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The basics of container stowage planning and why it is so important

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 :

  1. The scheduled list of ports that the ship will be calling at, in the order of rotation ;
  2. 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 ;
  3. A summary of the number of hazardous, reefer and OOG containers per port that are planned to be loaded on the ship ;
  4. 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..

stowage planning and how it works - shipping and freight resource

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..

stowage planning - bay number


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..

how stowage planning works


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..

  1. F for Felixstowe
  2. A for Antwerp
  3. Ae for Antwerp Empty
  4. H for Hamburg
  5. L for Le Havre
  6. R for Rotterdam
  7. 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..

restowIf 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

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Hariesh Manaadiar
Hariesh Manaadiar
I am Hariesh Manaadiar, the Founder of Shipping and Freight Resource.. I have been in the dynamic shipping and freight industry for over three decades and have worked in several sectors.. I share my experiences and knowledge of the industry through this blog for those looking for help in the industry.. Stay subscribed for more free useful content about shipping, freight, maritime, logistics, supply chain and trade..


  1. Hi Hariesh, I enjoyed your article and it seems to have piqued a lot of interest. I know the article is quite old now but just a point of interest on your bayplan. Felixstowe, Hamburg, Antwerp etc would have no space to back load its exports as you have layered your stow. Stows should be in columns in order to provide ground space for back loading, every effort should be made not to load different ports on top of each other. Empties will, inevitably, be the exception to this rule as they are used for “topping” off stows.
    The larger vessels we have now often invert the weight plan underdeck ie. heavy at the top, light at the bottom in order to lower the vessels GM which is increasing as vessel size increases.


    • Hi Sue, the container would be put back on a different vessel that was heading to the correct port. Easier if the container came off before it was supposed to as the correct port would be further down the rotation, if after it should have come off a different service would be needed to carry the container.

  3. HC container can put below of above standar 40 cont. Especialy on underdeck bay, depend from how much stackheight every bay.

    @Martin Baez

    HC 40 container still 2 TeU when planning. 2,25 TeU is for 45 feet cont. No matter 2 Teu or 2,25 Teu, ussually 45 feet put on ondeck Top Tier Above 40 feet.

  4. Good article and very useful blog for all those of us related to the marine transportation industry.
    However your article is missing the mentioned bayplan example which is crucial for those who don’t have experience with that to be able to understand it.
    Keep up the good work!

  5. Hi Hariesh
    Thanks for an exceptional report n blog . The positive responses and interactive communique bear testimony to that. An interesting and important analogy has been tabled re nose being the fore (front) etc as it helps with easy identification. If I may add my two bits please:- the PORT (left) side of the vessel is identified by the light / colour RED which incidentally is the same as PORT wine . GREEN is the light / colour of the STB / Starboard side (opposites at best red / green left / right)
    Container / Cellular vessels are so because of cells / guides for container stowage . Each one for a twenty foot container TEU being a twenty foot equivalent . A 40′ stow position is twice that of a teu and takes up an even bay stow number . If we had two 20′ units from the fore it would be bays 1 and 3 but a 40′ would be bay 2 . Reading BRT stows Bays latitude / Rows longititude andTiers being the height .

    • “There’s no Red Port Left, it’s all gone down my Throat” . . . . That’s how to remember aboard a Gaff Rigged sailing Vessel – or any vessel. Facing the bow, Port and Left are on the same side and the Red Running Light is also on the Left. The Throat Halyard (the one hat hoists the Gaff) is on the left side of the vessel. Therefore, common sense only needs to be applied to understand that by default, Starboard is Right, the Green Running Light is Right, and the Peak Halyard (the one that tops off the Gaff) is on the Right side of the vessel as well.

  6. Hariesh, thank you for this explanation of a complicated subject which (like air traffic control, rocket science, etc.?) most of us could never contemplate understanding or taking up as a career.

    Clearly it was written some time before the introduction of the SOLAS regulations, but certainly confirms what they were aiming at – accurate weights of containers are important so that the stowage planners can ensure that not only are the containers stowed in order of discharge port – for convenience – but also that heavier containers are stowed near the bottom of the stacks and lighter containers near the top – for safety.

    It is important for all shippers to comply with these requirements and to be aware which VGM declaration method is best for them i. e. Method 1 (weighbridge on site), Method 1 (third party weighbridge) or Method 2 (weighing the contents during loading).

    Every shipper needs to investigate these options to determine which method is the most practical and cost efficient – using a weighbridge is not always the best and cheapest, although it may appear to be the easiest.

