46 CFR § 143.590
Propulsor redundancy on vessels that move tank barges carrying oil or hazardous material in bulk
April 15, 2021
(a) A towing vessel must be provided with at least two independent propulsors unless the requirements of §143.595 are met.
(b) There must be independent controls for each propulsor at each operating station.
(c) In the event of a failure of a single propulsor, the remaining propulsor(s) must have sufficient power to maneuver the vessel to a safe location.