In view of the recent incidents relating to stack collapses on board and containers lost at sea, I thought a refresher on “What is container stowage planning and how it works” would be in order..
This is also to remind everyone in the shipping chain – exporters, agents, freight forwarders, carriers, documentation teams, vessel operators, and stowage planners, the importance of providing and using the correct information for the planning and stowage of the vessel..
So, what is stowage planning..??
In simple terms, it is the act of allocating space on board the ship for containers that have to be loaded from a certain port(s) to be discharged at certain port(s) without those containers having to be rehandled at any of the way ports along the route..
This is probably the most important of all ship operation functions and can be quite intensive in terms of activities and functions..
Tools required :
- The scheduled list of ports that the ship will be calling at, in the order of rotation ;
- A summary of the number of containers – size/type/weight of containers and container numbers per port that are planned to be loaded on the ship ;
- A summary of the number of hazardous, reefer and OOG containers per port that are planned to be loaded on the ship ;
- List and summary of containers on board already on board for ports past your port.. For the purposes of this article, we will consider this port to be Durban..
Definitions :
Profile – is the cross-sectional view of the entire ship covering both the deck and under-deck of the ship.. The profile gives the total view of the stow positions of which containers are to be discharged at which port..
The port operations team and stevedores can identify the sequence of loading and which bays the ship must discharge and/or load from looking at this profile..
The profile provides the full cross section of a ship at one glance.. The enlarged version of this will be the actual bay itself..
Bayplan – is the complete cross sectional view file covering both the deck and under-deck of the entire ship, but displayed or printed per bay..
Bay – each container vessel is split into compartments which are termed as Bay and depending on the size of the ship it will proceed from 01 to 88 bays (you can read my take on an interesting comparison between stowage plans of older ships and current Triple E type ships) where Bay 01 is the bay towards the Bow (the front) of the ship and Bay 88 is the Stern (the back) of the ship..
Below is the view of Bay 19..
Odd numbered bays (1,3,5 etc) means that it is a 20’ container stow and Even numbered bay (2,4,6 etc) means that it is a 40’ container stow..
Confused..?? Look at the below picture.. I have used Bay 09/11 (10) and Bay 13/15 (14) as an example here..
What you are seeing here is the cross-section of the ship both on deck and under deck.. Each of the small square blocks represents a 20’ unit space..
Row is the position where the container is placed across the width of the ship.. If you refer to the image above, Row numbers are circled in Green..
It starts with 01 in the center and progresses outwards with odd numbers on the right (starboard) and even numbers on the left (port)..
Tier denotes at which level the container is placed – basically how high the container is stacked on board.. In the above image, Tier numbers are circled in Red..
Hatch Covers (the dark intermittent lines in the above picture) are the covers that separate the deck from the under-deck..
The area above the line is called the deck (the area that is visible to us when we look at the ship) and the area below the line is called under-deck (the area that is not visible to us from outside the ship)..
Although currently, computers do most of the work, the basis on which they work is the tried and tested methods that have been followed for many years around..
- the list of containers that are to be loaded onboard is segregated by destination..
- space is allocated to each of the containers
- firstly in the order of destination – the farthest destination at the bottom and the next port of call right on top
- secondly in the order of weight – the heaviest boxes at the bottom and lightest at the top
For reasons of lashing and securing containers, a 40’ container can sit on top of two 20’s, but two 20’s cannot sit on top of 40’ (unless it is under deck and surrounded by other containers or within cell guides)..
In the above profile, I have used various alphabets and colors..
- F for Felixstowe
- A for Antwerp
- Ae for Antwerp Empty
- H for Hamburg
- L for Le Havre
- R for Rotterdam
- X to indicate that its a 40’ contr..
The rotation for this vessel is Felixstowe, Antwerp, Le Havre, Hamburg and Rotterdam..
So because, Felixstowe is the first port of call after Durban, containers bound for Felixstowe are stacked right on top of other containers followed by containers meant for Antwerp, Le Havre, Hamburg and Rotterdam..
Rotterdam will be the last port of call hence it is right at the bottom of the heap..
In this fashion, the entire ship is filled with the containers that are to be loaded at each load port while also taking into account the containers that are ALREADY present on board from the previous ports..
If you notice in the image on the right, there is a container in stow position 110910 (Bay 11, Row 09, Tier 10) – circled in red and marked L for Le Havre.. By reading the bay plan, one can identify a stow position and where a particular container is located..
A restow is a move where a container is off loaded from on board the ship and put back onto the ship either at the same stow position or a different stow position..
This could be due to incorrect stowage of a container – say loaded wrongly for Le Havre instead of Felixstowe or a change of destination was requested at a later stage to now discharge this container in Felixstowe..
In order to reach this container, all the 12 containers meant for Antwerp (A and Ae) has to be “restowed” because Antwerp is the next port after Felixstowe..
Then the hatch cover (the dark line between the deck and under deck) has to be opened to reach under deck..
Then the 1 container to Le Havre (L) in position 110912 must be “restowed” as well and only then the container in position 110910 can be discharged in Felixstowe..
As you can imagine, this involves considerable cost and wastage of time for the ship to restow 12×40′ containers and 1×20′ container to discharge this one container that was stowed incorrectly..
So to avoid these costs and wastage of time, it is imperative that the right destination, correct weight, and hazardous cargo info if any is accurately passed onto the ship..
Each of the bays have deck stress or tier weight which is the maximum allowed weight that each of the tier/row can carry as per the design of the ship..
For example if there are about 4 containers in a tier each weighing 26 tons, it may not be possible to accommodate all 4 in one tier as this might affect stability due to the heavy nature of the cargo..
However, if there are 5 tiers of empty containers as shown in Bay 15, it might be possible to load.. These calculations will be performed by the computer itself and it will show up as errors..
Some of the most commonly used software for ships planning are CASP, MACS3 and Bulko.. These use the BAPLIE file format structured by UNEDIFACT..
Also interesting to note that a lot of Container stowage is done in centralised hubs these days..
As we have seen in the recent articles relating to container collapses onboard ships, correct stowing planning and proper lashing of containers on board is of utmost importance to avoid may maritime disasters..
Article republished with some critical updates
The post The basics of container stowage planning and why it is so important appeared first on Shipping and Freight Resource.
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