46 CFR 143.205: General.

(a) Machinery and electrical systems must be designed and maintained to provide for safe operation of the towing vessel and safety of persons onboard under normal and emergency conditions.

(b) The crew of each towing vessel must demonstrate the ability to operate the primary and auxiliary machinery and electrical systems for which they are responsible, and to do so under normal and emergency conditions. This includes, but is not limited to, responses to alarms and restoration of propulsion and steering in the event of failure.

(c) Propulsion machinery, including main engines, reduction gears, shafting, bearings, and electrical equipment and systems, must:

(1) Be maintained to ensure proper operation;

(2) Be suitable for route and service; and

(3) Have suitable propulsion controls to provide the operator full control at each operating station.

(d) Repairs and minor alterations to existing towing vessels must be made in accordance with this part. New installations that are not replacements in kind must comply with the requirements of subpart C of this part, if applicable.