Glossary Term
Net Tonnage (NT)
Net Tonnage, or NT, is an official tonnage figure calculated under the International Convention on Tonnage Measurement of Ships, 1969. It is a formula-based measurement tied to the vessel’s usable earning or cargo-related internal volume, so it is different from weight-based figures such as displacement or deadweight. On private yachts, NT is often much lower than gross tonnage because the vessel usually has limited cargo space.
On yachts, NT appears in documentation, compliance thresholds, and some fee or administrative calculations, so it can matter during registration, certification review, and survey work. It is most relevant on larger yachts and commercial-style support vessels, where official tonnage figures influence how the vessel is recorded and assessed by flag or port authorities.
NT is commonly confused with gross tonnage, but the two figures answer different questions. Gross tonnage reflects total enclosed volume, while net tonnage is intended to represent the vessel’s usable capacity under the convention’s rules. For yacht discussions, NT is usually a paperwork and compliance term, not a shorthand for carrying ability or physical size.