Most enquiries we receive give us dimensions and a weight. That is enough to quote something, but rarely enough to quote the right thing — and the gap usually shows up later as a crate that is stronger and more expensive than it needed to be, or one that fails in a way nobody anticipated.
Here is what actually determines the design.
1. The dimensions of the item, not the crate
Give us the item and let us design around it. If you specify the crate's external dimensions, you have already made decisions about wall thickness, clearance and bracing on our behalf — usually conservatively.
Include anything that projects: handles, spigots, control boxes, protruding shafts. These drive internal clearance more than the main body does.
2. Weight, and where it sits
The total weight matters, but the centre of gravity matters more. It determines where fork pockets and lifting points go — they must be arranged symmetrically relative to the centre of gravity, or the crate will tip during handling regardless of how strongly it is built.
If the load is off-centre, tell us. It is the single most common cause of a handling incident with an otherwise sound crate.
3. How the item stands
Does it rest on legs, a flat base, or a small footprint? This changes the base design fundamentally. Where the item has a narrow standing area, the load needs distributing across all the skids with crosspieces, otherwise you get point loads that punch through the floorboards.
We also need to know whether the item can be bolted down. Fixing the contents to the base — with screws running through into the skids — is what stops it shifting and tipping. Items that cannot be fixed have to be held by tight fit and blocking instead, which is a different and usually bulkier design.
4. Where it is going, and how
Road within the EU, sea freight, or air? This decides three things at once: whether ISPM 15 treatment is needed, how much moisture protection the design must carry, and what accelerations the packaging has to survive.
The differences are not marginal. Road transport securing is calculated against 0.8 g forward, while rough-sea conditions bring sustained transverse accelerations and repeated reversals. A crate designed for a domestic delivery is not automatically a crate that survives the North Atlantic in February.
5. Whether it will be stacked, and by whom
Stack pressure from above is one of two major forces the base has to absorb — the other coming from below, from forklifts and slings. If crates will be stacked two or three high, or if a freight forwarder might stack them without asking, say so.
This also determines lid design. Lid girders sitting directly on battens create point loads that cave the battens in under stack pressure; internal posts or purpose-made connectors solve it, at a cost.
6. How it will be lifted
Forklift, crane slings, or both. Crates lifted by slings need provision designed in — typically notches in the skid ends — because passing cables around an undesigned crate crushes the ends, and a short cable concentrates that crushing on the top panel.
It is worth stating the obvious here: long slings crush less than short slings. If your consignee's crane setup is known to be tight, tell us and we will reinforce where the cables will actually bear.
7. Storage before and after
How long will the crate sit before it ships, and where? Outdoor storage before departure is one of the most common causes of mould appearing on packaging that left our yard clean. Similarly, if the consignee will store the crate outdoors for months, the specification should reflect that rather than assuming prompt unpacking.
8. Whether it comes back
One-way or returnable changes the construction entirely — fastening method, whether panels are demountable, and how much you should invest per unit. It is worth deciding deliberately rather than by default. Under ISPM 15, a treated and unaltered crate keeps its mark for its whole service life, so a returnable crate does not need re-treating on every trip.
A few construction facts worth knowing
These come up constantly in specification conversations:
- Crate or box? An open crate is a framework; a box is fully sheathed. As a rule of thumb, crates stop being the right answer above about 1000 kg of contents — beyond that, boxes are used because a crate no longer provides sufficient stability.
- Diagonal bracing should meet the horizontal members as near 45° as possible, and never outside 30–60°. Two crossing diagonals make a panel considerably stronger than one. Above 1500 mm internal height, diagonals stop being optional.
- Vertical boarding absorbs vertical forces better than horizontal boarding, and on side walls vertical batten spacing should not exceed 1000 mm.
- Container floors have limits. Line load is capped at roughly 4.5 t/m for a 20 ft container and 3.0 t/m for a 40 ft. A 16-tonne item over 4 m is fine in a 20 ft and not permitted in a 40 ft — which is exactly the sort of thing that is cheaper to design around than to discover at the terminal.
What good looks like
The best enquiries we get are a drawing or photo of the item, its weight and centre of gravity, the destination and mode, and one sentence about what happens at each end. That is usually enough to design something that is right rather than merely strong — and to tell you honestly where you could spend less.
