Structural strength
The main deck and hatch covers on modern bulk carriers usually have a structural capacity of around 2.0 to 2.5 t/m2 of uniformly distributed load (UDL). The challenge is that the main deck and the hatch covers are not designed to take the point loads from the containers and the cargo securing equipment. Local supporting structures for the container socket and/or other lashing devices must be considered. In addition, the transverse and longitudinal hatch cover stoppers may need to be modified.
Bulk carrier cargo holds are designed for large loads from bulk cargo, and the overall strength is more than sufficient to carry the relatively light containers. However, the same challenge with point loads as for the deck and hatch covers applies.
Stability documentation
If the containers are stowed in the holds only, the existing stability calculation and resulting metacentric height (GM) limit curve covers the transport of containers. The loading condition with containers must comply with existing stability limits.
When containers are carried on deck, compliance with applicable stability and longitudinal strength criteria in deck cargo loading conditions must be shown in updated/amended stability manuals. In general, intact GM limit curves shall be recalculated considering the additional wind profile area from the containers.
Probabilistic damage stability calculations may also be required for ships with reduced freeboard (B-60/B-100), see IACS UI LL65. For ships with B freeboard (without reduction), it may be necessary to reassess the damage stability calculations of SOLAS Chapter XII (flooding of single holds), depending on how compliance was documented originally.
Loading computer
The Loading Computer System (LCS) will have to be updated as necessary with new GM limits, profile curves or other stored data. In cases where the ship does not need any new limits or data, a test condition with deck cargo shall be provided. Please note that some LCS do not support non-bulk cargo and deck cargo.
Cargo securing
The stowage and securing of cargo other than bulk cargo is to be described in an approved Cargo Securing Manual (CSM). Many bulk carriers already have such an approved manual because they are intended for carriage of breakbulk, e.g. steel coils. With the information given in the CSM, the crew can design and execute a safe cargo securing of containers.
The CSS Code Annex 1 specifies lashing methods for two tiers of containers. If three tiers or more are intended, the container lashing method must be shown in a container securing arrangement and be submitted for approval. If the intended container loading conditions vary in terms of number of container tiers, container weights, or floating conditions of the vessel, an approved lashing computer system would be required.
Fire safety
Cargo holds shall in general be equipped with a fixed gas fire extinguishing system, typically a CO2 system. However, some bulk carriers have a flag state exemption for such a fire extinguishing system, as they are designed for non-combustible cargo only. Containers are in general combustible, hence a gas fire extinguishing system in the cargo holds is required. The exception is empty containers, which constitute low fire risk and should, in DNV’s opinion, be permitted. However, this exception must be accepted by the flag administration.
Dangerous goods
In case the vessel is intended to carry containers containing dangerous goods, SOLAS Chapter II-2 Regulation 19 must be observed, and the vessel must be equipped and certified accordingly. The stowage and segregation requirements of the IMDG Code must be observed when planning the container stowage.
- Fire detection: SOLAS Chapter II-2 provides clear guidelines on the fire protection systems for cargo spaces for vessels over 2,000 GT but it does not cover fire detection inside cargo spaces. This is unique to bulk carriers as dedicated container vessels would have sample extraction smoke detection system and other means of fire detection inside cargo spaces.Experience from handling several large fires on container vessels is that early detection is the single most effective way to fight the fire and bulk carriers will remain at a disadvantage in this regard unless a detection system is installed.If we couple this with the frequency of misdeclaration of contents of the container, the risk factor related to fire safety is high on conventional bulk carriers carrying containers as cargo, especially inside the cargo holds.
- Fire fighting: Fighting a fire inside a container comes with its own challenges. Given the widespread problem of misdeclaration, operators are recommended to equip their vessels with suitable means to fight a fire both inside and outside the cargo space. An extinguishing medium such as mobile water monitors and water mist lances, irrespective of whether the vessel has a document of compliance (DOC) for carriage of dangerous goods or not, could be effective in case of an emergency. As for fixed fire extinguishing systems for holds, most conventional bulk carriers that are approved to carry dangerous goods, will already have such a system installed.
