Glossary
What Is a Certificate of Inspection (COI)?
A Certificate of Inspection (COI) is the document the U.S. Coast Guard issues to a vessel that has passed federal inspection, authorizing it to carry more than six paying passengers. The COI states the approved route, the minimum crew, the required safety equipment, and the maximum number of persons permitted aboard.
The COI is the legal bright line between a six-pack operation and a genuine commercial passenger vessel. Under 46 U.S.C. 2101, a vessel of less than 100 gross tons carrying more than six passengers with at least one paying passenger is a small passenger vessel, regulated under 46 CFR Subchapter T. Subchapter T covers vessels under 100 gross tons carrying more than six but not more than 150 passengers, or with overnight accommodations for 49 or fewer. Such a vessel cannot legally operate without a valid COI aboard.
Earning one is structural, not clerical. The Coast Guard reviews hull construction, stability, subdivision, fire protection, machinery, electrical systems, and lifesaving appliances. Many production yachts were never built to those standards and cannot be retrofitted economically, which is why the Miami charter fleet skews heavily toward six-passenger operations even on boats with the deck space for twenty.
A COI is not open-ended. For most domestic vessels the certificate runs five years, and one year for vessels carrying more than 12 passengers on international voyages. Either way the vessel must pass an annual inspection within a three-month window before or after each anniversary date, so a current COI reflects a recent inspection, not a decade-old one.
Read the certificate itself rather than taking a broker's word. The route line matters: a COI endorsed for protected or partially protected waters does not authorize an ocean run, so a boat cleared for Biscayne Bay may not be cleared to take you offshore or across to Bimini. The manning line tells you how many credentialed crew must be aboard. The persons-permitted line is a hard ceiling that includes crew, not just guests. Finally, check the expiry and the last annual endorsement date stamped on the certificate; an expired or unendorsed COI is not a technicality, it suspends the vessel's authority to carry passengers at all, and a Coast Guard boarding will end the trip on the spot.