Following is a glossary of sailing and nautical terms using US English. We hope you find it useful. Do not hesitate to request additional entries here.

abaft. Behind; as in: The stern is abaft the beam.
abeam. At a right angle to the boat; as in: That buoy lies abeam of us.
aboard. On the boat; as in: If we go aboard the boat now we will be able to leave
adrift. No power, unsecured; as in: Without wind and no engine we would be adrift.
afloat. Floating, as in: Our life jackets will keep us afloat.
aft and after. Direction; as in: Go aft to the stern of the boat.
aground. (not to be confused with grounding at anchor). Stuck on the bottom; as
in: That boat seems to have run aground.
ahead. In front of the boat; as in: Our destination lies ahead.
aid to navigation (ATON). A buoy, channel marker, or light meant to guide
navigation; as in: Be sure to look for any aid to navigation to help guide us into the harbor. An online reference is here:
aloft. Up in the rigging; as in: Our radar reflectors are aloft.
altocumulus clouds. Forming discernable globs, may appear in layers; as in:
Altocumulus clouds usually promise rain soon.
amidships. In the middle of the boat; as in: You will find the galley amidships.
anchor. A device, usually deployed from the bow, used to secure the boat to the
bottom; as in: The use of more than one anchor will limit swing room.
anchor light. A white light that shines so it is visible from all around the vessel
required when anchored or moored between sunset and sunrise. The best place for this light is usually at the top of the highest mast; as in: Once successfully anchored we turn on the anchor light.
anchor watch. Observations taken over a period of time to determine whether the
anchor is holding; as in: During heavy weather it might be a good idea to set an anchor watch.
apparent wind. The wind that is felt on the boat; as in: The apparent wind has
dropped since we went from a beam reach to a broad reach.
astern. Behind the stern of the boat; as in: The competition has fallen astern.
athwartships. Running across the boat from side to side, at a right angle to the
centerline; as in: The transom runs athwartships.
autopilot. Self steering with no need for a helmsperson; as in: With the
autopilot engaged and a proper lookout posted, no one needs to stay at the helm.
auxiliary engine. A small engine (outboard or inboard, gasoline or diesel) used to power a
sailing vessel when not under sail; as in: when we come into the anchorage we'll start the auxiliary engine, head into the wind, furl our sails, then proceed to anchor.
aweigh. Anchor being lifted off the bottom, weighing anchor; as in: Anchors
aweigh my boys!
back. A sail that is trimmed to windward; as in: Sometimes we need to
back the jib to help us tack. Can also refer to the wind moving counterclockwise; as in: The wind is backing.
backstay. A stay (usually cable or rod) that runs from near or at the top
of the mast to the stern of the boat; as in: Your backstay seems to be tensioned properly.
backwind. When a forward sail blocks the wind from an after sail; as in: The jib is
producing a backwind affecting the main.
bahamian moor. Anchoring by setting two anchors, one fore and one aft; as in: A
bahamian moor will limit the amount of swing room while at anchor.
bail. To remove water from a boat; as in: Let's bail the dinghy to get the water
balance. To create a happy medium between weather and lee helm; as in: The
helm seems to have perfect balance.
ballast. Weight in the keel to keep the boat upright; as in: Ballast can be lead or
bascule bridge. An opening bridge as opposed to a fixed bridge; as in: We can
make it through that bascule bridge as long as we get an opening.
batten. A rod or strip used to stiffen the leech of a sail; as in: Some mainsails have
at least one batten that runs from leech to luff.
batten down. Prepare for heavy weather; as in: Batten down the hatches.
batten pocket. The opening into which the batten fits; as in: A batten pocket will
have some means of closure at one of its ends.
beam. The widest part of the boat; as in: The boat's length is 50 feet and her
beam is 14 feet.
beam reach. Point of sail with wind coming over the beam; as in: Fall off to a
beam reach from a close reach.
bear away. To turn away from the wind; as in: Please bear away to a beam reach
from a close reach.
bearing. The bearing to an object from the boat expressed in degrees; as in: The
bearing to the lighthouse is 180° magnetic.
beat. Sailing close hauled; as in: A beat to weather (the wind).
below. Underneath the deck; as in: I'm going below to fix drinks.
berth. 1, Where people sleep on a boat; as in: I'm going to my berth. 2, A boat's
slip at the dock; as in: The local marina has a berth for our boat.
bight. That part of a line between its ends or a loop; as in: Tie a bowline on a
bilge. The lowest, deepest part of a boat; as in: Checking the bilge is part of our
daily routine.
Bimini. 1, an Island in The Bahamas. 2, a collapsible canvas top to shield the
cockpit from sun; as in: In the strong sun of the tropics all were glad to have the bimini up.
binnacle. A support for a compass; as in: If you place metal objects close to
the binnacle you may cause deviation in the compass.
bitter end. The end of a line; as in: Hold onto the bitter end so we don't lose the
blanket. To stop the wind from filling a sail; as in: The jib is forming a blanket to
the main.
block. A device used to change the angle of a line, a pulley; as in: Lead the line
through the block then back to the winch.
board. To go on a boat; as in: Let's board the boat now.
boat hook. Pole with a hook to lift and handle line; as in: Use the boat hook to
grab the line.
boat on the right. When two power boats cross the boat on the right is the
stand-on vessel; as in: As we enter the harbor with our engine engaged we will watch carefully for any boat on the right.
bolt rope. The rope that is in the luff of a sail to strengthen it; as in: To put on
the mainsail guide the bolt rope through the slot in the mast.
boom. A spar that supports the foot of the mainsail; as in: The reef lines and
outhaul may be fed through the boom.
boom gallows. A device running athwartships aft of the mast to support the boom
when the sail is not set; as in: Most modern boats use a topping lift to support the boom rather than a boom gallows.
boom vang. A device to hold the boom down; as in: Use the boom vang to
prevent the boom from rising up while on a run.
bosun's chair. A lightweight, secure seat used for going aloft; as in: While at the
dock we'll go up the mast using the bosun's chair to replace the faulty anchor light.
bow. The forward part of a boat also called 'the pointy end'; as in: Go to the bow
to drop the anchor.
bow pulpit. Guardrail and support at the bow for the lifelines; as in: The lifelines
attach to the bow pulpit with special fittings.
bow line. A dock line used to secure the bow from sideways motion; as in: After
arriving in our slip we tied the port bow line onto the piling.
bowline. (Pronounced "boh-lin") type of knot used to create a temporary, non-
slipping loop in the end of a line; as in: Tie a bowline on the dock line and drop it over the piling.
bowline on a bight. A type of knot used to create a temporary, non-slipping
double loop anywhere on a line; as in: Since we are without a bosun's chair we'll tie a bowline on a bight to go aloft.
breast line. A dock line that runs at a right angle to the centerline of the boat; as
in: We'll bring the boat closer to the dock with a breast line for easier boarding.
bridgedeck. The deck that joins the hulls on a catamaran; as in: Standing on the
bridgedeck gives a great view.
bridle. A line used to distribute the load from a tow or an anchor to two points on
the boat; as in: When we anchor a catamaran we always set up a bridle.
broad reach. Point of sail with the wind coming over the boat's quarter; as in: Fall
off from a beam reach to a broad reach.
Bruce anchor. A type of claw anchor; as in: The Bruce anchor is very
bulkhead. A support below deck to strengthen the boat; as in: That bulkhead is
made of wood.
bunk. A bed in a boat, can also be called a berth; as in: Time to go to my bunk.
buoy. A floating aid to navigation; as in: Leave the red buoy to starboard while
by the lee. Sailing on a run with the wind coming over the same side of the boat
as the boom is on; as in: Watch out for an accidental jibe when sailing by the lee.
cabin. A room in a boat; as in: Time to go down to my cabin.
calm. No wind blowing; as in: The wind has become calm.
canvas. The sails of a boat; as in: Your canvas looks bristol.
capacity plate. A metal plate, located near the stern, stating its carrying capacity
and maximum size of outboard engine; as in: The capacity plate on the transom of the dinghy allows for up to six adults and a 15 horsepower engine.
capsize. Turned over in the water; as in: It is very difficult to capsize most boats.
cardinal points. North, south, east, and west; as in: Our compass has the
cardinal points
cast off. Letting go of a line; as in: Cast off and get underway.
cat boat (cat rig). A type of boat with no jib; as in: He chose a cat rig for the
simplicity of it.
catamaran. A multihull having two hulls; as in: Her catamaran sailed fast and
cay. (Pronounced "key") small, low island ; as in: Marina Cay is a popular
stopover while in the BVI's.
center of effort. The point in the sail plan that is the balance of all wind
forces; as in: She moved the center of effort forward to ease weatherhelm.
center of lateral resistance. The point on the hull where all hydrodynamic forces
are in balance; as in: The boat turns about its center of lateral resistance.
centerboard. A board or appendage that is retractable in the hull or keel; as in: He
raised the centerboard before coming ashore.
centerline. A line running down the middle of the boat bisecting the bow and
stern; as in: The beam of the boat lies perpendicular to its centerline.
chafe. Wearing away of a line or sail due to friction; as in: Don't let the anchor line
chafe on the bow.
chain plate. Metal strap or fitting on the hull where stays are attached; as in:
Our chain plate is bolted to the hull.
channel. A navigable waterway often marked with aids to navigation; as in: Stay
in the channel and you'll be safe.
chart. A nautical map; as in: Read the chart carefully to determine the proper
chart #1. The official U.S. book that defines all symbols, abbreviations, and terms
used on U.S. nautical charts; as in: Check out chart #1 to find out what that squiggly line on the chart means.
chart datum. The reference level for depths listed on a chart; as in: The chart
datum on many charts is the average of the low tides meaning, for example, when a depth of 6 feet is given that is the depth of water at that point at the average low tide, so most of the time there will actually be a greater depth.
charter. Renting a boat; as in: Let's charter a catamaran in the BVI's.
chock. Fairlead for dock or anchor lines; as in: Lead the dock line through the
chock to prevent chafe.
chop. Waves that are short but steep; as in: On blustery days like this there's a
lot of chop on the water.
circumnavigation. To take a trip around something; as in: Circumnavigation of the
world has been accomplished by many sailors.
cirrostratus clouds. Wispy clouds lying in sheets, may cover the entire sky and
produce halo effects; as in: Cirrostratus clouds often foretell a storm.
cirrus clouds. High altitude, wispy and unsubstantial; as in: Those cirrus clouds
may or may not be the harbinger of weather to come.
cleat. A metal (usually) object around which a line can be fastened; as in: He ran
the dock line from a cleat on the boat to a piling.
cleat hitch. A type of knot; as in: She tied the dock line to the cleat with a proper
cleat hitch.
clew. The after lower corner of a sail; as in: The outhaul is attached to the clew of
the mainsail.
close hauled. A point of sail, sailing as close to the wind as possible, also known
as beating; as in: Sailing close hauled can be challenging.
close reach. A point sail between close hauled and a beam reach; as in: Returning
to the crew overboard, she sailed the boat on a close reach.
clove hitch. A type of knot; as in: He tied the fenders to the lifelines using a clove
coastal. Near the shore; as in: In coastal sailing we don't go out of sight of land.
cockpit. An area inset in the deck where the boat is steered; as in: We gathered in
the cockpit and took turns at the helm.
cockpit locker. typically the largest locker on deck usually located under cockpit
seating; as in: We store the life jackets in our cockpit locker along with the flares.
code flags. See 'signal flags'.
coil. A neat arrangement of line which can be stowed; as in: She made a coil of
the line and put it away.
COLREGS. The International Navigation Rules; as in: If you know the COLREGS you
will be a better sailor.
companionway. The entryway that leads from the cockpit to the cabin; as in: He
went down the companionway to go to the galley.
compass. A device containing a magnet that will align itself with the magnetic field
of the earth indicating direction; as in: Read the compass carefully to determine your heading.
compass card. A flat disk in the compass marked in degrees around which the
compass needle rotates; as in: The compass card has marks for each 5 degree increment.
compass rose. A duplicate of the compass card found on nautical charts; as in:
Use the compass rose to draw our ship's course.
conch. (Pronounced "konk") a brightly colored univalve mollusk; as in: Whenever we
go to The Bahamas we always order conch fritters and cracked conch.
cotter pin. A small pin (usually stainless steel) to help secure fittings; as in: It is
good to check all cotter pins at the beginning of the season.
course. The heading or compass direction that is steered; as in: The course to
steer is 190° magnetic.
crew. All who participate in the handling of the boat; as in: The crew did a great
job bringing the boat to the dock.
cringle. An eye in the sail that is reinforced with a metal ring; as in: That cringle
represents the first reef tack.
cross beam (arm). Any of the beams that join the two hulls of a catamaran; as
in: The cross beam creates structural strength and is often made from extruded, anodized aluminum.
cruise. Two or more days spent underway on a boat; as in: Our cruise through The
Bahamas lasted a week.
cruising boat. A boat used mostly for cruising rather than racing; as in: That
sailboat looks like a fine cruising boat.
cumulonimbus clouds. The thunderstorm cloud, tall with a dark bottom; as in: We
will try to avoid those cumulonimbus clouds on the horizon.
cumulus clouds. Puffy cotton balls, harbinger of good weather; as in: Those
cumulus clouds tell me we have at least two days of good weather.
cunningham. A line used to put tension in the luff of a sail; as in: Tighten the
cunningham to bring the draft forward in the mainsail.
current. The horizontal movement of water usually caused by tides or wind; as in:
Compensation for the current is necessary when sailing in many coastal areas.
custom boat. A boat built to the specifications of one particular customer; as in:
He ordered a custom boat to suit his needs.
cutter. A type of sailboat with one mast and two sails forward; as in: Many
cruising boats are cutter rigged.

