- type
- concept
- created
- Tue Apr 07 2026 02:00:00 GMT+0200 (Central European Summer Time)
- updated
- Tue Apr 07 2026 02:00:00 GMT+0200 (Central European Summer Time)
- sources
- raw/articles/PRD
- tags
- container shipping logistics specifications
Container Types and Weights
Overview
Container specifications are fundamental to the container assembly algorithm and fill optimization. Paper is a dense commodity, so weight limits are typically reached before volume limits. The marketplace must respect these physical constraints when proposing container loads.
Container Specifications
| Container Type | Internal Dimensions (L x W x H) | Max Payload | Paper Capacity | Primary Use Case |
|---|---|---|---|---|
| 20ft Standard | 5.9m x 2.35m x 2.39m | 21,700 kg (21.7 MT) | 18-22 MT | Small orders, intra-EU truck shipments |
| 40ft Standard | 12.0m x 2.35m x 2.39m | 26,680 kg (26.68 MT) | 24-26 MT | Standard international shipping |
| 40ft High Cube | 12.0m x 2.35m x 2.69m | 26,460 kg (26.46 MT) | 24-28 MT | Large diameter rolls (extra 30cm height) |
Algorithm Target Weights
The container assembly algorithm uses target weight ranges that are more conservative than the hard maximums to account for packaging, dunnage, and loading practicalities:
| Container | Target Min | Target Max | Hard Max |
|---|---|---|---|
| 20ft | 15.0 MT | 21.0 MT | 21.7 MT |
| 40ft | 18.0 MT | 26.0 MT | 26.68 MT |
| 40ft HC | 18.0 MT | 26.0 MT | 26.46 MT |
Minimum utilization is 70% -- the algorithm will not propose a container that is less than 70% full. For a 40ft container (26.68 MT max), this means at least ~18.7 MT.
Loading Considerations
Roll Orientation
Paper rolls can be loaded in two orientations:
- Eye-to-sky (standing on end with core vertical): Standard for rolls > 800mm diameter. Max stack height is 2,390mm for standard containers and 2,690mm for high cube.
- On side (laying flat): Used for narrow or light rolls. Requires blocking and bracing to prevent shifting.
Stacking
- Maximum rolls stacked = container internal height / roll diameter
- Bottom rolls must have sufficient crush resistance to support upper rolls
- Dunnage (protective material) placed between roll tiers
Protection
- Edge protectors required to prevent damage during transit
- Moisture barriers (VCI or PE wrap) mandatory for ocean freight
- Blocking and bracing to prevent load shift
Standard Roll Diameters
| Roll Type | Diameter Range |
|---|---|
| Full reel | 1,200-1,500mm |
| Partial reel | 400-800mm |
| Standard | 800-1,500mm |
Weight vs Volume
For paper cargo, weight is almost always the binding constraint. Paper density means that a container will reach its weight limit well before it runs out of physical space. This simplifies the bin-packing problem to primarily a weight-addition problem rather than a 3D spatial packing problem.
The 40ft High Cube provides 30cm more height (2.69m vs 2.39m) but slightly less maximum payload (26.46 MT vs 26.68 MT). It is primarily useful when shipping large-diameter rolls that need the extra stacking height.
Freight Economics
The freight cost per metric ton drops dramatically when a container is fuller:
| Scenario | Freight Cost | Per MT |
|---|---|---|
| 8 MT in a 40ft container | ~EUR1,200 | EUR150/MT |
| 26 MT in a 40ft container | ~EUR1,200 | EUR46/MT |
This 69% reduction in per-ton freight cost is the core economic argument for the marketplace's container assembly feature. The container flat rate is roughly the same whether it carries 8 MT or 26 MT -- only the per-ton economics change.
Sources
- raw/articles/PRD -- section 8.2 (Container Specifications), 8.5 (Roll Loading Constraints)
Related
- wiki/concepts/container-assembly -- uses these specs for bin-packing
- wiki/concepts/container-fill-optimization -- LCL vs FCL freight comparison
- wiki/concepts/incoterms-in-paper-trading -- shipping terms affect who pays freight