What are “lost slots”..??

I had a question from a reader (Sriram) saying that he has been quoted by a shipping line for Lost Slots and he wanted to know what are Lost Slots and how is it calculated..

I wrote a few articles previously about Out of Gauge (OOG) Cargo.. Let me jog your memory a bit..

OOG is cargo that extends over and above the standard measurement of a General Purpose container.. OOG cargo is carried in Open Top containers (OT) or Flat Rack containers (FR) due to the nature and size of the cargo..

The design and carrying capacity of container ships are based on TEU (Twenty 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 sits on it and so that it maybe secured to the deck..

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

Image of slots on deck
Image downloaded from – http://maritime-connector.com

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..

image for oog cargo
Image downloaded from http://www.freightaction.co.uk used as an example only..

For example if a cargo is loaded on a Flat Rack container 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..

OOG cargoes are generally packed in the center of the container, 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 this picture of a fully loaded ship, you can see how close the containers are loaded and you can see that there is no space for this 0.5 meter protrusion..

stowage on ship
Image courtesy Manaadiar Images

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

The loss of space caused to the shipping line by this OOG cargo is called LOST SLOTS.. The shipping line will charge the client of the OOG cargo these lost slots as they are losing revenue as they cannot load any cargoes to the left, right and on top of this container..

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 ondeck 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..

If you have had any experience with OOG cargo, please do share..

14 thoughts on “What are “lost slots”..??

  1. 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..

  2. 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.

  3. 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?

  4. 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..

  5. 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

  6. 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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