Hull Scantling Calculation

1. MAIN PARTICULAR / APPENDIX INFORMATION of SHIP :

Length between Perpendicular (L) in M

Length Water Line (Lwl) in M

Breadth of ship (B) in M

Draft?(T) in M or can be obtained by T=0.66H+0.9 in M

Height?(H) in M

Block coefficient (CB) = Δ / (L.B.T)

Displacement (Δ) in Ton

Volume of Displacement ? in M^3

Frame spacing (a) in M

Web Frame spacing (e) in M

Material factor (k)?

Yield strength (ReH) in N/mm^2

2. SCANTLING CALCULATION

2.1?Bottom Shell Plating:?

#Length co-efficient (CL)?????= 1?????????????????????????for L ≥ 90 m???????(BKI vol.II.ref.sec-4,

A.2.2)?

?????????????????????????????????????????????=?(L/90)^0.5??????????for L < 90 m

#Service coefficient (CRW)??= 1 for unlimited range service???????????(BKI vol.II.ref.sec-4, A.2.2)

???????????????????????????????????????????= 0,90 for service range P

???????????????????????????????????????????????= 0,75 for service range L

???????????????????????????????????????????????= 0,60 for service range T

#Distribution factor (CF x CD)?= 1 for midship,????????????????????????????(BKI vol.II.ref.sec-4, B.1)

#Wave coefficient, (Co) , see below for detail.????????????????????(BKI vol.II.ref.sec-4, A.3)

#nf???????????????????????????????????= 1,0 for transverse framing???????????????(BKI vol.II.ref.sec-6, A.1)

?????????????????????????????????????????= 0,83 for longitudinal framing

#Probability factor, (f)???????????????????????????????????(BKI vol.II.ref.sec-4, A.2)

????????????????????? = 1,0 for plate panels of the outer hull (shell plating, weather decks)

?????????????????????????????????????????= 0,75 for secondary stiffening members of theouter hull (frames,

?????????????????????????????????????????????deck beams), but not less than fQ according to Section 5, D.1.

?????????????????????????????????????????= 0,60 for girders and girder systems of the outer hull (web frames,

?????????????????????????????????????????????stringers, grillage systems), but not less than fQ/1,25

#Basic external dynamic load (Po)

???Po (kN/m2) = 2.1(CB+0.7) x Co x CL x f

2.2?Bottom Plate Thickness

#Load at bottom (PB)

??PB (kN/m2) = 10T + Po x Cf

σ perm????????????= permissible design stress [N/mm2]

??????????????= (0.8 + L/450)x230/k [N/mm2]???????for L < 90 m

???????????????????????= 230/k [N/mm2]???????????????????????????????for L ≥ 90 m

σLB?????????= Maximum bottom design hull girder bending stress [N/mm2] according to

???????????????????????????Section 5, D.1.

As a first approximation σLB and τL may be taken as follows:

σLB????????????????=?(12.6√L)/k [N/mm2]???????????for L < 90 m

???????????????????????=?120/k [N/mm2]??????????????????????????????for L ≥ 90 m

τL???????????????????= 0

Corrosion addition (tk)??????????????????????????????????????????????(BKI vol.II.ref.sec-3, k)

???????????????????????= 1,5 mm???????????????????????????????????????????for t' =10 mm???????????

????????????????= 0.1xt'/√k + 0.5 mm, max.3.0mm????for t' >10mm

#Ships with lengths L < 90 m

The thickness of the bottom shell plating within?0,4 L?amidships is not to be less than:

tB1 = 1.9 . nf . a√PB.k + tk [mm]

Within 0,1 L forward of the aft end of the length L and within 0,05 L aft of F.P. the thickness is not to be less than tB2.

#Ships with length L ≥ 90 m

The thickness of the bottom plating is not to be less than the greater of the two following values:

tB1 = 18.3 . nf . a√PB/σpl?+ tk?[mm]

tB2 = 1.21 . a√PB.k?+ tk?[mm]

σ pl?=??√(?σperm^2-3τL^2) - 0.89.σLB??[N/mm2]

2.3 Minimum Bottom plate thicknes

At no point the thickness of the bottom shell plating shall be not less than :

tmin?= (1.5 - 0.01 . L)√(L.k)??[mm]????????for L < 50 m??????????????????????(BKI vol.II,ref.Sec-6, B-3)

tmin?= √(L.k)?????????????????????????[mm]?????????for L ≥ 50 m

tmax?= 16.0 mm????????????????????????????????????????in general