(a) Fuel systems for towing vessel main engines and generators must have a documented maintenance plan to ensure proper operation of the system.

(b) A continuous supply of clean fuel must be provided to main propulsion engines and generators.

(c) The fuel system must include filters and/or purifiers. Where filters are used:

(1) A supply of spare fuel filters must be provided onboard; and

(2) Fuel filters must be replaced in accordance with manufacturer's requirements or the vessel's TSMS, if applicable.

(d) Except as otherwise permitted under § 143.210 or § 143.520, no fuel other than diesel fuel may be used.