Gross register tons
Gross register tons (GRT) means the gross ton measurement of the vessel under 46 U.S.C. chapter 145, Regulatory Measurement. For a vessel measured under only 46 U.S.C. chapter 143, Convention Measurement, the vessel's gross tonnage, ITC is used to apply all thresholds expressed in terms of gross register tons.
33 CFR § 101.105
Unless otherwise specified, as used in this subchapter: