Ballast
Seawater carried in tanks to keep an unladen ship stable and properly trimmed — and the term for a non-revenue, empty leg.
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.
On TheMaritime
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 TonnageDWT
The total weight a ship can carry — cargo plus fuel, stores, crew and water — at her load line, in metric tonnes.
Time Charter EquivalentTCE
A voyage’s daily earnings net of voyage costs — the single number that makes a voyage charter comparable with a time charter rate.
Laden
A ship carrying cargo — the revenue-earning leg of a voyage, the opposite of ballast.
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: June 2026.