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What are “lost slots”..??

During the course of shipping business, you may have seen or come across the term “Lost Slots”.. In this article I explain what are Lost Slots and possible methods of calculation of lost slots..

I have written quite a few articles about Out of Gauge (OOG) Cargo.. Let me jog your memory a bit..

OOG is cargo that cannot fit inside a General Purpose container and requires special containers such as Open Top containers (OT) or Flat Rack containers (FR) or Platform containers due to the nature and size of the cargo..

The design and carrying capacity of container ships are based on TEU (Twenty-Foot Equivalent Unit) specifications which is 20 x 8 x 8.6 feet or 6 x 2.4 x 2.4 meters.. That is the dimension of a single slot on board a container ship..

These dimensions of the slots are fixed when the ship is designed and fittings are set such that the corner posts of the container sit on it and so that it may be secured to the deck..

In the below image you can see how the deck of a container ship looks like with the securing points for containers to be placed on deck..

what are lost slots - shipping and freight resource

Any dimensions above the 6 x 2.4 x 2.4 m will be considered as OOG and containers with such cargo will NOT fit within these dimensions..

For example, if a cargo is loaded on a Flat Rack container (as shown below) and its dimensions are 6 x 3.4 x 3.4 m, the cargo will be over-wide and over-high by 1 meter respectively..

what are lost slots - shipping and freight resource

OOG cargoes are (and should be) generally packed in the center of the container for equal weight distribution, so we can assume that this cargo will be protruding over the width of the container by 0.5 meters on each side and 1 meter above the height of the container..

If you look at the below image of a fully loaded ship, you can see how close the containers are loaded and you can see that there is no space for protrusion of any kind as the boxes are tightly stowed..

what are lost slots - shipping and freight resource


Therefore if the above OOG container is loaded on deck, no containers can be loaded to the left, right and on top of this container..

If the shipping line has to load this OOG cargo with the above example, they may have to compromise loading a few other containers to the right, left and above this container..

If we take the minimum of say 1 container on each side, it means that the shipping line is losing 3 slots on board the ship in order to accommodate this 1 container..

This loss of space caused to the shipping line by this OOG cargo is called LOST SLOTS..

Because they are losing these 3 slots, naturally the shipping line will have to charge the shipper of this OOG cargo for these lost slots as they are losing revenue..

The calculation of the number of lost slots and the cost for the same will depend on various factors like

  • How full the ship is
  • How many slots will be lost
  • Where would be the most effective and easiest placement of this container to facilitate easy access for loading and discharge
  • The port rotation of the ship
  • Whether there will be any restows en route or not

A shipping line has to take all of this into account before they advise the client the details of the lost slots and its associated costs..

This is also the reason that the shipping lines sometimes take a while to advise you the costs for OOG cargo, so please be patient..

OOG cargo is not restricted to on-deck loading only and depending on the stowage of the ship, type of cargo, port rotation, OOG cargo may also be loaded below deck where also such lost slots will occur..

In order to assist the line with the exact calculations, when booking OOG cargo, the client must ensure that the exact dimensions and weight of the cargo is advised to the shipping line..

There have been several cases where the client misdeclares the information to the shipping line either out of ignorance or to try and save a few $$$..

But such misdeclarations could end up in extra costs for additional handling, cancellations, vessel delays etc..

Article reposted from 2014 after few 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. Can a shipping line justifiably notify of ‘lost slot’ spaces 2 weeks after vessel departure?
    We had 3 x units measured at 244cm wide, they were each loaded to 20′ flat racks.
    However, after securing the the measurement on the survey report was made 245cm apparently because of the ratchets used for securing the cargo….
    The report was submitted to the carrier and the cargo was accepted for carriage, no comment was made about additional charges until almost 2 weeks after vessel departure. Do we have any recourse on this, will the carrier be obliged to provide evidence of the lost-slots as @ 245cm it is highly unlikely any slots were actually ‘lost’.

    • Hi David, if all the information was provided to the carrier at the time of quoting and there has been no deviation from those measurements, you can argue that point with the carrier.. Besides that, if there was any issues at the time of loading, that should have been notified to you by rights.. But 2 weeks later is a big stretch.. Did they take 2 weeks to send you the final invoice for the shipment..?? Its not normal..

  2. Hi Hariesh,

    A very valid topic that confuses many so thumbs up for bringing the article.

