Frequently used boating terms and phrases
Abandoned vessel

These vessels become derelict vessels quickly and then subject the boating public to safety issues, become locations for illegal activity, illegal housing, opportunities for theft and vandalism and ultimately cost the taxpayers to be removed by Local, County or State authorities.

Aids to Navigation (ATONS)

Charted objects available to assist in determination of position, safe course, or to warn of danger (e. g. buoys, beacons, fog signals, lights, radio beacons, range marks). Also, electronic device used for navigation.


A boat propelled by an engine producing air thrust. This type of boat does not include ground effect vessels or air cushion vehicles (hovercraft).

Auxiliary Sail

A vessel with sail as its primary method of propulsion and mechanical propulsion as its secondary method.


Blood Alcohol Concentration of 0.08 means 0.08 gram or more per 100 milliliters of the blood of a person or per 210 liters of his or her breath.

At Anchor

Held in place in the water by an anchor; includes “moored” to a buoy or anchored vessel and “dragging anchor.”

Auxiliary Sailboat

A sailboat also equipped with an engine.

Boat (also see “Vessel”)

“Vessel” includes every description of watercraft used or capable of being used as transportation on the water, other than a seaplane.

Boating Under the Influence (BUI)

(see also “Operating Under the Influence” (OUI))

Cabin Motorboat

A motorboat equipped with accommodation spaces, i.e., bunks or berths.


A small narrow boat, propelled by paddles. Canoes usually are pointed at both bow and stern and are normally open on top, but can be covered.

Capacity Plate

Manufacture-required information label providing maximum horsepower and weight carrying limits displayed in view of operator.


Overturning of a vessel.

Carbon Monoxide Poisoning

Death or injury resulting from an odorless, colorless gas generated from auxiliary boat equipment (stoves, heaters, refrigerators, generators, hot water heaters, etc.), another boat’s exhaust, or the exhaust of the vessel on which persons were either aboard or in close proximity.

Cold Water Immersion/Submersion

Cold water immersion is associated with two significant medical emergencies: near drowning and hypothermia. A boater’s chance of surviving cold water immersion depends on having sufficient flotation to keep their head above water, controlling their breathing, having timely rescue by themself or others, and retaining body heat.

Collision with Fixed Object

The striking of any fixed object, above or below the surface of the water.

Collision with Floating Object

Collision with any waterborne object above or below the surface that is free to move with the tide, current, or wind, except another vessel.

Collision with Commercial/ Governmental/Recreational Vessel

Any striking together of two or more vessels, regardless of operation at the time of the accident, is a collision.

Collision with Submerged Object

A boat’s collision with any waterborne or fixed object that is below the surface of the water.

Congested Waters

Where the body of water is either too small or narrow to safely accommodate the number of boats on it.

Crossing the Bar

The bar is the area where the deep waters of the oceans meet with the shallower waters near the mouth of rivers. Most accidents and deaths that occur on coastal bars are from capsizing.


Proceeding normally, unrestricted, with an absence of drastic rudder or engine changes.

Documented Vessel

A vessel of five or more net tons owned by a citizen of the United States and used exclusively for pleasure with a valid marine document issued by the Coast Guard. Documented vessels are not numbered.


Underway, but proceeding over the bottom without use of engines, oars or sails; being carried along only by the tide, current, or wind.


Death or injury resulting from an electrical current that comes in contact with water causing electrocution of the victim.

Emergency Position Indicating Radio Beacon (EPIRB)

An EPIRB is used to alert Search and Rescue assets in the event of an emergency by transmitting a coded message on the 406 MHz distress frequency via satellite and earth stations to the nearest Rescue Coordination Center. An EPIRB is for use on a boat and is registered to that boat.

Engine Cut-Off Switch

A device used to stop the engine and boat propeller in the event of the helmsperson being thrown out of their seat. It consists of a length of cord or plastic wire connected to a switch on the engine or dashboard of the boat.

Excessive Speed

Speed above that which a reasonable and prudent person would have operated under the conditions that existed. It is not necessarily a speed in excess of a posted limit.

Failure to Vent

Prior to starting the engine, failure to turn on the powered ventilation system that brings in “fresh air” and expels gasoline vapors from the engine compartment.

Fall in Vessel

Any operator or passenger who slips, trips, or falls on board or within the vessel.