daggerboard. A centerboard, not hinged but going straight up and down; as in:
The daggerboard was lowered through its slot.
danger bearing. A bearing that is plotted to a hazard or an object nearby a
hazard; as in: Our navigator plotted the danger bearing to the rocky shoal and, since the hazard lay to port, said to the helmsperson "Do not allow the rock to bear more than 135°".
danger sector. Red light shining out to mark a dangerous area of water; as in: We
could see the danger sector from a distance and avoided that area.
daysailor. A boat used for short day sails and without a cabin; as in: We had a lot
of fun in our daysailor last summer.
dead. Exactly; as in: She steered the boat dead ahead.
dead reckoning. Also known as ded. reckoning and DR. Calculating the course of a
boat from only the heading, speed, and time; as in: They kept up their dead reckoning until they could fix their position.
deck. The surface covering the hull of a boat; as in: Standing on deck is a good
way to catch some sun.
deep beam reach. This is a point of sail just below a beam reach (about 20°
below) or about 110° relative to the bow and used in the deep beam man overboard recovery technique: as in: When one of the crew fell overboard we immediately turned to a deep beam reach.
depower. To decrease the power of the sails allowing the boat to heel less; as in:
Depower the sails to decrease weatherhelm and heel.
depth sounder. A device that measures the depth of the water; as in: Reading
the depth sounder carefully we can avoid running aground.
deviation. Error in the compass caused by undue magnetic influences; as in: The
can of peanuts set down next to the compass caused a deviation of some 20 degrees.
dew point. The temperature at which air is fully saturated, the temperature at
which dew starts to form; as in: When the temperature drops to the dew point fog is possible.
dinghy. Small, lightweight boat; as in: After anchoring we went ashore in the
displacement. The weight of water a boat displaces, her weight; as in: That boat
has a displacement of 12 tons.
displacement hull. A heavier boat that does not plane, moving through the water
it displaces water; as in: A displacement hull will not be as fast as a planing hull.
distress signals. Indicators signifying a vessel is in danger, a request for
assistance; as in: Internationally recognized distress signals offer a wide range of options depending on what the situation is. For instance; if you are in distress in the ocean you might release orange smoke or dye marker so a plane could spot you, if your vessel is on fire then those flames will act as a distress signal, or if you are foundering at night you might send up parachute flares. Below is an illustration of possible distress signals courtesy of the USCG:

