Decoding SOLAS Chapter 12: The Key to Bulk Carrier Safety

In this regulation, we have some important terms to understand:

1. Bulk Carrier: It's a type of ship mainly built to transport large quantities of dry cargo, like grain or minerals. This includes ships like ore carriers and combination carriers.
2. Bulk Carrier of Single-Side Skin Construction: This is a bulk carrier where part of the cargo space is right next to the ship's outer side. If it has a double-side skin, the gap between them should be less than 760 mm for older ships or 1,000 mm for newer ones.
3. Bulk Carrier of Double-Side Skin Construction: This is a bulk carrier where all cargo spaces are surrounded by a double-side skin, except in specific cases.
4. Double-Side Skin: This is how the sides of the ship are built, with an outer shell and a double bottom connected by a long wall. This design can include hopper side tanks and top-side tanks if they're part of this structure.
5. Length of a Bulk Carrier: The ship's length, as defined by the International Convention on Load Lines.
6. Solid Bulk Cargo: It's any dry material, not liquid or gas, made of small pieces or particles that can be loaded directly onto a ship without special containers.
7. Bulk Carrier Bulkhead and Double Bottom Strength Standards: These are the rules for how strong the bulkheads (walls) and double bottoms of certain parts of the ship must be. The details can change according to specific rules decided by a conference of governments and may get updated.
8. Bulk Carriers Constructed: It means ships that have started to be built, including laying the keel or getting to a similar stage of construction.
9. A Similar Stage of Construction: This is the point in ship construction when work starts on a specific ship, and they've put together at least 50 tonnes or one percent of the estimated structural material, whichever is less.
10. Breadth (B) of a Bulk Carrier: The width of the ship, as defined by the International Convention on Load Lines.

Bulk carriers must follow the rules in this chapter in addition to any other rules that apply from different chapters.

For bulk carriers constructed before July 1, 1999, subject to the application of regulations 4 or 6, compliance with these regulations shall follow the schedule below, referring to the enhanced program of inspections required by regulation XI-1/2:

• For bulk carriers aged 20 years or more on July 1, 1999, compliance must be achieved by the date of the first intermediate survey or the first periodical survey* after July 1, 1999, whichever occurs first.
• For bulk carriers aged 15 years or more but less than 20 years on July 1, 1999, compliance must be met by the date of the first periodical survey* after July 1, 1999, but not later than July 1, 2002.
• For bulk carriers aged less than 15 years on July 1, 1999, compliance should be attained by the date of the first periodical survey* after the ship reaches 15 years of age, but not later than the date when the ship reaches 17 years of age.

*Refer to the Application of SOLAS regulations XII/3, XII/7, and XII/11 for the definition of the term "Periodical Survey" (MSC.1/Circ.1463).

For single-side skin construction bulk carriers of 150 meters or more in length, designed to transport solid bulk cargoes with a density of 1,000 kg/m3 and above, and constructed on or after July 1, 1999, they must have the capability to withstand flooding of any one cargo hold under all loading conditions when loaded to the summer load line. The ship should maintain a satisfactory condition of equilibrium, as specified in paragraph 4.

Double-side skin construction bulk carriers of 150 meters or more in length, with any part of the longitudinal bulkhead located within B/5 or 11.5 meters, whichever is less, inboard from the ship's side at a right angle to the centerline at the assigned summer load line, designed for the transport of solid bulk cargoes with a density of 1,000 kg/m3 and above, and constructed on or after July 1, 2006, must meet the same requirements for flooding and equilibrium as specified in paragraph 4.

Single-side skin construction bulk carriers, 150 meters or longer, designed to carry solid bulk cargoes with a density of 1,780 kg/m3 and above, and constructed before July 1, 1999, should also have the capability to withstand flooding of the foremost cargo hold in all loading conditions when loaded to the summer load line, as per paragraph 4. Compliance with this requirement should follow the implementation schedule outlined in regulation 3.

The condition of equilibrium following flooding should meet the standards set forth in the annex to resolution A.320(IX) - Regulation equivalent to regulation 27 of the International Convention on Load Lines, 1966, as amended by resolution A.514(13). The assumed flooding should consider only the flooding of the cargo hold space to the water level outside the ship in that condition. The permeability of a loaded hold is assumed to be 0.9, and the permeability of an empty hold is assumed to be 0.95, unless a specific permeability relevant to a particular cargo is assumed for the volume of the flooded hold occupied by cargo, and a permeability of 0.95 is assumed for the remaining empty volume of the hold.

