Coast Guard regulations cover recreational boaters, commercial vessel operators, licensed mariners, and Coast Guard service members, and they live mostly in Titles 33 and 46 of the Code of Federal Regulations. What you must do depends on which of those you are. A weekend boater has equipment and registration rules to meet. A commercial captain has inspection certificates and a credential to keep current. A tanker operator has pollution controls and response plans to maintain. The penalties for getting it wrong range from fines in the low thousands to loss of the credential you work under.
Required Equipment on a Recreational Boat
Every recreational vessel must carry at least one wearable, Coast Guard-approved personal flotation device for each person on board, used according to the conditions on its approval label. Boats 16 feet or longer must also carry a throwable PFD.1eCFR. 33 CFR 175.15 – Personal Flotation Devices Required Children under 13 have to actually wear an approved PFD while the vessel is underway, unless they’re below decks or in an enclosed cabin. State laws often set a different age cutoff and can override the federal one.
Motorized recreational boats need Coast Guard-approved portable fire extinguishers. For boats built in 2018 or later, extinguishers must carry a 5-B or 20-B rating, and one 20-B unit substitutes for two 5-B units. Boats under 16 feet need one extinguisher if they have enclosed engine or fuel spaces. Boats 26 to under 40 feet need two. Boats 40 to 65 feet need three. Older boats built between 1953 and 2017 can still use B-I or B-II rated extinguishers if they haven’t expired.
Boats 16 feet and longer operating on coastal waters, the Great Lakes, or the high seas must carry visual distress signals covering both day and night. Three hand-held red flares meet both because they are rated day and night. An electric SOS distress light can serve as the nighttime signal in place of pyrotechnics.2eCFR. 33 CFR Part 175 Subpart C – Visual Distress Signals
You also need a way to make an audible signal. Boats 12 meters (about 39.4 feet) or longer must carry a whistle. Boats 20 meters and up add a bell. At 100 meters, a gong is required as well. Boats under 12 meters don’t need a formal whistle but must have some means of making an efficient sound signal.3eCFR. 33 CFR 83.33 – Equipment for Sound Signals (Rule 33)
Registration and Navigation Rules
Mechanically propelled recreational vessels must be registered and numbered in the state where they’re primarily used. The registration number goes on the forward half of each side of the hull in plain block characters at least three inches tall.4eCFR. 33 CFR 173.27 – Numbers: Display; Size; Color Fees vary by state and boat length; for vessels under 26 feet they run roughly from under $10 to around $190 depending on the state and renewal cycle.
Operators must follow the Navigation Rules, which set right-of-way procedures, lighting, and sound signals for collision avoidance. Every self-propelled vessel 12 meters or longer must carry a copy of the Navigation Rules on board.5eCFR. 33 CFR 83.01 – Application (Rule 1)
Boating Under the Influence
Operating a vessel while intoxicated is a federal offense. The blood alcohol threshold is 0.08 percent for recreational boaters and 0.04 percent for commercial vessel operators. Below those numbers, an officer’s observations of impaired speech, movement, or behavior can still support a violation.6eCFR. 33 CFR Part 95 – Operating a Vessel While Under the Influence of Alcohol or a Dangerous Drug
Federal penalties include a civil fine of up to $5,000 or prosecution as a class A misdemeanor carrying up to one year in jail.7Office of the Law Revision Counsel. 46 USC 2302 – Penalties for Negligent Operations and Interfering With Safe Operation Refusing a chemical test when an officer has reasonable cause is admissible as evidence, and you’ll be presumed to be under the influence in any administrative proceeding.
When You Must Report an Accident
The operator or owner of a recreational vessel involved in a reportable accident must file a Boating Accident Report with the state reporting authority. An accident is reportable if someone dies, suffers an injury requiring treatment beyond first aid, disappears from the vessel under circumstances suggesting death or injury, the boat is destroyed, or property damage reaches $2,000 or more.
The deadlines are tight. A death within 24 hours, an injury beyond first aid, or a disappearance must be reported within 48 hours. Property-damage-only incidents at or above the $2,000 threshold must be reported within 10 days.
Commercial vessel casualties follow separate, generally stricter rules. The property damage threshold for a reportable marine casualty on a commercial vessel is $75,000, and a “serious marine incident” involving property damage kicks in at $200,000.8Federal Register. Marine Casualty Reporting Property Damage Thresholds
Commercial Vessel Inspection
Commercial vessels that carry passengers or perform services like towing must meet much heavier standards than recreational boats. The central document is the Certificate of Inspection, issued by the Coast Guard after review of the vessel’s design, construction, stability, hull integrity, and fire safety systems. A vessel covered by Subchapter T (small passenger vessels under 100 gross tons) cannot operate without a valid COI on board.9eCFR. 46 CFR 176.100 – When Required
The COI states the maximum number of passengers allowed, the minimum crew, and the authorized routes. Carrying more than six passengers for hire triggers the full inspection requirements. Vessels carrying six or fewer may qualify for less demanding standards at the discretion of the local Officer in Charge, Marine Inspection.10eCFR. 46 CFR Part 176 – Inspection and Certification
A COI is valid for five years for most domestic vessels, but only 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. Miss it and the COI lapses; the vessel cannot legally operate until reinspection and endorsement.
Commercial vessels also undergo periodic drydock and internal structural examinations of the hull below the waterline. Towing vessels exposed to salt water more than six months out of any 12-month period need drydock exams at least twice every five years, with no more than 36 months between them. Vessels in predominantly fresh water need at least one every five years. The local OCMI can order additional drydock exams if damage or deterioration is suspected.11eCFR. 46 CFR 137.300 – Intervals for Drydock and Internal Structural Examinations
Merchant Mariner Credentials
Anyone operating a commercial vessel professionally needs a Merchant Mariner Credential from the Coast Guard. The MMC consolidates what used to be several separate documents into one credential listing every endorsement the holder is qualified for, such as Master, Able Seaman, or a specific engineering rating.12eCFR. 46 CFR 10.201 – General Characteristics of the Merchant Mariner Credential
You also need a valid Transportation Worker Identification Credential from TSA. Without a current TWIC, the Coast Guard can deny the MMC application, and losing your TWIC later can trigger suspension or revocation.
An original MMC requires documented sea service time for the specific endorsement, passing written knowledge and proficiency exams on subjects like navigation and safety, and a medical exam on Form CG-719K showing you meet standards for vision, hearing, and general fitness. A drug test is mandatory; failing it blocks the credential. The Coast Guard also reviews criminal records for suitability.13eCFR. 46 CFR Part 10 Subpart B – General Requirements for All Merchant Mariner Credentials Application fees typically run between $145 and $240 depending on whether you took a certified preparatory course or are sitting the Coast Guard exam directly, plus a $45 issuance fee.
An MMC is valid for five years. To renew, you must satisfy at least one currency requirement: at least one year of sea service during the previous five years, a comprehensive open-book exercise, an approved refresher course, or three years working as a qualified instructor or in a position closely related to vessel operations. Officer endorsement holders who use the instructor or shore-side route must also demonstrate current knowledge of the Rules of the Road through an open-book exercise.
Pollution and Discharge Rules
The Coast Guard enforces the domestic side of MARPOL through the Act to Prevent Pollution from Ships. Violations carry a civil penalty of up to $25,000 per offense, with each day of a continuing violation counted separately. A false statement in connection with MARPOL requirements is a separate offense, up to $5,000 per statement.14Office of the Law Revision Counsel. 33 USC 1908 – Penalties for Violations
Any discharge of oil or oily mixtures from a vessel’s bilge must keep the oil content below 15 parts per million, inside or outside 12 nautical miles from land. The vessel must be en route rather than anchored, must have functioning oily-water separating equipment with a 15 ppm bilge alarm, and the discharge cannot include cargo residues or come from a cargo pump room.15eCFR. 33 CFR 151.10 – Control of Oil Discharges
Vessels 26 feet and over must display a durable placard in each machinery space stating that oil discharge is prohibited and warning of penalties.16eCFR. 33 CFR 155.450 – Placard A separate garbage placard is also required, showing that dumping plastics overboard is banned everywhere and that other garbage discharge is prohibited in navigable U.S. waters except in limited circumstances.17eCFR. 33 CFR 151.59 – Placards Manned oceangoing ships of 400 gross tons and above must maintain a written garbage record book documenting every discharge or disposal.18eCFR. 33 CFR Part 151 Subpart A – Garbage Pollution and Sewage
Tank vessels that carry oil in bulk as cargo must have an approved Vessel Response Plan detailing procedures and resources for handling a spill.19eCFR. 33 CFR 155.1015 – Applicability Nontank self-propelled vessels of 400 gross tons or more that carry oil as fuel also need a VRP. Those with an oil capacity of 250 barrels or greater must identify specific contracted response resources capable of handling the maximum probable discharge. Smaller nontank vessels between 400 gross tons and the 250-barrel threshold still need the plan but aren’t required to pre-contract response resources.
Commercial vessels that take on and discharge ballast water must use a Coast Guard-approved ballast water management system. The discharge standard caps living organisms at fewer than 10 per cubic meter for organisms 50 micrometers or larger, and fewer than 10 per milliliter for organisms between 10 and 50 micrometers. Indicator bacteria like E. coli and intestinal enterococci are capped at 250 and 100 colony-forming units per 100 milliliters, respectively.20eCFR. 33 CFR 151.2030 – Ballast Water Discharge Standard (BWDS)
Any vessel with an installed toilet must have an operable Marine Sanitation Device. Vessels 65 feet or shorter can use a Type I, II, or III device. Vessels longer than 65 feet must use a Type II or Type III. Type III is a holding tank that prevents any overboard discharge. Many states and federally designated no-discharge zones prohibit all overboard sewage discharge regardless of treatment, requiring pump-out at shore-side facilities.21eCFR. 33 CFR Part 159 – Marine Sanitation Devices
Rules That Apply to Coast Guard Members
Coast Guard service members are held to military standards as a branch of the armed forces. All active-duty and Selected Reserve members are subject to the Uniform Code of Military Justice, which governs discipline and conduct across every military branch.22Office of the Law Revision Counsel. 10 USC Ch. 47 – Uniform Code of Military Justice Starting in 2026, able-bodied active-duty and Selected Reserve members must complete physical training at least four days per week and pass a fitness test twice a year, with time and distance requirements scaled by age group. The service maintains zero-tolerance policies on hazing, bullying, and sexual assault, with established reporting channels. These rules govern the people enforcing the maritime regulations above; they don’t apply to civilian boaters or mariners.