33 CFR 155.420: Oily mixture discharge piping on small oceangoing ships

Last reviewed: October 14, 2026

This section sets pumping, piping and discharge requirements for oceangoing ships of 100 gross tons and above but less than 400 gross tons with main or auxiliary machinery spaces. Such a ship needs a pump, fixed piping to a reception facility, a weather deck outlet, a way to stop the pump and a stop valve. Ships with approved oily-water separating equipment and drilling rigs or other platforms are excluded.

Applies toOceangoing ships of 100 gross tons and above but less than 400 gross tons that are fitted with main or auxiliary machinery spaces.

What it says

  1. No person may operate a covered ship unless it has at least one pump installed to discharge oily mixtures through a fixed piping system to a reception facility.

    33 CFR 155.420(a)(1)“The ship has at least one pump installed to discharge oily mixtures through a fixed piping system to a reception facility;”

  2. The required piping system must have at least one outlet accessible from the weather deck.

    33 CFR 155.420(a)(2)“The piping system required by this section has at least one outlet accessible from the weather deck;”

  3. A ship on an international voyage must have a shore connection meeting the specifications in § 155.430 at the outlet, or at least one adapter meeting those specifications that fits the required outlets.

    33 CFR 155.420(a)(3)“the outlet required by this section has a shore connection that meets the specifications in § 155.430, or the ship has at least one adapter that meets the specifications in § 155.430 and fits the required outlets;”

  4. A ship not on an international voyage must have an outlet shore connection that is compatible with reception facilities in the ship's area of operation.

    33 CFR 155.420(a)(4)“the outlet required by this section has a shore connection that is compatible with reception facilities in the ship's area of operation;”

  5. The ship must have a means on the weather deck near the discharge outlet to stop each pump used to discharge oily mixtures.

    33 CFR 155.420(a)(5)“The ship has a means on the weather deck near the discharge outlet to stop each pump that is used to discharge oily mixtures;”

  6. The ship must have a stop valve installed for each outlet required by this section.

    33 CFR 155.420(a)(6)“The ship has a stop valve installed for each outlet required by this section.”

  7. Paragraph (a) does not apply to a ship that has approved oily-water separating equipment for processing oily mixtures from bilges or fuel oil tank ballast.

    33 CFR 155.420(b)“Paragraph (a) of this section does not apply to a ship that has approved oily-water separating equipment for the processing of oily mixtures from bilges or fuel oil tank ballast.”

Common questions

Does 33 CFR 155.420 apply to drilling rigs?

No. This section does not apply to a fixed or floating drilling rig or other platform.

“This section does not apply to a fixed or floating drilling rig or other platform.”

Where must the oily mixture discharge outlet be on a ship of 100 to under 400 gross tons?

The piping system must have at least one outlet accessible from the weather deck.

“The piping system required by this section has at least one outlet accessible from the weather deck;”

Can a ship with oily-water separating equipment skip the pump and piping requirements?

Yes, if the ship has approved oily-water separating equipment for processing oily mixtures from bilges or fuel oil tank ballast, paragraph (a) does not apply.

“Paragraph (a) of this section does not apply to a ship that has approved oily-water separating equipment for the processing of oily mixtures from bilges or fuel oil tank ballast.”

The text of 33 CFR 155.420

Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR

Pumping, piping and discharge requirements for oceangoing ships of 100 gross tons and above but less than 400 gross tons

(a) No person may operate an oceangoing ship of 100 gross tons and above but less than 400 gross tons that is fitted with main or auxiliary machinery spaces unless:

(1) The ship has at least one pump installed to discharge oily mixtures through a fixed piping system to a reception facility;

(2) The piping system required by this section has at least one outlet accessible from the weather deck;

(3) For a ship on an international voyage, the outlet required by this section has a shore connection that meets the specifications in § 155.430, or the ship has at least one adapter that meets the specifications in § 155.430 and fits the required outlets;

(4) For a ship not on an international voyage, the outlet required by this section has a shore connection that is compatible with reception facilities in the ship's area of operation;

(5) The ship has a means on the weather deck near the discharge outlet to stop each pump that is used to discharge oily mixtures; and

(6) The ship has a stop valve installed for each outlet required by this section.

(b) Paragraph (a) of this section does not apply to a ship that has approved oily-water separating equipment for the processing of oily mixtures from bilges or fuel oil tank ballast.

(c) This section does not apply to a fixed or floating drilling rig or other platform.

Sections it refers to

The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.