Bulk carriers constructed before July 1, 1999, which have been assigned a reduced freeboard in compliance with regulation 27(7) of the International Convention on Load Lines, 1966, as adopted on April 5, 1966, may be regarded as complying with paragraph 3 of this regulation.

Bulk carriers that have been assigned a reduced freeboard in compliance with the provisions of paragraph (8) of the regulation equivalent to regulation 27 of the International Convention on Load Lines, 1966, adopted by resolution A.320(IX), as amended by resolution A.514(13), may be considered as complying with paragraphs 1 or 2, as applicable.

Regarding bulk carriers assigned reduced freeboard in compliance with the provisions of regulation 27(8) of Annex B of the Protocol of 1988 related to the International Convention on Load Lines, 1966, the condition of equilibrium following flooding should meet the relevant provisions of that Protocol.

Bulk carriers, with a length of 150 meters or more and constructed with single-side skin design, intended to transport solid bulk cargoes with a density of 1,000 kg/m3 or higher, and built on or after July 1, 1999, must possess adequate strength to endure flooding of any single cargo hold up to the water level outside the vessel. This requirement applies in all loading and ballast conditions, considering dynamic effects caused by water in the hold, and in accordance with the recommendations established by the Organization.*

*Refer to the Recommendation on Compliance with SOLAS Regulation XII/5 (Resolution 3 of the 1997 SOLAS Conference).

Bulk carriers, measuring 150 meters or more in length and constructed with double-side skin design, where any part of the longitudinal bulkhead is located within B/5 or 11.5 meters, whichever is less, inboard from the ship's side at a right angle to the centerline at the assigned summer load line, designed for bulk cargoes with a density of 1,000 kg/m3 or higher, and built on or after July 1, 2006, must adhere to the structural strength requirements outlined in paragraph 1.

Section 1: Bulk Carriers Constructed Before July 1, 1999

Bulk carriers with a length of 150 meters or more, featuring single-side skin construction, and designed to transport solid bulk cargoes with a density of 1780 kg/m3 and higher, constructed before July 1, 1999, must adhere to the following specifications within the framework outlined in Regulation 3:

• • The transverse watertight bulkhead separating the two foremost cargo holds and the double bottom of the foremost cargo hold must possess the necessary strength to withstand flooding of the foremost cargo hold. This requirement takes into account dynamic forces resulting from water presence and complies with the Bulk Carrier Bulkhead and Double Bottom Strength Standards. These standards are to be treated as mandatory for compliance.
  • In assessing the need for strengthening the transverse watertight bulkhead or double bottom to meet the criteria in 1.1, certain restrictions may be considered:
  • • Constraints on how the total cargo weight is distributed among cargo holds.
    • Constraints on the maximum deadweight.
    • These restrictions, as detailed in 1.2.1 and 1.2.2, must be observed when transporting solid bulk cargoes with a density of 1780 kg/m3 and above, ensuring compliance with the requirements in 1.1.

Section 2: Bulk Carriers Constructed After July 1, 2006 (Double-Side Skin Construction)

• Bulk carriers with a length of 150 meters or more, constructed on or after July 1, 2006, featuring double-side skin construction across all areas, must meet the subsequent criteria:
• • Primary stiffening structures within the double-side skin cannot be located within cargo hold spaces.
  • The space between the outer and inner shells at any transverse section must not be less than 1000 mm, measured perpendicular to the side shell. The construction of the double-side skin must allow for inspection access, as per Regulation II-1/3-6 and its accompanying Technical Provisions.
  • Clearances between the outer and inner shells are not mandatory in areas where cross ties, upper and lower end brackets of transverse framing, or end brackets of longitudinal framing are situated.
  • The minimum width of the clear passage within the double-side skin space, around obstructions such as piping or vertical ladders, must not be less than 600 mm.
  • In cases where the inner and/or outer skins are transversely framed, the minimum clearance between the inner surfaces of the frames shall not be less than 600 mm.
  • When the inner and outer skins are longitudinally framed, the minimum clearance between the inner surfaces of the frames shall not be less than 800 mm. Beyond the parallel part of the cargo hold length, this clearance may be reduced based on structural configuration but shall never fall below 600 mm.
  • The minimum clearance described above refers to the shortest distance between assumed lines connecting the inner surfaces of the frames on the inner and outer skins.
  • With the exception of top-side wing tanks, if present, the double-side skin spaces shall not be used for cargo storage.

