A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

aerate 
To force air and oxygen into livewells to keep fish or bait alive. Also, to force air under the running surface of a hull. 

aft 
The rear of the boat. 

aft cabin 
Sleeping quarters beneath the aft or rear section of the boat (sometimes called a mid cabin when located beneath the helm). 

alee 
The side of a boat or object away from the direction of the wind. 

aloft 
Above deck in the rigging. 

aluminum fish boat 
Small, lightweight, durable trailerboat constructed of aluminum that is either welded or riveted; generally used for freshwater fishing. 

amidships 
Center section of a boat. 

anchorage 
A location intended or suited for anchoring. 

anti-fouling paint 
A special paint applied to a boat's hull to prevent marine growth. 

apparent wind 
The direction and velocity of wind as felt in a moving boat. 

astern 
The direction toward or beyond the stern. 

athwart 
Perpendicular to a boat's centerline. 

aweigh 
An anchor that is off the bottom. 

axle ratio 
The relationship of revolutions of a tow vehicle's axle to that of its driveshaft or transaxle, e.g. 2.74:1.



B

backing down 
Maneuvering in reverse when offshore fishing while attempting to land a fish. 

bail 
To remove water with a bucket or pump. Also, a component that controls fishing line on a spinning reel. 

bait station 
Area on a fishing boat for preparing bait. 

baitwell 
Compartment on a fishing boat for holding live bait, usually with a pump to circulate the water and an aerator to provide oxygen. 

ballast 
Weight added to the bottom of a boat to improve stability. 

bass boat 
Low-profile, outboard-powered boat,; generally no more than 22 feet long and typically equipped with rod lockers, casting decks with pedestal seats, and livewells. 

bay boat 
Low-profile, inshore fishing boat intended for use in protected coastal waters; frequently made with rolled-edge construction. 

beach catamaran 
Small, lightweight sailboat less than 25 feet long that can be easily launched and retrieved from a beach. 

beam 
Measurement of a boat at its widest point. Also, a transmitted radio, sonar or radar signal. 

bear off 
To turn away from the wind. 

bearing 
Direction to an object. 

berth 
A place to sleep aboard a boat. Also, a boat slip. 

bilge 
Lowest section inside a boat's hull where water collects. 

bimini top 
A canvas cover over the helm or cockpit area. 

bitt 
Vertical post extending above the deck to secure docking lines. 

bluewater fishing boat 
Mid-size to large deep-V boats suitable for offshore fishing. They are typically fitted with outriggers, fish boxes, aluminum towers, a host of electronics and large fuel tanks. 

bow 
Forward portion of a boat. 

bow eye 
A stainless steel U-bolt on a boat's bow stem used to secure tow lines or trailer winch hooks. 

bow stop 
Rubber blocks on a boat trailer into which the boat;s stem rests. 

bowrider 
A runabout boat with open-bow seating. 

bowsprit 
A spar extending forward of the bow on a sailboat. 

breakaway lanyard 
Emergency safety cable on a boat trailer that activates trailer brakes in the event the trailer becomes detached from the tow vehicle while underway. 

bridge clearance 
Distance from waterline to a boat's highest point. 

bulkhead 
Transverse wall in a boat that usually bears weight and supplies hull support. 

bunks 
Long carpeted sections of a boat trailer that support the boat's weight. 

buoy 
An anchored floating object that serves as a navigation aid. Also used to mark a mooring spot.



