Ballast
Seawater carried in tanks to keep an unladen ship stable and properly trimmed; also the term for a non-revenue, empty leg.
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How it works
Ballast is weight (almost always seawater pumped into dedicated tanks) taken on to give an empty or partly loaded ship the draught, stability and trim she needs to sail safely. A ship "in ballast" is sailing without cargo.
Commercially, the ballast leg is the unpaid repositioning voyage from a discharge port to the next load port; minimising ballast distance is central to voyage economics. Ballast water must be managed under the IMO Ballast Water Management Convention to avoid spreading invasive species.
Where it shows up on The Maritime
Also known as: in ballast, ballast leg, ballast voyage.
Related terms
Draught
The vertical distance from the waterline to the bottom of the keel: how deep the ship sits in the water.
Deadweight Tonnage (DWT)
The total weight a ship can carry (cargo plus fuel, stores, crew and water) at her load line, in metric tonnes.
Time Charter Equivalent (TCE)
A voyage’s daily earnings net of voyage costs: the single number that makes a voyage charter comparable with a time charter rate.
Laden
The state of a ship carrying cargo: the revenue-earning leg of a voyage, and the opposite of ballast.
More vessel size and tonnage terms
A plain-English reference definition: our own explanation of a standard shipping concept, not a licensed source or legal advice. See the full glossary or the broader maritime dictionary.
Last reviewed: .