Section 5 Hull 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 11 Ore Carriers - Section 5 Hull framing

Section 5 Hull framing

Parent topic: Chapter 11 Ore Carriers

5.1 General

5.1.1 The framing requirements given for oil tankers in Pt 4, Ch 9, 5 Hull framing are to be applied, except as provided for in this Section.

5.1.2 Lateral buckling of longitudinal and transverse ordinary stiffeners is to be assessed in the following areas in association with a factor of safety of not less than 1,15 (allowable utilisation factor to be reduced by at least 1/1,15 = 0,87). Details are to be submitted:

  • hatchway coaming;
  • inner bottom;
  • sloped stiffened panel of topside tanks (if any);
  • longitudinal bulkhead;
  • top stool and bottom stool of transverse bulkhead (if any) and
  • stiffened transverse bulkhead (if any).

5.2 Symbols

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

h = load height, in metres, on the weather deck for primary and secondary members between ore hatchways
= 1,8 for secondary members forward of 0,075L from F.P.
= 4,2 + 2,04E for primary members forward of 0,075L from F.P.
= 1,5 between 0,075L and 0,12L from F.P.
= 1,2 + 2,04E elsewhere
= where but not to be greater than 0,147
K 1 = 1,6 in the forward 0,12L
= 1,06 elsewhere
K 2 = 0,00054 in the forward 0,075L
= 0,00033 elsewhere.

5.2.2 Other symbols are defined in Pt 4, Ch 11, 1.4 Symbols and definitions.

5.3 Bottom longitudinals in double bottom tanks

5.3.1 The section modulus of bottom longitudinals in the double bottom in the centre hold is to satisfy the requirements of Table 1.6.2 Shell framing (longitudinal) in Chapter 1.

5.3.2 In general, the span of longitudinals in the double bottom in the centre hold is not to exceed 2,5 m or 0,01L, whichever is the greater, and the span in the wing tanks is not to exceed the greater of 3,6 m or 0,02L.

5.4 Deck structure in way of centre hold

5.4.1 Where the hatch coamings are situated inboard of the longitudinal bulkhead, the deck between the two is to be fitted with suitably supported longitudinals complying with Pt 4, Ch 9, 5 Hull framing.

5.5 Primary and secondary members inside line of ore hatchways

5.5.1 The section modulus of secondary members between hatches is to be not less than:

Z = k (K 1 TD + K 2 hB l e 2 s) cm3

but need not exceed twice the value given by the second term within the brackets in the formula.

5.5.2 The section modulus of primary members between hatches is to be not less than:

Z = 5,46kbh l e 2 cm3

Forward of 0,075L from the forward perpendicular, the depth of the primary member is to be not less than twice that of the secondary member supported.

5.5.3 Particular attention is to be paid to the scarfing of deck beams into the structure outside the line of openings. Substantial brackets or equivalent arrangements are to be provided.

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