C

can buoy 
Cylindrical navigation buoy with a flat top, generally green in color. 

capsize 
To flip a boat over. 

capstan 
A winch used for hauling heavy objects such as anchors. 

cast off 
To unfasten all lines in preparation for departure. 

casting platform 
Elevated deck clear of obstruction used by anglers to make casts, often equipped with pedestal chairs. 

catamaran 
A twin hulled boat, either power or sail. 

cavitation 
Inefficient low-pressure pockets on propellers form bubbles that collapse against the blades resulting in premature wear. 

center console boat 
Fishing boat with the helm station located amidships for maximum walk-through space around the perimeter of the boat. 

centerboard 
A keel-like pivoting device, typically in a trunk, that can be lowered or raised to act as a keel. 

channel 
The navigable portion of a waterway. 

chart plotter 
Electronic navigation device that displays charts for use in plotting a course. 

chart recorder 
An electronic depth sounder that records bottom structure data on paper. 

charts 
Paper or electronic navigation maps. 

chine 
Portion of the hull where the bottom and sides intersect (can be rounded or angled). 

chopped fiberglass 
Fiberglass strands cut and simultaneously mixed with resin and applied to a boat mold by using a chopper gun. 

chumming 
Placing fish or fish parts in the water to attract game fish. 

class I hitch 
Trailer hitch with a weight-carrying capacity up to 2,000 pounds; available as a bumper mount, step bumper or bumper/frame mount. 

class II hitch 
Frame-mounted trailer hitch with a weight-carrying capacity of up to 3,500 pounds. 

class III hitch 
Frame-mounted trailer hitch with a weight-carrying capacity of up to 5,000 pounds. 

class IV hitch 
Frame-mounted trailer hitch with a weight-carrying capacity of up to 10,000 pounds. 

cleat 
Hardware on a boat or a dock to which lines are attached. 

coaming 
A raised edge, as around the cockpit or a hatchway, to keep water out. 

Coast Guard safety package 
Basic safety gear required by federal law consisting of a personal flotation device; a throwable flotation device; visible distress signals; fire extinguisher; and a horn, whistle or bell. 

cockpit 
Deck space for the crew of a boat, typically recessed. 

COLREGS 
Coast Guard term for the navigation rules of the road; full name is International Regulations for Preventing Collisions at Sea. 

come about 
To tack or change heading relative to the wind. 

companionway 
Entryway from the deck to the belowdeck cabin area. 

convertible 
A bluewater fishing boat typically more than 35 feet long with a full cruising salon, a fish-fighting cockpit and many other saltwater fishing features. 

coring material 
Any of a variety of lightweight materials used between layers of fiberglass laminates to add strength. 

counter rotation 
The act of two propellers spinning in opposite directions on a single shaft. 

coupler 
Component on a boat trailer that connects to the hitch ball. 

course 
Direction in which a boat is steered. 

cruiser 
A boat with overnight accommodations. 

cuddy cabin 
Belowdecks accommodations in the bow area for overnighting and stowage. 

cure 
Hardening process for resin-soaked fiberglass laminates. 

curtains 
Attachable front and side enclosures that protect the helm area from weather.



D

daggerboard 
A keel-like device that is manually raised and lowered vertically without using a hinge. 

davit 
A small crane used to hoist a boat or dinghy or other object. 

dead ahead 
Directly ahead of the bow. 

deadrise 
Degrees of V-shape hull angle measured at the transom of planing powerboats. 

deck boat 
Blunt-bowed power boat generally characterized by an open deck and generous passenger seating. 

deep-V 
A hull shape characterized by a sharp deadrise, typically more than 20 degrees. 

depth sounder 
Electronic sonar device that displays water depth. 

deviation 
The amount of error from displaying magnetic north in a boat's compass caused by the boat's own magnetic interference. 

differential GPS (DGPS) 
A highly accurate global positioning system (GPS) that utilizes a differential radio beacon and receiver to compute and correct the error of all visible satellites sending data to a conventional GPS unit. 

dinette 
A small dining area usually consisting of a table and facing bench seats; it can often be converted into a berth. 

dinghy 
A small sailboat, often raced, that can be sailed on and off a beach. Also a tender, either rowed or equipped with power, used to go to and from a larger vessel. 

direct drive 
An engine configuration in which the driveshaft runs in a straight driveline through the bottom of the hull. 

displacement 
The weight of water displaced by a hull. Also, a type of hull that smoothly displaces water as opposed to riding on top of it. 

displacement hull 
A hull shape designed to run through water rather than on top of it in the manner of a planing hull. 

downrigger 
A gunwale-mounted weighted line device used for deep-water trolling. 

draft 
Vertical distance a boat penetrates the water. 

drogue 
A parachute-like sea anchor. 

dry weight 
Weight of the boat without fuel and fresh water. 

dual-console boat 
A type of boat with twin dashboards separated by a centerline walk-through deck leading to the bow.



