46 CFR § 30.10-37
Keel laying date—TB/ALL
April 15, 2021
The term keel laying date means the date upon which progressive construction identifiable with a specific vessel begins, including construction of the first module or prefabricated section of the hull that is identifiable with that vessel.
[CGD 74-127, 41 FR 3843, Jan. 26, 1976]