(p.163) Appendix A. Glossary and Abbreviations
(p.163) Appendix A. Glossary and Abbreviations
Aft: Facing, or running along to the rear of a boat or ship.
Amidships: Located in the middle of a boat or ship; also termed “midships.”
Athwartships: Running across a boat or ship from side to side.
Beam: The dimension of boat or ship measured from side to side perpendicular to the centerline; usually measured amidships at the location where the measurement is at maximum.
Becket: A short piece of rope looped through a board to form an eye, through which the steering oar is placed as a bracket.
Bench: Seat fitted around the sides and aft end of a boat.
bhp: Abbreviation for “brake horsepower,” a measurement of diesel engine power.
Bilge: The space between the bottom of the hull and the lowest deck or floors. The area of the hull of a round-bottom craft where the bottom gradually becomes the sides (referred to as the “turn of the bilge”).
Bitt: Cast-metal posts with heads to which rope or towlines can be secured.
Bow: The front or forward portion of a boat or ship.
Bulkhead: A vertical structural partition of a boat or ship, other than the hull, that forms a type of wall and divides the boat or ship into compartments; usually constructed so as to be watertight.
Bulwark: The upper section of the hull planking or plating that extends above and around the upper deck, usually for protection against breaking seas.
Camber: A slope upward toward the center of a surface, as on a deck amidships for shedding water.
Carvel- built: A form of boat hull construction where the planking is laid such that planks butt up against each other rather than overlap; i.e., the edge of an upper plank is up against and level or flush with the top edge of the lower plank, with the two planks nailed or riveted to the boat frames rather than to each other.
Ceiling: The inner planking of a boat laid on the inside of a boat’s frames.
Centerline: An imaginary horizontal line that runs down the exact middle of a boat or ship from bow to stern, dividing it into two equal halves.
Chine: A boat hull shape where the bottom and sides meet at an angle rather than as a curved shape; “hardchined” is a hull shape where this angle is very sharp or narrow, and “soft-chined” is a hull shape where this angle is wider; a chine hull form is initially more resistant to heeling (or tipping) over than a rounded-bottom hull form, but is less stable and less resistant to further heeling once over at an angle compared to a round-bottomed boat.
Clinker-built: A form of boat hull construction where the planking overlaps; i.e., the edge of an upper plank overlaps the top edge of the lower plank, with the two planks nailed or riveted together.
Coble: A small, wooden- hulled flat- bottomed coastal fishing boat that originated in Great Britain. Typically, cobles were clinker-built, between 15 and 30 feet in overall length with a fairly large beam, pronounced sheer, deep forefoot, and a square stern, and were designed to be launched from the beach directly into the seas. They could be rowed or sailed.
Deadrise: The angle between the bottom and a horizontal plane in the middle of a boat, or the upward slope of the boat’s bottom from the keel to the bilge. The flatter the bottom of a boat is, the less deadrise it has.
Deck: A horizontal surface in boat or ship construction that usually runs completely forward to aft, from side to side.
Deep-V hull: A boat- bottom shape that takes the form of a sharp V angle to improve boat movement through the water.
Depth: The vertical measurement of a boat’s or ship’s size from the gunwale to the keel.
dia: Abbreviation for “diameter.”
Dipping lugsail: A lugsail with its tack secured well forward of the mast. The sail is set to leeward of the mast such that, when coming about on an alternate course under sail, the forward end of the gaff has to be dipped to the new leeward side.
(p.164) Displacement: The weight or mass of water that a boat or ship displaces when afloat, usually measured in pounds or tons.
Displacement hull: A hull design where the boat’s or ship’s hull is fully immersed whether underway or at rest.
Double-ended: A hull shape that is sharp at both the bow and stern; i.e., the bow and stern hull forms are identical or nearly identical.
Draft: The measurement of the portion of a boat’s or ship’s hull that is underwater from the waterline to the lowest point of the hull.
Entrance: The immersed portion of a boat’s hull forward of the waist.
Fender: A device attached to the sides of a boat, usually at the gunwale, to protect the boat from damage due to rubbing or collision.
Flare: A hull shape that spreads out from the sides of a boat rather than being straight up and down or plumb; a boat’s bow that has flare is a better design for reducing the amount of sea spray as the boat moves through the water.
Floor: Vertical flat planks or plates that run in a transverse manner, connecting the vertical keel with the lower ends of the frames.
Forward: Facing, or running along to the front of a boat or ship.
Frame: A hull member of strength that runs either athwartships or longitudinal (i.e., forward to aft); also referred to as a rib.
Freeboard: The vertical measurement of the portion of a boat’s or ship’s hull that is above the waterline to the gunwale.
Freeing port: Holes in the bulwark or rail that allow water to drain off the deck back into the sea.
FRP: Abbreviation for “fiberglass-reinforced plastic.”
Full-load displacement: The weight of water displaced by a boat or ship when fully loaded with equipment, supplies, crew, and fuel.
Garboard strake: The hull plank or strake closest to the boat’s keel.
gpm: Abbreviation for “gallons per minute.”
Gunwale: A hull member of strength that runs forward and aft on both sides along the top side, or sheer, of a boat.
hp: Abbreviation for “horsepower.”
Keel: The bottommost strength member of the hull; it usually runs from the bow all the way to the stern along the bottom of the boat.
Keelson: A large wooden or metal beam that is installed on the inside of a boat or ship along and over the keel as a means of reinforcement.
