46 CFR 143.595: Duplicate vital auxiliaries on single-propulsor towing vessels
Last reviewed: October 14, 2026
This section requires a towing vessel to have independent, duplicate vital auxiliaries. If any single vital auxiliary fails, the propulsion engine must still provide propulsion adequate to maintain control of the tow. The duplicate unit must be fully capable of taking over the failed unit's operation.
What it says
A towing vessel must have independent, duplicate vital auxiliaries.
46 CFR 143.595(a)“A towing vessel must have independent, duplicate vital auxiliaries.”
For this section, vital auxiliaries are the equipment necessary to operate the propulsion engine, and they include fuel pumps, lubricating oil pumps, and cooling water pumps.
46 CFR 143.595(a)“vital auxiliaries are the equipment necessary to operate the propulsion engine, and include fuel pumps, lubricating oil pumps, and cooling water pumps.”
If any single vital auxiliary fails or malfunctions, the propulsion engine must continue to provide propulsion adequate to maintain control of the tow.
46 CFR 143.595(a)“In the event of a failure or malfunction of any single vital auxiliary, the propulsion engine must continue to provide propulsion adequate to maintain control of the tow.”
If a vital auxiliary fails, the corresponding independent duplicate vital auxiliary must be fully capable of assuming the operation of the failed unit.
46 CFR 143.595(b)“the corresponding independent duplicate vital auxiliary, described in paragraph (a) of this section, must be fully capable of assuming the operation of the failed unit.”
Common questions
What counts as a vital auxiliary on a towing vessel?
Vital auxiliaries are the equipment necessary to operate the propulsion engine. They include fuel pumps, lubricating oil pumps, and cooling water pumps.
“vital auxiliaries are the equipment necessary to operate the propulsion engine, and include fuel pumps, lubricating oil pumps, and cooling water pumps.”
What must happen if a vital auxiliary fails on a towing vessel?
The propulsion engine must continue to provide propulsion adequate to maintain control of the tow. The corresponding duplicate must be fully capable of assuming the operation of the failed unit.
“the corresponding independent duplicate vital auxiliary, described in paragraph (a) of this section, must be fully capable of assuming the operation of the failed unit.”
Do towing vessels need duplicate vital auxiliaries?
Yes. A towing vessel must have independent, duplicate vital auxiliaries.
“A towing vessel must have independent, duplicate vital auxiliaries.”
The text of 46 CFR 143.595
Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR
Vessels with one propulsor that move tank barges carrying oil or hazardous material in bulk
(a) A towing vessel must have independent, duplicate vital auxiliaries. For the purpose of this section, vital auxiliaries are the equipment necessary to operate the propulsion engine, and include fuel pumps, lubricating oil pumps, and cooling water pumps. In the event of a failure or malfunction of any single vital auxiliary, the propulsion engine must continue to provide propulsion adequate to maintain control of the tow.
(b) In the event of a failure, the corresponding independent duplicate vital auxiliary, described in paragraph (a) of this section, must be fully capable of assuming the operation of the failed unit.
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.