# 33 CFR § 157.09: Segregated ballast > Federal · Regulations · In force URL: https://www.frixlaw.com/law-library/statutes/ecfr-33-157.09 ## Section - **Citation:** 33 CFR § 157.09 - **Heading:** Segregated ballast - **Jurisdiction:** Federal - **Kind:** Regulations - **Status:** In force - **Text as of:** September 22, 2026 - **Source:** Publisher's official text - **Location:** Title 33—Navigation and Navigable Waters > CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY > SUBCHAPTER O—POLLUTION > PART 157—RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK > Subpart B—Design, Equipment, and Installation ## Text (a) A new vessel of 70,000 tons DWT or more must have segregated ballast tanks that have a total capacity to allow the vessel to meet the draft and trim requirements in paragraph (b) of this section without recourse to the use of oil tanks for water ballast. (b) In any ballast condition during any part of a voyage, including that of lightweight with only segregated ballast, the vessel's drafts and trim must have the capability of meeting each of the following requirements: (1) The molded draft amidship (dm) in meters without taking into account vessel deformation must not be less than dm in the following mathematical relationship: dm = 2.0 + 0.02L (2) The drafts at the forward and after perpendiculars must correspond to those determined by the draft amidship as specified in paragraph (b)(1) of this section, in association with the trim by the stern of no more than 0.015L. (3) The minimum allowable draft at the after perpendicular is that which is necessary to obtain full immersion of the propeller. (c) The vessel may be designed to carry ballast water in cargo tanks during the condition described in § 157.35. (d) Segregated ballast spaces, voids, and other noncargo-carrying spaces for a vessel of conventional form must be distributed: (1) So that the mathematical average of the hypothetical collision (Oc) and the hypothetical stranding (Os) outflows as determined by the application of the procedures in § 157.19 and appendix B is 80 percent or less of the maximum allowable outflow (OA) as determined by § 157.19(b)(1); and (2) To protect at least 45 percent of the sum of the side and bottom shell areas, based upon projected molded dimensions, within the cargo tank length. When the vessel design configuration does not provide for the spaces to be distributed to protect at least 45 percent of the side and bottom shell areas, the spaces must be distributed so that the mathematical average of the hypothetical collision (Oc) and the hypothetical stranding (Os) outflows, determined by application of the procedures in § 157.19 and appendix B, is a further 2 percent less than the maximum allowable outflow (Oa) for each 1 percent by which the shell area protection coverage required is not achieved. (e) A ballast space, void or other non-cargo-carrying space used to meet requirements in paragraph (d) of this section must separate the cargo tank boundaries from the shell plating of the vessel by at least 2 meters. (f) A vessel of conventional form for application of this section has: (1) A block coefficient of .80 or greater, (2) A length to depth ratio between 12 and 16, and (3) A breadth to depth ratio between 1.5 and 3.5. (g) Segregated ballast spaces, voids, and other noncargo-carrying spaces for a vessel not of conventional form must be distributed in a configuration acceptable to the Coast Guard. [CGD 74-32, 40 FR 48283, Oct. 14, 1975, as amended by CGD 74-32, 40 FR 49328, Oct. 22, 1975; CGD 75-201, 41 FR 1482, Jan. 8, 1976] ## Nearby sections - [33 CFR § 157.01 § 157.01 Applicability.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.01.md) - [33 CFR § 157.02 § 157.02 Incorporation by reference: Where can I get a copy of the publications mentioned in this part?](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.02.md) - [33 CFR § 157.03 § 157.03 Definitions.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.03.md) - [33 CFR § 157.04 § 157.04 Authorization of classification societies.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.04.md) - [33 CFR § 157.05 § 157.05 Performing calculations for this part.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.05.md) - [33 CFR § 157.06 § 157.06 Appeals.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.06.md) - [33 CFR § 157.07 § 157.07 Equivalents.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.07.md) - [33 CFR § 157.08 § 157.08 Applicability of subpart B.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.08.md) - [33 CFR § 157.09 § 157.09 Segregated ballast.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.09.md) - [33 CFR § 157.10 § 157.10 Segregated ballast tanks and crude oil washing systems for certain new vessels.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.10.md) - [33 CFR § 157.10a § 157.10a Segregated ballast tanks, crude oil washing systems, and dedicated clean ballast tanks for certain new and existing vessels of 40,000 DWT or more.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.10a.md) - [33 CFR § 157.10b § 157.10b Segregated ballast tanks, dedicated clean ballast tanks, and special ballast arrangements for tank vessels transporting Outer Continental Shelf oil.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.10b.md) - [33 CFR § 157.10c § 157.10c Segregated ballast tanks, crude oil washing systems, and dedicated clean ballast tanks for certain new and existing tankships of 20,000 to 40,000 DWT.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.10c.md) - [33 CFR § 157.10d § 157.10d Double hulls on tank vessels.](https://www.frixlaw.com/law-library/statutes/ecfr-33-157.10d.md) --- Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/ecfr-33-157.09. Check the current official text before relying on it. Not legal advice.