46 U.S.C. § 14104 — Measurement to determine application of a law

(a) Whenever whether a U.S. law applies to a vessel^* depends on that vessel's tonnage, the vessel must be measured under this part.

(b) If some other statute allows for an "alternate tonnage" to be used instead, the Secretary may set that alternate tonnage by regulation. Any such regulation counts as an "interpretive regulation" for purposes of section 553 of title 5. Until the Secretary actually sets an alternate tonnage, the tonnage the statute itself establishes keeps applying to vessels measured under chapter 143 or chapter 145 of this title.

(c) Every federal agency's head must make sure that any of the agency's own regulations naming specific tonnages line up with whatever alternate tonnages the Secretary has put in place.