Sail - A piece of fabric that catches or directs the wind and so powers a vessel.
Sailing Rig - The equipment used to sail a boat, including sails, booms and gaffs, lines and blocks.
Sailor Prop - A prop with a blade area of 44% of the circle described by the blades. This style prop reduces drag under sail, but at the expense of having less thrust while under power, including close quarters maneuvering (such as at a dock).
Scandalize - On a gaff rig the sail is made loose footed, the clew is brought forward along the boom and the sail cloth is drawn up in folds along the gaff and mast. From this position the sail is instantly available for use.
Schooner - Sailing ships with at least 2 masts (foremast and mainmast) with the mainmast being the taller. Word derives from the term "schoon/scoon" meaning to move smoothly and quickly. ( a 3-masted vessel is called a "tern").
Scope - Technically, the ratio of length of anchor rode in use to the vertical distance from the bow of the vessel to the bottom of the water. Usually six to seven to one for calm weather and more scope in storm conditions.
Screw - A boat's propeller.
Scupper - Drain in cockpit, coaming, or toe-rail allowing water to drain out and overboard. When in toe rail, properly known as "freeing port"
Scuttle - A round window in the side or deck of a boat that may be opened to admit light and air, and closed tightly when required.
Sea Cock - A through hull valve, a shut off on a plumbing or drain pipe between the vessel's interior and the sea.
Sea Room - A safe distance from the shore or other hazards.
Seamanship - All the arts and skills of boat handling, ranging from maintenance and repairs to piloting, sail handling, marlinespike work, and rigging.
Seat Locker - A storage locker located under a cockpit seat.
Seaworthy - A boat or a boat's gear able to meet the usual sea conditions.
Self-bailing Cockpit - A watertight cockpit with scuppers, drains, or bailers that remove water.
Self-tacking - Normally applied to a sail that requires no adjustment other than sheeting when boat is tacked.
Secure - To make fast.
Set - Direction toward which the current is flowing. Also, to position, as in "to set a sail".
Shaft Log - A tube which contains the prop shaft. It is permenantly bonded to the hull on its aft end and sealed with a stuffing box on the forward end to maintain its water tight seal.
Sheer - The line of the upper deck when viewed from the side. Normal sheer curves up towards the bow and stern.
Reverse sheer curves down towards the bow and stern. Compound sheer, curving up at the front of the boat and down at the stern, and straight sheer are uncommon.
Sheer Strake - The topmost planking in the sides, often thicker than other planking.
Sheets - Lines used to control the position of a sail. Typically named for the sail they control so the main is controled by the main sheet, the jib by the jib sheets etc.
Ship - A larger vessel usually thought of as being used for ocean travel. A vessel able to carry a "boat" on board.
Shrouds - Lateral supports for the mast, usually of wire or metal rod. A line or wire running from the top of the mast to the spreaders, or from the spreader brackets, then attaching to the side of the vessel.
Skeg - For sailboats, usually refers to a structural support to which the rudder is fastened.
Slab Reefing - Also points reefing, and sometimes jiffy reefing. Reduces the area of the mainsail by partially lowering the sail and resecuring the new foot by tying it to the boom with points, or light lines attached to the sail.
Slack - Not fastened; loose. Also, to loosen.
Snapshackle - A specialized type of shackle. Its primary characteristic is that it can be released under load by pulling on a pin which opens a large, curved jaw.
Sole - The floor of the cockpit or cabin.
Sounding - A measurement of the depth of water.
Spar - Any pole or beam aboard but generally used to refer to the mast(s) or boom(s).
Spigot - A short cylindrical projection on one component designed to fit into a hole on another, esp. the male part of a joint between two pipes.
Spinnaker - A large, triangular sail, most often symmetrical, flown from the mast in front of all other sails and the forestay. Used sailing downwind.
Sprit - The spar that supports the peak of a spritsail.
Splashboard - A raised portion of the hull forward of the cockpit intended to prevent water entering.
Spreaders - Short horizontal struts extending from the mast to the sides of the boat, changing the upward angle of the shrouds. Some very early Catalina 30's and Catalina 38's used wooden spreaders, but all modern Catalinas use aluminum spreaders.