    I am writing because I do not follow your calculation in the example and do not understand you get 3 lost slots. With the described example I get it to 5 lost slots. You have one lost slot on each side and one on top, yes. But you also have 1 slot on top of each side, unless the containers there would be hanging in the air 😉 Makes sense?

    • Hi Hans, if you notice, I mentioned “If we take the minimum of say 1 container on each side, it means that the shipping line is losing 3 slots on board the ship in order to accommodate this 1 container..”

      Depending on the stowage of the ship and where this container can be loaded on the ship, there could be 3 or 5 or more slots lost at a maximum..

      My calculation of 3 slots was a simple calculation with a minimum slot loss..

    • Writer is either explaining of loss slot in cargo hold which can be 3 slots killed but if on deck then will be subjected to weight of the cargo to be justified and POD is concerned. 1st POD has better chances of less slots killed

  3. Good Day All, I have a question and require some feedback please. I am a cargo surveyor and was appointed to conduct an import survey on 1 x 40-ft FTrack on which 1 Mill Motor was loaded. The cargo was declared oog by width, and only marginaly by height. My inspection and subsequent report covered the visible arrival condition of the cargo and flat rack, outside of the discharge port, whilst this lay secured atop of the road truck-trailer that was used to transport same to the end user. I passed comment on the cargo and container, on the methods employed during lashing and securing at the load port and the fact that no evidence of shifting or visible damage was observed.

    The Client has subsequently come back to me asking if I had conducted a measurement survey. I’ve replied that I did not, and I am now being accused of an incomplete report, which is questioning my ability / professionalism.

    Hence my question Sir …. does a measurement survey form part of a import survey, or was this to have been verified and declared at the load port?

    Please to hear response

  4. Sir,

    Please tell us the calculation for Slot Loss for 40’FR OOG slot loss ,if 20’ft rate is USD1100 per TEU from Hamburg to Mumbai JNPT.
    1.What would be the rate 40’FR(OW+OH)
    2. If the cargo is Over width & Over height then How many time 20’ft slot loss will be there.
    3.USD 1100 x ___ TEU = USD___ per 40’ FR

    Thanks & regards.

    Prakash Patil

    • Hello Prakash, trust you would have read the article.. As mentioned, there is no fixed formula for someone other than the line concerned to calculate.. It depends fully on the line involved and suggest you speak to the line with the dims of the cargo and they will advise you..

  5. Your explanation is clear and to the point with necessary photos. The blog is interesting and through word-of-mouth, I have encouraged another friend of mine to subscribe as well.

  6. Hi!

    Have noticed that TEU with different load bearing capacity like 21000 or some were with 28000 KGs. In shipping terminology they termed as heavy or super heavy or light. Many experts could find type container’s number as well.

    Could any may please elaborate on above?

  7. Hi Hariesh,
    You mentioned that one of the factors for calculating the lost slots was “how full the ship is”.

    How exactly does this affect the lost slots calculation?
    Is it possible to not have any charges if the ship is not sufficiently full?

    Thanks in advance for your reply!

    • Hi Harish, whether the ship is full or not, there will be for sure the lost slot charges.. Lost slot calculations will depend on “how full the ship is” because the line has to decide where on the ship to place these OOG cargoes and whether they have the required space/area to carry these cargoes safely without affecting the operations of the other cargoes on board..

  8. As per own experience, mentioned cargo 600m x340m x 340m / weight not more than 20tons stuffed on 40’FR, there’s 6FFS lost slots (2 for each side on 2 for the height)

    • Hi Maan!
      No you have 8 Lost slot as your container is a 40’Flat:
      2 slots in lenght + 2 slots in height on each side 2 x 2 x 2 =8

  9. The stowage and securing of the cargo on a flat rack should be supervised by a competent cargo surveyor. requires that all Shippers using flat rack for their cargo provide a lashing certificate, issued by a competent cargo surveyor prior to acceptance and loading of the cargo. If the Shipper does not provide the lashing certificate, Shipping Company will nominate an independent surveyor to confirm safe loading, lashing, and protection of the cargo against the normal risks of ocean transportation. The costs for such surveyor are added to the account of the Customer.

    • Hi Capt.Babooa, it is in everyone’s interest especially the cargo interests that a suitable survey and inspection is done.. You are right, a few of the lines insist that the customer provide a surveyors certificate or a lashing certificate..


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