46 CFR 502.55: Effective date of rules.

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.]