(a) All owners or managing operators of more than one existing towing vessel required to have a COI by this subchapter must ensure that each existing towing vessel under their ownership or control is issued a valid COI according to the following schedule:

(1) By July 22, 2019, at least 25 percent of the towing vessels must have valid COIs on board;

(2) By July 20, 2020, at least 50 percent of the towing vessels must have valid COIs on board;

(3) By July 19, 2021, at least 75 percent of the towing vessels must have valid COIs on board; and

(4) By July 19, 2022, 100 percent of the towing vessels must have valid COIs on board.

(b) All owners or managing operators of only one existing towing vessel required to have a COI by this subchapter must ensure the vessel has an onboard, valid COI by July 20, 2020.

(c) A new towing vessel must obtain a COI before it enters into service.