But ds should not be less than 1 m.

ds = 0.5+(95,000/20,000) = 5.25 m

Double side width is taken as 2.0 m to get the required ballast volume.

ds = 2.0 m

Minimum double bottom depth (dB)

dB = B/15 or dB = 2.0 m

whichever is lesser

dB = 42/15 = 2.8 m

A double bottom height of 2.0 m is provided to get the required ballast volume.

dB = 2.0 m

Structural configuration adopted has a single centerline longitudinal bulkhead. According

to Maritime Law of India (Appendix V111:63, Regulation 24), Length of cargo hold shall not exceed

10m or (0.25bi /B +0.15) x LL (for longitudinal bulkhead provided at centerline), whichever is greater.

[LRS Part 4, Chapter 9, Section 1.3.9]

(0.25bi /B +0.15) LL = 35.85 m

For length of cargo tanks and tank boundaries refer General Arrangement Plan.

Type Of Framing System

The bottom shell, inner bottom and deck are longitudinally framed (for L > 75m). The

side shell, inner hull bulkheads and long bulkheads are also longitudinally framed (L > 150m). When

the side shell in long framed, the inner hull bulkhead is also to be framed longitudinally. Primary

members are defined as girders, floors, transverses and other supporting members.

LONGITUDINAL STRENGTH

Design vertical wave bending moment (P3, C4, S5.2)

The appropriate hogging or sagging design hull vertical wave bending moment at

amidships is given by the following:

M w = f1 f2 Mwo

Where,


M wo = 0.1C1 C2 L2 B (C b + 0,7) kN m

Cb is to be taken not less than 0,60

C1 is given in Table 4.5.1 = 10.163

C2 = 1, (also defined in 5.2.2 at other positions along the length L)

f1 = ship service factor. For unrestricted sea-going service f 1 = 1,0

f2 = –1,1 for sagging (negative) moment

f2 = for hogging (positive) moment

= 1.025

M wo = 0.110.1631(229.89) 242(.825+0.7)

= 3440180.424 KNm

M w = 1-1.13440180.424 =-3784198.47 (sagging)

= 11.0253440180.424 =3526184.935 (hogging)

Permissible Still water Bending Moment

Ms = fsnCwL2B(CB+0.7) KNm

fsn = 0.072 for sagging bending moment

Cw = 10.75-{(300-L)/100}3/2

Ms = 0.07210.163(229.89)242(0.825+0.7)

= 247692.991 KNm

Hull Moment of Inertia (P3, C4, S5. 8)

Imin = 3L 10 –5 m4

= 139.373 m4

Minimum Hull Section Modulus [LRS Part 3, Chapter 4, Section 5]

The hull midship section modulus about the transverse neutral axis, at the deck or keel is

to be not less than

Z min = f1KL C1L2B (CB + 0.7) x 10-6 m3

1.9C b

(C b + 0.7)

(| M s + M w |)

kL


f1 = ship’s service factor. T be specially considered depending upon

the service restriction and in any event should not be less than 0.5.

For unrestricted sea going service f1 = 1.0

f1 taken as 1

For M.S; KL = 1 [Part 3 Chap.2 Sec 1.2]

C1 = 10.75 – [(300-L)/100] 1.5 for 90<L<300m

= 10.163

CB = Block Coefficient = 0.825

Zmin = 34.4018 m3

Hull Envelope Plating

Itemization of parts is shown in figure 8.2.

