Section 4 Single bottom structure
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Inland Waterways Ships, July 2022 - Part 4 Ship Structures (Ship Types) - Chapter 2 Ferries and Roll on-Roll off Ships - Section 4 Single bottom structure

Section 4 Single bottom structure

Parent topic: Chapter 2 Ferries and Roll on-Roll off Ships

4.1 General

4.1.1 The requirements of Pt 4, Ch 1, 6 Single bottom structure are to be applied together with the requirements of this Section. Additionally, scantlings for structural members of longitudinally framed single bottoms are given in Table 2.4.1 Longitudinally framed single bottom. The scantlings of longitudinals are based on end connections in accordance withPt 3, Ch 10, 3 Secondary member end connections.

Table 2.4.1 Longitudinally framed single bottom

Item Parameter Requirement
(1) Girders Web and face plate thickness
(0,01dw + 3) mm
  Width of face plate bf = 100 mm
(2) Bottom transverses Modulus Z = 7D1kSle 2 cm3
(3) Bottom longitudinals Modulus Z= (2 + 0,1L1)D1 ksle 2 cm3
Symbols
L, B, D, T, S, s, le, Z, I, k and t are as defined in Pt 4, Ch 2, 1.5 Symbols and definitions 1.5.1
b f = width of face plate, in mm
d w = web depth of floor or girder, in mm
D 1 = D but need be taken not greater than T + 0,4 m
L 1 = L but is to be not less than 40 m, nor more than 100 m

4.2 Girders (longitudinal framing)

4.2.1 A centreline girder is generally required in ships with a breadth, B, of more than 6 m. Alternatively, side girders may be fitted under pillars supporting the deck structure, but generally adequate support for docking purposes is to be provided on the centreline. Girders are to have the same depth as transverses.

4.3 Transverses (longitudinal framing)

4.3.1 Transverses are to be fitted at a spacing not exceeding 2,5 m. Vertical stiffeners having a depth not less than 50 mm are to be fitted to the transverses at every fourth longitudinal. In between the transverses, brackets are to be fitted connecting the transverse side frames to the outer bottom longitudinal.

4.3.2 Where transverses support point loads, the required section modulus and shear area are to be verified by direct calculation. For permissible stresses, see Pt 4, Ch 2, 7 Direct calculation procedures.

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