Section 3 Hull envelope plating

3.1 Shell and deck plating

3.1.1 The thickness of shell and deck plating is to be as necessary to give the hull section modulus required by Pt 4, Ch 5, 2.1 General and to satisfy the requirements listed in Table 5.3.1 Shell and deck plating.

Table 5.3.1 Shell and deck plating

Item of plating		Thickness for ships classed 100A1	Thickness for ships having extended protected water service notation
(a)	Keel	The separate requirements of Pt 4, Ch 1 General Cargo Ships or Pt 4, Ch 10 Single Hull Oil Tankers, whichever is applicable, for keel width and thickness need not be applied, except where L > 100 m and the bottom has a rise of floor
(b)	Bottom shell and bilge	In accordance with the requirements of Pt 4, Ch 1 General Cargo Ships or Pt 4, Ch 10 Single Hull Oil Tankers, whichever is applicable	In accordance with the requirements of Pt 4, Ch 1 General Cargo Ships or Pt 4, Ch 10 Single Hull Oil Tankers, whichever is applicable, reduced by 12,5 per cent, but is to be not less than required by (c) below
		For chines, see Pt 4, Ch 5, 3.1 Shell and deck plating 3.1.2
(c)	Side shell from upper turn of bilge or chine to deck	The greater of the values obtained from Pt 4, Ch 1 General Cargo Ships or Pt 4, Ch 10 Single Hull Oil Tankers, whichever is applicable, for the appropriate framing arrangement
(d)	Deck	In accordance with the requirements of Pt 4, Ch 1 General Cargo Ships or Pt 4, Ch 10 Single Hull Oil Tankers, whichever is applicable	In accordance with the requirements of Pt 4, Ch 1 General Cargo Ships or Pt 4, Ch 10 Single Hull Oil Tankers, whichever is applicable, reduced by 2 mm, but is to be not less than the deck basic end thickness as required by Pt 3, Ch 5 Fore End Structure and Pt 3, Ch 6 Aft End Structure
		In pontoon barges with deck cargoes the deck thickness derived from (d) may be required to be increased
(e)	Swim ends	The bottom shell plating thickness is to be maintained up to the summer load waterline for the rake plating. Above this point the thickness may be tapered to that of the side shell requirements from a point not less than 1 m above the load waterline

3.1.2 On ships with two chines each side, the bilge plating should generally be calculated from the bottom plating formulae. On hard chine ships, flanged chines will not, in general, be approved, but where a chine is formed by knuckling the shell plating, the radius of curvature, measured on the inside of the plate, is to be not less than 10 times the plate thickness. Where a solid round chine bar is fitted, the bar diameter is to be not less than three times the thickness of the thickest abutting plate. Where welded chines are used, the welding is to be built up as necessary to ensure that the shell plating thickness is maintained across the weld.