Fig.2

For longitudinally framed system [LRS Part 4, Chapter 9, Section 4]

= O/C = 235/175 = 1.34

J = 1720.5{(1-1/)/O} for < 2

= 56.53

1) Deck plating

t = s/J + 2.0

s = spacing of deck longitudinals = 850 mm

J = 56.53


t = 17 mm

2) Sheer strake

The greatest of the following is to be taken:

a) t = 0.0042 s hT1k

s = spacing of longitudinals = 700 mm

hT1 = 1.36T = 19.04

k = 1, for mild steel

t = 15.17 mm

or

b) t = s/J + 2 = 17 mm

t = 17 mm

Selected t = 17 mm

3) Side shell above mid-depth


a) t = 0.001s(0.059L1 + 7) FD/ kL

s = spacing of side shell longitudinals = 700 mm

FD = 0.67 (refer ‘DEFINITIONS’)

L1 = 190 m (refer ‘DEFINITIONS’)

kL = 1 (refer ‘DEFINITIONS’)

t = 12.67 mm

or

b) t = 0.0042 s hT1k, whichever is greater

hT1 = 19.04 m, as shown in pervious sections

k = 1 (refer ‘DEFINITIONS’)

t = 15.18 m

Selected t = 16 mm

4) Side shell below mid-depth


a) t = 0.001s (0.059L1 + 7) FB/kL


= 12.67 mm

But not less than

t = 0.0042 s hT1k

s = spacing of shell longitudinals = 850mm

t = 15.18 mm

Selected t = 16 mm

5) Bottom shell and bilge


a) t = s/J + 2.0

s = spacing of bottom and bilge longitudinals = 850 mm

J = 56.53

t = 17 mm

b) t = 0.0052s

hT2 = T + 0.5CW m but need not be taken greater than 1.2T

= 16.52

FB = 0.67 (refer ‘DEFINITIONS’)


t = 16.61 mm

Selected t = 17 mm

6) Keel Plating

Keel plating should be equal to thickness of bottom shell + 2 mm

t = 19 mm,

but need not exceed t = 25 k = 25 mm

Selected t = 19 mm

Width of keel plate is to be not less than 70B mm, but need not exceed 1800 mm and is

to be not less than 750 mm. ( LRS part 4, chapter1,table 1.5.1)

70B = 2940mm

w = 1800 mm

hT2k

1.8-FB


7) Inner bottom Plating

t = t0 / 2-FB

t0 = 0.005s kh1

s = spacing of inner bottom longitudinals = 850mm

k = 1

h = distance in m, from the plate in consideration to the highest

point of the tank, excluding hatchway.

t0 = 0.72 (h+Rbi)

= 19.4

R = 0.36 (refer previous sections)

b1 = B/2 = 21 m

t = 18 mm

8) Inner hull plating

same as outer shell,t = 18mm

Hull Framing [LRS Part 4, Chapter 9, Section 5]

1) Bottom Longitudinals

The section modulus of bottom longitudinals within the cargo tank region is not to be

less than greater of the following:

a) Z = 0.056kh1sle2F1FS cm3

K = 1 (refer ‘DEFINITIONS’)

h1 = (h0 + D1/8), but in no case be taken less than L1/56 m or

(0.00L1 + 0.7) m, whichever is greater & need not be taken

greater than (0.75 D + D1/8), for bottom longitudinals.

h0 = distance in m, from the midpoint of span of stiffener to

highest point of tank, excluding hatchway.

= 22 m

D1 = 16 m (refer ‘DEFINITIONS’)

h1 = 18.5 m

s = spacing of bottom longitudinals = 850 mm


le = s, where le = effective span of longitudinals which are

assumed to be supported by web frames spaced at 5s, where s = basic frame

spacing in midship region = 850 mm

le = 4.25 m

F1 = Dc1/(25D-20h)

c1 = 75/(225 – 150FB), at base line of ship.

FB = 0.75 (refer ‘DEFINITIONS’)

c1 = 0.667

h = distance of longitudinal below deck at side, in meters

= 22 m

D = 22m (refer ‘DEFINITIONS’)

F1 = 0.1334

FS = 1, at upper deck at side and at the base line

Z = 2121.84 cm3

b) Z = 0.0051kh3sle2F2 cm3


h3 = ho+ Rbi

b1 = 21 m

R = (0.45+0.1 L/B)(0.54 – L/1270) = 0. 358

D = 22 m

h3 = 29.52

but not greater than or equal to,0.75D+Rbi

= 24.02

Therefore h3 = 24.02

Z = 1880.79 cm3

Greater of the two is to be taken, i.e. Z = 2121.84 cm3

Selected Half bulb section of scantling 430x21 .