E

EPIRB 
Acronym for emergency positioning indicating radio beacon. When this electronic device is activated, it transmits a radio signal with user registration data and positioning information to a network of satellites that assist the Coast Guard in conducting an emergency rescue. 

express cruiser 
A cruising boat without a deck-level salon. Sometimes called a sunbridge cruiser.



F

fathom 
Nautical depth measurement equaling six feet. 

fender 
A cylindrical or round cushion used to protect the hull sides of a boat, typically used when tied up at dock. 

fetch 
To clear a buoy, point of land or object without having to make a tack. 

fiberglass 
Glass fibers either loose or woven, reinforced with resin and used in the construction of many boats. 

fighting chair 
A fix-mounted chair used to help land large game fish on bluewater fishing boats equipped with a footrest, gimbal-mounted rod holder, safety harness and other fish-fighting gear. 

fin keel 
A keel shaped like the fin of a fish that is shorter and deeper than a full-length keel. 

fish finder 
Electronic device that uses sonar to locate and display fish on a monitor. 

fix 
The position of a boat recorded in coordinates or bearings. 

flare 
A pyrotechnic device used to indicate distress. Also, the outward curvature of the sides on the bow of a boat. 

flat-bottom boat 
Type of boat or hull shape with very little or no deadrise. 

flats boat 
Type of small, inshore saltwater fishing boat with moderate deadrise and draft, usually equipped with a raised platform aft used by a guide pushing a long pole to silently maneuver the boat through shallow tidal water. 

flying bridge 
Raised, second-story helm station, often located above the primary helm. 

following sea 
Wave pattern running in the same direction as the boat. 

fore 
Located at the front of a boat. 

foredeck 
Forward part of the main deck, ahead of the superstructure. 

foul-weather gear 
Jacket, pants and hat used during inclement weather. 

founder 
To sink. 

four-cycle engine 
A gasoline- or diesel-powered internal combustion engine that takes four cycles or strokes of the piston to complete its power phase. Also called four-stroke engine. 

frame-mount hitch 
Hitch fastened to the frame of a tow vehicle. 

freeboard 
Vertical distance between the waterline and the top of the hull side. 

furling 
Rolling or folding a sail on its boom.



G

gaff 
A metal pole with a hooked end used to boat a fish. Also a pole or spar that holds the upper portion of a four-sided sail. 

galley 
The kitchen area on a boat. 

gelcoat 
A combination of resin and pigment that comprises the smooth outside coating of a fiberglass boat. 

genset 
Another name for a gas- or disel-powered electric generator. 

give way 
Yield to other traffic. 

GPS 
Acronym for global positioning system, a satellite-based navigation system that uses trasmitted signals and mathematical triangulation to pinpoint location. 

gross axle weight rating (GAWR) 
The maximum weight an axle is designed to carry. 

gross combined weight rating (GCWR) 
The maximum allowable weight of a fully loaded tow vehicle plus its fully loaded trailer, including passengers and cargo. 

gross trailer weight rating (GTWR) 
The maximum allowable weight of trailer and its cargo. 

gross vehicle weight rating (GVWR) 
The maximum allowable weight of a fully equipped tow vehicle including passengers and cargo. 

gunkholing 
To explore creeks, coves marshes or other shallow areas near shore. 

gunwale 
The upper edge of the side of a boat. 

gybe 
Also spelled jibe. To change the course of a boat so that the boom swings over to the opposite side.



