46 C.F.R. § 45.157 Scuppers and gravity drains.
Title 46 - Shipping
Scuppers and gravity deck drains from spaces above the freeboard deck that penetrate the shell below a line 24&inch; or .05B above the summer loadline, whichever is greater, must have an automatic nonreturn valve. This valve may be omitted if the piping is of thickness not less than extra heavy pipe.
Title 46: Shipping
PART 45—GREAT LAKES LOAD LINES
Subpart D—Conditions of Assignment
§ 45.157 Scuppers and gravity drains.
