Tonnage Cross-Reference

Tonnage cross-reference is the link between SOLAS applicability and the way a ship’s tonnage is measured. SOLAS expresses most of its size thresholds in gross tonnage, but the Convention does not measure tonnage itself: gross and net tonnage are computed under the 1969 International Convention on Tonnage Measurement of Ships, in force 18 July 1982, using the molded volume formulas GT = K1 V and the net-tonnage relation. The certified gross tonnage on the International Tonnage Certificate is the figure that decides whether a SOLAS chapter, a MARPOL annex, or a manning rule applies. Suez and Panama canal tonnages are separate and not used for SOLAS.