Commercial Vessel Compliance

10/21/2015: Tonnage applicability: Dual-tonnage vessels

The Coast Guard’s Office of Commercial Vessel Compliance provided the Dual-Tonnage Applicability Table to better illustrate the applicability of tonnage based manning requirements for dual-tonnage vessels.

The table provides clarity for vessels measured under both 46 U.S.C. Chapters 143 and 145, the Regulatory Measurement System (GRT) and the Convention Measurement System (GT ITC). GRT is used to determine the number of crew required. However, in certain cases depending on voyage and vessel particulars, the Convention Measurement System (GT ITC) is applied for determining the applicable tonnage level required for MMC/STCW endorsements. This table is intended to compliment Marine Safety Manual Volume III, Chapter B3, Paragraph B.3. and will be included in the next update.

The table is also available on the Towing Vessel National Center of Expertise FAQ website.


This blog is not a replacement or substitute for the formal posting of regulations and updates or existing processes for receiving formal feedback of the same. Links provided on this blog will direct the reader to official source documents, such as the Federal Register, Homeport and the Code of Federal Regulations. These documents remain the official source for regulatory information published by the Coast Guard.

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