Some of the people in the industry can identify where a container has been stowed on board of a ship just by reading the stow position (also known as cell position) and also whether it is a 20’ or a 40’ container that is stowed there..
How they do this..?? Mainly based on experience in handling stowage plans, but there is a formula to it..
I will explain below..
090482 is an example of a stow position.. This is basically divided into 3 parts
09 / 04 / 82 – where 09 is the bay, 04 is the row and 82 is the tier – translated in English it means :-
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 40 (for example) where Bay 01 is the bay towards the Bow (the front) of the ship and Bay 40 is the Stern (the back) of the ship.. Odd numbered bays (1,3,5 etc) means that it is a 20’ stow and Even numbered bay (2,4,6 etc) means that it is a 40’ stow..
Confused..?? Look at the below picture.. I have used Bay 09/11 (10) 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 block represents a 20’ unit space.. The bold lines represent the hatch covers that separate the deck (is the part where containers are loaded, that is visible to us when you see the ship) and under deck (which is not generally visible when you are standing outside the ship)..
Row is the position where the container is placed across the width of the ship.. If you refer to the above diagram, the Row numbers are circled in Red.. It starts with 01 in the centre and progresses outwards with odd numbers on the right and even numbers on the left..
Tier denotes at which level the container is placed – basically how high the container is stacked on board.. In the above diagram, the Tier numbers are circled in Blue..
Getting back to our stow position 090482 now – in the above diagram you will see that stow has an alphabet R – which i have used for the port of Rotterdam (each line, vessel or chief officer have their own alphabets for the ports).. So what i am saying here is that in stow position 090482 there is 20’ container that is stowed for discharge at Rotterdam..
So when you see a stow position as above you will know
09 = bay number and container is a 20’ (because its an odd number).. If it shows for example 10 then the container is a 40’..
04 = row number
82 = tier number which denotes that this is a 20’ container which is stowed ON DECK.. Usually ON DECK tier number starts from 80 and increases by 2 per tier, so it will be 80, 82, 84, 86 etc.. If the tier number shows 02,04,06 etc then its stowed UNDER DECK..
Lets look at a couple of scenarios from the above diagram..
Scenario 1 = 090482 is a 20’ container stowed ON DECK on Bay 09, Row 04 and Tier 82 – container is going to R for Rotterdam..
Scenario 2 = 110482 is also a 20’ container stowed ON DECK on Bay 11, Row 04 and Tier 82 which is basically the adjacent bay to the Rotterdam container and this container is going to L for Le Havre..
Scenario 3 = 090102 – which is a 20’ container stowed UNDER DECK on Bay 09, Row 01 and Tier 02 which is bottom most tier and this container is going to D for Dublin..
Scenario 4 = 100484 – is a 40’ container in stowed ON DECK on Bay 10, Row 04 and Tier 84 and this container is going to F for Felixstowe.. This container is basically sitting on TOP of the Rotterdam and Le Havre containers.. Since this is a 40’ container and sitting across both 9 and 11 bays , this bay is given the number 10.. The container is shown as sitting on 9 but the corresponding slot on 11 is marked with an X which means that this slot is NOT available for placing another container because there is a 40’ container already there..
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 under deck and surrounded by other containers or within cell guides)
So this is how a stow position is coined and how you identify whether a container is a 20’ or 40’ and whether it is stowed under deck or on deck just by reading the stow position provided..