Spring Line - A mooring line rigged fore and aft used to prevent the boat from moving forward or astern while made fast to a dock. Also, a line used to control the boats motion when docking or leaving a dock.
Spritsail - A four-sided fore and aft sail set on the mast, and supported by a spar from the mast diagonally to the peak of the sail.
Squall - A sudden, violent wind often accompanied by rain.
Square Knot - A knot used to join two lines of similar size. Also called a reef knot.
Stanchion - Vertical post near a deck's edge that supports lifelines. A timber fitted in between the frame heads on a wooden hull or a bracket on a vessel, approximately one meter high, to support the bulwark plank or plating and the rail.
Standing Part - That part of a line which is made fast.The main part of a line as distinguished from the bight and the bitter end.
Standing Rigging - Permanent rigging used to support the spars. May be adjusted during racing, in some classes.
Stand-On Vessel - That vessel which has right-of-way during a meeting, crossing, or overtaking situation.
Starboard - The right side of a boat when looking forward.
Stay - A line or wire from the mast to the bow or stern of a ship, for support of the mast (fore, back, running, and triadic stays).
Staysail - A sail that is set on a stay, and not on a yard or a mast.
Steaming Light - A white navigation light mounted on the front of the mast that must be lit at night whenever your engine is running. Sometimes referred to as the masthead light although that term more commonly refers to the anchor light that is actually mounted at the top of the mast.
Stem - The most forward vertical structural member in the bow.
Step - To raise. To "step the mast" is to bring it vertical and secure all of the standing rigging to keep it properly in place. The opposite is to "unstep the mast".
Stern - The after part of the boat.
Stern Line - A docking line leading from the stern.
Stow - To put an item in its proper place.
Stuffing Box - A fitting designed to allow a shaft (typically rudder or prop) to exit the boat while keeping water out of the boat.
Strake - On wooden boats, a line of planking running from the bow to the stern along the hull.
Swamp - To fill with water, but not settle to the bottom.
Sweat And Tail - Sweat is the act of hauling a halyard to raise a sail or spar done by pulling all slack outward and then downward. Tail is controlling, coiling, and securing the runnning end of the halyard.
Tabernacle - A hinged mast step located on deck. Since it is hinged, the mast may be lowered easily.
Tack - On a triangular sail, the bottom forward corner. Also, to turn the bow of the boat through the eye of the wind so the boat can "zigzag" to travel upwind.
Taffrail - The rail at the stern of the boat.
Tang - A fitting, often of sheet metal, used to attach standing rigging to a spar, or to the hull.
Thwart - A transverse structural member in the cockpit. In small boats, often used as a seat.
Thwartships - At right angles to the centerline of the boat.
Tide - The periodic rise and fall of water level in the oceans.
Tiller - A bar or handle for turning a boat's rudder or an outboard motor.
Toe-rail - A low rail, often slotted, along the side of the boat. Slots allow drainage and the attachment of blocks.
Topmast - A second spar carried at the top of the fore or main mast, used to fly more sail.
Topping Lift - A line or wire rope used to support the boom when a boat is anchored or moored.
Topsides - The sides of a vessel between the waterline and the deck; sometimes referring to onto or above the deck.
Trampoline - The fabric support that serves for seating between the hulls of a catamaran.
Transom - The flat, or sometimes curved terminating structure of the hull at the stern of a boat.
Trapeze - Wire gear enabling a crewmember to place all of his weight outboard of the hull, thus helping to keep the boat level.
Traveler - A fitting across the boat to which sheets are led. In many boats the traveler may be adjusted from side to side so that the angle of the sheets can be changed without significantly altering sail shape, to suit conditions.
Trim - Fore and aft balance of a boat.
Turtle - To turn upside down. More severe than a capsize. Also a spinnaker sail bag designed to facilitate the launching of the spinnaker.
Twing - Similar to a Barber hauler, a twing adjusts the angle of sheeting.
Underway - Vessel in motion, not moored or aground