Distress Signals

dock. A float or pier where a boat can tie up to; as in: The crew did a fine job
bringing the boat into the dock.
dock line. A line used to attach a boat to a dock; as in: A good dock line is usually
made of nylon to provide stretch. See illustration below:
Boat tied to dock with dock lines

dodger. A spray shield that protects the cockpit; as in: All were happy the boat
came equipped with a dodger when the wind and waves came up.
dolphin striker. Cables underneath a multihull that help support the structure; as
in: The dolphin striker is often hidden away on catamarans.
douse. To lower a sail; as in: Coming into the anchorage we douse and cover the
downhaul. Used to place tension in the luff of a sail; as in: Applying tension to the
downhaul changes the shape of the mainsail.
downwind. The direction in which the wind is traveling; as in: Since our
destination is downwind we'll only fly the spinnaker.
draft. 1, The depth of the boat underwater; as in: This boat has a 6 foot draft. 2,
The amount of curve or fullness in a sail; as in: Moving the draft forward will reduce our weather helm.
drag. The anchor moving along the bottom; as in: We took care to set the anchor
so that it would not drag.
drift. The velocity of a current usually measured in knots; as in: The drift of this
current is 2 knots.

ease. To let out a line, to decrease tension; as in: When falling off we ease the
ebb. When the tide goes out; as in: We should leave before the ebb tide.
eddy. Circular current; as in: An eddy in the Gulf Stream can be very large. electrolysis. Corrosive action caused by electrical current flowing between
dissimilar metals; as in: Without sacrificial zinc anodes electrolysis can cause great damage on boats.
emergency tiller. A small tiller that fits into the top of the rudder post which can be
used to steer the boat if main equipment fails.
end for end. To reverse a line; as in: When we end for end the main sheet we will
increase it's life span.
estimated position (EP). A position that is estimated from the DR and one other
indicator of position; as in: After taking a bearing she placed a small square on the chart to indicate the estimated position.
eye. Loop, often in the end of a line; as in: The sewn in eye in the dock line is very
eye of the wind. Exactly where the wind is coming from; as in: We tack the boat
by putting the bow through the eye of the wind.
fair. Without obstruction or sharp corners; as in: That boat has a fair
transition from the deck to the cockpit.
fairlead. A lead with a minimum of friction to reduce chafe; as in: The line is led
from the block to winch through a fairlead.
fairway. The central part of a channel; as in: The boat in the fairway is avoiding
the shoal.
fake. Making large loops of line to avoid kinks; as in: We will fake the main halyard
before dropping the mainsail.
fall off. To turn away from the wind; as in: Going from a beam reach to a broad
reach we fall off.
federally required equipment. Specific items to be carried on board vessels
registered or documented in the U.S.; as in: Federally required equipment for a vessel 7 to 12 meters includes: One PFD for each passenger, one type IV throwable floatation device, three day distress signals and three night distress signals which may be combined into three day/night distress signals, fire extinguisher(s), sound making device, navigation lights, and ship's paperwork (registration or documentation). Vessels 12 to 20 meters must also carry a copy of the Rules of the Road, a bell, and a dedicated ship's whistle (horn).
fend off. To push away; as in: We may need to fend off as we back our boat into
the slip.
fender. Bumper placed outside the hull to prevent damage at a dock; as in: We
tied the fender to the lifeline using a clove hitch.
fetch. Distance to the windward shore; as in: A larger body of water has more
fetch than a smaller one.
figure eight. A type of knot, also called a stopper knot; as in: Tying a figure eight
at the end of a line prevents it from running out through the block.
fish hook. A wire that has come unattached and sticks out of a cable, can cause
cuts and abrasion; as in: Check the cables frequently for fish hooks.
fix. A position known with some certainty; as in: We fix our position when two or
more bearings cross.
flag etiquette. The proper display of flags; as in: Flag etiquette dictates that the
vessel's national flag is flown from the stern while courtesy flags and flags displaying a meaning (i.e. the quarantine flag) are flown from the starboard spreader.
float. Generic name for a multi-hull's ama or hull; as in: A trimaran has 3 floats; 2
amas and a hull.
float plan. An itinerary for the boat to be filed with friends or family; as in: Before
they left on their voyage to Hawaii they filed a float plan with their family members.
flood. The incoming tide; as in: We will wait for the flood tide before returning.
fluky. Winds that are light and variable; as in: With these fluky winds sailing is not
an option.
fog. A cloud at ground level formed when the temperature drops to the dew point
creating tiny particles of moisture suspended in the air. Two major types that affect mariners are radiation and advection fog; as in: Radiation fog usually persists for short periods forming on clear, cool nights when the surface boundary layer drops to its dew point. And, advection fog forms when warm moist air blows across a body of cooler water which lowers the temperature of the moist air to the dew point and can last for days even with the wind blowing.
following sea. Waves coming from behind; as in: Going downwind we will
encounter following seas.
foot. 1, the bottom edge of a sail; as in: We can tension the foot of the
mainsail with the outhaul. 2, to sail slightly lower than close hauled; as in: If we foot after tacking we will build up good boat speed.
foresail: Any sail that is forward of the mast; as in: This boat is designed to use
one foresail.
forestay (also headstay). A stay running from the bow to the upper mast upon
which can be fastened a foresail; as in: The forestay attaches to the bow with a stem fitting.
foretriangle. The area defined by the mast, deck, and forestay; as in: A larger
foretriangle means that a larger jib can be carried.
forward. Toward the bow; as in: Go forward to throw the bow line.
foul. 1, Tangled; 2, A description of the bottom; as in: Do not anchor in any area
with a foul bottom.
foul weather gear. Clothing appropriate for heavy weather conditions; as in: With
the storm coming put on your foul weather gear.
fractional rig. A rig where the forestay (headstay) terminates below the top of the
mast; as in: A racing boat is usually a fractional rig.
freeboard. The height of the deck above the water; as in: A boat with a lot of
freeboard is a dry boat.
front. The leading edge of a high or low pressure system; as in: As the cold front
comes through the winds usually veer, or move clockwise.
full sail. All sails are set; as in: Under 15 knots of wind we often go under full sail.
full wing deck. A solid deck joining the ama and hull on a trimaran; as in: That
trimaran has a full wing deck.
furl. To neatly put away a sail while still attached to the spars; as in: We furl the
sails as we approach our destination.

gaff rig. A rig that uses a spar to raise the top edge of a four edge sail; as in: A gaff rig boat is
pretty but lots of work.
galley. The kitchen on a boat; as in: We do most of our cooking in the galley.

