1. Multiyear procurement authority for amphibious vessels (a) Authority for multiyear procurement Except as provided in subsection (b) and subject to section 2306b of title 10, United States Code, the Secretary of the Navy may enter into one or more multiyear contracts for the procurement of the following: (1) Three amphibious transport dock vessels designated LPD–31, LPD–32, and LPD–33. (2) One amphibious landing helicopter assault vessel designated LHA–9. (b) Limitation on contract authority The Secretary of the Navy may not enter into a contract under subsection (a) until the date on which the Secretary certifies to the congressional defense committees that the procurement of the vessels specified in such subsection is consistent with— (1) the most recent 30-year shipbuilding plan of the Navy; and (2) the most recent Commandant’s Planning Guidance of the 38th Commandant of the Marine Corps. (c) Limitation on contract modification The Secretary of the Navy may not modify a contract entered into under subsection (a)(1) if the modification would increase the total target price of the three amphibious transport dock vessels by more than 10 percent above the target price specified in the original contract awarded for the vessels under subsection (a)(1). (d) Use of incremental funding for LPD–31 and LHA–9 With respect to a contract entered into under subsection (a) for the vessel LPD–31 or the vessel LHA–9, the Secretary may use incremental funding to make payments under the contract. (e) Authority for advance procurement The Secretary of the Navy may enter into one or more contracts, beginning in fiscal year 2021, for advance procurement associated with the vessels for which authorization to enter into a multiyear procurement contract is provided under subsection (a) and for equipment or subsystems associated with the vessels, including procurement of— (1) long lead time material