(a) General. Tonnage thresholds are applied using the vessel's tonnage assigned under this part, and as provided for by paragraphs (b) through (d) of this section. In general, and except as under paragraphs (b) and (c) of this section, tonnage thresholds expressed in terms of “gross tonnage,” “gross tonnage ITC,” or “GT ITC” are applied using Convention Measurement System tonnage (if assigned) and thresholds expressed in terms of “gross tons,” “registered gross tons,” or “GRT” are applied using the Regulatory Measurement System tonnage (if assigned). Similarly, in general, and except as under paragraphs (b) and (c) of this section, tonnage thresholds expressed in terms of “net tonnage,” “net tonnage ITC,” or “NT ITC” are applied using Convention Measurement System tonnage (if assigned) and thresholds expressed in terms of “net tons,” “registered net tons,” or “NRT” are applied using the Regulatory Measurement System tonnage (if assigned).

(b) Thresholds found in international conventions. Unless otherwise provided for by law, apply tonnage thresholds in international conventions as follows:

(1) For vessels measured under the Convention Measurement System, apply all tonnage thresholds using Convention Measurement System tonnage, except as provided for under the following international tonnage grandfathering provisions, which may be applied at the option of the vessel owner:

(i) Under Article 3(2)(d) of the Convention:

(A) For a U.S. flag vessel, this Article allows associated tonnage thresholds in effect on or before July 18, 1994 to be applied, at the vessel owner's option, using Regulatory Measurement System tonnage to a vessel whose keel was laid on or before July 18, 1982, and which did not subsequently undergo alterations resulting in a change in its tonnage of a magnitude deemed by the Commandant to constitute a substantial variation in its tonnage.

(B) For a foreign flag vessel, this Article allows associated tonnage thresholds in effect on or before July 18, 1994, to be applied, at the vessel owner's option, using the foreign country's national measurement system tonnage to a vessel whose keel was laid on or before July 18, 1982, and which did not subsequently undergo alterations resulting in a change in its tonnage of a magnitude deemed by that country to constitute a substantial variation in its tonnage.

(ii) Under International Maritime Organization (IMO) Resolutions A.494 (XII) of November 19, 1981 and A.541 (XIII) of November 17, 1983:

(A) For a U.S. flag vessel, these resolutions allow tonnage thresholds in effect on July 18, 1994 to be applied using the gross register tonnage (Regulatory Measurement System), to a vessel whose keel was laid on or after July 18, 1982 but before July 19, 1994, and which did not subsequently undergo alterations resulting in a change substantially affecting its tonnage as deemed by the Commandant.

(B) For a foreign flag vessel, these resolutions allow tonnage thresholds in effect on July 18, 1994 to be applied, at the vessel owner's option, using the foreign country's national measurement system tonnage, to a vessel whose keel was laid on or after July 18, 1982, but on or before July 18, 1994, and which did not undergo alterations after July 18, 1994 of a magnitude deemed by that country to constitute a substantial variation in its tonnage subject to the provisions of these resolutions.

(iii) Any other international grandfathering provisions as authorized under appropriate International Maritime Organization instruments to which the United States is a party, or which are otherwise recognized or accepted by the United States.

(2) For all other vessels, apply all tonnage thresholds using Regulatory Measurement System tonnage.

(c) Thresholds found in Federal statutes and regulations. Unless otherwise provided for by law, apply tonnage thresholds in Federal statutes and regulations as follows:

(1) For vessels measured under the Convention Measurement System only, apply all thresholds using Convention Measurement System tonnage.

(2) For vessels measured under the Regulatory Measurement System only, apply all thresholds using Regulatory Measurement System tonnage.

(3) For all other vessels, apply thresholds in effect before July 19, 1994 using the vessel's Regulatory Measurement System tonnage, and all other thresholds using the vessel's Convention Measurement System tonnage.

(d) Alternate tonnage thresholds. 46 U.S.C. 14104 authorizes the Coast Guard to establish tonnage thresholds based on the Convention Measurement System as an alternative to tonnage thresholds based on the Regulatory Measurement System. Although 46 U.S.C. 14104 addresses only thresholds in Federal statutes, it does not preclude establishing alternate tonnage thresholds for Federal regulations that currently specify thresholds that were based on the Regulatory Measurement System, where appropriate.

(1) If an alternate tonnage threshold is prescribed or authorized by Federal statute or regulation, apply the alternate tonnage threshold using the Convention Measurement System tonnage.

(2) A vessel regulated under paragraph (d) of this section must not be measured under the Regulatory Measurement System.

[USCG-2011-0522, 81 FR 18720, Mar. 31, 2016]