One unit: 6.2 m long, 3.1 m wide, 3.4 m high, 28 tonnes. Destination Houston. The first question from the shipper was whether it could go in a 40HQ to save the flat rack premium. It cannot, and the reason is arithmetic, not opinion.

A 40HQ has about 12.03 m of internal length, 2.35 m of width and 2.39 m of height, with a door opening of roughly 2.34 × 2.58 m. A 3.1 m wide, 3.4 m high machine does not pass the door, let alone the walls. This article covers one cargo type only: out-of-gauge machinery on a flat rack. Open top is a different discussion.

Step 0: measure against the envelope, not the website

Use the actual packing dimensions, not the catalogue. If any dimension exceeds the container envelope, the choice is flat rack, open top or break bulk — and for a 3.1 m width the answer is flat rack with carrier approval.

  • Length over 12.03 m, width over 2.44 m, height over 2.59 m: out of gauge
  • Flat rack deck is typically 2.44 m wide; anything beyond that is over-width
  • Payload is not the container's nominal capacity; check the carrier's flat rack limit and the road leg limit

Step 1: book earlier than you think

Out-of-gauge space is deck space, and it is approved by the carrier, not by the booking system. Allow 7–14 days before the cut-off; some carriers want 10 working days for over-width or over-height units. Booking late means the flat rack is confirmed and the vessel is not.

Step 2: get the dimensions into the booking

Send the carrier the length, width, height, weight, centre of gravity and lifting points. The booking confirmation must show the OOG dimensions and the flat rack type. If the B/L later shows “1×40FR” without the dimensions, the destination terminal may re-measure and re-rate the cargo.

Step 3: agree the lashing plan before loading

Lashing is engineering, not rope. The plan should state the lashing points on the machine and on the flat rack, the angle (typically 30–60 degrees), the timber dunnage, and the calculated maximum securing load. A third-party survey before sailing is normal for over-width units; some carriers require it.

Step 4: prepare the documents

  • Dimension drawing or dimension sheet, signed by the shipper
  • Weight per piece and total, plus centre of gravity
  • Lifting points and lifting method
  • Packing list and commercial invoice
  • Carrier booking approval showing OOG dimensions
  • Lashing plan and, where required, survey report
  • Photos before lashing, after lashing and at gate-in
  • Dangerous goods declaration if the unit carries batteries or fuel

Step 5: the loading checklist

  1. Confirm flat rack type, payload and deck condition at the yard
  2. Place timber dunnage and check the deck is dry and clean
  3. Position the unit so the centre of gravity sits over the deck centre
  4. Apply the lashing plan: number of points, angle, tension
  5. Fit protection at contact points; no welding without carrier approval
  6. Third-party survey and sign-off, with photos at each stage
  7. Record final dimensions and weight on the tally sheet
  8. Seal, gate-in, and confirm the B/L remarks carry the OOG dimensions

Where these files usually go wrong

  • Quoted as standard FCL, then the flat rack premium and OOG surcharge arrive later
  • Booking made without carrier approval; the unit is rolled at the cut-off
  • Lashing done at the port by stevedores with no approved plan
  • Centre of gravity not declared, so the unit sits off-centre and cannot be stacked or lifted safely
  • Road leg not checked: the port can take 3.1 m, the truck to the site cannot without a permit

For an out-of-gauge unit, the quote is the smallest part of the work. The flat rack type, the approval, the lashing plan and the survey are what decide whether the unit sails on the booked vessel.

If you have a dimension sheet, send it over WhatsApp with the destination. We will confirm whether it is flat rack, open top or break bulk, and what the carrier will ask for.