2) Deck Longitudinals

The modulus of deck longitudinals within the cargo tank region is not to be less than

greater of the following:


a) Z = 0.056kh1sl2eF1FS cm3 ( LRS, part 4,chapter 9,5.3.1)


h1 = (h0 + D1/8), but in no case be taken less than L1/56 m .

h0 = 0 ( for deck longitudinals)

L1 = 190 m

D1 = 16

(h0 + D1/8) = 2

L1/56 = 3.39

h1 = L1/56 = 3.39

s = 850 mm

le = 4.25m

F1 = Dc1 / (4D + 20h)

h = 0 (for deck longitudinals)

c1 = 60 / (225 – 165FD) at deck


c1 = 0.593

F1 = 0.1475

Fs = 1, at upper deck at side and at baseline of ship

Z = 429.9 cm3

b) Z = 0.0051kh3sl2eF2 cm3

R = 0.36

bi = B/2 = 21m

h3 = h0 + Rbi = 7.56 m

s = 850 mm

le = 4.25m

F2 = Dc2 / (D + 2.18h)

c2 = 165 / (345 – 180FD)


c2 = 0.785

F2 = 0.785

Z = 464.7 cm3

Greatest of the two is to be taken, i.e. Z = 464.7 cm3

Taken half bulb section of scantling 260x12.


3) Side Shell Longitudinals ( LRS part 4, chapter 9,5.3.1)

From standardization point of view the side shell is divided into longitudinal fields as

shown in fig 8.2. Design of the longitudinals for each field is done using the information for the

lowest longitudinal in each field.

Fig. 1.3 Plate fields for the determination of side,

inner hull and CL bulkhead longitudinals

The modulus of side shell longitudinals within the cargo tank region is not to be less than

greater of the following:

a) Z = 0.056kh1sle2F1Fs cm3

b) Z = 0.0051kh3sle2F2 cm3

where,

h1 = (h0 + D1/8), but in no case be taken less than L1/56 m .

s = 850 mm

le = 4.25m

k = 1

FD = 0.75

D1 = 16

L1 = 190m

L1/56 = 3.39

h = distance of longitudinal below deck at side, in meters

h3 = h0 + 2xRb1

For side longitudinals above D/2,


F1 = Dc1 / (4D + 20h)

F2 = Dc2 / (D + 2.18h)

For side longitudinals below D/2,

F1 = Dc1/(25D-20h)

F2 = Dc2/(3.18D-2.18h)

Table 1.1 – Determination of scantlings of side longitudinals

Item REG 1 REG 2 REG 3 REG 4

ho 5 10 15 20

D1 16 16 16 16

h1= h0+D1/8 7 12 17 22

h3 20.12 25.12 30.12 35.12

F1 0.12 0.12 0.12 0.12

F2 0.73 0.73 0.73 0.73

Fs 1 1 1 1

a) Z 722.211 1238.076 1650.768 2063.46

b) Z 1141.82 1427.62 1656.25 1884.89

Taken Z 1141.82 1427.62 1656.25 2063.46

Section Half bulb Half bulb Half bulb Half bulb

Scantling 370x13 400x14 430x15 430x21

Z of taken section 1150 1450 1800 2150

1.2.4. Inner Hull, Inner Bottom And Longitudinal Bulkheads

The inner hull, inner bottom and longitudinal bulkheads are longitudinally framed.