Falls Overboard

Any operator or passenger who falls off of the vessel.

Fiberglass (Plastic) Hull

Hulls of fiber-reinforced plastic. The laminate consists of two basic components, the reinforcing material (glass filaments) and the plastic or resin in which it is embedded.

Fire/Explosion (Fuel)

Accidental combustion of vessel fuel, liquids, including their vapors, or other substances such as wood.

Fire/Explosion (Other)

Accidental burning or explosion of any material onboard except vessel fuels or their vapors.

Float Plan

Left by the boater before a boating excursion, a float plan provides details on the trip, including details about the boat and the people onboard. A float plan is used by search and rescue personnel to assist in reducing the search area in order to locate the boater(s) in the shortest amount of time possible.


A boat filling with water, regardless of method of ingress, but retaining sufficient buoyancy to remain on the surface.

Force of Wave/Wake

The track in the water of a moving boat; commonly used for the disturbance of the water (waves) resulting from the passage of the boat’s hull.


Any stage of the fueling operation; primarily concerned with introduction of explosive or combustible vapors or liquids on board.


Running aground of a vessel, striking or pounding on rocks, reefs, or shoals; stranding.

Hazardous Waters

Rapid tidal flows (the vertical movement of water) and/or currents (the horizontal flow of water) resulting in hazardous conditions in which to operate a boat.

High-Profile Case

A boat incident or accident that involves celebrities, like movie stars or athletes, or generates a significant amount of press interest such as a human-interest story.

Hit and Run

A boat accident where the boat operator of one or more of the boats involved does not render aid as required by law and leaves the scene of the accident without reporting it or both.


A motorized vessel designed primarily with accommodation spaces with little or no foredeck or cockpit, with low freeboard and with a low length to beam ratio.

Hull Failure

Defect or failure of the structural body of a vessel (i.e., hull material, design, or construction) not including superstructure, masts, or rigging.

Ignition of Spilled Fuel or Vapor

Accidental combustion of vessel fuel, liquids, and/or their vapors.

Improper Anchoring

Where a boat is either in the process of being anchored incorrectly or incorrectly held in place in the water by an anchor.

Improper Loading

Loading, including weight shifting, of the vessel causing instability, limited maneuverability, or dangerously reduced freeboard.

Improper Lookout

No proper watch; the failure of the operator to perceive danger because no one was serving as lookout, or the person so serving failed in that regard. Every vessel shall at all times maintain a proper look-out by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision.


An engine mounted inside the confines of a vessel which powers a drive shaft that turns a water jet impeller or that runs through the bottom of the hull and is attached to a propeller at the other end.

Inflatable Boat

A vessel constructed with its sides and bow made of flexible tubes containing pressurized gas. On smaller inflatables, the floor and hull beneath it is often flexible.

Jet Ski/Jet Skiing

A common term used to describe personal watercraft (PWC). “Jet Ski” is a trademark of the Kawasaki Corporation used to identify a stand-up variety of PWC.


A small boat with a cockpit that is propelled by a double-bladed paddle by a sitting paddler.

Inadequate On-board Navigation Lights

Insufficient and/or improper lights shown by a boat that indicate course, position, and occupation, such as fishing or towing.


Only one state, Alabama, has an endorsement on their driver’s license for boating. States have a system for issuing Boat Course Completion certificates, generally recognized with reciprocity in the United States and Canada. The cards or certificates usually do not have an expiration date. Some states allow for revocation of boating privileges.

Life Jacket (see also “Personal Flotation Device”)

A device that is worn on a person’s upper-body designed to save them from drowning and provide buoyancy in the water. All vessels must be equipped with one U.S. Coast Guard–approved life jacket for each person onboard. The quantity and type depend on the length of the vessel and the number of people onboard and/or being towed. Each life jacket must be in good and serviceable condition, be the proper size for the intended wearer, and be readily accessible.

Life Jacket-Inflatables

Authorized by the U.S. Coast Guard for use by persons 16 years of age and older. Inflatables are more comfortable, encouraging regular use, however they require regular maintenance and attention to the condition of the inflator. Some Inflatables are required to be worn to satisfy carriage requirements and are not authorized for personal watercraft, for white water paddling, water skiing or similar towed water sports or in below freezing conditions. Always read the manufacturer’s information booklet and label provided with all life jackets.

