ballast any portable or fixed weight carried to make a vessel more stable or seaworthy. Types of ballast include sand, concrete, lead, scrap, pig iron, and sea- water.
ballast tanks water tanks that are filled or emptied to aid in a vessel's stability; also used in subs for submerging.
batten strip of wood or steel used in securing tarpaulins.
beam the extreme width of a vessel.
berth bed, bunk, or sleeping compartment. Also, any place where a ship is moored.
bilges the rounded portions of a ship's bottom or shell.
bilge pump pump that removes water from the bilges.
binnacle a stand that houses a compass for easy viewing.
block a pulley or system of pulleys. boiler steam generator.
booby hatch access hatch on the weather deck with a hood and sliding cover to keep water out.
bollard iron or wooden fixture on a vessel or dock to which mooring lines are attached.
boss the curved or swollen portion of the ship's underwater hull around the propellor shaft.
bosun boatswain—petty officer in charge of rigging, sail maintenance, anchors, and deck operations.
bosun's chair a seat for hoisting a person aloft for repairs.
bow front of a ship. Also known as a prow.
bowsprit spar that projects over the bow, used to hold the lower ends of head sails, or used for observation.
bridge an observation platform, often forming the top of a bridge house or pilot house, giving a clear view of the weather deck.
bulkhead any one of the partition walls that divide the interior of a ship into compartments or rooms.
cabin the living quarters for officers and passengers.
cabin boy one who waits on the passengers and officers of a ship.
cabin class ship accommodations above tourist class but below first class.
capstan drum- or barrel-shaped apparatus operated by hand or by motor for hauling in heavy anchor chains.
cargo hatch the large opening in the deck to permit loading of cargo below.
cargo net net used to haul cargo aboard.
cargo port an opening with a watertight door in the side of a ship to allow the loading and unloading of cargo.
chafing gear rubber hoses, sheaths, and other materials used to protect ropes from wearing where they rub on sharp edges.
chart house small room adjacent to the bridge for charts and navigating instruments.
cleats piece of wood or metal having two projecting arms or horns on which to belay ropes.
clinometer instrument that indicates the angle of roll or pitch of a vessel.
companionway a hatchway in a deck with a set of steps or ladders leading from one deck to another.
cordage collective term for all the ropes on a vessel.
cradle wooden frame where boats are stowed on shore.
cross tree athwartship pieces fitted over the trees on a mast.
crow's nest lookout perch attached to or near the head of a mast.
cuddy a small cabin.
davit small crane on a ship's side for hoisting boats or supplies.
deadlight a porthole lid or cover.
deep waterline the depth of a vessel in the water when carrying the maximum amount of allowable weight or cargo.
derrick a type of crane used for hoisting and swinging heavy weights.
door, airtight a door constructed to prevent the passage of air.
door, watertight a door constructed to prevent the passage of water.
draft the depth of a vessel below the waterline. Also spelled draught.
draft marks numbers on a vessel's bow or stern indicating the draft or depth of the vessel below the waterline.
dry dock a hollow floating structure designed to submerge in order to float a vessel into it, and then to lift the vessel out of the water for repairs or construction.
fantail the overhanging stern section on some vessels.
fathom nautical unit of measurement, in the United States 6 feet, or 1.829 meters.
fender protective plate, bundles of rope, old tires, or other material running along the side of a ship to prevent scratches and dents from rubbing against other vessels or piers.
fetch the distance from a wind's point of origin over the sea to a vessel, affecting the height of waves. Also, to swing around or veer.
fin a projecting keel.
flotilla fleet of small vessels.
flotsam and jetsam debris, goods, or cargo cast or washed from an imperiled or wrecked ship.
flukes the hooks or holding claws of an anchor.
fore the front of a ship or bow area.
fore and aft lengthwise of a ship.
forecastle structure on the upper deck of a ship toward the fore; the crew quarters on a merchant ship.
foul the sea growth or foreign matter covering the underwater portion of a ship's shell.
founder to sink after filling with water.
galley kitchen.
gangplank board or platform used for boarding passengers or cargo.
gangway an opening in a ship's side for the passage of freight or passengers.
grapnel similar to a small anchor, a device used for recovering small items dropped overboard or to hook onto lines from a distance.
graybeards choppy, frothy waves.
gunwale the upper edge of a side of a vessel.
guys wires, ropes, or chains used to support booms, davits, and suchlike.
halyards light lines used in hoisting signals or flags; also, the ropes used in hoisting gaffs, sails, or yards.
hatchway accessway or opening in a deck.
hawse hole through which the anchor chain is hoisted or released; any hole through which a chain or cable is passed.
hawser rope or cable used in mooring or towing. head toilet.
heave to to stop the forward motion of a vessel and lie dead in the water.
heel the leaning of a vessel to one side, caused by wind, waves, or shifting cargo.
helm the steering apparatus, including the tiller, the rudder, and the wheel.
hog scrub broom used for scraping a ship's bottom underwater.
hold space below deck for cargo.
jack ladder ladder with wooden steps and side ropes.
jury temporary structures, such as makeshift masts or rudders, used in an emergency. Also known as jury-rigging.
keel the main structural member running fore and aft along the bottom of a vessel, also known as the backbone.
keelson a beam running above the keel of a vessel.
knot unit of speed, 1 nautical mile (6,080 feet) an hour.
lanyard rope having one free end and one attached to any object for the purpose of remote control; also, any rope used for fastening riggings.
lee the side of a vessel sheltered from the wind, or leeward; opposite of the windward side.
list deviation of a vessel from an upright position, caused by waves, wind, bilging, or shifting cargo.