Section 3 Primary members supporting transverse side framing
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Ships, July 2022 - Part 4 Ship Structures (Ship Types) - Chapter 10 Single Hull Oil Tankers - Section 3 Primary members supporting transverse side framing

Section 3 Primary members supporting transverse side framing

Parent topic: Chapter 10 Single Hull Oil Tankers

3.1 General

3.1.1 The requirements of this Section are applicable to side stringers and transverse webs associated with transverse framing.

3.1.2 The minimum thickness and constructional detail requirements of Pt 4, Ch 10, 7 Construction details and minimum thickness are to be complied with.

3.2 Symbols

3.2.1 The symbols used in this Section are defined as follows:

h 1 = head, in metres, from stringer to highest point of tank excluding hatchway, but not less than 2,5 m
Q x = shear force at the actual section under consideration, obtained from shear force diagrams constructed as indicated, in kN (tonne-f)
S 1 = span, in metres, of the horizontal girder measured between span points, but to be taken not less than the lesser of (1,2 + 0,02L) m or 3 m.

3.2.2 Other symbols are defined in Pt 4, Ch 9, 1.6 Information required for CSR Double Hull Oil Tankers.

3.3 Structural arrangements

3.3.1 Side shell stringers are to be fitted as required by Table 10.3.1 Requirements for stringers. Alternatively, the number of stringers may be derived by direct calculation, particular regard being given to secondary bending effects on the frames supported.

Table 10.3.1 Requirements for stringers

Ship depth, in metres Number of stringers
D ≤6,0 0
6,0<D ≤7,5 1
7,5<D ≤11,0 2

3.3.2 Where the spacing of bulkheads (oiltight or non-oiltight) exceeds 15 m, side transverses are to be fitted in line with each bottom transverse.

3.3.3 Where side transverses are not required, bottom transverses are to be adequately supported at the side shell and longitudinal bulkhead, and the lower side stringer is to be suitably buttressed from the bottom transverse.

3.3.4 Cross-ties, where fitted, are to comply with the requirements of 2.10 and are, in general, to be aligned with the stringers.

3.3.5 Where the ship is fitted with a trunk, the scantlings as given in this Section are to be modified as required by Pt 4, Ch 10, 6 Trunked construction.

3.4 Scantlings

3.4.1 The section modulus of side stringers is to be not less than:

3.4.2 The net sectional area of the web at any section is to be not less than:

where Q x is calculated from a shear force diagram constructed using the shear force at the span point, Q 1 given by the following:

3.4.3 The moment of inertia of the stringer is to be not less than:

3.4.4  Where side transverses supporting side stringers are fitted, they are to have a section modulus not less than that required by Pt 4, Ch 10, 2.7 Side transverses. Where the side transverse does not support side stringers, the section modulus required by Pt 4, Ch 10, 2.7 Side transverses may be reduced by 20 per cent.

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