The question, which is a perfectly legitimate one, of the choice of the location of containers on board ships, regularly resurfaces in discussions between shipping companies and shippers. But the answer is less simple than it seems.
Reserve a place for your container on board a ship in the same way you would choose your seat on board an airplane. This seems like a simple matter. A inexperienced salesperson in a shipping company may even be tempted to let his beloved client believe that he has this power. But the “Shipping Operations” service, a department that coordinates stopovers with Shipplanners, who are responsible for the stowage plan, and Stevedores will quickly remind him that the assessment of a container's position on board for a crossing is much more complex than it seems.
The shipping company remains master aboard…
Under “liberty clauses” (1), the company has full rights to decide the place on board of containers according to certain criteria that mainly concern safety matters, these may be specific to them or dictated by the regulations (the IMDG code for example, that concerns dangerous goods).
The stowage space on board a modern container ship is no longer partitioned off between hold and deck, as was the case on conventional ships, the container itself theoretically provides sufficient protection of the goods. In contrast, a container ship is "sliced up" into a series of separate cargo spaces called bays. The Shipplaner must best solve the following equation: optimize the stability of the ship whilst at the same time facilitating the unloading and loading operations during the coming stopovers, limiting movements to a minimum. This is because having to temporarily dock containers to access others, and then reloading the first ones, only generates loss of time and money for the shipping company.
Ensuring the stability of the ship
The golden rule is to load the heaviest containers at the bottom of the hold and the lighter containers at the top, as a means to naturally aid the stability of the ship.
However, this equation is not systematically achievable, due to the physiognomy of containerized exchanges. The adjustment is then made by using ballast tanks filled with seawater in the lower parts of the ship: by emptying or filling them, the desired stability can be achieved.
However, here again things are not so simple. Massively ballasting, in addition to the weight of the cargo, has an impact on the draft, and therefore the capability of the ships to enter certain docks. In addition, by increasing the "submerged" surface of the hull there will be over-consumption of fuel and therefore a negative impact on the environment.
It also happens that for ships passing through the Suez Canal, a company will be tempted to stow more "topside", because of a lower taxation applied by the canal authorities on the containers on deck compared to the containers located in the hold. This situation can lead to an increased use of ballast than would otherwise be necessary ...
Management of the typology of goods
The 20' heavy non-dangerous containers are very likely to end up in the hold, followed by the 40' heavy non-dangerous ones. On deck, we find the lightest containers and those containing dangerous goods, these are subject to the "jettison clause" (2), as are the empty containers. The latter group represents a significant proportion: 20 to 30% of the containers loaded on the East Coast transatlantic route to Europe and on the route from Europe to Asia are empty.
Connected Reefers are a special case, because they depend on the power supply points on board ships, which are by nature concentrated in the same area and not scattered over the entire ship. Usually, the reefers are stowed in front of the bridge, either in the hold or on deck, with the possibility of physical access for the on-board staff if the need to intervene arises. Temperature monitoring, one of the roles of the First Mate, is now carried out remotely and periodically.
Oversized goods known as “Out of Gauge” or OOG are also primarily stowed on deck, for questions of access for loading and unloading and optimization of the loading of the ship.
What to do in the event of "mandatory hold stowage"?
It has become quite rare, but a letter of credit can sometimes require " mandatory hold stowage". A clause imposed by the banks, inherited from conventional shipping. In this case, and only in this specific case, the following conditions must be met:
- That the shipper makes this particular need known in writing at the time of booking.
- That they receive affirmation that this requirement has been taken into account in the booking confirmation.
- That the clause has been brought to the notice of the company and has been accepted by them making reference to the letter of credit concerned.
If these 3 criteria are met, the shipper can effectively claim hold stowage, without additional costs, unless it causes numerous additional movements ("extra move"). If this is the case however, the additional handling operations not provided for in the initial stowage plan will be invoiced.
Some common-sense rules…
The shipper must then systematically check that the company provides him with a clean, dry and odorless container, and above all one without perforations resulting from past impacts and / or corrosion. Surface corrosion is not a valid reason for refusal by the shipper. The provision of a pierced container is however a legitimate reason for returning the empty container to the depot for substitution with a compliant container, at the expense of the supplier. Shutting (briefly!) a member of staff in the container in broad daylight, to carry out the control, remains the most effective way to avoid suffering from this kind of disagreeable situation!
The dunnage and securing of the goods inside the container are entirely the responsibility of the shipper and are at their cost, in the case of FCL / FCL transport. This requirement has become more important today than it was twenty years ago for the following reasons:
- Longer vessels, up to 400 meters, are naturally subject to “parametric rolling” (see a video illustrating this phenomenon), that is to say the combined action of roll and pitch on the extremities during a long cycle. Imagine the movements undergone by the higher-most containers on deck aft and forward in the event of heavy seas! A good image to illustrate this would be to imagine making the goods travel inside a giant washing machine drum in the "spin" mode...
- Climatic variations more predictable but more severe, especially in winter. Winter in the North Atlantic can, under normal operating conditions, generate 30 degree angle lists over periods of several days (see a video). Shippers must be aware of the constraints that are dictated by the elements and take them into account in their internal dunnage procedures when carrying out stuffing. It is notable that there is a rise in the use of air cushions as dunnage inside the containers: this new technology, particularly well adapted, resolves a good deal of problems when used in addition to conventional cushioning on the floor.
(1) Liberty Clauses: these clauses allow shipping companies, under certain circumstances, to be able to free themselves of a certain number of obligations or to benefit from rights which they would not avail themselves of under normal conditions.
(2) Jettison Clause: in case of extreme peril, this clause allows for the throwing overboard of a container.
Photo : Anne Kerriou