46 CFR §71.50-29

1. (a)If you use only divers for the underwater survey portion of the Alternative Hull Examination (AHE), you must provide the Officer in Charge, Marine Inspection (OCMI), with a written hull examination report. This report must include thickness gauging results, bearing clearances, a copy of the audio and video recordings, and any other information that will help the OCMI evaluate your vessel for a credit hull exam. The third party examiner must sign the report and confirm the validity of its contents.
2. (b)If you use an underwater ROV as the predominant means to examine the vessel's underwater hull plating, you must provide the OCMI with a report in the format that is accepted by the OCMI, per § 71.50-27(b) of this part.
3. (c)The OCMI will evaluate the hull examination report and grant a credit hull exam if satisfied with the condition of the vessel. If approved and you exclusively use divers to examine the hull plating, you may receive a credit hull exam up to 36 months. (Underwater examinations are required twice every 5 years). If approved and you use an underwater ROV as the predominant means to examine the underwater hull plating, you may receive a credit hull exam up to 60 months (5 years).
4. (d)At least 60 days prior to each scheduled underwater exam, the owner may request a waiver from the OCMI if:
   1. (1)A satisfactory exam has been completed within the last three years;
   2. (2)The conditions during the last exam allowed at least 80 percent of the bottom surface to be viewed and recorded; and
   3. (3)The results of the last exam indicated that an extended interval is safe and reasonable.