Section 1 General

101. Application

1. The hull structure, constructed in aluminium alloy complying with the requirements in Sec 2, is to be in accordance with requirements in this chapter.

2. Requirements, not included in this chapter, are to be in accordance with those in Ch 3.

102. The scantling reduction

1. The requirements, except for those in the Par 2 below, are to be in accordance with Ch 3.

2. Basic stiffener spacing, = m

103. Bottom structures

1. Longitudinal stiffeners

(1) Single bottom as well as double bottoms are normally to be stiffened longitudinally.

(2) The longitudinals should preferably be continuous through transverse members. If they are to be cut at transverse members, (i.e., watertight bulkheads), continuous brackets connecting the ends of the longitudinals are to be fitted.

(3) Longitudinal stiffeners are to be supported by bulkheads and transverses.

2. Transverses

(1) Transverses are to be continuous around the cross section : i.e., floors, side webs and deck beams are to be connected. Intermediate floors may be used.

(2) In the engine room plate floors are to be fitted at every frame. In way of thrust bearings addi-

tional strengthening is to be provided.

3. Longitudinal girders

(1) Web plates of longitudinal girders are to be continuous in way of transverse bulkheads.

(2) A center girder is normally to be fitted for docking purposes.

(3) Manholes or other openings should not be positioned at ends of girders without due consid- eration being taken of shear loadings.

4. Engine girders

(1) Under the main engine, girders extending from the bottom to the top plate of the engine seating are to be fitted.

(2) Engine holdingdown bolts are to be arranged as near as practicable to floors and longitudinal girders.

(3) In way of thrust bearing and below pillars additional strengthening is to be provided.

5. Double bottom

(1) Manholes are to be cut in the inner bottom, floors and longitudinal girders to provide access to all parts of the double bottom. The vertical extension of lightening holes is not to exceed one half of the girder height. The edges of the manholes are to be smooth. Manholes in the inner bottom plating are to have reinforcement rings. Manholes are not to be cut in the floors or girders in way of pillars.

(2) In double bottoms with longitudinal stiffening, the floors are to be stiffened at every bottom longitudinal.

(3) In double bottoms with transverse stiffening, longitudinal girders are to be stiffened at every transverse frame.

(4) The longitudinal girders are to be adequately stiffened against buckling.

104. Side structures

1. Side structures are normally to be longitudinally or vertically stiffened.

2. The continuity of the longitudinals is to be as required for bottom and deck longitudinal respectively.

105. Deck structures

1. Decks are normally to be longitudinally stiffened.

2. The longitudinals should preferably be continuous through transverse members. If they are to be cut at transverse members, (i.e., watertight bulkheads), continuous brackets connecting the ends of the longitudinals are to be fitted.

3. The plate thickness is to be such that the necessary transverse buckling strength is achieved, or transverse buckling stiffeners may have to be fitted intercostally.

106. Bulwarks

The scantlings of bulwarks are to be in accordance with Ch 3, 511. and 609.

107. Flat cross structures

The scantlings of flat cross structure are to be in accordance with Ch 3, 104.

108. Bulkhead structures

The scantlings of bulkhead structures are to be in accordance with Ch 3, 105.

109. Superstructures and deckhouses

1. In superstructures and deckhouses, the front bulkhead is to be in line with a transverse bulkhead in the hull below or be supported by a combination of girders and pillars. The after end bulkhead is also to be adequately supported. As far as practicable, exposed sides and internal longitudinal and transverse bulkheads are to be located above girders and frames in the hull structure, and are to be

in line in the various tiers of accommodation. Where such structural arrangement in line possible, there is to be other effective support.

2. Sufficient transverse strength is to be provided by means of transverse bulkheads or structures.

3. At the break of superstructures, which have no set-in from craft side, the side plating is to

is not

girder extend

beyond the ends of the superstructure, and is to be gradually reduced in height down to the deck or bulwark. The transition is to be smooth and without local discontinuities. A substantial stiffener

is to be fitted at the upper edge of plating. The plating is also to be additionally stiffened.

4. In long deckhouses, openings in the sides are to have

well rounded corners. Horizontal stiffeners

are to be fitted at the upper and lower edges of large openings for windows. Openings for doors

in the sides are to be substantially stiffened along the house corners and deck plating is to be increased locally.

edges. The connection area between deck-

5. Deck girders are to be fitted below long deckhouses in line with deckhouses sides.

6. Deck beams under front and aft ends of deckhouses are not to be scalloped for a distance of 0.5m from each side of the deckhouse corners.

7. Casings supporting one or more decks above are to be adequately strengthened.

110. Definition of span ( )

The definition of span is in accordance with Ch 3, 107.