galley down. Term used to describe the layout on a catamaran where the galley
placed on the lower level along with the cabins; as in: They preferred to have the galley down because it allowed for a larger salon on the upper level.
galley up. Term used to describe the layout on a catamaran where the galley is
placed on the upper level along with the salon; as in: She wanted to the galley up because it allows for more interaction when meals are prepared.
gear. Equipment on a boat; as in: A neat boat has all its gear stowed.
genoa. A large foresail whose clew extends beyond the foretriangle (mast); as in:
In lighter air we always use our genoa.
gimbal. Swinging supports that allow a stove to stay level in seas; as in: We were
glad to have a gimbal support on our stove as we crossed the Gulf Stream.
give-way vessel. The vessel that must keep out of the way of another vessel; as
in: The port tack boat is the give way vessel when meeting a starboard tack boat.
gooseneck. The fitting that attaches the boom to the mast; as in: We tack the
mainsail on close to the gooseneck.
grommet. A small snap ring sewn into canvas; as in: The dodger has more than
one grommet to secure it.
ground tackle. The anchor and anchor rode; as in: For ground tackle my boat uses
a plow anchor with all chain rode.
grounding at anchor. When the tide goes out leaving a boat aground while
anchored, not to be confused with running aground; as in: We should have checked the tide tables to prevent our grounding at anchor.
gudgeon. A metal fitting on the transom of a small boat used to attach the rudder;
as in: The pintle fits into the gudgeon.
gunwale. The rail that sticks up at the edge of the deck; as in: Walking on deck
feels more secure if there is a gunwale.
gust. A puff of strong wind; as in: Sailing is more challenging in gusty winds.

halyard. A line that raises a sail; as in: We get under sail by raising the main
handbearing compass. A compass used to take bearings by holding it in your
hand; as in: We can fix our position by taking bearings with the handbearing compass.
hank. A fitting used to attach the foresail to forestay; as in: We hank on the
foresail before raising it.
hard a-lee (helm's a-lee). A command issued as the steerer turns the helm to
tack the boat; as in: Ready about...Hard a-lee.
hard over. Turning the helm as far as possible; as in: The wheel is hard over but
with no way on we aren't turning.
hatch. An operable opening in the deck; as in: Once we anchor we can open the
haul out. To take a boat out of water; as in: Every year we haul out our boat and
put her in dry dock.
head. 1, the top corner of a triangular sail; as in: We attach the halyard to the
head of the sail. 2, The bathroom on a boat; as in: Many boats have more than one head. 3, The front of the boat, the bow area, the stem; as in: Going to the head of the boat provides an excellent view.
head down. To turn away from the wind; as in: Head down to fill the sails.
head off. Or head down, to change course by turning away from the wind; as in:
Head off to fill the sails with air.
head to wind. Pointing the boat directly into the eye of the wind, in-irons; as in:
When the boat is head to wind it is easy to trim the mainsheet.
head up. To turn towards the wind; as in: Head up to luff the sails.
header. A shift in the wind causing a turn away from the wind; as in: When we get
a header it may be time to tack.
heading. The course to steer; as in: Change heading to 090°.
headsail. A foresail; as in: A sloop has one headsail while a cutter has two
headstay. Also called forestay, a cable that runs from the bow to the upper part
of the mast; as in: Our headsail attaches to the headstay.
heave. To throw; as in: Heave the line to the other boat.
heave to. A technique to nearly stop the boat's motion while under sail; as in: As
we heave to the foresail will be backed to windward.
heavy weather. Strong wind and large waves; as in: Our boat does very well in
heavy weather.
heel. The angle the boat sails at; as in: Stronger wind creates more heel.
helm. The tiller or wheel; as in: Turn the helm to change heading.
helmsman or helmsperson, steerer. The person who is steering the boat; as in: As
we got to the channel the helmsman guided us into the marina.
high. To sail high is to sail closer to the wind than is optimal; as in: Sailing high
slows us down.
hike. To lean out over the rail; as in: The crew will hike out to reduce the heel of
the boat.
holding ground. The type of bottom in an anchorage; as in: This anchorage has
good holding ground.
hull. The underbody of a boat; as in: This hull is solid fiberglass.
hull speed. The theoretical highest speed for a displacement hull boat; as in: We
use the square root of the water line length to help determine the boat's hull speed.

in irons. Head to wind and not moving through the water; as in: Catamarans are
more prone to being caught in irons when tacking than monohulls.
inboard. Inside the boat; as in: We have an inboard diesel engine.
inflatable. A device that must be inflated such as a life jacket, life raft, or dinghy;
as in: Some life jackets can be inflated with air or automatically with CO2 cartridges.

jackline or safety line. A line or strap on deck running fore and aft upon which
safety harnesses can be tethered; as in: In heavy weather we rig a jackline on our boats.
jib. A foresail (headsail) that fits inside the foretriangle (not extending beyond the
mast); as in: As we approach our anchorage we will furl the jib.
jib sheet. A line that controls the jib; as in: Trim the jib sheet according to the
jibe. To turn the stern of the boat through the eye of the wind; as in: To jibe
under control we first trim the mainsheet.
jibe-ho. A command issued while jibing just prior to the boom swinging across the
centerline; as in: Ready to jibe...Jibe-ho.
jury rig. Improvised replacement for gear especially when dismasted; as in: After
the mast came down we set up a jury rig to continue on our way.

kedge anchor. Any anchor used to kedge off.
kedge off.
Using an anchor to pull the boat into deeper water; as in: If we run
aground we might be able to kedge off.
keel. An extension of the hull that goes deeper into the water and provides
stability from heel and sideways resistance to wind; as in: A well designed keel can provide lift to windward.
ketch. A type of boat with two masts the second of which is lower and is stepped
forward of the rudder post; as in: The ketch design provides a wide variety of possible sail combinations.
knockdown. When the heel of the boat approaches 90°; as in: Most sailors will
never experience a knockdown.
knot. 1, used to fasten a line to itself or another object; as in: A useful knot
onboard is the simple clove hitch. 2, one nautical mile per hour; as in: The knot meter gives us our speed through the water.