The symbols used in this section are defined as follows:

b1 = the greatest distance in meters, from the centre of the plate panel

or midpoint of the stiffener span, to the corners at top of the tank

on either side.

c1 = 60 / (225 – 165FD) at deck

= 1.0 at D/2

= 75/(225 – 150FB), at base line of ship

c2 = 165/(345 – 180FB) at deck

= 1.0 at D/2

= 165/(345 – 180FD) at baseline of ship


h = load height, in meters measured vertically asfollows:

(a) for bulkhead plating the distance from a point one third of the height of the plate panel above its lower edge to the

highest point of the tank, excluding hatchway

(b) for bulkhead stiffeners or corrugations, the distance from the midpoint of span of the stiffener or corrugation to the

highest point of the tank, excluding hatchway

h1 = (h + D1/8), but not less than 0.72(h + Rb1)

h2 = (h + D1/8), in meters, but in no case be taken less than L1/56 m .

h3 = distance of longitudinal below deck at side, in meters, but is not to

be less than 0

h4 = h + Rb1

h5 = h2 but is not to be less than 0.55h4

t0 = 0.005s kh1

t1 = t0(0.84 + 0.16(tm/t0)2)

tm = minimum value of t0 within 0.4D each side of mid depth of

bulkhead

1) Longitudinal Bulkhead Plating

For the determination of scantlings of longitudinal bulkhead plating [16, Part 4, Chapter

9], the fields in fig. 1.2 are assumed.

Region1

b1 = 21 m

h = 3.33

h1 = 5.33

t =

t0 = 0.005s kh1

= 11.85 mm

t = 10.27 mm

but not less than t1

t1 = t0 (0.84+0.16(tm / t0 )2

= 11.85 mm ( Selected 12 mm)

Region2

t0

2-FB


b1 = 21 m

h = 6.66

h1 = 10.18

t0 = 13.56

t1 = t0 (0.84+0.16(tm / t0 )2

= 13.56 mm ( Selected 14mm)

Region3

b1 = 21 m

h = 9.33

h1 = 11.33

t0 = 11.38t1 = t0 (0.84+0.16(tm / t0 )2

= 14.78 mm

t = 12.81 mm

t1 = 14.78 mm (selected 15mm)

Region4

b1 = 21 m

h = 12

h1 = 14

t0 = 15.91

t = 13.79 mm

t1 = t0 (084+0.16(tm / t0 )2

= 15.91 mm (Selected 16mm)

2) C.L Longitudinal Bulk Head Longitudinals and Inner Hull Longitudinals

Inner hull and longitudinal bulkheads are to be horizontally stiffened. The modulus of

longitudinals is not to be less than greater of the following:

(a) Z = 0.056kh2sl2eF1 cm3

(b) Z = 0.0051kh4sl2eF2 cm3


The inner hull and bulkhead plating is divided into various strakes for the determination

of center line bulkhead longitudinals and inner hull longitudinals.

L1/56 = 3.39

s = 850 mm

le = 4.25m

Table 1.2 Determination of scantlings of CL longitudinal bulkhead longitudinals .

Region 1 Region 2 Region 3 Region 4

b1 21 21 21 21

h 5 10 14 18

h2 7 12 16 20

h4 12.488 17.488 21.488 25.488

F1 0.12 0.12 0.12 0.12

F2 0.73 0.73 0.73 0.73

Z1 722.211 1238.076 1650.768 2063.46

Z2 713.81 999.6 1228.24 1456.88

Taken Z 722.211 1238.076 1650.768 2063.46


Scantling 300x14 370x16 430x15 430x21


Table 1.3 Determination of scantlings of inner hull longitudinals

Region 1 Region 2 Region 3 Region 4

b1 21 21 21 21

h 5 10 14 18

h2 7 12 16 20

h4 18.536 23.536 27.536 31.536

F1 0.12 0.12 0.12 0.12

F2 0.73 0.73 0.73 0.73

Z1 722.211 1238.076 1650.768 2063.46

Z2 1059.51 1345.31 1573.94 1802.58

Taken Z 1059.51 1345.31 1650.768 2063.46


Scantling 370x13 400x14 430x15 430x21


3) Inner Bottom Plating and Longitudinals


The inner bottom is to be longitudinally framed and the inner bottom plating thickness is

to be

t = t0 / 2-FB

t0 = 0.005s kh1

h = 20 m

D1 = 16

R = 0.36

h1 = h + D1/8 = 22m

t0 = 20mm

t = 18.12 mm

Selected t = 18 mm

The modulus of longitudinals is not to be less than greater of the following:

(a) Z = 0.056kh2sl2eF1 cm3

h = 20 m

D1 = 16 m

h2 = h + D1 / 8 = 22 m

c1 = 0.667

F1 = 0.095

Z = 2063.46 cm3

(b) Z = 0.0051kh4sl2eF2 cm3

h4 = h + Rbi = 31.536m

c2 = 0.785

F2 = 0.64

but minimum value of F2 = 0.73

Z = 2063.46 cm3

. Hence, Half bulb section of scantling 430x21 is taken having section modulus of 2150

cm3.

1.2.5. Primary Members Supporting the Hull Longitudinal Framing

1) Centre girder (LRS part 4 chapter 1,8.3.1)


(a) Minimum depth of centre girder

dDB = 28B + 205 T mm

dDB = 1943.04 mm

Given 2.0m.

(b) Minimum thickness of centre girder( LRS, part 4, chapter 9,14.2.5)

t = (0.008 dDB + 1) k

= 17 mm

Given thickness = 17 mm

2) Floors and Side Girders ( LRS part 4, chapter 9,14.2.5)

t = (0.007dDB + 1) k

= 15 mm

but not to exceed 12 k = 12 mm

given thickness = 12 mm

t = 12 mm

3) Deck Transverses

Section modulus of deck transverses is not to be less than

Z = 53.75 (0.0269sL + 0.8) (ST + 1.83)k cm3

s = 4.25 m

L = 233 m

ST = span of transverse

= 13.3 m

Z = 53.75 (0.269 4.25 233+ 0.8) (13.3 + 1.83) 1

= 22313.4 cm3

The section selected is a T-section with scantlings as follows

1500X25 web and 300X25 flange with the section modulus as 25400 cm3

4) Vertical web on centerline longitudinal bulkhead

Section modulus of vertical web is to be not less than

Z = K3shsSs2k (sm3)

K3 = 1.88


s = 4.25

hs = distance between the lower span point of the vertical web

and the moulded deckline at centreline, in meters

= 18 m

Ss = span of vertical web, in meters, and is to be measured

between end span points.

= 13 m

Z = 24575.64 cm3

Taken 1500x 300x 25/25, with Z = 25400 cm3

1.2.6. Primary Members End Connections [LRS Part 3, Chapter 10, Section 3]

The following relations govern the scantlings of bracket:

(a + b) 2l

a 0.8 l

b 0.8 l

l = 90 2 - 1 mm

1) Bracket connecting deck transverse and inner hull

l = 90 2 - 1 mm

= 90 { 2 ( 25400 / [ 14 + 25400]) – 1}

= 2088.0 mm

a 0.8l = 1670.4 mm

b 0.8l = 1670.4 mm

Given a = 2300 mm and b = 2000 mm

t = thickness of web itself = 21 mm

Flange breadth to be not less than

bf = 40 (1 + Z / 1000) mm, but not less than 50mm

= 40 (1 + 25400 / 1000 )

= 1056 mm

2) Bracket connecting deck transverse and center line bulkhead web

Z

(14 + Z)

Z

(14 + Z)


l = 90 2 - 1 mm

= 90 { 2 ( 25400 / [ 14 + 25400]) – 1}

= 2088.0 mm

a 0.8l = 1670.4 mm

b 0.8l = 1670.4 mm

Given a = 2300 mm and b = 2000 mm

t = thickness of web itself = 21 mm



= 40 (1 + 25400 / 1000 )

= 1056 mm

3) Bracket connecting center line vertical web and inner bottom plating

l = 90 2 - 1 mm

= 90 { 2 ( 25400 / [ 14 + 25400]) – 1}

= 2088 mm

a 0.8l = 1670.4 mm

b 0.8l = 1670.4 mm

Given a = 2300 mm and b = 2000 mm.

