The Merchant Shipping (Additional Safety Measures for Bulk Carriers) Regulations 1999

Damage stability requirements applicable to bulk carriers

6.—(1) Bulk carriers of 150 m in length and upwards of single side skin construction, designed to carry solid bulk cargoes having a density of 1000 kg/m³ and above, constructed on or after 1st July 1999 shall, when loaded to the summer load line, be able to withstand flooding of any one cargo hold in all loading conditions and remain afloat in a satisfactory condition of equilibrium, as specified in paragraph (3).

(2) Subject to paragraph (4) and regulation 14, bulk carriers of 150 m in length and upwards of single side skin construction, carrying solid bulk cargoes having a density of 1780 kg/m³ and above, constructed before 1st July 1999 shall, when loaded to the summer load line, be able to withstand flooding of the foremost cargo hold in all loading conditions and remain afloat in a satisfactory condition of equilibrium, as specified in paragraph (3).

(3) (a) The condition of equilibrium referred to in paragraphs (1) and (2) is satisfactory provided that:

(i) the final waterline after flooding, taking into account sinkage, heel and trim, is below the lower edge of any opening through which progressive down flooding may take place. Such openings shall include air pipes, ventilators and openings which are closed by means of weathertight doors or hatch covers (even if they comply with the requirements of the Merchant Shipping (Load Line) Regulations 1998), but exclude–

(aa) those openings which are closed by means of watertight manhole covers, watertight flush scuttles or side scuttles of the non-opening type, provided that the means of closing comply with the Merchant Shipping (Load Line) Regulations 1998;

(bb) remotely operated sliding watertight doors, except that in the case of doors separating a main machinery space from a steering gear compartment, watertight doors may be of a hinged, quick-acting type kept closed at sea, whilst not in use, provided that the lower sill of such doors is above the summer load line; and

(cc) small cargo access openings closed by watertight gasketed covers of steel or equivalent material;

(ii) if pipes, ducts or tunnels are situated within the assumed extent of flooding, arrangements are made so that progressive flooding cannot thereby extend to compartments other than those assumed to be floodable in the calculation for each case of damage;

(iii) in the case where no part of the deck is immersed, the angle of heel due to asymmetrical flooding does not exceed 17 degrees, and in any other case the angle of heel due to asymmetrical flooding does not exceed 15 degrees;

(iv) the metacentric height in the flooded condition is positive;

(v) the righting lever curve has a minimum range of 20 degrees beyond the position of equilibrium in association with a maximum righting lever of at least 0.1 metres within the 20 degree range. The area under the righting lever curve within this range shall be not less than 0.0175 metre-radians. Unprotected openings shall not be immersed within this range unless the space concerned is assumed to be flooded. Within this range, the immersion of any of the openings listed in sub-paragraph (i) and other openings capable of being closed weathertight is permitted; and

(vi) the Certifying Authority is satisfied that the stability is sufficient during intermediate stages of flooding. However it should never be significantly less than that required by sub-paragraph (v).

(b) The assumed flooding referred to in sub-paragraph (a) above need only take into account flooding of the cargo hold space.

(c) The permeability of a loaded hold for the purposes of sub-paragraph (a) above shall be assumed as 0.9 and the permeability of an empty hold shall be assumed as 0.95, unless a permeability relevant to a particular cargo is assumed for the volume of a flooded hold occupied by cargo and a permeability of 0.95 is assumed for the remaining empty volume of the hold.

(4) Bulk carriers constructed before 1st July 1999 which have been assigned a reduced freeboard in compliance with Schedule 4 paragraph 5(3) of Merchant Shipping Notice MSN1701(M) are deemed to comply with paragraph (2) of this regulation.