Section 2 Self-supporting steel hatch covers
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 2 Self-supporting steel hatch covers

Section 2 Self-supporting steel hatch covers

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

2.1 Plating

2.1.1 The thickness of the plating of steel hatch covers is to be not less than required by Table 11.2.1 Steel hatch cover scantlings.

Table 11.2.1 Steel hatch cover scantlings

Item Parameter Requirements
Top plating for h H ≤ 0,75 m Thickness The greater of:

t = 6s mm

t = 2 mm, see Note

Top plating for h H > 0,75 m Thickness The greater of:

t = 6,6smm

t = 2 mm, see Note

Bottom plating for double plate covers Thickness The greater of:

t = 5s mm

t = 2 mm, see Note

Webs and stiffeners Section modulus Z = 7,5 × s × h H × lo 2 cm3
Inertia I = 2,1 × Z × lo cm4
Minimum thickness The greater of:

t = 0,018d w mm

t = 4 mm

Effective plating to be included in the section modulus Width The lesser of:

w = 0,08t m

w = s m

The symbols are defined in Pt 3, Ch 11, 1.2 Symbols 1.2.1

Note The top plating thickness may be reduced, when the plating is stiffened by swedges or equivalent, provided the maximum permissible stresses and deflections of Table 11.2.2 Parameters for direct calculation are not exceeded. Proposals are to be submitted for approval.

Table 11.2.2 Parameters for direct calculation

Item Bending stress in N/mm2
(kgf/mm2) 		Shear stress in N/mm2
(kgf/mm2) 		Deflection in metres
Steel covers 117,7 (12,0) 68,7 (7,0) 0,004lo
Aluminium covers 69,6 (7,1) 40,2 (4,1) 0,004lo

2.2 Webs and stiffeners

2.2.1 The scantlings of steel cover webs and stiffeners are to be not less than required by Table 11.2.1 Steel hatch cover scantlings.

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