Navigation
If containers are carried as deck cargo, bridge visibility (SOLAS V Reg. 22) and COLREG requirements must be considered. The so-called castle stowage of containers obstructing max permissible blind sectors for visibility is normally not accepted.
The voyage
Voyage planning: On a container vessel weather routeing is a very important part of the voyage planning process. Heavy weather, resulting in parametric and synchronous rolling, has been a common factor in nearly all claims related to container stack collapses. Readers interested in knowing more would find GARD’s ‘Why do containership stacks collapse and who is liable?’ useful. Advanced weather routeing software and services are available, and operators should consider adopting these technologies for the safe execution of the voyage. Appropriate weather limiting factors must be defined or rather re-defined, such as the maximum wave and swell height, as these factors will be different depending on whether the vessel is carrying bulk cargo or containers.
Navigation
- Vessel manoeuvring: Where containers are loaded on deck, the vessel’s windage area will be greater. Consequently, the ship will behave differently at sea and during berthing and unberthing, especially when the wind speeds are high or there are strong gusts. Additional tugs may also be needed to assist vessel manoeuvring during berthing / unberthing operations. The watchkeeping officers should consider the higher windage area affecting the manoeuvrability of the vessel.
- Lookout: Containers loaded on deck can obscure visibility of the watchkeepers and interfere in safe lookout. The vessel’s loading software should be able to advise the crew whether the SOLAS requirements for minimum visibility are being met or not.
Monitoring during voyage: During the voyage, the crew will need to actively monitor the lashings as they are likely to slacken during the voyage due to vessel movements. In addition to the lashings, the vessel will also need to monitor stability conditions during stages of the voyage. Bunker consumption during passage will affect the stability of the vessel which will need to be compensated with ballast, especially if the vessel has a low GM at departure from load port.
Safe access
Safe access to the container cargo needs to be observed to allow for monitoring of securing arrangements during the voyage. Under-deck spaces must be accessible and provided with ventilation, illumination, and atmosphere check to allow safe access.
Mooring and towing equipment
The side projected area of containers stowed on deck and hatch covers is to be considered for the selection of mooring and towing lines, and for the loads applied to shipboard fittings and supporting hull structure.
Class notations
It is recommended that you apply the class notation Container, which provides a design standard enabling the safe and reliable transport of containers on ships, especially if three or more tiers of containers are intended.
It is also recommended that you ensure compliance with the Code of Safe Practice for Cargo Stowage and Securing (CSS Code) Annex 14 by assigning the class notation Safelash.
Can an owner refuse to carry containers on board?
Charterparties for bulk vessels almost always contain trading exclusions and cargo exclusions. Not surprisingly, owners of dry bulk vessels would not have contemplated the carriage of containers when entering into medium- or long-term time charterparties. Can owners refuse an order to load containers on board a bulk vessel where the charterparty does not expressly exclude them?
The position is uncertain. However, owners can look to the vessel description clause in the charterparty, which would usually indicate the contemplated trade. For example: “Vessel is a bulk carrier, fully fitted to carry grains and in a thoroughly efficient state to trade dry bulk cargoes” indicates that the vessel has been chartered to carry dry bulk cargoes, including grain in particular. It remains to be seen whether it might be arguable that this excludes carriage of containers (which will in any event depend on the terms of the particular charterparty) and it will be interesting to see whether this is raised in the future.
As discussed below, a conventional dry bulk vessel will need modifications to her design, approvals/permissions, and additional documentation before carriage of containers can be contemplated. In short therefore, a conventional bulk vessel may not be considered cargo worthy or seaworthy as-is, and owners may be able to reject the carriage of containers under a standard dry bulk charterparty.
Where a wide range of trades not specifically including reference to containerised cargo is covered by the charter, the owners would probably not be obliged to have fittings for containers. Of course, that is not the same as an ability to refuse to carry containers, but it does put some of the expense of doing so onto the charterer unless the ship has been expressly chartered for the purpose of carrying containers.
The argument that charterers would be obliged to provide and pay for (and remove, at their cost at the end of the charter period) any modifications required to allow carriage of containers can be further strengthened by the charterparty terms. See for instance NYPE 1993 cl.7: “The Charterers shall provide and pay for necessary dunnage and also any extra fittings requisite for a special trade or unusual cargo …” It seems likely that carriage of containers on a drybulk vessel would be a special trade or unusual cargo. The Baltime form only requires that the ship has fittings “for ordinary cargo service” and again, it seems likely that fittings for containers would fall outside this description on a drybulk ship.
