46 CFR § 502.55
Effective date of rules
April 15, 2021
The publication or service of any substantive rule shall be made not less than thirty (30) days prior to its effective date except:
(a) As otherwise provided by the Commission for good cause found that notice and public procedure thereon are impractical, unnecessary, or contrary to the public interest;
(b) In the case of rules granting or recognizing exemption or relieving restriction; interpretative rules; or statements of policy.
(c) Interpretive rules, general statements of policy, or rules of agency organization, procedure, or practice. [Rule 55.]
[78 FR 45071, July 26, 2013]