H

harbor master 
The person at a harbor in charge of anchorages, berths and harbor traffic. 

hard chine 
A sharp angle at the intersection of the hull's side and bottom. 

hard over 
Turning the steering wheel or tiller all the way in one direction. 

hard-top 
A large fiberglass roof or platform over the helm area. 

hatch 
A deck opening. 

hauling 
To lift a boat from the water. 

hawse pipe 
Fittings in the deck or gunwale through which the anchor rode or dock lines run. 

head 
Toilet facilities or room where they are located. 

head seas 
Waves coming from the direction a boat is heading. 

heading 
The direction a boat is pointed. 

headway 
Forward motion of a boat in the water. 

heave 
To pull on a line. Also to throw a line. 

heaving to 
Setting the sails so the boat makes little headway, either used in a storm or a waiting situation. 

heel 
To temporarily tip or lean to one side. 

helm 
Area of a boat where operational controls are located. 

high-performance boat 
A type of boat capable of running at high speeds, often equipped with high horsepower and exotic propulsion systems, sometimes used for racing. 

hitch 
Steel framework on a tow vehicle used to hook up a trailer. 

hitch ball 
The ball-shaped component of the hitch that fits into the trailer coupler. 

holding tank 
Storage tank for gray water. 

houseboat 
A large, flat-bottom boat with square sides and house-like characteristics, such as comfortable furniture and living accommodations. 

hull 
The structural body of the boat that rests in the water.



I

inboard engine 
An internal combustion engine often mounted amidships that runs a driveshaft through the hull bottom. 

inboard/outboard (I/O) 
See stern drive. 

inflatable 
Capable of being inflated either with air, as in a life raft or life vest. 

inflatable boat 
A type of boat with air chambers into which air is pumped either manually or automatically for buoyancy, some having rigid bottoms. 

inner liner 
Smooth-finished, molded fiberglass structure adjacent to the inside portion of the hull. 

inverter 
Device that changes 12-, 24- or 32-volt direct current (DC) from a battery to 120-volt alternating current (AC).



J

jack plate 
A mounting device for an outboard motor that enables operators to vertically raise or lower the motor, thereby controlling propeller depth in the water. 

jet boat 
A boat powered by an engine with a water pump used to create propulsion. 

jibe 
See gybe.



K

keel 
The bottom-most portion or longitudinal centerline of a hull. 

kicker motor 
A small auxiliary outboard motor. 

kill switch 
A switch with a lanyard that automatically shuts off an engine if disconnected. 

kite fishing 
A technique that involves attaching a fishing line to a kite to present bait at a distance from the boat. 

knot 
Speed measured in nautical miles per hour.



L

laminate 
A single layer of material used in multi-layered fiberglass construction. 

latitude 
Geographic distance north or south of the equator expressed in degrees and minutes. 

leaning post 
Wide, padded bolster at the helm used instead of conventional seats. 

lee 
Direction toward which the wind blows. 

lee side 
The side of an object that is sheltered from the wind. 

leeway 
To slip sideways downwind while moving forward. 

lifeline 
Safety lines on deck that are grabbed to prevent falling overboard. 

list 
A continuous lean to one side due to improper weight distribution. 

livewell 
Compartment on a fishing boat designed to keep fish or bait alive. 

LOA 
Length overall; the distance between the most forward part of the boat and the most aft part. 

locker 
A stowage compartment, whether equipped with a lock or not. 

longitude 
Geographic distance east or west of the prime meridian expressed in degrees and minutes. 

Loran C 
Electronic navigation system that measures the time difference in the reception of radio signals from land-based transmitters.



M

make fast 
To secure a line. 

marinization 
The addition of marine components to automotive engines. 

MAYDAY 
A radio distress call. 

midships 
Location near the center of a boat. 

modified-V hull 
A modification of the deep-V hull shape with a deadrise of less than 20 degrees. 

mold 
A hollow reinforced cavity that is the mirror-image or reverse-image of the boat and into which fiberglass, gel coat and resin are laid during composite-hull construction. 

monohull 
A boat with a single hull. 

mooring 
Permanent ground tackle fixed to a buoy that boats can tie to. 

motoryacht 
A large powerboat greater than 40 feet with luxurious interior accommodations for long-range cruising. 

multihull 
A boat with more than one hull, such as a catamaran or trimaran.



