OUPV & 100-Ton Master

OUPV — the "six-pack":

The Operator of Uninspected Passenger Vessels credential authorizes carrying up to SIX passengers, at least one of whom is carried for hire, on an uninspected vessel. It is the classic charter-fishing / dive-boat license. It never authorizes carrying seven or more passengers, and it does not authorize operating an inspected vessel.

Master (25/50/100 GRT):

A Master credential authorizes operating inspected vessels up to the licensed tonnage (commonly 25, 50, or 100 gross register tons) and carrying passengers up to the number stated on the vessel's Certificate of Inspection (COI) — which can be far more than six. The tonnage you are licensed for is set by the tonnage of the vessels on which you earned and demonstrated your service.

The seven-passenger line:

The bright line in U.S. law: carrying MORE than six passengers makes the vessel a "small passenger vessel" that must be inspected (hold a COI), and the operator must hold a Master's license, not an OUPV. This is the most common conceptual exam question in this subject.

Tonnage terms:

Gross register tons (GRT) is a measure of a vessel's internal volume, not its weight. Licenses are tonnage-limited (e.g., "Master 100 GRT"); the limit reflects the size of vessel you may command.

Inland:

Waters shoreward of the COLREGS Demarcation Lines and other designated inland waters. An inland-only credential does not authorize operating seaward of the demarcation lines.

Great Lakes:

A distinct route covering the Great Lakes and connected waters.

Near coastal:

Authorizes operation on the oceans not more than 200 nautical miles offshore. This is the route most coastal charter operators hold.

Oceans:

Authorizes operation beyond 200 nautical miles offshore — required for true offshore work.

Demarcation Lines:

The COLREGS Demarcation Lines (published in the Navigation Rules and on charts) mark the boundary between waters where the International Rules (COLREGS) apply seaward and the Inland Rules apply shoreward. They also separate "inland" from "near coastal" for credential purposes.

OUPV sea service:

Generally 360 days of sea service, of which at least 90 days must be within the three years immediately before application. (Routes and tonnage can affect specifics.)

Master 100 GRT sea service:

Generally 720 days of sea service, with a portion on vessels of appropriate tonnage and recency, to support the higher tonnage and inspected-vessel authority.

Definition of a "day":

A day of sea service is a minimum of four hours aboard a vessel in operation. Watchstanding or day-working underway counts; sitting at the dock not operating does not.

Minimum age:

You must be at least 18 years old to hold an officer endorsement such as OUPV or Master.

TWIC:

A valid Transportation Worker Identification Credential (TWIC) — which requires a TSA security threat assessment — is a prerequisite to obtaining or renewing the Merchant Mariner Credential (MMC).

Physical and renewal:

A current medical certificate is required, and the MMC officer endorsement is generally valid for five years, with recency-of-service or exam, a physical, and drug-test compliance required at renewal.

What Subchapter T covers:

Small passenger vessels of under 100 gross tons carrying more than six passengers (and certain vessels carrying at least one passenger for hire). These are inspected vessels and must hold a valid COI. (Subchapter K covers similar vessels carrying more than 150 passengers or with overnight accommodations for more than 49.)

Certificate of Inspection (COI):

The COI states the route and operating area, the maximum number of passengers, the minimum crew (manning), and the required lifesaving and firefighting equipment. The passenger number on the COI is an absolute limit — exceeding it is a serious violation.

Posting the COI:

The COI must be framed under transparent material and posted in a conspicuous place aboard the vessel.

Passenger safety orientation:

Before getting underway, the operator must give passengers a safety orientation covering the location and use of life jackets, emergency exits, and what to do in an emergency.

Stability letter / capacity:

Inspected small passenger vessels are assigned a maximum number of persons based on stability and other criteria; the figure on the COI (not the builder's capacity plate) governs the passenger-for-hire operation.

Life jackets (PFDs):

One Coast Guard-approved, properly sized, readily accessible wearable PFD for each person aboard. Vessels 16 feet and over must also carry at least one Type IV throwable device, immediately available. A Type I offshore PFD has the most buoyancy and will turn most unconscious wearers face-up.

Fire extinguishers:

Approved marine fire extinguishers (rated "B" for flammable-liquid fires) in numbers based on vessel length and whether a fixed system is installed. The Roman numeral (B-I, B-II) is the size, not the fire class.

Backfire flame arrestor:

Required on each inboard gasoline engine (other than outboard motors) to prevent a carburetor backfire from igniting engine-space vapors. Diesels do not require one.

Ventilation:

Gasoline-powered vessels with enclosed engine/fuel spaces require ventilation (ducts and often a powered blower) to purge explosive vapors; run the bilge blower before starting a gasoline engine.

Visual distress signals (VDS):

Required on coastal waters, the Great Lakes, and the high seas (and connected waters to a point two miles wide). A hand-held red flare is approved for both day and night; orange smoke is day-only; an SOS electric light is night-only.

Sound-producing device and backfire/navigation gear:

An efficient sound signal is required; vessels 12 meters and over must also carry a bell (Navigation Rules, Rule 33). Proper navigation lights are required when operating between sunset and sunrise or in restricted visibility.

Alcohol limit:

For commercial vessel operators the legal limit is a blood-alcohol concentration of 0.04 percent — at or above this the operator is considered intoxicated and may not operate the vessel.

Drug testing program:

To obtain or renew an MMC, an applicant must pass a chemical test for dangerous drugs and be subject to a random-testing program (46 CFR Part 16). Refusing or failing a required test is grounds for denial or action against the credential.

Post-incident testing:

After a serious marine incident, the marine employer must ensure alcohol testing within 2 hours and drug testing within 32 hours of those directly involved (46 CFR Part 4.06), unless documented safety concerns prevent it.

What is a reportable marine casualty:

Reportable casualties (46 CFR 4.05) include any death; an injury beyond first aid; groundings; collisions; loss of main propulsion or primary steering; and property damage above the threshold.

How to report:

Notify the nearest Coast Guard Sector/MSO immediately, and submit a written report on Form CG-2692 within five days. A timely, accurate logbook supports the report and demonstrates prudent seamanship.

Metacentric height (GM):

GM is the distance between the center of gravity (G) and the metacenter (M). A positive GM (M above G) means the vessel is stable and will right itself. Adding weight high raises G, reduces GM, and makes the vessel more tender (slower to return upright).

Stiff vs. tender:

A stiff vessel (large GM) snaps back quickly with a short, jerky roll. A tender vessel (small GM) rolls slowly and hangs at the end of each roll — uncomfortable, and a warning of reduced reserve stability.

Free surface effect:

Liquid free to move in a partially filled tank or a flooded space shifts to the low side as the vessel heels, moving G off-center and reducing effective GM. Press tanks full or pump them dry; remove accumulated bilge or firefighting water.

Passenger movement:

A sudden shift of passengers to one rail moves G off-center and can cause a dangerous list or capsize, especially on a tender or overloaded vessel. Actively manage where passengers stand, particularly in turns and wakes.

Capacity and good practice:

Never exceed the passenger number authorized by the credential and (for inspected vessels) the COI. In rough weather, prudent operators carry less than the fair-weather maximum, brief passengers, and require PFD wear when conditions warrant.