Section 3: Bulk Carriers Constructed After July 1, 2006 (Cargo Structure)

• For bulk carriers with a length of 150 meters or more, designed to carry solid bulk cargoes with a density of 1000 kg/m3 and higher, constructed on or after July 1, 2006, the following requirements must be met:
• • The cargo hold structure should facilitate the loading and unloading of all intended cargoes using standard equipment and procedures, without causing damage that could jeopardize structural integrity.
  • Effective continuity must be ensured between the side shell structure and the overall hull structure.
  • The structure of cargo areas should prevent the immediate cascading failure of structural components in the event of a single failure of one stiffening structural member. This design should mitigate the risk of complete stiffened panel collapse.

Section 1: Bulk Carriers Constructed Before July 1, 1999 (Aged 10 Years and Over)

• Bulk carriers with a length of 150 meters or more, featuring single-side skin construction, and constructed before July 1, 1999, that are 10 years of age or older, are prohibited from carrying solid bulk cargoes with a density of 1,780 kg/m3 and higher unless they have successfully completed one of the following:
• • A periodical survey*, in alignment with the enhanced inspection program during surveys, as mandated by Regulation XI-1/2; or
  • A survey of all cargo holds to the same extent as required for periodical surveys in the enhanced inspection program during surveys, as mandated by Regulation XI-1/2.
• • • Refer to the Application of SOLAS regulations XII/3, XII/7, and XII/11 (meaning of the term "Periodical Survey) (MSC.1/Circ.1463)

Section 2: Maintenance and Compliance

• Bulk carriers must comply with the maintenance requirements stipulated in Regulation II-1/3-1, along with the standards outlined in the "Standards for Owners' Inspection and Maintenance of Bulk Carrier Hatch Covers" adopted by the Organization through Resolution MSC.169(79).

These standards are subject to potential amendments by the Organization, provided that such amendments undergo the processes outlined in Article VIII of the present Convention concerning the procedures for amending the Annex other than chapter I.

The booklet mandated by regulation VI/7.2 shall receive an endorsement from the Administration or its representative to confirm compliance with regulations 4, 5, 6, and 7, as applicable.

1. Any restrictions related to the transport of solid bulk cargoes with a density of 1,780 kg/m3 or higher, in line with regulations 6 and 14 requirements, must be identified and documented in the booklet mentioned in paragraph 1.
2. Bulk carriers falling under the conditions of paragraph 2 shall bear a permanent marking on both the port and starboard sides of the midship section. This marking consists of a solid equilateral triangle with sides measuring 500 mm, and its apex should be positioned 300 mm below the deck line, painted in a color contrasting with that of the hull.

For bulk carriers constructed before July 1, 1999, falling within the regulatory scope of regulation 4.3, but designed with an insufficient number of transverse watertight bulkheads to meet that regulation, the Administration may grant an exemption from the application of regulations 4.3 and 6, subject to the condition that they adhere to the following stipulations:

1. In the case of the foremost cargo hold, the inspections specified for the annual survey in the enhanced program of inspections during surveys required by regulation XI-1/2 shall be substituted with the inspections detailed therein for the intermediate survey of cargo holds.
2. Installation of bilge well high water level alarms in all cargo holds or cargo conveyor tunnels, as relevant, is mandated. These alarms should trigger audible and visual alerts on the navigation bridge, as approved by the Administration or a recognized organization, in accordance with the provisions of regulation XI-1/1.
3. Provision of comprehensive information regarding specific cargo hold flooding scenarios is obligatory. This information must be accompanied by detailed instructions concerning evacuation readiness under the guidelines of section 8 of the International Safety Management (ISM) Code, forming the basis for crew training and drill procedures.

Prior to loading bulk cargo on bulk carriers with a length of 150 meters and more, the shipper is required to declare the cargo's density, in addition to providing the cargo information specified in regulation VI/2.

For bulk carriers subject to the provisions of regulation 6, unless these carriers fully comply with all relevant requirements of this chapter concerning the transport of solid bulk cargoes with a density of 1,780 kg/m3 and higher, any cargo declared to have a density ranging from 1,250 kg/m3 to 1,780 kg/m3 must undergo density verification by an accredited testing organization.*

When verifying the density of solid bulk cargoes, the procedure outlined in the Uniform Method of Measurement of the Density of Bulk Cargoes (MSC/Circ.908) should be followed.

