Seaworthy Shipping Containers

Seaworthy Shipping Containers

In this article, we provide some background information about what it is that makes a shipping container seaworthy, how its inspected and what type of repairs can be done to a container to make it seaworthy.

Basically, a shipping container is a large metal box that was originally designed to reduce the number of handling operations involved at ports. Quite simply, cargo would be off-loaded at the port, moved quay side and then loaded by crane into the hold where dockers would then move the cargo in to place.

Whilst ‘containerization’ originated several centuries ago, the true birth of the ‘intermodal’ shipping container was envisioned by Malcom McLean who grew increasingly frustrated at how long it took to load cargo on to and off a ship.

Today’s shipping containers are regulated by their own ISO standard that determines their sizes and tolerances. This is used to determine seaworthiness and ensures that containers built in one factory will stack on to containers from another.

Shipping Container Design and Structure

Used 40ft open top container with tarpaulin

Standard size shipping containers are designed and manufactured to international standards as set out within the International Convention for Safe Containers (CSC). This Container Safety Convention was drawn up by the IMO (International Maritime Organisation) in conjunction with the EEC. These standards ensure compliance between manufacturers and that the container itself is thoroughly tested prior to use.

Every new container design or indeed, modification, must have a prototype built that is then submitted for rigorous and very expensive testing. The results of these tests are then reviewed by one of a few recognised classification societies who ensure compliance and that the testing and inspection methods are accurate and standardised.

Maintenance and Repair of Shipping Containers

One of the main contributory factors in what makes a used shipping container seaworthy is the standard of the repairs carried out. Container repairs are the responsibility of the containers’ owner and one complete, the container has to be inspected to ensure all works have been carried out to the required standard.

Of the estimated 12 – 16 million shipping containers in use at this time, the majority of these are owned either by shipping lines or leasing companies.

Currently, there are two container maintenance programmes in use that ensure that all repairs have been undertaken to the required standard, that they have been looked after correctly and are classified as seaworthy. These are PES and ACEP, or The Periodic Examination Scheme and the Approved Continuous Examination Programme.

Any container within the periodic examination scheme will typically have a white sticker on the CSC (Container Safety Convention) plate that has an expiry date. In most cases, new containers will usually have this ‘stamped’ on the metal plate. When inspected, the examiner will only add an up-dated CSC sticker if the container passes inspection. Whilst some containers may be subjected to a periodic examination, and get a 3-year CSC sticker, other may only be issued with a sticker that’s valid for 3-months.

Whilst a 3-months CSC sticker is the minimum that’s normally given, our used containers come with a CSC plate that’s valid for 6-months. The maximum ‘validity’ given to a container is one that was just left the factory and these are usually valid for 5-years. Please note thought, that the date on the CSC plate is not necessarily an indicator as to the quality of the container. Very much the same is true for an MOT. For example, just because a car has 6-months left on its MOT, it is not necessarily of a better quality than a car with just 1-month left on it. Everything is very much dependent on how each vehicle has been handled and cared for since it was last tested.

20ft used shipping container

Any container that’s subject to the continuous examination program, will have the owner’s own and unique ACEP number applied to it. In some cases, this is in the same place as the CSC expiry sticker. And, every time a container goes in to one of their depots it will be checked and professionally repaired.

The CSC plate is very much like the MOT as it only indicates it was good at time of inspection. So, if someone hits the container with a forklift after its been issued with a CSC sticker, any shipping line, container facility or port will reserve the right to refuse the container on the grounds of safety or their belief that it is not seaworthy. Likewise, any company involved in the entire shipping process will reserve the right to refuse to handle your container if they believe that the safety of their staff will be compromised.

Ultimately, it is the responsibility of the containers’ owner to have all repairs carried out to the required standard. Whilst this system may have flaws, very much like the MOT system, it does mean that issues with structural integrity are very rare within the industry.

Container repairs to seaworthy standards

Besides the two procedures mentioned above, that are also two main types of repair standards that are used to ensure seaworthiness.

The majority of shipping lines have their containers repaired to the Unified Container Inspection and Repair Criteria (UCIRC) standard as issued by the International Chamber of Shipping (ICS). Whilst leasing companies and their customers work to a similar set of standards that were issued by the International Institute of Container Lessors (IICL) within which, leasing companies can elect to meet a number of grades numbered 1 through 5. In general, grade 5 is the lowest standard and therefore the cheapest in terms of repair costs. So, if you do buy containers direct from a leasing company, they will have been repaired to the lowest grade (5). In fact, its very rare for container to be repaired to anything higher than grade 5 these days. In fact, the higher grades were ultimately deemed to have been too strict. In brief, IICL grade 5 is broadly similar to the UCIRC standards that outline the requirements for a structurally sound and therefore safe shipping container.

Whilst there are other repair standards, the above are the two most widely used and recognised standards in the world.

Please note that adherence to repair standards is no guarantee of the overall look of the containers. Cosmetics are irrelevant in the world of shipping. Only the structural integrity matters thus ensuring the container had the capacity to securely and safely transport goods around the world.

How do I get my container checked to see if its seaworthy?

If you own your own container, getting it moved to a depot, professionally repaired to a seaworthy standard and then delivered back to you is rarely going to be a viable options. If your container is in a relatively good condition, we might buy it back from you. That was, we cover the cost of collecting and repairing the container. You can then choose to buy a shipping container from us with a valid CSC plate but do specify you want a CSC plated container when ordering from us or anyone else for that matter.

to check your container is seaworthy, there should be a small metal plate welded onto the container doors with the containers technical information on. this is called the CSC plate. On this plate there should be a CSC expiry date and of course you must ship within this date (subject to your specific shipping lines regulations). The export date on the metal plate may have an update sticker (a sticker with a new expiry date on it) if it has been checked over again since leaving the factory.

If the CSC plate has no clear expiry date, then either it is not suitable for export use or perhaps it has an ACEP approval for export use. The acept scheme is an accredited continuous examination protocol used by shipping lines with their own containers. If there is an ACEP number on your shipping container, the ACEP owner will allow you to export this only if you meet their specific criteria for exporting the container, normally the stipulations are that you ship the container within 12 months of purchase and that no significant wear or damage has been caused in the 12 months since purchase. This is a very brief summary of a technical area, however you should not attempt to ship a container under ACEP unless you have purchased it direct from a professional trader, and you must ship it promptly (your supplier will be able to advise on any time limits)

Be very careful if looking to buy a seaworthy shipping container from eBay or any other private sales or classified ads. Members of the public may advertise a shipping container as ‘csc plated’ as there is a metal plate on the doors that will say it is csc plated – however many private sellers will not realise that a recent inspection needs to have been undertaken for any container to be exported.


If you have any questions about this article, our products or service please call our friendly team for free on 0800 999 8988 any time 08:30-19:00 weekdays or send us a message via the contact form on this website and we will get back to you.