33 CFR 155.430: Standard discharge connections for oceangoing ships

Last reviewed: October 14, 2026

This section requires oceangoing ships of 400 gross tons and above to have a standard shore connection for reception facilities. It sets the flange dimensions, allows a portable adapter in some cases, and sets flange material and pressure requirements.

Applies toOceangoing ships of 400 gross tons and above.

What it says

  1. All oceangoing ships of 400 gross tons and above must have a standard shore connection for reception facilities to discharge oily mixtures from machinery space bilges or ballast water containing an oily mixture from fuel oil tanks.

    33 CFR 155.430(a)“All oceangoing ships of 400 gross tons and above must have a standard shore connection for reception facilities to discharge oily mixtures from machinery space bilges”

  2. The connection must have an outside diameter of 215 millimeters (mm).

    33 CFR 155.430(a)(1)“Outside diameter = 215 millimeters (mm).”

  3. The bolt circle diameter must be 183 mm.

    33 CFR 155.430(a)(3)“Bolt circle diameter = 183 mm.”

  4. The flange must have a thickness of 20 mm.

    33 CFR 155.430(a)(5)“Flange thickness = 20 mm.”

  5. The connection must use 6 bolts and nuts, each of 20 mm in diameter and of suitable length.

    33 CFR 155.430(a)(6)“Bolts and nuts, quantity and number = 6 each of 20 mm in diameter and of suitable length.”

  6. A portable adapter that meets the specifications of paragraph (a) and fits the discharge shore connection may be substituted for the standard connection, for discharge of oily wastes from machinery space bilges.

    33 CFR 155.430(b)“A portable adapter that meets the specifications of paragraph (a) of this section and that fits the discharge shore connection”

  7. The flange must accept pipes up to a maximum internal diameter of 125 mm and must be steel or other equivalent material with a flat face.

    33 CFR 155.430(c)“The flange must be designed to accept pipes up to a maximum internal diameter of 125 mm and shall be of steel or other equivalent material having a flat face.”

  8. The flange and an oilproof gasket must be suitable for a service pressure of 6 kilograms/square centimeters (kg/cm2).

    33 CFR 155.430(c)“This flange, together with a gasket of oilproof material, must be suitable for a service pressure of 6 kilograms/square centimeters”

Common questions

Which ships need a standard discharge connection?

All oceangoing ships of 400 gross tons and above must have a standard shore connection for reception facilities.

“All oceangoing ships of 400 gross tons and above must have a standard shore connection for reception facilities”

Can a portable adapter replace the standard discharge connection?

Yes, for discharge of oily wastes from machinery space bilges, a portable adapter that meets paragraph (a) specifications and fits the shore connection may be substituted.

“for the discharge of oily wastes from machinery space bilges may be substituted for the standard discharge connection requirement of paragraph (a) of this section.”

What material must the discharge connection flange be made of?

The flange must be steel or other equivalent material having a flat face.

“shall be of steel or other equivalent material having a flat face.”

The text of 33 CFR 155.430

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

Standard discharge connections for oceangoing ships of 400 gross tons and above

(a) All oceangoing ships of 400 gross tons and above must have a standard shore connection for reception facilities to discharge oily mixtures from machinery space bilges or ballast water containing an oily mixture from fuel oil tanks. The discharge connection must have the following dimensions:

(1) Outside diameter = 215 millimeters (mm).

(2) Inner diameter = according to pipe outside diameter.

(3) Bolt circle diameter = 183 mm.

(4) Slots in flange = 6 holes 22 mm in diameter equidistantly placed on a bolt circle of the above diameter, slotted to the flange periphery. The slot width to be 22 mm.

(5) Flange thickness = 20 mm.

(6) Bolts and nuts, quantity and number = 6 each of 20 mm in diameter and of suitable length.

(b) A portable adapter that meets the specifications of paragraph (a) of this section and that fits the discharge shore connection, for the discharge of oily wastes from machinery space bilges may be substituted for the standard discharge connection requirement of paragraph (a) of this section.

(c) The flange must be designed to accept pipes up to a maximum internal diameter of 125 mm and shall be of steel or other equivalent material having a flat face. This flange, together with a gasket of oilproof material, must be suitable for a service pressure of 6 kilograms/square centimeters (kg/cm 2).

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.