land breeze. A breeze that blows from land to the water; as in: In the evening we
might catch a land breeze.
landmark. An easily visible object; as in: The lighthouse makes a handy landmark.
lanyard. A short line; as in: Some shackles have a lanyard for an easy grip to open
lash. Tie down; as in: We lash the dinghy to the foredeck.
latitude. Angular distance in degrees north or south of the earth's equator; as in:
The north pole is at 90° north latitude.
launch. 1, Moving a boat from land to water; 2, A small boat to take people from
shore to moored boats and vice versa; as in: We sounded our horn to let the launch know we wanted to go ashore.
lazarette. Usually, the aftermost locker on deck; as in: The starboard lazarette
holds the propane tanks.
lazy bag. A bag on top of the boom to cover the mainsail when it is lowered and
can be zipped up to fully protect the mainsail; as in: The lazy bag is truly a blessing for the lazy sailor.
lazy jacks. Lines running between the boom and mast that prevent the mainsail
from falling on deck as it is lowered; as in: Lazy jacks work very well just be sure the mainsail is in the eye of the wind as it is raised or the battens may catch on one of the lazy jack lines.
lead. (Pronounced "leed") the path of a line; as in: Be sure the lead for the anchor
line is fair.
lead line. (Pronounced "led line") a line with a weight attached to take soundings
i.e. read the depth of the water; as in: When anchored we can use a lead line to check the offset of our depth sounder.
lee and leeward (pronounced "lee" and "loo-ward"). Downwind; as in: That boat is
in our lee or, that boat is leeward of us.
lee helm. The tendency of a boat to turn down wind; as in: With only a foresail
set the boat has lee helm.
lee shore. A nearby shore that is downwind from us; as in: A lee shore can pose a
hazard for us.
leech. The back edge of a sail; as in: If the leech is flopping tighten the leech line
just until it stops.
leech line. A small adjustable line running inside the leech; as in: Ease the leech
line in light air to prevent cupping.
leeward boat. When two boats are on the same tack the windward boat shall keep
out of the way of the leeward boat; as in: The leeward boat is stand on while the windward boat is give way.
lie ahull. A storm tactic whereby no sail is set; as in: We tried to lie ahull but
found the motion not to our liking.
life jacket. Also PFD, used to keep a person afloat; as in: If you need a life jacket
it should be easily accessible.
life raft. A smaller boat used in emergencies usually inflatable; as in: Be sure
everyone knows how to launch the life raft.
lifeline. A wire or cable that runs along the outside of the deck supported by
stanchions to help restrain passengers; as in: All lifelines should be checked frequently for corrosion, loose fittings, and fish hooks.
lift. Opposite of header, a wind shift allowing the helmsperson to steer closer to the
desired course; as in: If we get a lift we may not need to tack.
light. 1, an aid to navigation that is illuminated; as in: The geographic range of
that light is shorter than its range of visibility. 2, a navigation light on the boat; as in: After anchoring we will turn on the anchor light.
lightweight anchor. A type of anchor with large, flat flukes; as in: We lowered the
lightweight anchor into a beautiful sand bottom.
line. Rope or cordage that has come onboard; as in: We carry extra line onboard
because we know we'll need it sometime. This line may go on to other, more specific, uses such as rode, sheets, halyards, or dock lines.
list. When a boat heels with no outside forces being applied; as in: The boat at the
dock had a prominent list.
local knowledge. First hand familiarity with a body of water that goes beyond
what may be found on a nautical chart; as in: When arriving at a small, unknown harbor they hailed a local fishing vessel for local knowledge on how to negotiate the channel.
longitude. The angular distance in degrees east or west of the prime meridian
running through Greenwich England; as in: The longitude of the International Date Line is both 180° east and west.
lubber's line. A post in a compass allowing the compass to be read from the side;
as in: If you use the lubber's line that is at 45° then compensate that much for the course.
luff. 1, the leading edge of a sail; as in: We have telltales just behind the luff of
our headsail. 2, the flapping of a sail; as in: We can prevent luff in the sail by properly reading the telltales and adjusting course.
lying ahull. Also, under bare poles. No sails set; as in: Lying ahull is sometimes
used as a storm tactic.

magnetic. Relating to the magnetic poles rather than the true north and south
poles; as in: Did you know that variation is the difference in degrees between true north and magnetic north?
main hull. The main hull (or center) hull on a trimaran; as in: The main hull is
where we live and the outer hulls or amas are for storage.
mainmast. The tallest mast; as in: On a ketch the mizzen mast is always shorter
than the mainmast.
mainsail. The main sail of a boat often the largest sail and raised on the mainmast;
as in: Leaving the anchorage the first sail we set is the mainsail.
mainsheet. A single line used to control the main; as in: Trim the mainsheet as we
head up into the wind.
man overboard. Also crew overboard or person in the water. When someone
onboard has accidentally fallen into the water; as in: It is best to practice man overboard drills before you really need them.
man overboard pole. A floating pole with a flag on top for greater visibility, to be
thrown into the water as soon as someone has gone over; as in: The flag on the man overboard pole is diagonal yellow/orange, the signal flag for "O" (Oscar) carrying the meaning "man overboard".
marina. An arrangement of docks providing spaces for boats to tie up; as in: Call
ahead to the marina on the VHF to see if they have a slip available for us.
marlinspike. A pointed tool used to untie knots or pry apart various things; as in:
Using a marlinspike can assist in untying a bowline.
mast. A pole made from wood, aluminum, or carbon fiber from which a sail is set;
as in: The mast on most boats have stays to hold them upright.
masthead fly. A device used to indicate wind direction; as in: Watch the
masthead fly to know where the wind is coming from.
masthead light or steaming light. A white light shinning forward through an arc
of 225° indicating a vessel is under mechanical propulsion. The light may be located at the top of a short mast on a powerboat but is located about 2/3 of the way up the forward mast on a sailboat; as in: Turn on the masthead light when under power at night.
Mediterranean (Med.) mooring. Means of tying up to a dock with an anchor or
mooring set further out; as in: After anchoring our vessel just off the dock we ran stern lines ashore in the dinghy to achieve our first Mediterranean mooring.
meeting head-on. When two power vessels meet head-on they should each turn
to starboard; as in: Meeting head-on with another vessel, as we power into the harbor, we'll turn to starboard.
meridian. Longitude; as in: Did you know the prime meridian passes through
Greenwich England and is opposite the International Date Line?
mizzen. The aftermost sail on a ketch or yawl carried on the mizzen mast; as in:
We set the mizzen along with the main to create a full sail plan.
monohull. A boat with a single hull; as in: A monohull will heel more than a
mooring. A permanent anchor with a floating buoy to tie up to; as in: Most of the
time we can easily leave the mooring by sailing off.
multihull. A boat with two or three hulls; as in: The multihull is becoming more

nacelle. A compartment on a catamaran created by a structural component; as in:
We can stow anchor lines in the nacelle.
nautical mile. One minute of latitude or about 1.15 statute miles; as in: A nautical
mile is easy to measure by referring to the latitude on a nautical chart.
Navigation Rules. Both the international (COLREGS) rules and the U.S. inland
rules; as in: A knowledge of the Navigation Rules will make anyone a better mariner. The full online version can be found here:
neap tide. Tides that occur during quarter phases of the moon and not as strong
as spring tides; as in: The neap tide happens when the moon and sun are not aligned.
no go zone. The area into the wind where it is not possible to sail; as in: If our
destination lies upwind we must tack to get there as going straight to it puts us in the no go zone.

off the wind. Sailing downwind; as in: On a broad reach or run we are sailing off
the wind.
offshore. Out of sight of land; as in: Sailing to The Bahamas we will be offshore.
on board. On a boat; as in: On board we have enough provisions to last a week.
on the wind. Sailing into the wind; as in: On a close reach or beating we are on
the wind.
one design. A single design from which many boats are made; as in: The
Lightening is a popular one design race boat.
open wing deck. Having the deck on a trimaran completely open; as in: Smaller
trimarans with folding amas often have an open wing deck arrangement.
outboard. 1, outside the hull; 2, removable engine mounted at the transom; as in:
Our dinghy has an eight horsepower outboard.
outhaul. A sail control that attaches to the clew and allows tensioning of the foot;
as in: In light air we ease the outhaul.
overhang. When the bow and or stern extend beyond the waterline; as in: Many
older boats have a lot of overhang.
overpowered. Too much power in the sails producing excessive heel and difficult
steering; as in: When the wind speeds up we depower the sails to prevent being overpowered.
override. When a wrap of line runs over another wrap on a winch; as in: Good
winch technique will prevent an override.
overtake. To come up from behind; as in: When we overtake another vessel we
must keep out of her way.
overtaking situation. When one vessel overtakes another she is the give-way
vessel and must keep out of the way of the boat being overtaken; as in: A sailboat in an overtaking situation with a slow power boat must keep out of the power boat's way.

