Export packaging for sea freight vs air freight – differences in materials, costs and risks
A customer calls with the question: “I need to send a MV switchgear to Saudi Arabia – by sea or by air?” The answer is never simple, because the choice of transport mode triggers a chain of consequences regarding packaging materials, crate design, costs and risks. Packaging that works perfectly on a ship will be unnecessarily heavy and expensive on a plane. Conversely, a lightweight air freight crate will not survive four weeks in a container on the Indian Ocean. In this article, we break these differences down into their constituent parts – from the perspective of a company that packs for both modes of transport on a daily basis.
The transport sector – why the type of freight makes all the difference
What lies ahead for the cargo at sea
Sea transport involves the longest exposure of cargo to harmful factors. A container on a ship remains at sea for between two and eight weeks, depending on the route. During this time, the goods are exposed to relative humidity of up to 95%, salty air that accelerates corrosion, and condensation – known as ‘container rain’ – which occurs when the outside temperature drops at night and moisture condenses on the container ceiling and drips onto the cargo.
Added to this are mechanical stresses: the ship’s rolling generates lateral accelerations of up to 0.8 G, port handling by gantry cranes causes impacts and jolts, and the stacking of containers on deck means that compressive forces may act on the crate from above. In our experience, we have seen containers where unsecured boxes have shifted by over a metre – damaging both the goods and adjacent cargo.
What lies ahead for cargo in the air
Air transport takes less time – between one and five days – which drastically reduces the duration of exposure to the elements. The cargo spends no more than a few hours in the open air (airport apron, transfer belt). Humidity and salt content therefore do not pose a significant risk. The main risks are jolts during loading and unloading on cargo conveyors, vibrations during flight, changes in atmospheric pressure (the cargo hold is not always fully airtight) and the need to comply with strict weight limits.
Every kilogram of packaging in air freight directly affects the freight cost – air freight rates are calculated per weight or volume kilogram (volumetric weight: length × width × height in cm / 6000). That is why optimising the weight of the packaging is the number one priority in air freight, which cannot be said of sea freight, where freight is charged by volume (CBM) and a few dozen kilograms more or less per crate makes no difference to the cost.
Packaging materials – what to use for sea travel and what for air travel
Corrosion protection
In export packaging for sea transport, corrosion protection is absolutely essential. We use full vacuum packaging in barrier aluminium foil (ALU), heat-shrink film and VCI (Volatile Corrosion Inhibitors) film. VCI film releases volatile inhibitors which settle on metal surfaces and form an invisible protective layer – effective even at humidity levels exceeding 90%. Inside the packaging, we place desiccants (silica gel or bentonite) in quantities tailored to the volume of the package and the planned transport time – usually 30–50 g per dm³ of free space. Components protected in this way can withstand up to 24 months without corrosion.
In air freight, the situation is quite different. The short transit time (1–5 days) and the controlled conditions in the cargo hold mean that full vacuum packing is usually unnecessary. It is sufficient to wrap the goods in VCI film (without an aluminium layer) and include a basic quantity of desiccants. Aluminium barrier film – which is heavier and more expensive – is not needed, as the cargo is not exposed to salty air or temperature fluctuations lasting several weeks. Doing away with aluminium foil and vacuum packing reduces the weight of the packaging by several to over ten kilograms – which, given air freight rates, results in a tangible saving.
Design of the transport crate
For maritime transport, we design solid-walled transport crates made of solid wood, often reinforced with steel corner fittings. The base is fitted with skids whose cross-section is tailored to the weight of the load and the method of handling (forklift, crane). The crate must withstand the lateral accelerations caused by the ship’s rolling motion. The whole structure is sturdy, but also heavy.
We take a completely different approach to aircraft construction. We build the fuselage using waterproof plywood, OSB boards, or a combination of solid timber and plywood. The structure is up to 40–60% lighter than its maritime counterpart with the same internal dimensions. We opt for aluminium or plastic reinforcements instead of heavy-duty steel fittings. The skids are lower and narrower. The aim is to minimise gross weight whilst maintaining sufficient mechanical protection during loading, flight and unloading.