Life Jacket-Readily Accessible

You must be able to put the life jacket on in a reasonable amount of time in an emergency (vessel sinking, on fire, etc.). Life jackets should not be stowed in plastic bags or in locked or closed compartments, and they should not have other gear stowed on top of them. Vessel operators should ask everyone on their vessel to wear a life jacket whenever on the water, they can save lives, but only if they are worn.

Life Jacket-Throwable

Not designed or intended to be worn but is designed to be thrown to a person in trouble in the water and grasped and held by the user until rescued.

Machinery Failure

Defect and/or failure in the machinery or material, design or construction, or components installed by the manufacturer involved in the mechanical propulsion of the boat (e.g., engine, transmission, fuel system, electric system, and steering system).

Marine Pollution

Marine pollution occurs when harmful, or potentially harmful, effects result from the entry into the ocean of chemicals, particles, industrial, agricultural and residential waste, noise, or the spread of invasive organisms.

Missing or Inadequate Navigation Aids

The absence of or ineffective presence of navigation aids.


Any vessel equipped with propulsion machinery. Preferred use powerboat vs motorboat.

National Association of State Boating Law Administrators (NASBLA)

A national nonprofit, 501(c)3 organization that works to develop public policy for recreational boating safety. NASBLA represents the recreational boating authorities of all 50 states and the U.S. territories.

Navigable Waters

Coastal waters, including bays, sounds, rivers, and lakes that are navigable from the sea.

Navigation Rules

On May 17, 2010, the U.S. Coast Guard published a Final Rule, which placed the Inland Navigational Rules into the Code of Federal Regulations. This move was in accordance with the U.S. Coast Guard and Maritime Transportation Act of 2004, which repealed the Inland Navigation Rules as they appeared in United States Code.

Numbered Vessel

An undocumented vessel numbered by a state with an approved numbering system under Chapter 123 of title 46, U.S.C.

Open Motorboat

Craft of open construction specifically built for operating with a motor, including boats canopied or fitted with temporary partial shelters.

Off-Throttle Steering

Term used to identify the problems associated with, and the various solutions for the loss of steering control of a personal watercraft when and operator instinctively releases the throttle in an emergency maneuver.

Operating Under the Influence (OUI)

A crime involving drinking or being under any kind of intoxicant and operating a vessel. A person shall not operate any motorboat or vessel, or manipulate any water skis, surfboard, or similar device while intoxicated or under the influence of any controlled substance.

Operator Inattention

Failure on the part of the operator to pay attention to the vessel, its occupants, or the environment in which the vessel is operating.

Operator Inexperience

Lack of practical experience or knowledge in operating a vessel or, more particularly, the vessel involved in the accident.

Overloaded Boat

Exceeding the designed load limits of a vessel. Excessive loading of the vessel causes instability, limited maneuverability, dangerously reduced freeboard.


An engine not permanently affixed to the structure of the craft, regardless of the method or location used to mount the engine, e.g., motor wells, “kicker pits,” motor pockets, etc.


Excessive loading of the vessel causing instability, limited maneuverability, dangerously reduced freeboard, etc.

People on Gunwale, Bow, or Transom

Standing/Sitting on the upper edge of the side of a boat, usually on a small projection above the deck; and/or standing/sitting on the most forward part of the boat; and/or standing/sitting on the back of the boat.

Person Struck by Vessel

A person is struck by a boat.

Person Struck by Propeller

A person is struck by the propeller, propulsion unit, or steering machinery.

Personal Flotation Device (PFD)

A term used in regulatory language and refers to a U.S. Coast Guard-approved buoyant device designed to assist in keeping a person afloat in the water. The more commonly accepted term is “Life Jacket.”

Personal Locator Beacon (PLB)

A PLB is a small, relatively low-cost, battery-powered device. When activated, a PLB will send out a distress signal once every 50 seconds for a minimum of 24 hours. A PLB works in the same way as an EPIRB by sending a coded message on the 406 MHz distress frequency via satellite and earth stations to the nearest Rescue Coordination Center. A PLB is registered to the person, not a boat.

Personal Watercraft (PWC)

Craft designed to be operated by a person or persons sitting, standing or kneeling on the craft rather than within the confines of a hull.