N

nautical mile 
A distance of 6,076.12 feet or 1,852 meters, which is about 15 percent longer than a statute mile. Equivalent to one minute of latitude on a navigation chart. 

nun buoy 
Conical navigation buoy that is usually red.



O

outboard bracket 
Support device for mounting outboard engines that extends aft of the transom. 

outboard motor 
Internal combustion engine mounted at the transom that incorporates motor, driveshaft and propeller. 

outdrive 
The lower unit of a stern-drive motor that houses the drive gears and to which the propeller fastens. 

outrigger 
Poles designed to spread out fishing lines and keep them from tangling while trolling. 

overboard 
Over the side of a boat and into the water.



P

personal flotation device (PFD) 
A safety vest or jacket capable of keeping an individual afloat. 

personal watercraft (PWC) 
A small, lightweight craft designed for sitting or standing with motorcycle-like handlebars and squeeze throttle, usually jet-propelled. 

piling 
A post driven into the ground below the waterline to support a pier, dock, etc. 

pilot house 
A fully enclosed helm compartment. 

pitch 
Theoretical distance a propeller would travel in one revolution. Also, the rise and fall of a boat's bow and stern. 

planing hull 
A boat hull designed to ride on top of the water rather than plowing through it. 

pleasure boating 
Recreational day boating in runabouts, deck boats, pontoon boats, bowriders and sportboats. 

plot 
To plan a navigation course using a chart. 

poling platform 
Small elevated stand on a flats boat used by a fisherman to silently pole through shallow water and scout for fish. 

pontoon boat 
A type of boat with a flat deck attached to airtight flotation tubes or logs. 

port 
The left side of a boat when facing the bow. Also, a marina harbor or commercial dock. 

power catamaran 
A multihulled powerboat with two identical side-by-side hulls. 

power cruiser 
A powerboat with overnight accommodations, typically up to 40 feet long. 

propeller 
A rotating multi-blade device that propels a boat through the water. 

pulpit 
Forward deck and railing structure at the bow of a boat. 

PWC 
See personal watercraft.



Q

quarter 
The aft side of a boat from amidships to stern. 

quartering 
The practice of aiming the boat's bow at a 45-degree angle to oncoming waves. 

quarters 
Living and sleeping areas of a vessel.



R

racer 
A sailboat designed primarily for speed and competition with a minimum of built-in creature comforts. 

racer/cruiser 
A fast sailboat designed with comfortable accommodations. 

radar 
Electronic device using high-frequency radio waves to detect objects and display their positions on a monitor. 

range 
Distance a boat can travel at cruising speed on a tank of fuel. Also, the distance to an object. Lastly, in intracoastal navigation, a set of two markers that, when lined up one behind the other, indicate the deepest part of the channel. 

receiver box 
Part of a hitch that receives and holds the hitch bar or shank. 

receiver hitch 
A hitch with a receiver from which a hitch bar or shank can be removed. 

resin 
Liquid substance used in fiberglass composite construction that, when combined with a catalyst, bonds laminate materials together. 

reverse chine 
A chine that angles downward from the hull designed to direct spray out and away from the boat. 

RIB (rigid inflatable boat) 
An inflatable boat fitted with a rigid bottom. 

rocket launcher 
A device designed for a fishing boat that bolts to the cockpit floor or is incorporated into a bench seat, to hold mulitple fishing rods. 

rod holder 
Device designed to safely and securely hold fishing rods either vertically or horizontally. 

rode 
Line, chain, cable or any combination of these used to connect the anchor to the boat. 

rolled-edge skiff 
A fishing boat designed to run in coastal waters, constructed of a simple, one-piece fiberglass hull without a top deck and characterized by rounded top edges without true gunwales. 

roller trailer 
A trailer outfitted with rollers instead of bunks. 

rubrail 
Protective outer bumper that runs around the boat at the point where the top deck meets the hull. 

rudder 
Underwater fin mounted below the hull near the stern that controls boat steering. 

runabout 
A small, lightweight, freshwater pleasurecraft intended for day use. 

running lights 
Required navigation lights that a vessel uses at night to indicate position and status.



