Section 4 Ship structure

4.1.1 The requirements of this Section are additional to those given in other parts of these Rules and in separate Rules for specific ship types.

4.1.2 Other than as permitted in Pt 7, Ch 7, 4.3 Coal bunker bulkheads 4.3.2, separation between coal bunkers and adjacent spaces is to be gastight. In oil or chemical tankers, coal bunkers are to be separated from cargo tanks by means of cofferdams.

4.1.3 Boiler room access doors are to comply with Pt 3, Ch 11, 6.4 Companionways, doors and accesses on weather decks, as applicable.

4.1.4 Coaling ports on the side shell are to comply with parts of Pt 3, Ch 11, 8 Side and stern doors and other shell openings as applicable.

4.1.5 No side scuttles are to be fitted in spaces appropriated exclusively for the carriage of coal.

4.1.6 All openings from coal bunkers are to be located clear of the defined hazardous area for the particular ship type.

4.2.1 Coal bunker hatchways are to be provided with gasketed steel covers and coamings, complying with Pt 3, Ch 11 Closing Arrangements for Shell, Deck and Bulkheads, as applicable.

4.2.2 Coal bunker hatchways are to be located clear of the defined hazardous area for the particular ship type.

4.3.1 The scantlings of main coal bunker boundary bulkheads which are counted towards the number of bulkheads required by Pt 3, Ch 3, 4 Bulkhead requirements, or which form the boundary of deep tanks, are to satisfy the requirements of Pt 4, Ch 1, 9 Bulkheads. Other boundaries are to satisfy the requirements of Pt 4, Ch 1, 9 Bulkheads, but the load head may be taken to the top of the bunker. The scantlings of cofferdam bulkheads not forming the boundaries of a cargo tank in oil or chemical tankers are to satisfy the requirements of Pt 4, Ch 9, 7 Transverse oiltight bulkheads. In all cases when flooding is envisaged as a means of fire-extinction, the moduli of stiffening members on bunker bulkhead boundaries are to be increased by 25 per cent.

4.3.2 Where the coal bunker is situated immediately forward of the engine room, the aft coal bunker bulkhead may be non-watertight. The scantlings for this bulkhead are to be as required for watertight bulkheads (Pt 4, Ch 1, 9 Bulkheads) but the load head may be taken to the top of the tank. With this arrangement, the forward end of the coal bunker may, if appropriate, be regarded as the engine room forward bulkhead.

4.3.3 The thickness of the plating in way of the bulkhead knuckles in the region of the hoppers and the plating of the hopper apexes is to be increased by 1,5 mm over that derived from Pt 7, Ch 7, 4.3 Coal bunker bulkheads 4.3.1 and Pt 7, Ch 7, 4.3 Coal bunker bulkheads 4.3.2. However, the minimum thickness of the lowest strake in the coal hopper is to be not less than 9 mm. Where solid stainless steel is employed, the plate thickness may be reduced by 10 per cent or 1 mm, whichever is the lesser.

4.3.4 Non-watertight coal bunker bulkhead scantlings are to be as required by Table 1.4.8 Non-watertight pillar bulkheads in Pt 4, Ch 1 General Cargo Ships, but the thickness of the lowest strake is to be not less than 9 mm.

4.3.5 The scantlings of the boundaries of compartments intended for the storage of ash in liquid or slurry form will be specially considered.

4.3.6 Watertight doors may be fitted in watertight bulkheads between permanent and reserve bunkers, and may be of the sliding, hinged or equivalent type. They are to be accessible at all times, see also Pt 3, Ch 11, 9 Watertight doors .

4.3.7 Arrangements are to be made by means of screens or otherwise to prevent the coal from interfering with the closing of watertight doors.

4.4.1 For the purpose of longitudinal strength, the requirements for the relevant ship types are to be applied.

4.4.2 The calculation of still-water shear forces and bending moments are to cover both departure and arrival conditions, and any special mid-voyage conditions caused by variation in coal bunkering and ballast distribution. Details of typical coal stowage rates are to be submitted, as well as trim and stability data for these conditions.

4.4.3 Where local reduction of double bottom depth is proposed to accommodate coal handling equipment, the strength of the double bottom and scarfing arrangements will require special consideration. Adequate scarfing of longitudinal material in way of double bottom and hopper tanks should be arranged.

4.5.1 Ventilators serving coal bunkers or boiler rooms are to comply with Pt 3, Ch 12, 2 Ventilators as applicable. In addition, the atmosphere in the bunkers is to be sampled by means of fixed or portable monitors as follows:

1. prior to entering the space − for oxygen deficiency,

2. prior to opening the hatchways − for accumulation of flammable gases.

4.5.2 Ventilator exits from main coal bunkers and coal processing spaces are to discharge clear of the defined hazardous area for the particular ship type and not less than 3 m from the nearest intake or opening to accommodation and enclosed working spaces, and from possible source of ignition.