CFR › Title 46 › Part 69 › §69.17146 CFR §69.171Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗Copy linkFor the purpose of this subpart, a tonnage mark is considered submerged when—(a)In salt or brackish water, the upper edge of the tonnage mark is submerged; and(b)In fresh or tropical water, the upper edge of the line for fresh and tropical waters is submerged.