S

safety chains 
Legally mandated chains that connect the trailer to the tow vehicle as a safety measure in case the coupler detaches. 

safety harness 
A harness worn by a boater attached to the boat with a tether to reduce the chances of going overboard. 

sag 
To slide or drift off course. 

salon 
Full-sized, well-appointed cabin on the main deck level of a motoryacht, convertible or megayacht used for entertaining. 

saltwater fishing boat 
Any fishing boat used in the ocean or coastal waters that's specially equipped to handle the harsh saltwater environment. 

scope 
The ratio of anchor rode to vertical depth. 

scud 
To run before the wind in bad weather. 

scuppers 
Gravity fed drain in a boat to allow water to drain out and overboard. 

scuttle 
To cut holes or open ports to purposely let water in to make a boat sink. 

scuttlebutt 
Gossip. So named after a water cask around which sailors used to gather and drink. 

sea anchor 
A canvas, cone-shaped device deployed to keep the bow headed into the wind to help safely ride out a storm. Also called a drogue. 

seacock 
Through-hull fitting with a valve between the interior and the exterior of the boat. 

seaworthy 
Ability to handle rough weather. Also called sea-kindly. 

sedan cruiser 
A type of large boat equipped with a salon and a raised helm or bridge. 

selective availability 
Intentional degradation of GPS signal used for position fixing by the U.S. Department of Defense for purposes of national security. With selective availability turned on, positions can be fixed to about 300 meters. With selective availablity turned off, positions can be fixed to about 100 meters. 

self-bailing 
Drains water overboard automatically. 

semi-displacement hull 
A hull shape with soft chines or a rounded bottom that enables the boat to achieve minimal planing characteristics. 

sheer 
Line of the deck or gunwale from bow to stern as viewed from outside the boat. 

side console 
A dash-panel unit affixed to the side of a boat. If only one, helm controls are affixed to it. 

skeg 
A fin or vertical projection below the hull that provides directional stability. Also, a fin-like projection at the bottom of an outboard. 

skiff 
A small, simple, shallow-draft boat. 

skiing/wakeboarding boat 
Low-profile, pleasure boats with minimal deadrise specifically designed for waterskiing and/or wakeboarding. These boats are usually characterized by an inboard engine and a towing pylon. Wakeboard boats are often equipped with a tower or extremely tall pylon to fasten the tow line in a manner to aid vertical jumping and water-ballast devices to increase the weight of the boat. 

slip 
A boat berth between two piers or floats. Also, the slight loss of efficient power delivery as a propeller spins in the water. 

sole 
The deck floor. 

sonar 
A method to locate objects and determine distance by transmitting sound waves through water and measuring the time it takes the echo to bounce back. Used in depth finders and fish finders. 

sounding 
Charted water depth. 

sportfish 
A type of bluewater fishing boat with at least two sleeping cabins and many dedicated fish-fighting features. 

spring line 
A docking line attached amidships to control fore and aft movement. 

stand by 
An order to crew to be ready, be prepared. 

stand on 
Maintain course and speed. 

starboard 
The right side of the boat looking toward the bow. 

stateroom 
A room with sleeping quarters, a cabin. 

statute mile 
Distance of 5,280 feet, the standard measure of distance on land and most inland waterways. 

stem 
The most forward section of the hull. 

stepped hull 
A high-performance hull design with lateral notches, or steps, in the keel. 

stern 
Aft portion of a boat. 

stern drive 
Propulsion system composed of an inboard engine connected to a steerable drive unit extending through a cutout in the transom. 

stow 
To put an object away onboard a boat, to store. 

strakes 
Small linear protrusions that run longitudinally on both sides of the keel to give a planing hull lift and lateral stability. 

stringers 
Internal beams and braces that give a fiberglass hull structural support. 

surge brakes 
Hydraulic trailer brake system activated by the sudden inertia of a trailer pushing against the tow vehicle during a hard stop. 

swamp 
To fill a boat with water. 

sway 
Side-to-side wandering of a trailer under tow. 

swim platform 
A wide platform at the transom equipped with a ladder to make reboarding easier.



