46 CFR §190.01-90

1. (a)Existing structure previously approved will be considered satisfactory so long as it is maintained in good condition to the satisfaction of the Officer in Charge, Marine Inspection. Minor repairs and alterations may be made to the same standards as the original construction.
2. (b)Conversions, major alterations, new installations, and replacements, shall meet the applicable specifications in this subpart for new vessels.