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aback

With the sails trimmed on the windward side, or backed. A boat is caught aback when the wind suddently shifts and the sails are trimmed to the windward side.

abaft

Behind, toward the stern. Abaft the beam is the area between abeam and astern. Compare with aft.

abandon ship

To leave a sinking, burning, or otherwise fatally distressed vessel. An abandon ship bag (ditch bag, grab bag) is a container of emergency and survival gear prepared by the crew to take with them if they must abandon ship.

abeam, on the beam

Directly alongside at right angles to the boat.

able, ability

An able boat (able vessel) is especially seaworthy. A boat’s ability in a particular situation is an evaluation of her speed, comfort, and seaworthiness. Rough-water ability, for example, is how she handles waves. Related expressions include heavy-weather ability, windward (upwind) ability, light-air ability.

aboard, on board

In or on a boat. An object that is close aboard is very nearby. To go aboard a boat is to go on or in her.

acockbill(ed), cockbilled

Set at an angle. Describes the anchor as it lies on the rail or is hung over the bow, ready to be dropped.

adrift

Describes a boat drifting out of control, and loose, unsecured equipment.

advisory

See weather alert.

aerodynamics

The study of air flow around objects. Compare with hydrodynamics.

afloat

Floating.

aft, after

At or toward the stern, or behind. An aft (after) cabin is a cabin at or near the stern, the afterbody the hull near the stern, the afterdeck the deck near the stern, the spinnaker afterguy a control on a spinnaker pole that leads aft (in contrast to the foreguy, which leads to the foredeck near the bow). Compare with abaft, ahead, fore.

afterguard

The boat’s captain, navigator, and other officers. In sailing ships the officers historically worked aft near the steering wheel and slept in after cabins, which are more comfortable than cabins near the bow.

aground

Stuck on the water’s bottom. To run aground is to become stuck.

ahead

In front of or forward of the bow. A boat clear ahead is completely ahead.

aid to navigation, navigation aid

A buoy, daybeacon, lighthouse, range, or other charted object in or near the weather that identifies channels and helps a crew navigate safely.

air

Wind, breeze.

air tank

An airtight, watertight compartment that provides buoyancy to keep the boat afloat in case she takes on water.

alee

Away from the wind, to leeward. Hard alee, see hard.

all hands

The entire crew.

aloft

Above the deck, in the rig.

alongshore, longshore

Near shore, coastal.

alongside

Next to.

alter course

To change the direction in which the boat is steered.

American Boat and Yacht Council, ABYC

An organization that recommends standards and practices in boat and boat gear construction.

American Power Boat Association, APBA

A governing body of powerboat racing in the United States.

American Bureau of Shipping, ABS

An organization that supervises scantlings for marine construction.

American Outboard Federation, AOF

A governing body for racing by boats powered by outboard engines.

America’s Cup, the Auld Mug, the Cup

A trophy for sailboat racing donated by the New York Yacht Club in 1857 upon the condition that it shall be preserved as a perpetual challenge cup for friendly competition between foreign countries. The oldest international sporting trophy in continuous compeition, it is sailed approximately every four years in response to foreign challenges to the last winner. It has been held by yacht clubs in the United States, Australia, and New Zealand.

amidship(s), midship(s)

Toward the center of the boat. Midships section, see lines.

AMVER

See Automated Mutual Assistance Vessel Rescue System.

Anchor, Hook

A metal device that is lowered from the boat on rope or chain (anchor rode) and that digs into or lies on the water’s bottom and so holds the boat. To set the anchor is to help it dig in by pulling hard on the rode. When the anchor drags, it springs loose from the bottom, leaving the boat adrift. All anchors have flukes (points that dig into the bottom or grab rocks) and a shank (a vertical bar). Many also have a stock (a horizontal bar that prevents rolling over) and a crown (where the stock, flukes, and/or shank meet). Anchor types include those listed below.


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Anchor, Hook (cont'd)

Burying-type anchors hold by digging their flukes into the bottom. Among them are the lightweight (fluke) anchor (including the Fortress and Danforth, both of which have stocks) and the heavier stockless plow anchor (CQR), Bruce anchor, and mushroom anchor.

