Section 2 Minimum thickness requirements
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Special Service Craft, July 2022 - Part 7 Hull Construction in Aluminium - Chapter 4 Scantling Determination for Multi-Hull Craft - Section 2 Minimum thickness requirements

Section 2 Minimum thickness requirements

Parent topic: Chapter 4 Scantling Determination for Multi-Hull Craft

2.1 General

2.1.1 Unless otherwise specified in this Section, the requirements of Pt 7, Ch 3, 2 Minimum thickness requirements are to be complied with.

2.1.2 The thickness of plating and stiffeners determined from the Rule requirements is not to be less than the appropriate minimum requirement given in Table 4.2.1 Minimum thickness requirements for craft type.

2.1.3 In addition, where plating contributes to the global strength of the craft, the thickness is to be not less than that required to satisfy global strength requirements.

Table 4.2.1 Minimum thickness requirements

Item Minimum thickness (mm)
Catamaran Multi-hull Swath
Shell envelope      

Bottom shell plating

Side shell plating

Wet-deck plating
Single bottom structure      

Centre girder web

Floor webs

Side girder webs
Double bottom structure      

Centre girder

      

(1) Within 0,4L R amidships

(2) Outside 0,4L R amidships

Floors and side girders

Inner bottom plating
Bulkheads      

Watertight bulkhead plating

Deep tank bulkhead plating
Deck plating and stiffeners      

Strength/Main deck plating

Lower deck/Inside deckhouse, see Note 1

Superstructures and deckhouses, see Note 1      

Superstructure side plating

Deckhouse front 1st tier

Deckhouse front upper tiers

Deckhouse aft
Pillars      

Wall thickness of tubular pillars

Wall thickness of rectangular pillars
Symbols
ω = service type factor as determined from Table 4.2.2 Service type correction factors (ω)
km = 385/(σA + σu)
σA = specified minimum yield stress or 0,2% proof stress of the alloy in unwelded condition, in N/mm2
σu = specified minimum ultimate tensile strength of the alloy in unwelded condition, in N/mm2
bp = minimum breadth of cross section of hollow rectangular pillar, in mm
dp = outside diameter of tubular pillar, in mm
φp = but is not taken greater than 1 and not less than 0,5
φs = but is not taken greater than 1 and not less than 0,5
s = stiffener spacing, in mm
Note 1. Lower thickness may be acceptable depending on the location, loading and provision of protective sheathing as appropriate.

Table 4.2.2 Service type correction factors (ω)

Service type notation ω
Cargo 1,1
Passenger 1,0
Patrol 1,0
Pilot 1,1
Yacht 1,0
Workboat MFV 1,2
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