padeye. A metal or plastic eye fastened on deck through which a line runs; as in:
That padeye provides a convenient means to help guide the reef line.
painter. The line attached to the bow of a dinghy; as in: We tow the dinghy using
its painter.
parallel. Latitude; as in: The 45th parallel lies half way between the equator and
the north pole.
partial wing deck. A deck on a trimaran, joining the ama and hull, that has an
open area; as in: Many trimarans have a partial wing deck.
partners. The opening in the deck for a keel stepped mast; as in: When we pulled
the mast we were careful to cover the partners to prevent rain damage.
pay out. To ease; as in: Pay out enough line so there will be some slack.
pelorus. A device used to take bearings relative to the boat and, along with other
information, can determine the deviation of the ship's compass on a particular heading; as in: Using the pelorus we find the lighthouse bears 120° off the starboard bow.
PFD. Personal Flotation Device; as in: Always know where your PFD is located.
pier. An area suspended by posts that sticks out from shore; as in: The fishing pier
over there would not be a good place to tie up.
piloting. The art of navigating in coastal waters; as in: Piloting a boat into an
unknown harbor takes some knowledge and skill.
pinch. Sailing too close to the wind; as in: If you sail any higher you will pinch and
luff the sails.
pintle. A metal fitting on the rudder of a small boat used to attach the rudder to
the transom; as in: The pintle fits into the gudgeon.
pitchpole. To turn upside down in the water with the stern coming over; as in: It
takes very heavy, breaking seas to create a possible pitchpole.
plane. To skip along the water; as in: That speed boat is up on a plane.
planing hull. A hull which can get up on a plane; as in: Most cruising sailboats do
not have a planing hull.
plot. Drawing a boat's course on a nautical chart; as in: We plot our course before
we set out.
plow anchor. A type of anchor that looks like a farmer's plow; as in: Many cruising
boats will carry a plow anchor.
points of sail. Close hauled (beating), close reach, beam reach, broad reach, and
run; as in: Sailing a full circle we will cover all the points of sail. See illustration below:
Points of sail

port. 1, left side when looking forward; 2, a window in the side of the boat; 3,
where ships come in to dock; as in: When navigating into a port take caution in the channels.
port tack. A sailboat is on port tack when the mainsail is on the starboard side (the
wind will usually, but not always, be on her port side); as in: When we're on a port tack we must give way to starboard tack vessels.
preventer. A line or other device that prevents an accidental jibe; as in: When
running in waves and wind we usually rig a preventer.
protected water. An area of water that remains relatively calm because it is
surrounded by land and/or reefs; as in: We enjoy sailing on Biscayne Bay because it is protected water.
pulpit. A metal railing at the stern and/or bow that serves as an anchor point for
the lifelines; as in: The pulpit is strong enough to support lifelines but not strong enough for dock lines.

quarter. The area between the beam and stern; as in: We have a vessel
overtaking us off our port quarter.
quay. (Pronounced "key") a dock or landing place running along a body of water;
as in: Mediterranean (Med.) mooring is a good way to tie up to a quay.

race or regatta. A competition between boats; as in: Boats in a race do not have
special privileges over boats passing by but common courtesy should prevail.
radar. A means of sending out and receiving radio waves to detect objects in the
distance that may be obscured by weather or darkness; as in: Radar is very useful in areas prone to fog.
radar reflector. A device to reflect radar waves back to their source so that a
boat shows up more prominently on the radar screen; as in: Because wet sails may interfere with the radar beam boaters should consider using a permanently mounted radar reflector on each side of the mast.
rake. The fore or aft tilt of the mast; as in: If we rake the mast forward we will
reduce weather helm.
range. 1, the difference between high and low tide; 2, the extent of a light's
visibility; 3, when two objects line up, also called a transit, that may indicate a channel; as in: We will know to turn into the channel when the range markers line up.
ready about. A command issued prior to tacking; as in: Ready about...Tacking.
reef. 1, to decrease sail area; as in: We put in a reef before the storm hit. 2, a
shoal area; as in: Follow the channel markers carefully to avoid the reef.
reef knot. A type of knot also called a square knot; as in: We can tie two ends of
a line together with a reef knot.
rhumb line. The shortest distance between two points; as in: We will reach our
destination quickest if we can sail the rhumb line.
rig. 1, the mast, boom, stays, and sails; as in: Many modern boats are a sloop rig.
2, to prepare a boat for sailing; as in: As soon as we rig the boat we'll be able to sail.
rigging. Standing rigging is the cables and stays that support the mast while
running rigging is the control lines; as in: Common running rigging is composed of sheets, reef lines, halyards, and outhaul.
rights of the first boat anchoring. The first boat anchoring sets the anchoring
style for all following boats especially in small anchorages or ones with strong tidal currents; as in: Coming into an anchorage we observe the anchoring style of other boats understanding the rights of the first boat anchoring.
right of way. That vessel which has the legal authority to stay on her course
according to the Navigation Rules; as in: The stand on vessel has the right of way.
roach. 1, a small to large brown bug that invades many boats; 2, the convex area
of a sail on its leech; as in: Catamarans have a larger roach than monohulls.
rode. The anchor line including chain; as in: Anchor rode can consist of all chain or
chain and line.
roller furling. Furling a sail by rolling it up; as in: Many boats have a roller furling
roller reefing. Reefing a sail by rolling it up; as in: Roller reefing comes in a wide
variety of applications and can be combined with roller furling.
rolling hitch. A type of knot used to take the strain off another line, chain, or
object; as in: To hook up our snubber we use a rolling hitch.
rope. A line consisting of tightly twisted or woven fibers. Onboard one of the few items termed
rope is the boltrope that helps support the leading edge of the mainsail. When rope comes onboard it is usually referred to as line and then may go on to other, more specific meanings such as sheets, rode, or halyards. As in: At the marine store I'll get some rope to use as dock lines on the boat.
round turn and two half hitches. A type of knot that constricts with more tension
in the line; as in: A round turn and two half hitches can be used to tie the spring line to the piling.
rudder. An underwater appendage that controls the direction of the boat; as in:
When the helmsperson turns the wheel to starboard the rudder turns to starboard followed by the boat's bow turning to starboard.
rudder post. A round shaft leading from the rudder and connected to the helm; as
in: Turning the wheel turns the rudder post thus turning the rudder.
rules of the road. The Navigation Rules; as in: Following the rules of the road we
turn on the proper lights at sunset.
running. A point of sail; as in: Falling off from a broad reach we will be running.
running lights. The lights a boat shows at night; as in: At sunset we turn on our
running lights when underway.
running rigging. All the lines that control any part of the sails; as in: We check
our running rigging for wear on a regular basis.

