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The Safest Way to Stack Shipping Containers

How many shipping containers can you stack?
Are you a pro when it comes to stacking shipping containers? Are you highly skilled at safely stacking cargo containers? If you’re an employer, are your dock or shipyard workers expert at stacking shipping containers? If not, this blog contains helpful ideas on how to avoid accidents, injuries and costly fines from OSHA.

Where would the business world be without shipping containers? They allow products to be transported all over the world safely and in a cost-effective manner. They are easy to unload and store and they can carry almost any kind of product that needs to be shipped. No matter how they are being used, the key is to stack them safely.  If your job involves stacking cargo containers, you need to know how to do it the right way.

It seems easy enough. And OSHA provides clear guidelines for shipping container safety. Yet, many companies aren’t sure how to stack containers, let alone do it safely. (FLC), the leader in online forklift training, offers complete courses on forklift safety. These can help your workers stack shipping containers safely and correctly. If you want to create a safer workplace, sign up for our forklift training classes. You can save a bundle by bundling our Forklift Train the Trainer and Forklift Operator Training programs.


In the meantime, here’s what you need to know about:

  • Safely stacking shipping containers
  • Shipping container stacking height
  • How many shipping containers you can stack
  • How to inspect shipping containers
  • Stacking best practices
  • And more



Stacking cargo containers once they’re off the boar raises many questions. How many containers can you stack on top of each other? What is the top shipping container stacking height? What are the proper techniques for stacking on land?  How do shipping containers stack when on dry land?

Correct stacking techniques revolve around two key factors. Let’s start with the basics.

  • No height requirements.

On land, there is no maximum container shipping stacking height. However, stacking height should always be within reason. First, check your company’s procedures for stacking onsite. These will likely vary for stacking on warehouse shelves, open land, and elsewhere. Next, determine the max safe container shipping stacking height. This should align with where you will stack the containers and the type of lifting equipment you use.

  • Stability.

An open sea voyage creates a tougher stacking environment. Stacking cargo containers on land is much more stable. Yet, when stacked too high, containers pose their own set of safety hazards. Their large dimensions and heavy weight can create a high level of risk even when not bouncing around on the waves.


As a rule of thumb, always check with your site’s safety personnel before stacking shipping containers.



Recommended stacking techniques on land include:

  • Inspect the containers.

Always inspect shipping containers before stacking them. Make sure their structure is sound and they have no visible cracks or dents. Check the sides, sub-flooring, and corners posts for signs of wear-and-tear or damage. Look for rust on the inside and out. On long ocean transits, weak containers can damage products and put the crew at risk. Repair or replace any units that show structural damage of any type.

  • Stack using the corner posts.

Containers should be stacked corner post to corner post to be the most secure. The four corner posts of a container should align with the corner posts of the container above and below it. When stacking containers of different sizes, the larger containers go on top of smaller ones. Placing smaller containers on top runs the risk of falling through.

  • Use lashing rods to prevent sliding.

When on a truck or ship, lash containers together with lashing rods. This will keep them from sliding while in transit. Adding twist-locks to the containers will increase stability. It will also reduce the chances of an accident.

  • Use only trained and certified forklift operators.

Handling a forklift requires skill and training. It also involves a certain amount of risk. Forklifts are bulky and slow-moving. But even at slow speeds an impact can cause damage to people, products, and equipment. Forklifts can also tip over, which can cause fatal accidents. It’s against the law to use untrained forklift workers who aren’t certified. It can also cost you a lot of money if you get cited for an OSHA violation. Get certified today with FLC training packages!



How do shipping containers stack on a ship? As you might expect, stacking techniques on the high seas are different than on land.

  • Choose the correct on-board stowage for the vessel.

There are two types of stowage on a container ship. One is “fore and aft”. The other is “athwartships”. Fore and aft is lengthwise stowage, with the container pointing from front to back. Athwartships is horizontal stowage, with the containers stowed sideways. The type of stowage can depend on the size of the ship and the travel conditions. Fore and aft offers better protection against high winds, crashing waves, and rough seas.

  • Stack using the corner post method.

When stacking like-sized containers on top of each other, line them up corner-post to corner-post. The corner posts should sit a bit lower than the bottom of the container and a bit higher than the top.  The corner-posts and flooring of the container are designed to bear the weight of the container and those above it. When stacking different sizes, put the smaller containers on the bottom. That way, all four corner-posts of the larger top container have corner-posts to set on.

  • Secure the containers against slipping and toppling.

Travel on the sea is much rougher than travel on land. This makes it even more important to secure the containers against slipping and sliding. Cell guides with vertical guide rails can help keep containers in place. They also help ease the pressure of top stacked containers on the bottom ones. Lashing rods and twist-locks are also used to secure the containers to the vessel and the container underneath. This helps prevent slippage.

  • Choose the right lifting equipment.

Forklifts are often used to stack containers on ships. But it depends on the type of forklift and the height of the stack. Container forklifts are designed to handle 20’ and 40’ containers. Forklifts with forks may not be able to do the job. Check the capabilities of your forklift before using it to stack containers. If it isn’t suitable, you may need to rent a crane.

  • Container Stacking Safety

Many factors determine the safest methods for stacking shipping containers. The most important is making sure forklift workers are trained and certified. This includes knowing how to minimize the risk of accidents and damage.


FLC has all the forklift training your business needs to comply with OSHA guidelines. No matter where, when or how you use forklifts, we cover all the key safety practices. And we do it in an easy-to-learn format. Visit our course pricing page to get started today.

Updated on January 2020

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