1. (a) Gross register tonnage means the tonnage of a vessel, less certain spaces exempt under § 69.169, and is the sum of the following:

   1. (1) Under-deck tonnage (§ 69.163).
   2. (2) Between-deck tonnage (§ 69.165)
   3. (3) Superstructure tonnage (§ 69.167)
   4. (4) Excess hatchway tonnage (§ 69.115)
   5. (5) Tonnage of framed-in propelling machinery spaces included in calculating gross register tonnage (§ 69.121(d)(1)).
2. (b) Net register tonnage means gross register tonnage less deductions under § 69.119 and § 69.121.
3. (c) The authorized measurement organization must issue a U.S. Tonnage Certificate as evidence of a vessel's measurement under this subpart, which must also indicate the vessel's measurement under the Convention Measurement System in subpart B of this part, if applicable. There is no requirement to maintain the U.S. Tonnage Certificate on board the vessel.

[CGD 87-015b, 54 FR 37657, Sept. 12, 1989, as amended by USCG-2011-0522, 81 FR 18731, Mar. 31, 2016]