Steel coils are rolled steel sheet, whether hot-rolled, cold-rolled or galvanised. They are common on general cargo ships, MPPs and Handysize to Supramax bulk carriers, and on barges for short routes. Because the stowage factor is low, a hold reaches its weight limit long before its volume is used.
Heavy coils are usually stowed eye horizontal with the axis fore-and-aft, so they tend to roll sideways when the ship rolls and must be held with chocks, wedges and locking coils. Lighter or narrow coils are sometimes shipped eye vertical on pallets. The securing principles are set out in the CSS Code, including a dedicated annex for coiled sheet steel.
Besides shifting, the main threat is water and condensation. Cold steel carried into warm, humid waters can sweat and rust. Holds must be dry, ventilation must follow dew point readings, and dunnage must not be wet.
Cargo characteristics
| Parameter | Typical range |
|---|---|
| Weight per coil | ~5–30 t; hot-rolled usually ~10–25 t, cold-rolled often lighter |
| Dimensions | Outer diameter ~1–2.2 m; width ~0.6–2 m |
| Orientation | Eye horizontal fore-and-aft (eye to bow) for heavy coils; eye vertical (eye to sky) for light coils on pallets |
| Stowage factor | Low, roughly ~0.3–0.6 m³/t including dunnage |
| Load on structure | High line or point loads; transverse dunnage needed to spread them into the tank top |
| Sensitivity | Water, condensation and edge damage; cold-rolled and galvanised coils are most sensitive |
Stowage & securing principles
Rows on dunnage
Coils sit tight in athwartship rows on two or more lines of dunnage. Dunnage spreads the load and raises friction compared with steel on steel.
Chocks and wedges
End coils and coils not in contact are held by timber wedges on both sides. Gaps in the row are filled or chocked so the row cannot move.
Second tier and locking coils
Second-tier coils sit in the cradle between two coils below. A locking coil closes the row so the whole row locks together.
Row lashing
Rows open at the end or side are tied with steel bands or wire to ship structure according to the Cargo Securing Manual.
Friction and accelerations
Transverse forces from rolling are compared with friction and lashing capacity using the CSS Code method. Wet steel on steel provides almost no friction.
In containers and on flat racks
Coils in containers or on flat racks use timber cradles or saddles, are tied to lashing points, and are distributed within the container’s floor limits.
Pre-loading checks
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Weight, diameter and width of every coil from the packing list
Why it matters: Sets coils per row, tank top loads and the permitted number of tiers.
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Tank top load limits per hold
Why it matters: Coil line loads can exceed limits even when total hold mass is acceptable.
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Holds dry, clean and bilges working
Why it matters: Standing water and debris cause rust and reduce dunnage friction.
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Enough dry dunnage, wedges and steel bands
Why it matters: Short material leaves rows unlocked and securing improvised.
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Ventilation plan based on dew point
Why it matters: Wrong ventilation brings in humid air and triggers cargo sweat.
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Final GM and roll period
Why it matters: Low steel cargo makes the ship stiff with high accelerations that load the securing.
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Discharge order and crane SWL
Why it matters: First-port coils must be reachable and every lift must be within SWL.
Common risks
- Coils rolling and striking the hull because rows were not locked.
- Tank top deflection from line loads without enough dunnage.
- Rust from hold condensation or wet dunnage.
- A ship so stiff that violent rolling breaks the securing.
- Eye-vertical coils toppling because of weak pallets or banding.
- Coil edges damaged by unsuitable slings or forklifts.
Frequently asked questions
When are coils stowed eye vertical?
Eye vertical is mostly used for light or narrow coils shipped on pallets, including in containers. Heavy, wide coils are almost always stowed eye horizontal because they are more stable and the load spreads along the dunnage.
How many tiers of coils can be stacked?
It depends on coil weight, tank top strength and shipper instructions. Heavy coils are often stowed in one or two tiers only; the exact figure comes from the hold load limits and the ship’s Cargo Securing Manual.
Are STOWAGE.ID results for coils an official calculation?
No. Deck load and stability checks are shore-side planning. The Cargo Securing Manual, the class-approved onboard loading computer and the stability booklet remain the official reference.
General guidance for education. Follow the vessel’s Cargo Securing Manual, the shipper’s instructions and the surveyor’s directions.
Shore-side planning & decision support. The class-approved onboard loading computer remains the official reference.