Section 4 Portable wood, steel or aluminium covers with portable beams
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Inland Waterways Ships, July 2022 - Part 3 Ship Structures (General) - Chapter 11 Closing Arrangements to Openings in Shell and Deck, Ventilators, Air Pipes, Sounding Pipes and Discharges - Section 4 Portable wood, steel or aluminium covers with portable beams

Section 4 Portable wood, steel or aluminium covers with portable beams

Parent topic: Chapter 11 Closing Arrangements to Openings in Shell and Deck, Ventilators, Air Pipes, Sounding Pipes and Discharges

4.1 Wood, steel or aluminium covers

4.1.1 When wood covers are fitted, they are to have a finished thickness of not less than 25 mm, and are to be supported at their edges by beams spaced not more than 600 mm apart. The planks of the wood covers are to be connected at their underside by cross planks having the same thickness as the cover, a width of about 125 mm and spaced at a maximum distance of 1,5 m, see Figure 11.4.2 Portable wood cover.

4.1.2 The plating of steel covers is to comply with Table 11.2.1 Steel hatch cover scantlings, and the plating of aluminium covers is to comply with Table 11.3.1 Aluminium hatch cover scantlings.

4.1.3 The edges of the plating of steel or aluminium are to be adequately stiffened at their sides as necessary for the rigidity of the cover.

4.2 Portable beams, fore and afters and cross beams

4.2.1 Portable wood, steel or aluminium covers are to be supported by a system of beams and fore and afters with cross beams, where necessary, which are to have scantlings as required by Table 11.4.1 Scantlings of supporting structure for hatch covers with portable beams. For the layout of such arrangements, see Figure 11.4.1 Hatch cover layout with portable beams.

Table 11.4.1 Scantlings of supporting structure for hatch covers with portable beams

Item Parameter Requirements
Portable beams Section modulus
Z = 7,5 × b p × h H × b 2 cm3 see Note
Fore and after Section modulus
Z = 8,5 × b × h H × la 2 cm3
Cross beam Section modulus
Z = 34 × la × h H × b cm3
Additional fore and after (if fitted) Section modulus
Z = 4 × b × h H × la 2 cm3
Symbols

Z and h H as defined in Pt 3, Ch 11, 1.2 Symbols 1.2.1

b p, b and la = distances, in metres, as shown in Figure 11.4.1 Hatch cover layout with portable beams


Note The section modulus of wood portable beams is to be fourteen times the section modulus of steel portable beams.

Figure 11.4.1 Hatch cover layout with portable beams

Figure 11.4.2 Portable wood cover

4.3 Quality of timber

4.3.1 The timber of covers and portable beams is to be of good quality and well preserved.

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