Pontoon Boat

A boat consisting of a rigid structure connecting at least two parallel fore (front) and aft (back) rigid sealed buoyancy chambers.

Propeller Injury

An injury created by the propeller of the impacting boat. Cuts may be clean, curved, cupped or diagonal as compared to visible skeg line cut.

Proper Lookout

Every operator must keep a proper lookout, using both sight and hearing, at all times. Watch and listen for other vessels, navigational hazards, and others involved in water activities. Failing to keep a proper lookout is the most common cause of collisions.

Proper Ventilation

Ventilation systems are crucial. Their purpose is to avoid explosions by removing flammable gases (gasoline fumes). Properly installed ventilation systems greatly reduce the chance of a life-threatening explosion.


Also known as the Certificate of Number. Issued by government authority and required to be aboard vessel at all times with the exception of rental craft.

Registered Vessel

A numbered vessel under the Federal Boat Safety Act of 1971; any mechanically propelled vessel, regardless of horse power, used on waters subject to federal jurisdiction other than foreign, documented, and government vessels as well as tenders and lifeboats.

Rental Boat Safety

Many rental boat facilities that rent small fishing boats, PWC, Ski boats, all the way up to yachts operate from a marina or in retail markets near a body of water such as rivers lakes or coastal areas. Officially they are known as Liveries. Most liveries are regulated by each state and must comply with standards they impose.

Restricted Vision

A vessel operator’s vision is said to be restricted when it is limited by a vessel’s bow high trim, or by glare, sunlight, bright lights, a dirty windshield, spray, a canopy top, etc.


An open boat propelled by one or more persons using oars.

Rules of the Road Infraction

Violation of the statutory and regulatory rules governing the navigation of vessels.


Any boat whose sole source of propulsion is the natural element (i.e., wind) or a boat designed or intended to be propelled primarily by sail, regardless of size or type.

Sharp Turn

An immediate or abrupt change in the boat’s course of direction. Sinking – Losing enough buoyancy to settle below the surface of the water.


Losing enough buoyancy to settle below the surface of the water.

Skier Mishap

Skier mishap is defined by persons (1) falling off their water-skis, (2) striking a fixed or submerged object, or by (3) becoming entangled or struck by the tow line. Also includes mishaps involving inner-tubes and other devices on which a person can be towed behind a boat.


Operating at a speed, possibly below the posted speed limit, above that which a reasonable and prudent person would operate under the circumstances. Safe speed is the speed that ensures you will have ample time to avoid a collision and can stop within an appropriate distance. Safe speed will vary depending on conditions such as wind, water conditions, navigational hazards, visibility, surrounding vessel traffic density, and the maneuverability of your boat or PWC. Always reduce speed and navigate with extreme caution at night and when visibility is restricted.

Standup Paddleboard (SUP)

A vessel, typically 7’ – 15’ in length with enough width and flotation to stay afloat without momentum while boarded, that is propelled by a standing operator with the use of a single or double-bladed paddle.

Starting in Gear

The boat’s engine is started with the transmission in forward or reverse.

Steel Hull

Hulls of sheet steel or steel alloy, not those with steel ribs and wood, canvas, or plastic hull coverings.


An inboard/outboard engine system, with the engine inside the hull connected to an external lower unit containing a propeller. Steering is achieved by turning the lower unit.

Sudden Medical Condition

An incident where a person on a vessel experiences an unexpected medical condition.

Towed Water Sports

Engaging in any type of water activity while a person outside the vessel is being towed or aided by a tow line.


Engaged in towing any vessel or object, other than a person.


The term “vessel” includes every description of watercraft used or capable of being used as transportation on the water, other than a seaplane.

VHF Marine Radio

VHF marine radios save lives and are easy to use. They are more effective for marine communications than CB radios or mobile phones. No license is needed when used in recreational boats. VHF marine radios withstand rough weather and, if mounted to the boat, have Digital Selective Calling, to help aid in rescue.


Water surface turbulence left by a moving boat.


As a contributing factor of an accident, “weather” is supposed to signify a stormy or windy condition, usually connoting rough or high seas and dangerous operating conditions.

Wood Hull

Hulls of plywood, molded plywood, wood planking, or any other wood fiber in its natural consistency, including those of wooden construction that have been “sheathed” with fiberglass or sheet metal.