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 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 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.