What is OOG (out-of-gauge) cargo?
Typical OOG cargo includes machinery, vehicles, boats, transformers and steel structures. It is described by how far it exceeds the container's outline: over-height, over-width and over-length. Over-height pieces often go in an open top, loaded by crane through the roof; wide or long pieces go on a flat rack, which has open sides. On board, protruding cargo blocks neighboring slots, and the carrier charges for that lost space.
OOG differs from break-bulk cargo, although the two overlap. OOG still moves on container equipment through container terminals and ships. When a piece is too large or heavy even for flat racks, it ships as break bulk, lifted on its own into the hold or onto the deck of a general cargo or heavy-lift vessel. Cargo that stays within a flat rack's outline is called in-gauge.
OOG bookings need the carrier's approval, based on exact dimensions, weight, center of gravity, lifting and lashing points, and often a drawing. Special equipment is limited, so plan weeks ahead. Road legs may need oversize permits, escort vehicles or special trailers, and terminal handling and securing cost more than for standard boxes. A lashing survey at loading helps avoid damage disputes later.