Knee: Angular piece of wood or metal used to connect one structural member to another in a boat or ship.
Knot: A measure of speed in nautical miles (6,076 ft permile) per hour, rather than statute miles (5,280 ft permile) per hour.
kts: Abbreviation for “knots.”
Lapstrake: Another term for clinker-type construction of the hull, where the strakes or planks overlap one another.
Longitudinal: Running from forward to aft in a boat or ship; usually in connection with frame or bulkhead design.
MHS: Abbreviation for “Massachusetts Humane Society.”
MLB: Coast Guard abbreviation for “motor lifeboat.”
Molded: A measurement of any timber of a boat from the outside to the inside.
mph: Abbreviation for “miles per hour.”
MSB: Coast Guard abbreviation for “motor surfboat.”
nm: Abbreviation for “nautical miles.” One nautical mile is 6,076 feet or 1,852 meters, compared to a statute mile of 5,280 feet.
Pinnace: A small boat, of either carvel or clinker construction, used for transferring personnel or cargo from a ship to shore, usually in calm to moderate conditions. This type of boat was intended primarily for rowing.
Planing hull: A hull design where the boat’s or ship’s hull is intended to ride on the water’s surface rather than being fully immersed when underway, but when at rest is fully immersed.
PLB: Abbreviation for “pulling lifeboat.”
Port: Looking toward the bow, the left side of a boat or ship.
PSB: Abbreviation for “pulling surfboat.”
Rabbet: The notch cut into the stem- or sternpost where the hull planks are joined.
Relieving tube: A tube constructed so as to run from the main deck surface down to and through the bottom of a boat to aid in the draining of water off the deck and back into the sea.
Relieving valve: A one-way flapper-type valve that is installed in a relieving tube to allow drainage but prevent seawater from flowing back up and onto the deck.
RHIB: Coast Guard abbreviation for “rigid-hull inflat-able boat.”
Riser: A hull member of strength that runs forward and aft and is nailed or riveted to the inside surface of a frame.
RNLI: Abbreviation for the “Royal National Lifeboat Institute” in the United Kingdom.
Rocker: The forward-to- aft curvature of a boat’s keel.
RPM: Abbreviation for “revolutions per minute,” a measurement of engine and/or propeller-shaft rotation speed.
Run: The immersed portion of a boat’s hull aft of the waist.
(p.165) Scantling: Term used to define the dimensions of frames, planking, etc. that become part of a boat’s hull.
Scarf: A joint in a boat’s planking made by cutting back the ends of the planks at an angle and lapping them, with nails or rivets as fasteners.
Scupper: Any opening or tube leading through the side of a boat or ship used to drain water off of the deck.
Scuttle: A small, usually circular opening in a deck that provides access to a below-deck area, and usually fitted with a watertight manhole cover.
Self- bailing: A boat’s capability to automatically rid itself of any water that is inadvertently brought aboard by waves or seas; usually accomplished by some passive mechanical means of drainage.
Self-righting: A boat’s capability to automatically right itself in the event of a rollover or capsize; usually accomplished by counterweights or supplemental buoyancy, or both.
Semi-displacement hull: A hull design where the boat’s or ship’s hull is intended to partially ride on the water’s surface but still be somewhat immersed when underway, but when at rest is fully immersed. These tend to be hulls that are V-shaped forward, rounded amidships, and flattened aft.
Sheer: The forward-to- aft curvature, usually of a boat’s gunwale or uppermost portion of the hull, but also of a boat’s bottom; usually measured as the curvature of a boat’s lines toward the bow and stern.
Sheer strake: The highest plank on a boat’s hull, the top edge of which forms the boat’s sheer.
Sided: The width of a boat’s timber measured on the outside.
Single-ended: A hull design with a sharp bow and a square-shaped or flat stern.
Skeg: An underwater projection of the keel going aft that usually provides support and/or protection for the boat’s rudder.
Standing lugsail: A lugsail in which its tack is secured to the foot of the mast or near it, but the gaff is not
dipped when coming about on an alternate course under sail.
Starboard: Looking forward, the right side of a boat or ship.
Stem: The forwardmost hull member of strength, at the bow; usually connected to or integral with the keel of the boat.
Stern: The rear or aft portion of a boat or ship.
Sternpost: The aftermost hull member of strength, at the stern, usually connected to or integral with the keel of the boat and to which the rudder is mounted.
Sterntube: The bearing that supports the propeller shaft at the point where it emerges from the hull.
Strake: A plank laid longitudinally across a boat’s frames as part of the outer hull.
Stringer: A large beam or angle piece that is installed, usually longitudinally parallel and alongside the keel, to give additional strength to the hull and deck.
Superstructure: Any structure built above the main deck, such as a pilothouse or cabin.
Thwart: A seat installed athwartships in a boat on which an oarsman sits for rowing.
Tiller: A bar or lever used to turn the rudder of a boat or ship.
Transom: The flat plank that forms the stern of a flat stern or single-ended boat.
Transverse: Running across a boat or ship from side to side; usually in connection with frame or bulkhead design.
USCG: Abbreviation for the “United States Coast Guard.”
USLSS: Abbreviation for the “United States Life-Saving' Service.”
UTB: Coast Guard abbreviation for “utility boat-large.”
UTL: Coast Guard abbreviation for “utility boat- small.”
UTM: Coast Guard abbreviation for “utility boat-medium.”
Yawl: A two-masted sailing boat of either carvel or clinker construction (usually carvel).