Securing the load inside the box
In maritime transport, the securing system must withstand forces acting in all directions – the cargo must not shift even when the vessel is listing up to 45 degrees. We use solid wooden wedges, steel brackets welded to the base, straps with tensioners, and high-density PE foam. Each securing point is selected to suit the weight and dimensions of the component.
In air transport, the main risks are vertical shocks (turbulence, landing) and lateral shocks (braking on cargo conveyor belts). We use lighter cushioning materials: polyethylene foam, anti-vibration pads and securing straps. We replace wooden wedges with moulded foam inserts, which both cushion and secure the load – and weigh a fraction of what wood does.
Cost comparison – how much does it really cost to pack for a sea or air journey?
The costs of export packaging fall into two categories: the cost of the packaging itself (materials + labour) and the impact of the packaging’s weight and volume on freight costs. And this is where the paradox begins, one that surprises many customers.
Packaging cost
Sea freight packaging is more expensive than air freight packaging. It requires more material: a thicker solid wood crate, aluminium barrier film, vacuum packaging (sealing machine, pump), and a greater quantity of desiccants. In our projects, the cost of sea freight packaging is 20–50% higher than that of air freight packaging for the same component. The difference increases for corrosion-sensitive cargo, where full vacuum packaging in aluminium barrier film and VCI film is mandatory.
The impact of packaging on freight costs
Here, the situation is reversed. Sea freight is charged by volume (CBM – cubic metre). A few dozen kilograms more in a crate does not affect the rate. Air freight is charged by the kilogram – either by actual weight or volumetric weight (volumetric weight: length × width × height in cm / 6000), with the higher of the two values being used for billing.
An example from our experience: a control cabinet weighing 120 kg. Sea freight packaging – a solid wood crate, vacuum-packed with aluminium barrier film and VCI film, plus desiccants – adds 45 kg to the weight. Air freight packaging – plywood crate, VCI film without aluminium, lighter fastenings – adds 18 kg. A difference of 27 kg at an air freight rate of €5/kg equates to €135 in savings on freight alone. For a batch of 20 cabinets, this amounts to €2,700 – a sum that covers the cost of professionally redesigning the packaging for the air freight option.
When air freight is cost-effective despite higher freight charges
Air freight is many times more expensive than sea freight (roughly 8–15 times per kg), but in many situations it is the only sensible option. A delay in getting the customer’s production line up and running costs them thousands of euros a day in lost revenue. If sea freight takes 5–6 weeks and air freight 3 days, the 5-week difference may justify even very high freight costs. In such cases, lightweight air freight packaging – which is cheaper and quicker to produce – is a further argument in favour of choosing air transport.
Risks – what most commonly goes wrong at sea and in the air
The main risks in maritime transport
Corrosion. Number one. Salt-laden air and condensation inside containers will corrode unprotected metal surfaces within 2–3 weeks. Without VCI film and aluminium barrier foil, damage is almost inevitable.
Shift of cargo within the container. Inadequate securing of crates inside the container (lack of dunnage, straps or wedges) leads to cargo shifting during a storm. That is why we combine packing with container stowage services, thereby eliminating this risk.
Mechanical damage during handling. Crates are lifted by cranes, moved along rollers and stacked using forklift trucks at transhipment points. Each of these stages involves jolts and impacts.
Long response times to damage. If something goes wrong, the recipient only finds out 4–8 weeks later – once the container has arrived at its destination port. Complaints, repairs and reshipment mean months of delays.
Key risks in air transport
Shocks and drops on the cargo ramp. Air parcels are handled manually or on conveyor belts, which creates a risk of them being dropped. A lightweight box without adequate internal padding will not protect delicate electronics.
Changes in pressure and temperature. An aircraft’s cargo hold is not always completely airtight. A drop in pressure at cruising altitude and temperatures as low as -30°C can damage components that are sensitive to temperature fluctuations – such as plastic parts or LCD displays.
Weight and size restrictions. Exceeding the weight or size limits for a particular aircraft type will result in the shipment being refused. Packaging designed with a ‘safety margin’ – i.e. too heavy or too large – may disqualify the shipment from air transport.
Dangerous goods (DG). Certain materials used in packaging (e.g. calcium chloride-based desiccants) may be classified as dangerous goods for air transport. This requires additional documentation and certification – or substitution with materials approved for air freight.