tb = thickness of web itself = 15 mm



= 40 (1 + 25400 / 1000 )

= 1056 mm

Z

(14 + Z)

Z

(14 + Z)


1.2.7. Section Modulus Calculation

Table 1.4 – Section Modulus Calculation

ITEMS L(mm) B(mm) NO:

AREA(m2) LEVER

A L A L2 I own(m4)

DECK PLATE 21000 20 2 0.924 22 19.404 447.216 0

SIDE SHELLPLATE 8500 20 2 0.374 15.25 5.2734 86.978375

0.818

SIDE SHELLPLATE 8500 19 2 0.323 6.75 1.938 14.716688

0.818

BOTTOM SHELL PLATE 16675 17 2 0.56695 0.008 0.004536

3.628E-05 0

BOTTOM BILGE PLATE 2635 17 2 0.08959 1.15 0.103029

0.1184828

0

SHEERSTRAKE PLATE 2365 20 2 0.10406 21 2.18526 45.89046 0.0082

KEEL PLATE 3600 19 1 0.0684 0 0 0 0

INN HULL PLATE 18000 18 2 0.648 12 6.48 93.312 5.46

MARGIN PLATE 2800 18 2 0.1008 3.71 0.373968

1.3874213

0.029

INN BOT PLATE 17000 18 2 0.612 2 1.224 2.448 0

CENTRE GIRDER 2000 17 1 0.034 1 0.034 0.034 0.011

SIDE GIRDER 2000 12 6 0.144 1 0.144 0.144 0.008

CL BKD reg 1 5000 12 1 0.06 19.5 1.17 22.815 0.125

CL BKD reg 2 5000 14 1 0.07 14.5 1.015 14.7175 0.146

CL BKD reg 3 5000 15 1 0.075 9.5 0.7125 6.76875 0.15625

CL BKD reg 4 5000 16 1 0.08 4.5 0.36 1.62 0.1666

WING TANK HORI.GIRDER 1 370*13 2 0.0139 9 0.125 1.1259 0



DECK LONGITUDINALS 260*12 50 0.2065 21.87 4.13 98.76831

INNER HULL LONGITUDINALS IH 1 370*13 2 0.01392 19.15 0.266568 5.104

IH 2 370*13 2 0.01392 18.3 0.254 4.661

IH 3 370*13 2 0.01392 17.45 0.242 4.238

IH 4 370*13 2 0.01392 16.6 0.231 3.835

IH 5 370*13 2 0.01392 15.75 0.219 3.453

IH 6 400*14 2 0.01628 14.9 0.242 3.614

IH 7 400*14 2 0.01628 14.05 0.228 3.213

IH 8 400*14 2 0.01628 13.2 0.214 2.836

IH 9 400*14 2 0.01628 12.35 0.201 2.483

IH 10 400*14 2 0.01628 11.5 0.187 2.153

IH 11 430*15 2 0.01882 10.65 0.2 2.134

IH 12 430*15 2 0.01882 9.8 0.184 1.807

IH 13 430*15 2 0.01882 8.95 0.168 1.507

IH 14 430*15 2 0.01882 8.1 0.152 1.234

IH 15 430*21 2 0.024 7.25 0.174 1.261

IH 16 430*21 2 0.024 6.4 0.153 0.983

IH 17 430*21 2 0.024 5.55 0.133 0.739

IH 18 430*21 2 0.024 4.7 0.112 0.53

IH 19 430*21 2 0.024 3.85 0.092 0.355


BOTTOM LONGITUDINALS 430*21 40 0.444 0 0 0

INNER BOTTOM LONGITUDINALS

430*21 34 0.408 2 0.816 1.632

SIDE LONGITUDINALS

S 1 370*13 2 0.01392 19.15 0.266 5.104

S 2 370*13 2 0.01392 18.3 0.254 4.661

S 3 370*13 2 0.01392 17.45 0.242 4.238

S 4 370*13 2 0.01392 16.6 0.231 3.835

S 5 370*13 2 0.01392 15.75 0.219 3.453

S 6 400*14 2 0.01628 14.9 0.242 3.614

S 7 400*14 2 0.01628 14.05 0.228 3.213

