Section 2 Deck structure
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Ships, July 2022 - Part 3 Ship Structures (General) - Chapter 7 Machinery Spaces - Section 2 Deck structure

Section 2 Deck structure

Parent topic: Chapter 7 Machinery Spaces

2.1 Strength deck − Plating

2.1.1 The corners of machinery space openings are to be of suitable shape and design to minimise stress concentrations.

2.1.2 In the case of oil tankers (see Pt 3, Ch 6, 1.1 Application 1.1.3), or other ships having small deck openings amidships and machinery aft, where the width of machinery openings exceeds and the opening extends forward beyond a point aft of the poop front, the thickness of deck plating may be required to be increased locally.

2.2 Strength deck − Primary structure

2.2.1 Where a transverse framing system is adopted, deck beams are to be supported by a suitable arrangement of longitudinal girders in association with pillars or pillar bulkheads. Deep beams are to be arranged in way of the ends of engine casings and also in line with web frames where fitted.

2.2.2 Where a longitudinal framing system is adopted, deck longitudinals are to be supported by transverses in association with pillars or pillar bulkheads. For the maximum spacing of transverses, see Pt 3, Ch 7, 1.2 Structural configuration 1.2.4. Deck transverses are to be in line with side transverses or web frames.

2.2.3 Machinery casings are to be supported by a suitable arrangement of deep beams or transverses and longitudinal girders in association with pillars or pillar bulkheads. In way of particularly large machinery casing openings, cross ties may be required, and these are to be arranged in line with deep beams or transverses.

2.3 Lower decks

2.3.1 The scantlings of lower decks or flats are generally to be as detailed in Pt 3, Ch 5, 2 Deck structure, Pt 3, Ch 6, 2 Deck structure or Pt 4, Ch 1, 4 Deck structure, as appropriate. However, in way of concentrated loads such as those from boiler bearers or heavy auxiliary machinery, etc. the scantlings of deck structure will be specially considered, taking account of the actual loading.

2.3.2 In way of machinery openings, etc. particularly towards the aft end, decks or flats are to have sufficient strength where they are intended as effective supports for side framing, webs or transverses. Web frames and side transverses are to be supported by deep beams or deck transverses.

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