Section 5 Hull envelope plating
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 1 Dry Cargo Ships - Section 5 Hull envelope plating

Section 5 Hull envelope plating

Parent topic: Chapter 1 Dry Cargo Ships

5.1 General

5.1.1 This Section covers the requirements for the shell envelope plating, viz., keel, bottom, bilge and side shell plating. For deck plating, see Pt 4, Ch 1, 4 Deck plating and continuous longitudinal hatch side coamings . The thickness of shell envelope plating amidships is to be not less than required in Table 1.5.1 Shell envelope plating, but for ships over 65 m in length, the thickness of the bottom plating may require to be increased to obtain the midship section modulus required in Pt 3, Ch 4 Longitudinal Strength.

5.1.2 For requirements in respect of structural details, see Pt 3, Ch 10 Welding and Structural Details.

5.2 Keel

5.2.1 The thickness and breadth of the keel plate is to comply with the requirements of Table 1.5.1 Shell envelope platingand is to be maintained over the full length of the ship

5.2.2 The scantlings of a bar keel, if fitted, are to comply with the requirements of Table 1.5.1 Shell envelope plating.

5.3 Shell plating

5.3.1 The thickness of bottom shell and side shell plating is to be maintained over 0,5L amidships. Thicknesses are to comply with Table 1.5.1 Shell envelope plating and may be tapered to the end thickness in the fore end and aft end of the ship, see Pt 3, Ch 5 Fore End and Aft End Structure, according to the requirements for taper given inPt 3, Ch 3, 2.5 Principles for taper. Where the bottom is transversely framed, the bottom is, in general, to be reinforced with additional longitudinal stiffeners.

Table 1.5.1 Shell envelope plating

Item and parameter Requirement
(1) Plate keel breadth 0,1B but not less than 0,75 m
  Thickness As bottom plating t b When there is a rise of floor, the thickness is to be increased by 1 mm
(2) Bar keel thickness t = 0,37L + 10 mm
Height d k = 0,7L + 75 mm
(3) Bottom plating thickness The greater of:
    t b = (5,6 + 0,054L)
(4) Bilge plating thickness t = t b + 2 mm
(5) Bilge chine bars  
(a) Round bars diameter 3t b mm, but not less than 30 mm
(b) Square bars side 3t b mm, but not less than 30 mm
(c) Angle bars flange thickness t = 2t b mm
(6) Side shell plating The greater of:
Thickness t = (5,6 + 0,054L)
  t = 10s
(7) Minimum width sheerstrake W sh = 0,08D m
  but not less than 0,20 m
(8) Sheerstrake thickness t = side shell thickness + 5 mm
(9) Doublers clear of sheerstrake (when fitted)  
Width W d = between 0,10 and 0,45 m
Thickness The greater of
  t = 30W d
  t = required thickness for the side shell plating
Symbols
L, B, D, s, k and t are as defined in Pt 4, Ch 1, 1.5 Symbols and definitions 1.5.1
  d k = height of bar keel
  t b = thickness of bottom plating, in mm

Note The thickness of the bottom plating is also to satisfy the buckling requirements and hull girder stress criteria in Pt 3, Ch 4 Longitudinal Strength.

5.4 Bilge plating

5.4.1 The thickness of the bilge plating is to be maintained from amidships to well beyond the forward and aft shoulder of the bilge, but at least over the midship region. For definition of shoulders, see Pt 3, Ch 5, 2.4 Shell plating 2.4.2.

5.4.2 The bilge radius is to be at least 10 times the thickness of the bilge plating and the bilge strake is to extend at least 100 mm on either side of the radius of the bilge plate.

5.4.3 Square bilges, constructed by solid round, square or externally fitted angle bars, see Figure 1.5.1 Square bilge arrangements, are to comply with Table 1.5.1 Shell envelope plating. The bottom plating and the side shell plating, adjacent to the round, square or angle bars need not be increased in thickness above that of the bottom plating or side shell plating in way.

Figure 1.5.1 Square bilge arrangements

5.5 Sheerstake

5.5.1 The width and thickness of the sheerstrake is to comply with Table 1.5.1 Shell envelope plating, and is to be maintained over the length of the hatch opening, including one frame space forward and aft of the hatch opening, but at least over 0,5L amidships.

5.6 Shell openings

5.6.1 Openings in the shell plating are to have well-rounded corners; compensation is generally only required for openings having a width greater than 250 mm. Openings in way of or near to the bilge radius fitted in the midship region are to be circular or elliptical.

Copyright 2022 Clasifications Register Group Limited, International Maritime Organization, International Labour Organization or Maritime and Coastguard Agency. All rights reserved. Clasifications Register Group Limited, its affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as 'Clasifications Register'. Clasifications Register assumes no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant Clasifications Register entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.