S 8 400*14 2 0.01628 13.2 0.214 2.836

S 9 400*14 2 0.01628 12.35 0.201 2.483

S 10 400*14 2 0.01628 11.5 0.187 2.153

S 11 430*15 2 0.01882 10.65 0.2 2.134

S 12 430*15 2 0.01882 9.8 0.184 1.807

S 13 430*15 2 0.01882 8.95 0.168 1.507

S 14 430*15 2 0.01882 8.1 0.152 1.234

S 15 430*21 2 0.024 7.25 0.174 1.261

S 16 430*21 2 0.024 6.4 0.153 0.983

S 17 430*21 2 0.024 5.55 0.133 0.739

S 18 430*21 2 0.024 4.7 0.112 0.53

S 19 430*21 2 0.024 3.85 0.092 0.355

S 20 430*21 2 0.024 3 0.072 0.216

S 21 430*21 2 0.024 2.15 0.051 0.11

BULKHEAD LONGITUDINALS

BKD 1 300*14 1 0.0058 19.15 0.111 2.126

BKD 2 300*14 1 0.0058 18.3 0.106 1.942

BKD 3 300*14 1 0.0058 17.45 0.101 1.766

BKD 4 300*14 1 0.0058 16.6 0.096 1.598

BKD 5 300*14 1 0.0058 15.75 0.091 1.438

BKD 6 370*16 1 0.00807 14.9 0.12 1.791

BKD 7 370*16 1 0.00807 14.05 0.113 1.593

BKD 8 370*16 1 0.00807 13.2 0.106 1.406

BKD 9 370*16 1 0.00807 12.35 0.099 1.23

BKD 10

370*16 1 0.00807 11.5 0.092 1.067

BKD 11

370*16 1 0.00807 10.65 0.085 0.915

BKD 12

430*15 1 0.00941 9.8 0.092 0.903

BKD 13

430*15 1 0.00941 8.95 0.084 0.753

BKD 14

430*15 1 0.00941 8.1 0.076 0.617

BKD 15

430*15 1 0.00941 7.25 0.068 0.494

BKD 16

430*15 1 0.00941 6.4 0.06 0.385

BKD 17

430*21 1 0.024 5.55 0.133 0.739

BKD 18

430*21 1 0.024 4.7 0.112 0.53


BKD 19

430*21 1 0.024 3.85 0.092 0.355

BKD 20

430*21 1 0.024 3 0.072 0.216

BKD 21

430*21 1 0.024 2.15 0.051 0.11

6.239 53.0416 912.233 7.3708

Height of the neutral axis, hNA =

=

= 8.502 m from base line

Moment about keel,

I KEEL = Ah2 + IXX

= 912.233 + 7.371

= 919.604 m4

Moment about neutral axis,

I NA = I KEEL - A x (hNA)2

= 919.604- 6.239x (8.502)2

= 468.65 m4

Section modulus about deck,

ZDECK =

=

= 37.788m3

Section modulus about keel,

ZKEEL =

=

= 55.124m3

Required section modulus, ZMIN = 34.402 m3

AL

A

53.042

6.239

INA

h DECK

468.65

21-8.71

INA

hNA

468.65

8.507


Here ZDECK and ZKEEL are getting more than the minimum section modulus required. So the design is

satisfactory.

The maximum hull vertical bending stresses at deck, σDECK, and keel, σKEEL, are given by the

following, using the appropriate combination of bending moments to give sagging and hogging

stresses:

σDECK =( |Ms+Mw|x 10–3) / ZDECK N/mm2

= 94.347 N/mm2

σKEEL = (|Ms+Mw|x 10–3 )/ ZKEEL N/mm2

= 67.271 N/mm2

Calculation (midship) of ship

Documents

Transcript of Calculation (midship) of ship