(a) All construction-differential subsidy agreements and mortgages relative to vessels covered in § 289.2(a) shall provide, wherever possible, that the Maritime Administrator may, in his discretion, require the owner to insure, with commercial underwriters, the interest of the United States.

(b) All future construction-differential subsidy agreements and future operating subsidy agreements shall require that owners insure vessels covered in § 289.2 (a) and (d) in amounts acceptable to the Maritime Administration.