R

Radar
An electronic instrument that uses radio waves to find the distance and location of other objects. Used to avoid collisions, particularly in times of poor visibility.

Radio
An instrument that uses electromagnetic waves to communicate with other vessels. VHF (very high frequency) radios are common for marine use, but are limited in range. SSB (single sideband) radios have longer ranges.

Radio beacon
A navigational aid that emits radio waves for navigational purposes. The radio beacon's position is known and the direction of the radio beacon can be determined by using a radio direction finder.

Raft
1) A small flat boat, usually inflatable. 2) To moor with more than one boat tied together, usually using only one boat's anchor and rode.

Rail
The edge of a boat's deck.

Rake
A measurement of the top of the mast's tilt toward the bow or stern.

Reef
1) To partially lower a sail so that it is not as large. This helps prevent too much sail from being in use when the wind gets stronger.
2) A line of rock and coral near the surface of the water.

Reefing lines
Lines used to pull the reef in the sail.

Rhumb line
A line that passes through all meridians at the same angle. When drawn on a Mercator chart, the rhumb line is a straight line, because the Mercator chart is a distortion of a spherical globe on a flat surface. The rhumb line results in a longer course than a great circle route.

Ride out
To weather a storm, either at sea or at anchor.

Riding sail
Also called a stability sail. Any small sail set to help the boat maintain its direction without necessarily moving, as when at anchor or in heavy weather.

Rig
1) A combination of sails and spars.
2) To prepare the rig before sailing.

Rigging
The wires, lines, halyards and other items used to attach the sails and spars to the boat. The lines that do not have to be adjusted often are known as standing rigging. The lines that are adjusted to raise, lower and trim the sails are known as running rigging.

Right
To return a boat to its upright position.

Rigid inflatable
A small inflatable boat that has a solid hull but has buoyancy tubes that are inflated to keep it afloat.

Roaring Forties
A region between 40° South and 50° South where westerly winds circle the earth unobstructed by land.

Rode
A line or chain attached to an anchor.

Roll
A side-to-side motion of the boat, usually caused by waves.

Roller furling
A method of storing a sail, usually by rolling the jib around the headstay or rolling the mainsail around the boom or on the mast.

Roller reefing
A system of reefing a sail by partially furling it. Roller furling systems are not necessarily designed to support roller reefing.

Rope
Traditionally, a line must be over 1 inch in size to be called a rope.

Row
A method of moving a boat with oars. The person rowing the boat faces backward, bringing the blade of the oars out of the water and toward the bow of the boat, then pulling the oars through the water toward the stern of the boat, moving the boat forward.

Rowboat
A small boat designed to be rowed by use of its oars. Some dinghies are rowboats.

Royal mast
The small mast next above the topgallant mast.

Rub rail, rub strake, rub guard
A rail on the outside of the hull of a boat to protect the hull from rubbing against piles, docks and other objects.

Rudder
A flat surface attached behind or underneath the stern, used to control the direction the boat is traveling.

Rudder post
The post that the rudder is attached to. The wheel or tiller is connected to the rudder post.

Run aground
To take a boat into water that is too shallow for it to float in; the bottom of the boat is resting on the ground.

Runner
Also known as running backstay. Adjustable stay used to control tension on the mast.

Running
1) A point of sail where the boat has the wind coming from aft of the boat.
2) Used to describe a line that has been released and is in motion.

Running backstay
Also known as a runner. Adjustable stay used to control tension on the mast.

Running bowline
A type of knot that tightens under load. It is formed by running the line through the loop formed in a regular bowline.

Running lights
Navigational lights that are required to be used when a vessel is in motion.