Another type is the kedge (stock, nonburying) anchor. The best example is the large, heavy, cross-shaped fisherman’s anchor (yachtsman’s anchor), which holds the boat with its weight and by snagging rocks.

A third type is the lunch hook anchor, a small, light anchor used temporarily; one kind is the grapnel anchor (grapnel hook).

A storm anchor is an unusually heavy anchor of either the burying or kedge family, reserved for use in strong winds.

The helix anchor is a steel shaft screwed into the bottom for use usually with moorings.

A sea anchor does not hook the boat to the bottom, but rather provides drag against drift. See sea anchor.

The anchor and rode have associated equipment: The anchor light (riding light) is illuminated when the boat is anchored at night outside a special anchorage; see anchorage. The anchor’s rode sometimes leads over an anchor (stem) roller. An anchor sentinel (weighted dolly, kellet) is a weight slid partway down the anchor rode in order to increase the anchor’s catenary, or sag, which improves the anchor’s holding power. The anchor well is a locker recessed in the deck for stowing the anchor.

An anchor alarm is a feature of a GPS or other electronic navigation device or a depthsounder that sounds an audible alarm when the anchor drags and the boat shifts position. To buoy the anchor is to attach a buoy to is so it and its rode can be found if they must be abandoned. The anchor watch is the crew awake and on deck as lookouts while the boat is anchored. See straight up an down and swinging room.

anchorage

A place for anchoring. A good (safe) anchorage is protected by land and has relatively shallow water and good holding ground, without weed or rocks. A poor (unsafe) anchorage is otherwise. A special anchorage is an area set aside by the government for anchoring and mooring boats.

anemometer

A device that measures the wind’s speed and displays it on an indicator.

angle of attack

The angle between a sail and the wind or between the keel or rudder and the boat’s course.

antifouling paint

Paint applied to a boat’s underbody to prevent growth of barnacles and weed.

apparent wind

The strength and direction of the wind as felt in a moving boat. It is the true wind modified by the boat’s movement. An apparent wind indicator (AWI) shows the direction of the apparent wind. Compare with true wind.

appendage

A fin—the centerboard, keel, rudder, or skeg—under the boat that helps with steering and provides lateral resistance (and provides ballast, in the case of the keel). Most keels and skegs are fixed in place, while centerboards are retractable and rudders turn. Appendages usually have foil shapes to improve the flow of water around them and to provide lift.

arch, radar arch

A frame over a cockpit, bridge, or deck on which antennas, radars and radar reflectors, solar panels, lights, awnings, horns, and other items are mounted out of the way of the crew.

around the buoys

Racing for only a few hours on race courses with short legs defined by turning marks. Compare with ocean race.

ashore

To or on the shore, or land.

aspect ratio

The numerical ratio between a sail’s, keel’s, or other object’s height and its width. A relatively narrow sail has a high aspect ratio, a wide one a low aspect ratio.

astern

Behind or abaft the stern. A boat clear astern is completely astern.

asymmetrical

Having sides with different shapes or lengths. An asymmetrical spinnaker is longer on one leech than on the other. An asymmetrical leeboard in a scow or an asymmetrical hull in a catamaran (for example a Hobie Cat) is more rounded on one side than the other.

athwartships, thwartships, ‘thwartships

Across the boat, either inboard (toward the centerline) or outboard (toward the rail).

attached flow

Air or water flowing smoothly over a sail or appendage. Compare with stall.

Auld Mug

See America’s Cup.

Automated Mutual Assistance Vessel Rescue System, AMVER

A search-and-rescue (SAR) system run by the U.S. Coast Guard.

automatic pilot, autopilot

See self-steerer.

Automated Ship Identification transponder, ASI transponder

An option in a VHF radio that alerts the crew to nearby vessels.

auxiliary

1) An engine that provides motive power in a sailboat, or electrical power in any boat. 2) An auxiliary sailboat (auxiliary) is a sailboat with an engine.

awash

When waves wash over an object.

aweigh

See weigh anchor.

Awlgrip

A widely used brand of polyurethane paint that serves as a glossy, tough coating for topsides.