safety harness. A harness worn by crew and hooked onto the boat to prevent
crew overboard; as in: The safety harness comes with a tether that can be snapped onto the jackline.
safety net. The net in the bow area of a catamaran sometimes called the
trampoline; as in: The safety net provides a secure area for sunbathers.
sail tie. A short line or strap used to secure a furled sail; as in: We can wrap the
sail tie around the sail then tie the two ends together with a square knot.
saloon. The large social gathering area below deck on a boat; as in: We'll
have dinner in the saloon tonight due to the inclimate weather in the cockpit.
sailing by the lee. See "by the lee".
schooner. A boat with two or more masts, the forward of which is the same height
or shorter than the after; as in: When the schooner tied up she was the object of much attention.
scope. The ratio of anchor rode paid out to the depth of the water plus the height
of the deck above water; as in: Many recommend a scope of 7:1 for secure overnight anchoring.
scull. To move forward in a boat by swinging the rudder back and forth; as in: If
you scull a small boat you may be able to free her from the bottom.
scupper. A drain in the deck or cockpit; as in: The center cockpit boat uses a
scupper at each corner to drain the cockpit.
sea breeze. A breeze that comes from the water to the land; as in: The afternoon
sea breeze off the California coast can be quite strong.
sea room. The distance between the boat and shore; as in: It is good to have
enough sea room for safe sailing in any conditions.
seacock. A valve to shut off flow from a through-hull fitting; as in: It is good to
exercise the seacocks once in a while to prevent seizing.
seakindly. A boat that is comfortable in rough seas; as in: Usually, the larger the
boat the more seakindly she is.
seagull striker. On a catamaran, the reinforcing structure above the beam at the
bow; as in: The seagull striker adds considerable strength to the boat.
seaworthy. Ability to do well in heavy seas and weather; A larger vessel is not
necessarily more seaworthy.
secure. To fasten to a dock or cleat; as in: There are many knots we can use to
secure the dock line to the piling.
self-bailing cockpit. A cockpit that drains by itself; as in: Larger boats have self-
bailing cockpits.
set. The direction in which a current is traveling; as in: If the set of the current is
north our boat will be carried in that direction.
shackle. A metal device that secures a line to another object; as in: The outhaul
is attached to the clew of the mainsail with a shackle.
sheave. (Pronounced "shiv") The round turning part in a pulley or block; as in: A
yearly inspection of each sheave is a good idea.
sheer. The concave curve of the rail and deck; as in: Many boats have an
attractive sheer.
sheet. A control line for a sail; as in: The jib sheet pulls the sail aft and down.
sheet bend. A type of knot used to tie together two lines of unequal diameter; as
in: We can join the smaller dock line to the larger one using a sheet bend.
ship. A large vessel; as in: The rights of way are largely the same for a ship as for
a smaller boat.
shoal. A shallow area of rock or coral; as in: Paying attention to the aids to
navigation will prevent running into the shoal.
shorten sail. To reef or put on smaller sails; as in: Before the storm comes is a
good time to shorten sail.
shorthanded. A small crew; as in: Some boats have circumnavigated the globe
shroud. A wire or cable holding up the mast athwartships (side to side); as in:
Each shroud on this boat is made from stainless cable.
signal flags. Flags used to indicate either a letter, number, or representing a
meaning; as in: Each of the signal flags carries a different meaning for instance, A (Alpha) is the international flag that means diver down and is blue and white with a swallowtail.
sister ship. A boat of the same design; as in: Boats of the same make and model
are sister ships.
skeg. A small appendage on the hull near the stern; as in: The rudder is skeg
mounted on that boat.
skipper. The one who is in charge; as in: The skipper may or may not be the one
who steers the boat.
slip. A berth in a marina for a boat; as in: We called the marina ahead of time to
get our slip assignment.
sloop. A boat with one mast and one foresail; as in: Many modern boats are sloop
slug. A fitting on the luff or foot of a sail that allows it to attach to the mast or
boom by fitting into a slot; as in: Before we can raise the main we will have to bend it on by putting the sail slugs into the mast slot.
snap shackle. A shackle that can be easily moved by snapping open or shut; as
in: A safety harness may have a snap shackle at the end of its tether so a person can easily and safely move about the deck.
snub. Wrapping a line once or part way around a cleat or winch to take most of
the load off but still be able to control the line by hand; as in: When we are adjusting the position of the boat as we come into our slip we snub the spring line until she is positioned correctly.
snubber. A line, usually nylon, that takes the strain off the anchor chain and acts
as a shock absorber; as in: We always use a snubber with all chain anchor rode.
sole. The cabin floor; as in: The sole on this boat is teak and holly.
sound(ings). To take depth readings (the depth of the bottom); as in: We can
sound the bottom using a lead line; and, going out into the ocean we reach a point where we are off soundings.
sound signal. An indication or warning given by the boat's whistle (horn); as in: A
sound signal of five short blasts warns of danger or confusion as to the other vessel's intent, one prolonged blast is the sound signal given every two minutes by a power vessel in restricted visibility (fog), one prolonged followed by two short blasts every two minutes is the sound signal given by a sailing vessel in restricted visibility (fog). The Inland Rules require power boats to exchange sound signals as they approach each other but sailing vessels do not exchange such signals.
spar. A long cylindrical object made of wood or metal such as the mast, boom, or
gaff; can also apply to a buoy; as in: Every spar on a boat carries an important function.
speed made good. Velocity over the bottom regardless of current; as in: Her
speed made good was five knots.
speed through the water. The speed of the boat going through the water which
itself may be moving due to current; as in: Crossing the Gulf Stream, her speed through the water was greater than her speed made good.
spinnaker. A large colorful balloon shaped sail; as in: When the racing boats
rounded the windward mark they set their spinnakers to the delight of all spectators.
splice. To create a bond between two lines or an eye in the end of a line by
weaving the strands together; as in: That's a mighty nice looking eye splice you have there.
spreader. A horizontal support for the stays that sticks out from the mast; as in:
The spreader holds the shroud out thus increasing the strength of the rig.
spring line. A dock line, usually used in combination, to prevent fore and aft
motion of the boat; as in: We can secure the forward running spring line to the midship cleat.
spring tide. The tide at the new and full moon which is higher than the neap tides;
as in: The spring tide is caused when the moon and sun pull together.
square knot. A type of knot used to tie together two lines of equal diameter also
called a reef knot; as in: We can tie the two ends of this line together with a square knot.
SSB. Single sideband radio; as in: On good nights we talk around the world on the
stability. Not heeling; as in: This catamaran has greater stability than a monohull
of the same length.
stability curve. A graph showing the stability of a boat at various angles; as in:
The stability curve for a catamaran is very different than that for a monohull.
stanchion. A vertical metal support along the outside of the deck for the lifelines;
as in: A stanchion may be bent if it hits a piling during docking.
stand-on vessel. The vessel that has the right of way according to the rules of
the road; as in: A starboard tack boat is the stand on vessel when crossing the path of a port tack boat.
standing rigging. All wires or cables that hold up the mast; as in: Most standing
rigging is strong enough to take very large forces produced by the sails in heavy winds.
starboard. The right side facing forward; as in: Leave the red buoys to starboard
when returning.
starboard tack. When the mainsail is carried on the port side (the wind will usually,
but not always, be on her starboard); as in: When two boats approach each other on starboard tack the windward boat keeps out of the way of the leeward boat.
stay. A wire or cable supporting the mast, also see: "headstay" and "backstay"; as
in: A yearly inspection of each stay is a very good idea.
staysail. A second jib which is tacked behind the first one as in: A cutter rig has a
steer. To guide the boat with the rudder; as in: You steer a very good course.
steerageway. Having enough speed through the water to steer the boat; as in:
We usually need about two knots to have sufficient steerageway.
stem. The forward part of the bow; as in: She's a solid little boat from stem to
stem fitting. The fitting at the bow upon which is fastened the headstay; as in:
The stem fitting does for the headstay what the chainplates do for the shrouds.
step. To install a mast. Can be stepped on deck or on the keel; as in: One part of
commissioning a new vessel is to step the mast.
stern. The aftermost part of a vessel; as in: While underway we may tie the
dinghy to the stern.
stern line. A dock line that secures the stern from sideways motion; as in: Before
we can leave our slip we must remove the stern line.
stern pulpit. Guardrail and support for the lifelines at the stern of the boat; as in:
We can attach our BBQ to the stern pulpit.
sternway. Moving backwards through the water; as in: Once we gather enough
sternway we will be able to steer in reverse.
stiff. A boat not easily heeled; as in: This boat seems stiff not tender.
stow. To put something away on a boat; as in: We properly stow our gear so we
will know where it is when needed.
storm jib. A jib that is smaller and stronger than the working jib; as in: Before the
heavy weather hits we'll set the storm jib.
stratocumulus clouds. Dark, big puffy balls; as in: Stratocumulus clouds foretell
bad weather.
surf. To glide down the face of a wave; as in: Our boat speed doubles as we surf
down these waves.
swell. Long period waves usually generated by a storm many miles away; as in:
The waves are coming from the east but the swell is from the north.

