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..
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 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..
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..