    • Hello Ignacio, flatracks also have same dimensions and corner posts as a standard container and therefore can be stowed or overstowed by other containers.. However, if cargo is Out of Gauge (OOG), then there will be a different stow provided or in some case (if rotation permits) they may be the top most tier loaded.. In the case of OOG cargo the line will charge for lost slots as they are losing loading space for other normal cargo..

  7. Its a very informative article…..however can you please advise on the HC stowage…..since it is 1 ft taller than the 20′ & 40′ std is the TIER height based on the standard or HC contrs. Are there specific bays where only hc’s are stowed?

    • P R Rajesh

      I’ve seen a cargo planning in action and as per i could note, the tier height is based in standard containers.

      HC contaners are considered as 2.25 TEU when planning.

      If there are many HC containers in a tier, you are likely to reduce the quantity of containers to load in that specific tier because of the total height.

      Remarks: This is my own experience. Type of vessel: Pontoon Barge.


  8. If a container’s row number is even (e.g. 020682) it’s on port side, and if it’s uneven (e.g. 020184) it’s on starboard side. In your article you used left and right which define direction not a ship’s side. This information is more useful for checkers and for the ship’s crew.

    • Hi there, for discharging 13-06-12, total restow should include bay 15 port side deck “Ae” 20 containers because the hatch cover is entire piece covering both bays.

  9. Its a nice method.I have join this field before a month and i have asked from many persons in this field but they have not satisfied me.Thanks

  10. hi! im just a new seafarer but this sites helps me a lot of understanding whereabouts of the containers on the vessel…its a nice blog for newbies like me…i hope that you continue making more important and easier methods…


  11. why is that, that the numbering of tiers are not in sequence, like the tiers below deck started 02-12 and the tiers on deck started their no. in 80 or 82? where are the ties no. 14- 78?

  12. Thanks for your notes. they helped me a lot as I am applying for a Vessel planner position.
    They are a great help to everyone wishing to learn in this subject

  13. Hi, and what about the proper lashing of containers on deck( single, double bars, heigts) and the correct use of the different types of twislocks?

    • Hi Javier, these are important topics of course, but i am not an expert on the lashing aspect.. Would you be interested in elaborating further on the lashing methods you have mentioned above..?? Pls feel free to write a guest post on that subject if you are interested..

  14. Hi Manaadiar, regarding the stowage of vessels it is not possible to load 20′ on top of 40′ containers, considering that you have indicated that some line do practice this please be so kind as to supply the names of these companies. Any stowage co-ordinater worth their salt would never plan a vessel in this manner.
    The norm is 40′ on top of 20′ under deck and on deck if the confirg. of the bays allows for this.

  15. Hi Kerby, there are vsls and lines that do load 20’s on top of 40’s in certain circumstances , specially where there is a space restraint and there is no danger to the lashing and also when using fully cellular vsls with cell guides..

  16. This is how I had learnt about stows
    Stand at the accommodation of the vessel facing front(bow)
    1) yr nose is the fWD
    2) yr back is the AFT
    3) yr left hand is the PORTSIDE
    4) yr right hand is the STARBOARD SIDE

    Correct me if I am wrong

    • Sorry Niram, this is close but that is not right – take it from an old sea captain . . . . Aboard a ship, Port and Starboard are the names of the sides of the ship and have absolutely NOTHING to do with you or with your “hand”. If it did, the term Port and Starboard would change depending upon whether you were facing fore or aft.

      Also, ships do not have a “nose”, ships have a bow, which normally is the end of the ship that points in the direction the ship is heading.

      And, ships do not have a “back”, they have a stern which is normally the blunt end of the ship that points in the direction the ship has already been.

      And remember … your right hand is the one where the thumb is on the left and your left hand is the one where your thumb is on the right.

      If you keep those things in mind you will never embarrass yourself aboard a ship, or in a waterfront bar talking with an old salt.

  17. Hi Manaadiar, interesting website for newbies to the shipping industry. I work in a stevedoring industry and just reading your topic on stowage/planning. This is an imperative function, it my view it is the heart of operations, as it determines various costs. not only on the container sector but the breakbulk as well.
    Proper planning/stowage could mean greater returns to us all in the freight industry especially in this time of economic crisis.

  18. Hi Manaadiar, interesting website for newbies to the shipping industry. I work in a stevedoring industry and just reading your topic on stowage/planning. This is an imperative function, it my view it is the heart of operations, as it determines various costs. not only on the container sector but the breakbulk as well.
    Proper planning/stowage could mean greater returns to us all in the freight industry especially in this time of economic crisis. Thank you for an informative and innovative site.


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