Bureau Veritas has published a comprehensive set of guidelines to promote and support the safe carriage of containers in bulk carriers. In recent months there has been unprecedented demand for the carriage of containers. This has prompted charterers to explore the possibility of using of bulk carriers for that task. Bulk carriers, in general, are non-cellular vessels compared to container ships.
Whilst the carriage of containers in bulk carriers is possible, but only after extensive planning, assessment and scrutiny, operators must liaise with their insurance carriers, the Class society of their vessel(s) and corresponding Flag Administration for advice and guidance on the necessary modifications and/or additions to satisfy their requirements.
The fact that bulk carriers are indeed “not specially designed and fitted for the purpose of carrying containers” combined with the potential need to maximize the intake of containers, creates issues of concern related to the integrity of the vessel’s structure and the cargo itself, as well as the safety of the crew and the stevedores.
Type of hatch covers and size of hatchway opening
Normally, folding type hatch covers provide a bigger length of hatchway opening in comparison to side rolling types. The length of the hatchway is important. The ideal is to have big enough hatchway length to facilitate the loading/unloading and enough space in holds in order to load 2 bays of FEU (or 4 bays of TEU). Attention is required to the additional space needed for lashing equipment and working space for stevedores. Side rolling hatch cover railways extending transversally at the deck side may complicate the container deck arrangement.
Containers in holds and SOLAS requirement for fixed fire extinguishing system
Attention is drawn to SOLAS II.2/10.7.1 which requires ships > 2000 GT, with or without dangerous goods, to protect cargo holds with a fixed fire extinguishing system.
Containers on deck and hatch covers
If there are not such loading conditions, additional intact and damage stability requirements are applicable. Two cases exist as follows:
• Vessels with type B freeboard: Such vessels will already have a probabilistic damage stability calculation as per SOLAS II-1 Part B requirements and a “Minimum GM Curve” established and included in the vessel’s stability documentation. For these vessels the extra windage area due to the deck stowed containers is to be taken into account in the intact stability calculations.
• Vessels with type B-60 freeboard: Such vessels will need to develop the Minimum GM Curve as per SOLAS II-1 Part B probabilistic damage stability requirements. This curve is to be applicable when the vessel is carrying deck cargo. In addition, as per the above case, the deck containers windage area is to be taken into account in the intact stability calculations.
A consulting office will have to prepare all of the required files as above and submit them for review.
How many containers can be loaded?
The answer is that this will depend on the vessel’s cargo hold and hatch geometry, as well as on the scantlings of the inner bottom, deck and hatch covers. Based on Bureau Veritas’ experience the following guidance figures can be used as an initial estimate:
– Number of 20’ or 40’ bays in holds: Depending on hatch and hold length
– Number of stacks in holds: Stacks consisting of 4-6 tiers may be possible
– Number of stacks on decks: Stacks consisting of 3 tiers may be possible
– Number of stacks on hatch covers: Stacks consisting of 2 tiers may be possible
The above figures depend on the design options, stack weight, stack VCG, loading condition GM, loading condition Hull Girder Stresses and so on. For the number of bays, sufficient space to be considered for the lashing arrangement and stevedores working space. For the number of tiers on decks and hatch covers, the IMO visibility requirements are to be taken into account.
What are the implications for containers known to be carrying dangerous goods?
For carriage of packaged Dangerous Goods, BV address the following:
For studying a Bulk Carrier and its available equipment, refer to SOLAS II-2, Reg.19 (same in BV Rules NR467, Part C, Ch 4, Sect 12). For more information refer to Tables 19.1 and 19.3 of SOLAS (i.e. containers shall be considered as “packaged goods”).
For the stowage and exact location of the Dangerous Goods on board the ship, the IMDG code applies (out of Class scope).
Attention is required to be paid to dangerous goods segregation requirements, IMDG code applies (out of Class scope).
Assuming that the bulk carrier has a Document of Compliance (DoC) for carrying Dangerous Goods, then this carriage of Dangerous Goods shall be in compliance with the available/allowed list (for packaged goods).
If the ship does not have a DoC for carrying Dangerous Goods, then a surveyor should verify onboard the relevant vessel characteristics, to process the data and issue the relevant DoC and associated list of dangerous goods (packaged goods).
Even with ships equipped with a DoC, surveyor attendance and verification will be needed if new equipment is to be installed in order to include new classes of dangerous goods (packaged goods).
Download the guidance booklet: BV guidelines loading containers bulk carrier
Read another container related article: Safe loading and carriage of containers on vessels other than purpose-built container ships