tack. 1, To change tacks by putting the bow through the eye of the wind; as in:
We tack the boat with enough speed to carry us through. 2, The side of the boat opposite the side the boom is on; as in: Since the boom is on the starboard side then we are on port tack. 3, The forward lower corner of a sail; as in: We fasten the tack of the jib near the bow.
tail. Pulling on a line after the winch; as in: With self-tailing winches on our boat
the crew does not need to tail the lines.
tang. A metal fitting on the mast to which shrouds are attached; as in: We give
our rig, including each tang, a thorough yearly inspection.
telltale. A fine string or ribbon which may be located on a sail or in the rigging to
help determine wind direction and proper sail trim; as in: Reading the telltale on the starboard shroud it looks like we're on a beam reach.
tender. 1, Easy to heel; as in: This boat seems tender not stiff. 2, A small boat
used to ferry crew to and from a larger vessel; as in: Our ship's tender is fast and comfortable.
thimble. A ring inside an eye splice that protects the line from chafe; as in: A
mooring pendant often has a metal or plastic thimble through which we can run our mooring lines.
three point rig. Two shrouds and a headstay support the mast with no backstay;
as in: Many catamarans have a three point rig.
through-hull fitting. A metal or plastic device providing a secure hole in the boat
through which fluids can flow; as in: Inside of every below waterline through-hull fitting is a seacock to shut off the flow of water if needed
tidal current. The current (or flow of water) in channels that is associated with the ebb
and flow of the tide. 'Tide and Current Tables' is published by NOAA and is also available online; as in: Consult the Tide and Current Tables before leaving dock so there will be no surprises ahead.
tidal range. The difference, in units of measurement, between mean (average) high
tide and mean low tide. This can be found in a number of places from tide and current tables to the chart itself. Pay particular attention to the unit of measurement; as in: Since we have a large tidal range we will need correspondingly long dock lines to compensate.  
tide. The combined action of the sun and moon on large bodies of water causing
them to raise and lower; as in: When the tide is high many ships will leave the port.
tiller. An appendage increasing leverage on the rudder to steer the boat; as in:
You must push the tiller the opposite way you want the bow to move.
toggle. A metal fitting that allows sideways movement in standing rigging without
losing tension; as in: The modern toggle usually never needs servicing.
topping lift. A line that runs from the end of the boom to hold it up when the sail is
not set; as in: If the boom is too low after we furl the main we'll need to raise the topping lift.
topsides. The outer, upper sides of the hull; as in: Painting the topsides will make
them bright and shinning.
trailerable. A boat that is easily towed on a trailer; as in: A trailerable boat usually
has no fixed keel.
transit. When two objects line up, also called a transit, that may indicate a
channel; as in: We will know to turn into the channel when the transit range markers line up.
transom. The athwartships surface located at the very stern; as in: The outboard
engine mounts on the dinghy's transom.
traveler. An athwartships track upon which is mounted a block for the mainsheet
thus allowing side to side adjustment; as in: Dropping the traveler to leeward is one way to reduce weather helm.
trim. 1, To pull in or tension a line; as in: Trim the jib sheet to reduce the luffing.
2, The setting of a sail; as in: Adjust the sheets to get proper trim in the sails.
trimaran. A boat with three hulls; as in: The outer hulls on a trimaran are called
trucker's hitch. A type of knot used like a block and tackle to increase the amount
of tension in a line; as in: When we lash the dinghy on deck we'll use a trucker's hitch to make it more secure.
true. Relating to the true north and south poles rather than the magnetic poles; as
in: Did you know that variation is the difference in degrees between true north and magnetic north?
true wind. The wind speed and direction the boat would feel if it were at rest; as
in: When we head up from a beam reach to a close reach the apparent wind increases while the true wind remains the same.
tune. To adjust the standing rigging; as in: We had the rigger come down to tune
our boat.
turnbuckle. A fitting used in standing rigging to adjust its tension; as in: The rigger
tuned our mast by adjusting the tension at the turnbuckle.
twist. The distance, from a straight line, the leech of a sail falls off to leeward; as
in: We adjust the twist in the mainsail with the mainsheet.

under bare poles Also, lying ahull. No sails set; as in: Under bare poles is a storm
under power. With the engine on and engaged whether or not sails are set; as in:
If we are under power then we are considered a power boat by the rules of the road.
underway. Moving through the water; as in: Let's cast off the lines and get
upwind. Towards the direction from which the wind is blowing; as in: Our
destination lies upwind of us.
USCG. United States Coast Guard; as in: The USCG provides a wide variety of
resources for mariners.

v-berth. the most forward cabin in a monohull, so called because the bow forms a V.
vang. apparatus for boom adjustment; as in: Tighten the vang on a run to keep
the boom from rising.
variation. The difference in degrees between magnetic and true; as in: Variation is
caused by the magnetic north pole being out of alignment with the true north pole.
veer. The wind shifting clockwise; as in: The wind will often veer with the passage
of a cold front.
vessel. Any boat or ship: as in: A sea-going vessel may come in all shapes and
VHF. Very high frequency radio used onboard to call other boats and stations; as
in: Call the marina on VHF channel 16 then switch to a working channel.
voyage. A passage of some duration; as in: Our voyage from Florida to the Virgin
Islands lasted several days.

wake. The wave(s) caused by the motion of the boat through water; as in: Each
boat is responsible for any damage its wake might cause.
washboard. A plastic or wooden slat used to board up a companionway; as in:
Drop the washboard in when we leave the boat to close her up.
watch. Those crew on deck and responsible for the safe operation of the boat; as
in: When you are part of the night watch be sure to carry a flashlight with you.
waterline. Where the water's surface meets the hull; as in: We painted our
waterline blue to provide more eye appeal.
way and making way. Motion through the water; as in: We must reduce our way
before coming into the dock.
weather. 1, Conditions in the atmosphere; as in: Looks like we'll get some weather
today. 2, Upwind; as in: As we make our way to weather conditions may improve.
weather helm. The tendency of a boat to turn into the wind, to head up; as in:
There are many ways to reduce weather helm.
weigh anchor. To raise the anchor; as in: Let's weigh anchor and get underway. wheel. A circular device, often with spokes, used to steer the boat; as in: Grab
the wheel while I go below to make lunch.
winch. A mechanical device to increase the tension in a line consisting of a geared
drum and handle; as in: A winch is essential for providing enough tension in sheets and halyards on most boats.
windage. Surface exposed to the wind providing resistance; as in: The crow's nest
on that boat creates weight aloft and windage.
windlass. Winch for the anchor rode; as in: Many modern boats have an electric
windlass with a remote control.
windward. Towards the wind, upwind; as in: If our destination is to windward we
may have to tack to get there.
windward boat. The boat that is further upwind; as in: When two boats are on
the same tack the windward boat shall keep out of the way of the leeward boat.
wing deck. The deck on a trimaran that joins the ama to the hull; as in: The wing
deck may often be a wet place.

yacht. A pleasure boat over 33 feet in length; as in: She seems to be a well-found
yacht club. A club organized for the enjoyment of sailing; as in: The local yacht
club features many races and get-togethers throughout the summer.
yawl. A boat with two masts the second of which is shorter and stepped aft of the
rudder post; as in: The yawl was popular before the 1960's.

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