46 CFR 137.330: Scope of towing vessel drydock examination

Last reviewed: October 14, 2026

This section says what a drydock examination of a towing vessel must include. The vessel must be hauled out or placed in a drydock or slipway, and the inspector must examine the hull, shafts, rudders, propellers, cooling components, and sea chests. It also describes the internal structural examination.

Applies toAll towing vessels covered by this subchapter.

What it says

  1. The drydock examination must be conducted while the vessel is hauled out of the water or placed in a drydock or slipway.

    46 CFR 137.330(a)“The drydock examination must be conducted while the vessel is hauled out of the water or placed in a drydock or slipway.”

  2. The Coast Guard inspector or surveyor must examine the exterior of the hull, including bottom, sides, headlog, and stern, and all appendages for damage, fractures, wastage, pitting, or improper repairs.

    46 CFR 137.330(a)(1)“Examine the exterior of the hull, including bottom, sides, headlog, and stern, and examine all appendages for damage, fractures, wastage, pitting, or improper repairs;”

  3. The inspector or surveyor must examine each tail shaft for bends, cracks, and damage, including wear on the sleeves or other bearing contact surfaces. The tail shaft need not be removed if these items can otherwise be properly evaluated.

    46 CFR 137.330(a)(2)“The tail shaft need not be removed for examination if these items can otherwise be properly evaluated;”

  4. The inspector or surveyor must examine the rudders for damage, the upper and lower bearings for wear, and the rudder stock for damage or wear. Rudders need not be removed if these items can be otherwise properly evaluated.

    46 CFR 137.330(a)(3)“Examine the rudders for damage, the upper and lower bearings for wear, and the rudder stock for damage or wear.”

  5. The inspector or surveyor must open and examine all sea chests, through-hull fittings, and strainers for damage, deterioration, or fouling.

    46 CFR 137.330(a)(6)“Open and examine all sea chests, through-hull fittings, and strainers for damage, deterioration, or fouling; and”

  6. On wooden vessels, the inspector or surveyor must pull fastenings as required for examination.

    46 CFR 137.330(a)(7)“On wooden vessels, pull fastenings as required for examination.”

  7. An internal structural examination required by this part may be conducted while the vessel is afloat or out of the water.

    46 CFR 137.330(b)“An internal structural examination required by this part may be conducted while the vessel is afloat or while it is out of the water.”

  8. Fuel oil tanks need not be cleaned out and internally examined if an external examination determines their general condition to be satisfactory.

    46 CFR 137.330(b)“Fuel oil tanks need not be cleaned out and internally examined if the general condition of the tanks is determined to be satisfactory by an external examination.”

Common questions

Does a towing vessel have to be out of the water for a drydock examination?

Yes. The drydock examination must be conducted while the vessel is hauled out of the water or placed in a drydock or slipway.

“The drydock examination must be conducted while the vessel is hauled out of the water or placed in a drydock or slipway.”

Must the tail shaft be removed during a drydock examination?

No, not if the bends, cracks, damage, and wear can otherwise be properly evaluated.

“The tail shaft need not be removed for examination if these items can otherwise be properly evaluated;”

Can the internal structural examination be done while the vessel is afloat?

Yes. An internal structural examination required by this part may be conducted while the vessel is afloat or while it is out of the water.

“An internal structural examination required by this part may be conducted while the vessel is afloat or while it is out of the water.”

Do fuel oil tanks have to be cleaned out for the examination?

Not if an external examination determines the general condition of the tanks to be satisfactory.

“Fuel oil tanks need not be cleaned out and internally examined if the general condition of the tanks is determined to be satisfactory by an external examination.”

The text of 46 CFR 137.330

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

Scope of the drydock examination

(a) This regulation applies to all towing vessels covered by this subchapter. The drydock examination must be conducted while the vessel is hauled out of the water or placed in a drydock or slipway. The Coast Guard inspector or surveyor conducting this examination must:

(1) Examine the exterior of the hull, including bottom, sides, headlog, and stern, and examine all appendages for damage, fractures, wastage, pitting, or improper repairs;

(2) Examine each tail shaft for bends, cracks, and damage, including the sleeves or other bearing contact surfaces on the tail shaft for wear. The tail shaft need not be removed for examination if these items can otherwise be properly evaluated;

(3) Examine the rudders for damage, the upper and lower bearings for wear, and the rudder stock for damage or wear. Rudders need not be removed for examination if these items can be otherwise properly evaluated. This also includes other underwater components of steering and propulsion mechanisms;

(4) Examine the propellers for cracks and damage;

(5) Examine the exterior components of the machinery cooling system for leaks, damage, or deterioration;

(6) Open and examine all sea chests, through-hull fittings, and strainers for damage, deterioration, or fouling; and

(7) On wooden vessels, pull fastenings as required for examination.

(b) An internal structural examination required by this part may be conducted while the vessel is afloat or while it is out of the water. It consists of a complete examination of the vessel's main strength members, including the major internal framing, the hull plating and planking; voids; and ballast, cargo, and fuel oil tanks. Where the internal framing, plating, or planking of the vessel is concealed, sections of the lining, ceiling, or insulation may be removed or the parts otherwise probed or exposed to determine the condition of the hull structure. Fuel oil tanks need not be cleaned out and internally examined if the general condition of the tanks is determined to be satisfactory by an external examination.

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.