T

T-top 
Short, aluminum tower with overhead canvas to protect the helm. 

tack 
The lower corner of a sail. Also, each leg of a zigzag course. 

tender 
See dinghy. 

through-hull 
A fitting or object that goes all the way through a hull. 

tiller 
A bar connected to the rudder and used to steer the boat. 

tiller handle outboard 
A small, outboard motor that uses a handle fitted with engine controls to steer instead of a steering wheel. 

tongue jack 
Adjustable jack on the trailer tongue that raises and lowers the coupler. 

tongue weight 
The measurement of trailer weight when loaded with a boat on the hitch ball. 

topside 
The hull above the waterline. Also, everything above deck as opposed to below deck. 

tow rating 
Maximum weight a vehicle is rated to tow. 

trailer tongue 
Forward portion of a trailer where the coupler is mounted. 

trailer winch 
Device that uses a crank and cable to assist in launching and retrieving a boat. 

transducer 
An electronic sensing device mounted in a boat's bilge or at the bottom of the transom to provide data for a depth sounder. 

transom 
The rear section of the hull connecting the two sides. 

transom shower 
A plastic hose and shower head located near the transom that draws from a fresh water supply. 

trawler 
A pleasure boat more than 25 feet in length with a displacement hull. 

trim 
The way a boat floats in relation to the horizon, bow up, bow down or even. Also, to adjust a boat's horizontal running angle by directing the outboard or stern drive's thrust up or down. Also, to set a sail in correct relation to the wind. 

trim tabs 
Hydraulically adjusted horizontal plates located on the bottom of the transom that control the trim angle of a boat at speed. 

trimaran 
A type of boat with three side-by-side hulls, the center of which is usually larger with crew accommodations. 

trolling 
To fish by towing an array of baited lines or lures behind the boat. 

true wind 
Direction and velocity of wind as measured on land, distinct from apparent wind. 

tuna tower 
Tall aluminum tower used for spotting fish in the distance, often equipped with a second set of helm controls. 

two-cycle engine 
A gasoline- or diesel-powered internal combustion engine that takes two cycles or strokes of the piston to complete its power phase. Also called two-stroke engine.



U

underway 
A boat in motion. 

utility boat 
A small, open powerboat, constructed of either fiberglass or aluminum, with minimal features. These include jon boats, skiffs and work boats.



V

V-berth 
A bed or berth located in the bow that has a V-shape. 

V-drive 
Propulsion system where the drive shaft initially runs forward into a gear box and then runs aft and down through the hull. The driveline forms a V-shape with the gear box at the pivot point. 

variation 
Compass variable that accounts for the difference in degrees between true north and magnetic north. 

ventilation 
Air introduced into a spinning propeller from the water's surface. 

VHF 
Very high frequency; a bandwidth designation commonly used by marine radios.



W

wake 
Waves created by a moving boat. 

walkaround 
A type of offshore fishing boat with a small to mid-size cabin and a perimeter deck that allows easy passage around the entire boat. 

waterline 
The intersection of the hull and the surface of the water. 

waypoint 
The coordinates of a specific location. 

weigh 
To raise anchor. 

windlass 
Rotating drum device used for hauling line or chain to raise and lower an anchor.



Y

yachting 
To cruise in a motor yacht that typically ranges from 40 to 89 feet long. 

yaw 
To veer off course.



Z

zinc anodes 
Small pieces of zinc that attach to metal boat and engine components to help protect them from corrosion due to electrolysis, an effect caused when dissimilar metals are placed in a saltwater solution.