46 C.F.R. § 42.15-50 Air pipes.
Title 46 - Shipping
(a) Where air pipes to ballast and other tanks extend above the freeboard or superstructure decks, the exposed parts of the pipes shall be of substantial construction; the height from the deck to the point where water may have access below shall be at least 30 inches on the freeboard deck and 17 [CGFR 68–60, 33 FR 10062, July 12, 1968, as amended by CGFR 68–126, 34 FR 9014, June 5, 1969]
Title 46: Shipping
PART 42—DOMESTIC AND FOREIGN VOYAGES BY SEA
Subpart 42.15—Conditions of Assignment of Freeboard
§ 42.15-50 Air pipes.