Comparison of differences – sea freight vs air freight
| Parameter | Sea transport | Air transport |
| Transit time | 2–8 weeks | 1–5 days |
| The main threat | Corrosion, damp, container rain | Shocks, pressure changes |
| VCI film | Multi-metal – compulsory | Standard – recommended |
| ALU barrier film | Mandatory (vacuum-packed) | Unnecessary in most cases |
| Moisture absorbers | Large quantities + container loads | Minimum quantity |
| Body type | Solid wood, 18–25 mm thick | Plywood/OSB, 9–12 mm |
| Package weight | Higher (reinforcements, ALU, solid wood) | 40–60% lower |
| Packaging cost | 20–50% higher | Lower |
| Impact on freight costs | Minimum (CBM) | Direct (per kg) |
When to choose sea freight and when to choose air freight – practical tips
There is no one-size-fits-all answer – we assess each order on a case-by-case basis. However, based on hundreds of completed projects, we can outline some typical scenarios. We choose sea freight when: delivery time is not critical (the recipient accepts 4–8 weeks), the cargo weight exceeds 500 kg (air freight would be uneconomical), the goods can withstand prolonged exposure (provided they are properly packed), or when the shipment comprises multiple units in a single container. Air freight is the better choice when: time is of the essence (a breakdown on the recipient’s production line), the component is light but valuable (electronics, controllers, sensors), or when the project schedule does not allow for a wait of several weeks. In both cases, the key is to select packaging suited to the type of freight – and this is precisely what we do as part of our export packaging service.
Frequently Asked Questions (FAQ)
Can I use the same luggage for both sea and air travel?
Technically, yes, but this is sub-optimal in both respects. Sea-worthy packaging will be too heavy for air transport (unnecessarily increasing freight costs), whilst air-worthy packaging will not provide sufficient corrosion protection at sea. We design dedicated packaging for each mode of transport – the cost of the design difference is many times lower than the losses resulting from the use of unsuitable packaging
How much heavier is sea freight packaging than air freight packaging?
With the same internal dimensions, marine-grade packaging is 40–60% heavier. This is due to a thicker solid wood box (as opposed to plywood or OSB), steel fittings (as opposed to aluminium or none at all), aluminium barrier film, and a greater quantity of moisture absorbers. For a control cabinet weighing 120 kg, the difference is approx. 25–30 kg.
Is VCI film necessary for air transport?
We always recommend it for metal components, even during air transport. Although the risk of corrosion is significantly lower, VCI film provides additional protection in the event of delays (such as cargo waiting on the ramp or being held in a customs warehouse). However, we use VCI film without an aluminium barrier layer, which reduces weight and cost.
How much does it cost to ship by sea rather than by air?
Sea freight packaging is 20–50% more expensive than air freight packaging – mainly due to vacuum packing in aluminium foil, a thicker crate and a greater amount of protective materials. However, the savings on air freight packaging are partly offset by the higher freight cost per kilogram. We select the optimal option on a case-by-case basis, calculating the total cost: packaging + freight.
Are wooden crates permitted in air transport?
Yes, provided that the IATA requirements for cargo packaging are met. The timber must be ISPM 15 certified (for international routes). Crates must not contain materials classified as dangerous goods (DG) without the appropriate documentation. Weight and size limits depend on the type of aircraft and the airline.
How quickly can you prepare the goods for air freight?
We usually process air freight packaging more quickly than sea freight packaging – typically within 2–3 working days. Lighter crates require less material and take less time to produce. For urgent orders, we offer an express service with a turnaround time of 24 hours.
Summary
The difference between export packaging for sea and air transport cannot be reduced to a single factor – it is a different philosophy of packaging design, resulting from fundamentally different risks, exposure times and cost structures. At sea, the priority is corrosion protection and structural strength; in the air, it is low weight and shock absorption.
The key to finding the best solution lies in analysing the specific order: what we are packing, where it is going, by when, and by what means of transport. At Danpol, we handle both scenarios on a daily basis – we have the materials, facilities and experience to tailor the packaging to the type of freight, rather than the other way round.
Not sure whether to choose sea or air freight? Get in touch with us– we’ll analyse your request and suggest the best packaging option.
