Offshore Containers and Baskets

What makes a container "offshore"

An offshore container is lifted in open sea, from a moving vessel deck to an installation crane. Snatch loads, side impacts and dropped landings put far higher forces on it than port handling. Its structure, padeyes and lifting set are therefore designed, prototype tested and certified to offshore standards. DNV-ST-E271 (formerly DNV 2.7-1) covers offshore containers up to a maximum gross mass of 25,000 kg.

Configurations

• Cargo baskets, long and short, with open tops
• Closed containers with doors, for general cargo and stores
• Open-top and half-height containers for pipe, tools and loose items
• Waste skips and compactor units
• Bulk containers for dry powders
• Tank frames for fuel, chemicals and helicopter fuel
• Gas cylinder racks with secured cylinder bays

Key specifications

Standards and certification

DNV-ST-E271, EN 12079 and ISO 10855 cover the same ground. EN 12079 and ISO 10855 each come in three parts, for design and manufacture, lifting sets, and periodic inspection, examination and testing. IMO MSC/Circ.860 sets the IMO guidelines for approval of offshore containers. A container that also travels as an intermodal box needs a valid CSC plate under the International Convention for Safe Containers.

Each certified container carries a data plate with its maximum gross mass, tare, payload and certificate number, and an inspection plate marked at each periodic inspection. The plate details must match the certificate.

Failure modes and inspection

• Cracks at padeye welds and wear in the padeye hole. Inspect visually every year. NDT, often eddy current through the paint, follows at longer intervals, commonly 48 months.
• Distorted corner posts, bottom rails and floors from heavy landings. Check against the original drawings.
• Corrosion in floors, drains and box sections. Take thickness readings where in doubt.
• Doors, hinges and locking bars that bend or seize, and loose items left on the roof.
• Undocumented weld repairs to primary structure. Any approved repair needs testing before return to service.
• Lifting set damage, such as broken wires, deformed shackles and missing pins.

Periodic inspection runs at least every 12 months, done by an inspection body recognised under the standard.

Documentation

• Container certificate with certificate number matching the data plate
• Design approval or type certificate for the container design
• Latest periodic inspection report and the dates marked on the inspection plate
• NDT reports for the padeyes
• Lifting set certificate, with a thorough examination at least every 6 months in the UK under LOLER
• Repair records with the inspection body's approval

Integration and compatibility

Match the maximum gross mass to your crane curves at the radius you lift from, and to deck load limits where the container lands. Check that the lifting set's master link suits your hook. Cylinder racks and tank frames carry dangerous goods, so check the marking and segregation your operator requires. Slings and shackles also appear in crane attachments and rigging, and certified fuel tanks for helidecks in helicopter refueling systems.

Refurbishment and recertification

A container with lapsed certification can return to service if its design is known and its structure is sound. An inspection body examines it, runs NDT on the padeyes and may require a proof load test before issuing new dates. Missing plates, unknown design or unapproved repairs make this much harder. Unused surplus from cancelled projects often needs only an inspection to bring its dates current. Many fleets fit a new lifting set to every used container.