(Unless specified otherwise, this regulation applies to bulk carriers, regardless of their construction date)

Bulk carriers with a length of 150 meters or more must be equipped with a loading instrument capable of supplying data on hull girder shear forces and bending moments, in line with recommendations endorsed by the Organization.*

• Please refer to the Organization's recommendation on loading instruments (resolution 5 of the 1997 SOLAS Conference).

Bulk carriers measuring 150 meters or more in length, constructed before July 1, 1999, are required to comply with the provisions of paragraph 1 by the date of their first intermediate or periodical survey *** conducted after July 1, 1999.

*** For clarification on the term "periodical survey," please consult the document titled "Application of SOLAS regulations XII/3, XII/7, and XII/11" (MSC.1/Circ.1463).

Bulk carriers with a length of less than 150 meters, built on or after July 1, 2006, must be equipped with a loading instrument capable of providing information on the ship's stability in the intact condition. The computer software used for stability calculations should receive approval from the Administration and include standard conditions for testing related to the approved stability data.**

** For more details, please refer to the relevant sections in the appendix to the Guidelines for on-board computer use and application (MSC/Circ.891).

(This regulation applies to bulk carriers, regardless of their construction date)

Bulk carriers must be equipped with water level detectors in the following locations, each fitted with both audible and visual alarms:

In every cargo hold, two alarms are required. The first alarm activates when the water level exceeds 0.5 meters above the inner bottom of any hold. The second alarm triggers at a level not less than 15% of the cargo hold's depth but not exceeding 2 meters. For bulk carriers subject to regulation 9.2, it is sufficient to install detectors with the latter alarm only. These water level detectors should be placed in the aft section of the cargo holds. In cargo holds utilized for water ballast, an alarm override device may be installed. Visual alarms should distinctly differentiate between the two different water levels detected in each hold.

In any ballast tank situated forward of the collision bulkhead as required by regulation II-1/12, an audible and visual alarm activates when the liquid reaches a level not exceeding 10% of the tank's capacity. An alarm override feature may be included, which activates when the tank is in use.

In any dry or void space, excluding chain cable lockers, extending ahead of the foremost cargo hold, alarms should be triggered at a water level 0.1 meter above the deck, complete with both audible and visual indications. However, this requirement does not apply to enclosed spaces whose volume is less than 0.1% of the ship's maximum displacement volume.

The audible and visual alarms mentioned in paragraph 1 must be positioned on the navigation bridge.

Bulk carriers constructed before July 1, 2004, must meet the stipulations of this regulation no later than the date of their annual, intermediate, or renewal survey, whichever occurs first, following July 1, 2004.

Refer to Interpretation of SOLAS regulation XII/13 (MSC/Circ.1069)

(This regulation is applicable to bulk carriers, irrespective of their construction date)

Bulk carriers must ensure that the mechanisms for draining and pumping ballast tanks located forward of the collision bulkhead and the bilges of any dry spaces extending ahead of the foremost cargo hold are operable from an enclosed space that is readily accessible.

This enclosed space should be reachable from both the navigation bridge and the propulsion machinery control position, all without the need to cross open freeboard or superstructure decks.

If the pipes serving these tanks or bilges pass through the collision bulkhead, remote valve operation using actuators may be considered as an acceptable alternative to the valve controls specified in regulation II-1/12, provided that the location of these valve controls complies with this regulation.

Bulk carriers constructed before July 1, 2004, are obligated to meet the requirements of this regulation no later than the date of their first intermediate or renewal survey, post-July 1, 2004. This compliance deadline should not extend beyond July 1, 2007, under any circumstances.

Bulk carriers of 150 m in length and upwards of single-side skin construction, carrying cargoes having a density of 1,780 kg/m³ and above, if not meeting the requirements for withstanding flooding of any one cargo hold as specified in regulation 5.1 and the Standards and criteria for side structures of bulk carriers of single-side skin construction, adopted by the Organization by resolution MSC.168(79), as may be amended by the Organization, provided that such amendments are adopted, brought into force and take effect in accordance with the provisions

of article VIII of the present Convention concerning the amendment procedures applicable to the Annex other than chapter I, shall not sail with any hold loaded to less than 10% of the hold' s maximum allowable cargo weight when in the full load condition, after reaching 10 years of age. The applicable full load condition for this regulation is a load equal to or greater than 90% of the ship' s deadweight at the relevant assigned freeboard.