Charterers’ bills of lading – a solution?
Charterers’ bills of lading are signed by charterers as the “carrier” of the cargo, and not on behalf of the owners or master of the vessels. The intended effect is to direct all claims made under the bill of lading to the charterers as the named carrier.
Be that as it may, the owners of the vessel as the physical carrier of the cargo, would be considered the bailor of the cargo during the voyage, with a corresponding obligation to properly care for the goods in their possession. Owners therefore could still face claims in bailment from a cargo claimant. These claims would be governed by the law of the jurisdiction in which they are brought and are difficult to avoid. Owners may wish to consider incorporating Himalaya clauses into the charterparty, as well as an indemnity from charterers into their charterparties, for claims arising from the carriage of containers on deck.
Insurance cover
Carriage of containers on dry bulk vessels will, as a general rule, constitute to be an alteration of risk for both P&I and H&M cover. Owners should contact their underwriter to determine if the intended operation will have implication of the insurance cover. The risk evaluation by the underwriter will depend on the merits of each case and will take class and flag approval into account.
Flag state/class approval process
Documents submissions: Owners must seek permission from both the vessel’s flag state and classification society if containers are to be carried on a bulk carrier. Class and statutory requirements will possibly be applied on a “case by case” basis and will vary depending on the class society and the flag state administration. The approval process could take a few days especially when done for the first time. According to one estimate, it took class 8-10 days to give final approval for the vessel to take first cargo of containers on a bulk vessel. Furthermore, depending on the requirements of the class, owners may require approval for each voyage prior to loading to ensure that all strength and stability calculations are within the safe margins. Owners should also bear in mind that some port states might require submission of certain documents. Generally, the below listed items will likely have to be documented in order to obtain the necessary approvals which could be per voyage or on a more permanent basis:
- Container Stowage and Lashing Plan in line with CSS Code and/or Cargo Securing Manual (CSM).
- Structural drawings of new structural elements for the fixed securing equipment for cargo holds/deck/hatch covers.
- Revised loading conditions, departure and arrival, with containers as cargo to be submitted for review for each voyage.
- Any changes or modification to the vessel’s stability manual and software.
- Probabilistic damage stability calculations.
- Owners should also apply for Document of Compliance (DOC) for the carriage of dangerous goods, if necessary.
Owners should enter in a dialogue with their classification societies and flag states early to better understand the various requirements and approval process. It might also be a good idea to undertake a pre-assessment of the vessel to assess vessel suitability and the extent of modifications required.
Recommendations
We have above highlighted some of the technical and contractual risks for bulk carriers that are involved in a transition to carry containers as cargo. The risks mentioned are by no means exhaustive but give some indications as to what to expect. The below recommendations summarize the key points.
Due diligence of operators: Getting class and flag approvals after making the necessary modifications is only the first step when making a transition to carry containers. Approvals alone would not guarantee safe carriage. For example, crew must be trained and ready for the new operations.
Contractual considerations: It is prudent for owners to insert protective clauses and indemnity clauses in their charterparties and bills of lading where containers are intended to be carried on deck. Where charters’ bills of lading are issued, Owners may still face claims in bailment. Owners should therefore ensure that their charterparties and bills of lading contain a Himalaya clause, allowing them to rely on any defences available to charterers as the contractual carrier under the bills of lading
Limitations of the container trade: There are a many lessons to be learned from container vessels for bulk operators wishing to make the transition. Misdeclaration of dangerous cargo, misdeclared weights, improper lashings and poor packaging and securing of the cargo inside the containers are some of the key risks to guard against.
Crew training and familiarisation: Crew who have not had any exposure to carrying containers will need to be trained and familiarized by operators to ensure that the voyage can be executed safely. Some of the areas where this will be particularly important are the loading software, container lashings and navigation.
Apart from above guidance by DNV and Gard, Classification Society Bureau Veritas has developed a formalized approach to support the safe carriage of containers in bulk carriers.
Source : Maritime Cyprus
