Section 177.115 - Applicability to existing vessels(a) Except as otherwise required by paragraph (b) of this section, an existing vessel must comply with the construction and arrangement regulations that were applicable to the vessel on March 10, 1996, or, as an alternative, the vessel may comply with the regulations in this part.(b) Alterations, or modifications made to the structure or arrangements of an existing vessel, that are a major conversion, on or after March 11, 1996, must comply with the regulations of this part. Repairs or maintenance conducted on an existing vessel, resulting in no significant changes to the original structure or arrangement of the vessel, must comply with the regulations applicable to the vessel on March 10, 1996, or, as an alternative, with the regulations in this part. However, when outfit items such as furnishings and mattresses are renewed, they must comply with the regulations in this part.(c) Vessels described by 46 CFR 175.110(d) must comply with the regulations in § 177.500 .CGD 85-080, 61 FR 961, Jan. 10, 1996, as amended by USCG-2021-0306, 86 FR 73172 , Dec. 27, 2021