Centre of Gravity (CoG)
The centre of gravity is the point where the whole weight of a load can be considered to act. Inside a container it should sit close to mid-length and as low as possible; widely used carrier packing guidance keeps it within about ±5% of the inner length from the midpoint, roughly ±0.3 m for a 20-foot and ±0.6 m for a 40-foot box. An off-centre load overloads one end, stressing cranes, chassis and truck axles. On a ship, the vertical centre of gravity (KG) governs stability.
Related terms
- Metacentric Height (GM)
Metacentric height (GM) is the distance between a ship's centre of gravity (G) and its metacentre (M), calculated as KM minus KG.
- Axle Load
Axle load is the share of vehicle and cargo weight carried by one axle.
- Stuffing
Stuffing is loading goods into a container, either at the shipper's premises for FCL or at a CFS for LCL.
- Lashing
Lashing means securing cargo so it cannot shift under the accelerations of a sea voyage or a road journey.
- Stowage Plan
A stowage plan is the planned position of every container or cargo unit on board a vessel, built by line and terminal planners before the ship berths.
Covered in these guides
Deck Cargo Barge Stowage (180–330 ft): Deck Load, CoG, Trim and Sea-Fastening
A guide to stowing 180–330 ft deck cargo barges in Indonesia, covering deck load in t/m², zones, CoG targets, trim and heel, sea-fastening, dunnage and a worked example.
6 min read Vessel stowageMetacentric Height (GM) Explained: Calculation, Corrections and Limits
A deeper look at a ship's GM, from hydrostatic KM, loading KG and free surface correction to worked examples and the risks of too little or too much GM.
6 min read Vessel stowageShip Stability Basics for Planners: Displacement, KG, GM and the GZ Curve
Intact stability for cargo planners, covering displacement, KG, KM, GM, the GZ curve, righting moment, free surface and the IS Code 2008 general criteria.
6 min read