Determining how to stack shipping containers safely and effectively is no easy feat. You may think that you’re a pro at stacking, but are you really? And even if you’ve gotten great at stacking small things, like books or boxes, are you good at stacking something much larger?
How about stacking shipping containers? These containers may look easy to arrange, but the truth is that there’s a lot that goes into the techniques of learning to stack each type of shipping container.
Assembling Shipping Container Stacks Properly
There are several ways you may need to stack containers, including containers that are on land and those that are on a ship. It is important that you understand the differences between these two types of container stacking and how they need to be moved differently in both.
This is true even though both can be moved with a crane or other equipment as needed. You will need to consider several factors to carry it out accurately.
Shipping Container Stacking on Land
Stacking shipping containers on land requires skill and attention to detail as you are generally loading onto trucks or trains.
- Shipping container
- Forklift or crane
- Lashing rods
- Twist locks
Step One: Inspect Everything
The first step in the process of stacking shipping containers is to inspect the containers for quality. Look at not only the exterior but interior of the container. Check for any signs that there is structural damage including rust, cracks, or dents.
The sub-flooring and corners are two of the main areas where damage can go undetected but look carefully at the sides, doors, and the top of the cargo as well.
Step Two: Use the Corner Posts
Containers are designed to fit together almost like legos. That means you align the corner post of one shipping container with the corner post of the lower unit. Then align each corner post of the next container in the same way.
If you’re stacking containers that are different sizes, start with the smaller one. Stack them so that they match up to the size of the larger container. This allows each corner post to line up properly.
For example, two 20-ft containers could go on the first level (bottom container) with one 40-ft container lined up above. This will secure the smaller ones more easily.
Step Three: Lash all Containers
All of the stacked containers should be lashed together with lashing rods. Twist locks should also be used for added stability and to keep the containers in place.
Step Four: Certified Operators Only
Container forklifts are always used when moving shipping containers stacked, but only certified people should use them. If you are stacking shipping containers you need someone who knows what they are doing.
The wrong person using container forklifts could result in injury for you, them, or others. It could also mean damage to the shipping container, the products inside, the truck or ship being used to transport it, or the forklift itself.
Shipping Container Stacking on a Ship
Stacking shipping containers on ships can be more difficult than doing the same on land as you have to be aware of the elements. After all, thousands of shipping containers are lost at sea every year.
- Shipping container
- Forklift or crane
- Lashing rods
- Twist locks
Step One: Check the Stowage
The first thing is to determine where you’re going to put the container when dealing with ships. You can put them in fore and aft or athwartships. With fore and aft the storage is lengthwise. With athwartships the storage is horizontal, at right angles to the center.
The size of each of the ships and the weather expected will dictate how you should be stacking these containers. In bad weather fore and aft will provide the best protection from the elements.
Step Two: Use Your Corner Posts
The corner posts are still important when stacking on a ship. In fact, it may be even more important to line up each corner post so that like-sized containers are one on top of the other.
As with stacking on land, be sure that smaller containers are stacked below larger ones. This will allow you to line up each of the corner posts correctly and safely. You can do this using a forklift or crane if you have the proper crew.
Step Three: Secure Carefully
Each of these containers must be secured properly to ensure they won’t slide or move in transit. This is especially important when on a ship. That’s because the conditions can be rough and you want to make sure that nothing is going to be lost.
Lashing rods as well as twist locks will secure the container besides just the corners. This will keep it firmly attached to the deck and to each other, preventing slippage while on the rough seas, reducing overall risk.
Step Four: Use Appropriate Equipment
Appropriate equipment includes a container forklift. Once again, be sure that the person using the forklift knows what they are doing and has been certified to move shipping containers with that unit to reduce potential risk.
Be sure that the forklift you’re using is also designed to be used with shipping containers. Not all of them are and ones that are not could be damaged or cause injury when used this way.
Things to Consider When Planning Your Container Stacking
Buildings, structures, crew, loads, and other important items that could be damaged with lack of care or attention when using forklifts.
Mapping Cargo Containers
When you map out the cargo containers design that you need to stack you should think about:
- Size of each container
- Weight of each container
- Destination of each container
The size of the unit will dictate where it will go on the ship. Smaller containers go on the bottom because they need the security of larger containers holding them down. Larger containers go on the top to make sure the smaller containers don’t move too much and improve overall structure. If they are placed above they won’t have the same stability because the corner posts are not aligned.
The weight of the container could play a role as well. Containers that are much heavier should not be placed on top of lighter containers. While the container itself will weigh the same when empty, some products that are shipped will be much heavier still. These should be closer to the bottom of a stack load rather than the top.
Finally, the destination of the container must be taken into account. If all stacked containers will be offloaded at the same place then it does not matter which are placed where. If some of the cargo containers are to be offloaded in one location and the rest in another, however, you will need to stack them accordingly. That way, as few containers as possible will be moved to offload the correct ones.
Each Stacking Environment Has Different Needs
When determining proper stacking for shipping containers there needs to be consideration of where you are stacking them. Stacking containers on land requires slightly less work than stacking on a ship, for example. This is because the containers on a ship must be very careful of movement or potential damage and to maintain structure in a more difficult environment.
Stacking at a place of business requires careful consideration of buildings and other structures, however stacking at someone’s house requires additional care. Precision when using forklifts is always important, especially around buildings. It’s extremely important if there is something on site nearby that can’t be damaged.
Shipping Container Stacking Regulations
Regulations on stacking shipping containers vary slightly based on where you are or where your container is going. However, there are some general rules that are not only required, but make sense when it comes to safety.
- For safety purposes, you should always make sure that the crew person operating the forklift is certified.
- Never stack containers higher than eight tall to maintain structure.
- Always ensure corner posts are aligned on all stacks.
- Always use lashing rods to secure each unit and use other methods alongside if possible (including twist locks).
Let’s take a look at a few of the most commonly asked questions about getting started.
How high can you stack shipping containers?
You can stack up to eight pieces on top of each other and still maintain the overall structure and integrity of the stack. An amount greater than this height could make the entire load less stable and sacrifice safety. This could depend on other factors, however, including proper supports, the sea and winds. There is no set number of containers that can be on a single transport.
Can you stack a 20-ft container on a 40-ft?
It is possible to load this way however it is definitely not advised. The 20-ft container will not be as secure as the 40-ft, especially the higher it is on the stack. It is best to put two 20-ft containers below and then put a 40-ft unit on top of them to provide added security on each corner.
Can you stack open-top containers?
Open-top units are fitted with a roof once loaded, which means they are able to be stacked just like any other unit. The total height allowed would be the same once the roof is installed as this creates the necessary flooring with minimal limitations.
How much does a 10 foot shipping container weigh?
At 10 feet these units are approximately 2,200 pounds when unloaded. A 20 foot unit would weigh upwards of 3,970 pounds.
Stacking this type of unit takes practice and it takes attention to detail, meaning someone with experience, but it doesn’t have to be as difficult as you may think. Instead, take a look at the steps and make sure you’re stacking your smaller containers on the bottom or floor and lashing all of them together. From there, you’ll be doing great.
Make sure to leave us a comment at the bottom to let us know what you think and give us any information you might have about stacking.
Reviewing the stacking rules I note the limit is basically 9 high.
When did this rule change to allow the shipping lines to now stack 11 high both under deck and on-deck?