Cambridge
School of Navigation John Starkie, PhD, RNR
R Romeo
The way is off my ship.
You may feel your way past me
Rabbet, Race, Rack, RACON, RADAR, Radar reflector, Radiation fog, Radio, Raft, Rain, Rag bolt, Rail, Rain, Rainbow, Raise, Rake, Ram, Range, Rank, Rasing, Rating, Ratline, Rattle down, Reach, Ready about, Rebate, Reciprocal, Red duster, Red to red, Reef, Reef band, Reef knot, Reef tackle, Reel, Reeve, Reference port, Refit, Reflection, Refraction, Regatta, Relative bearing, Rhumb line, Rib, RIB, Riding light, Rig, Rigging, Righting moment, Right of way, Ring bolt, Rip tide, River, Roach, Roadstead, Rock, Rode, Rogue yarn, Rogue wave, Roll, Rope, RO-RO, Rose, Round up, Row, Rowlocks, Royal, Rubrail, Rubstrake, Rudder, Rule, Ruler, Rules of the road, Runabout, Running, Running backstay, Running lights, Running rigging, Running the gantlet
Rabbet
A rectangular recess along the edge or the end of a piece of wood. The word comes from the old French 'rabbat', meaning a recess into a wall.
In English the word 'rebate' is often used, but a rebate is something the tax man might give you.
Race
n A competition between boats (or anything) to discover which is the fastest.
n An exceptionally fast tide, perhaps where a tidal stream is confined into a channel or diverted around a headland. If the sea bottom is uneven the race may form overfalls.
See Rip tide.
Rack
n An arrangement of sheaves within two cheek plates arranged so that the lines passing through them are turned (change direction). A rack may be used to gather the lines from the mast (such as main, jib, spinnaker ha'lyards, reefing lines) so that they approach one or two winches on deck or on the coachroof.
During the Age of Sail cannonballs were kept in a rack, or garland, of wood on deck.
vb To rack a tackle is to fasten the two lines together with a seizing so that anything suspended by it will not fall if the free end of the line is released.
RACON
A RAdar beaCON. A buoy which, when it detects a radar signal, transmits its own call sign, in Morse code, at the same wavelength as the radar signal.
The radar screen of the ship carrying the radar shows a sequence of dots and dashes identifying the buoy.
RADAR
RAdio Detection And Ranging.
A detection system which uses radio waves to determine the range, altitude, direction, and/or speed of objects.
The radio signals are transmitted, and the echos are received, by an antenna mounted as high on the boat as practicable. The results are displayed on a screen. Interpretation of the results requires training and practice.
Radar reflector
A device to be carried by all vessels, and designed to reflect radar signals efficiently.
Radio
A form of communication using electromagnetic waves at a lower frequency (higher wavelength) than visible light. The waves can be modulated (either by frequency or amplitude) to transfer sounds (spoken words, music, etc) from a transmitter to a receiver over tens, hundreds, thousands or millions of miles.
Domestic and vehicle radios are usually receivers only. Information and entertainment is broadcast from transmitters owned and operated by national authorities (such as the British Broadcasting Corporation) or by private companies.
Two-way radios (walkie-talkies) have both a transmitter and a receiver on a simplex system; that is, the device can either broadcast or receive, but not both, at any one moment. Those used by boats and ships broadcast and receive with Very High Frequency radio waves between 30 and 300 MegaHertz.
Personal Mobile Radios (PMR) operate on 446MHz and are unlicenced.
Digital Selective Calling (DSC) allows pre-defined digital messages to be broadcast on a narrow waveband. A single press of a button will transmit a Mayday alert and, if programmed, the nature of the emergency. If the unit is linked to a GNSS the alert will incorporate the vessel's position.
Each DSC radio has a pre-assigned Maritime Mobile Service Identity which can be called uniquely from another DSC unit. Entering a vessel's MMSI number into a keypad allows that vessel to be called uniquely, although subsequent voice broadcasts can be received by any unit within range.
Raft
n A flat 'vessel' with no keel, no accommodation and no means of propulsion or steering.
Small boys make rafts from planks and oil drums, and use long poles to propel them around lakes and rivers.
Bathing rafts may be moored some tens of metres from safe beaches.
Thor Heyerdahl and his companions built balsa-wood rafts, with rudimentary sails and steering oars, to demonstrate the possibility that native South Americans could have 'sailed' to the Pacific Islands.
Inflatable 'rafts', 'steered' by several people with paddles are used for exciting recreational voyages down fast moving rivers and rapids.
Large hollow concrete rafts have been used as floating foundations for houses and bridges.
The rafts which painters and caulkers moor alongside ships are also known as catamarans.
vb To use a raft.
vb To moor alongside other boats on the same mooring buoy or alongside the same wharf. Rafting is normal in busy harbours, but it is courteous to ask permission before rafting alongside another vessel, and then to do so 'head to tail', so that privacies are not invaded. In getting from an outside boat to the wharf it is courteous to cross other boats away from the cockpit or companionway.
Rag bolt
An iron pin or bolt which has barbs cut into its shank so that when driven into wood it resists withdrawal.
It differs from a bolt in not having a thread cut into the shank, and so it cannot accept a nut.
Rail
A sort of fence around the boat to prevent the crew falling overboard.
A hand-rail is a long thin wooden or metal structure attached to parts of the vessel which the crew can hold to keep their balance. On smaller vessels they are often attached to the coachroof to make movement along the side decks safer. On many vessels they are above and alongside companionway steps or ladders.
A fife-rail is a strong wooden or metal structure around the base of, but not attached to, a mast. It has holes for belaying pins to which ha'lyards are belayed.
A pin-rail is a strong wooden or metal structure along the bulwarks or sides of a vessel. It has holes for belaying pins to which sheets and braces are belayed.
Rain
Drops of liquid water precipitated from clouds below about 5km high.
Heavy rain may 'deaden' the wind & sea, and reduce visibility significantly.
Ahead of a warm front the rain will usually be continuous and moderate to heavy.
At and following a cold front the rain will be intermittent, squally and possibly intense. Such squalls are often accompanied by changes in the direction of the wind.
Clouds which contain, and release, rain are termed 'nimbus' (Latin: dark cloud).
Rainbow
The refraction of sunlight or moonlight through falling raindrops appears as a semicircle of coloured light in the sky.
Rake
n The inclination of a mast from the perpendicular. Masts may be raked forward or aft, rarely to the side.
A bowsprit may be thought of as a mast raked forward 90°, perhaps a development of the Roman artemon.
n A (garden) tool with a long handle and many teeth (tines) at right angles to the handle. A rake with especially long tines may be used for combing the beach (beachcombing).
Ram
n A weapon used by Roman galleys. It consisted of an underwater projection below the stem which was forced into the hull of an enemy ship to damage and sink it.
v Accidentally or deliberately to collide with another vessel. When one vessel collides at right angles amidships of another vessel this is colloquially known as "T-boning", by association with the shape of the bone in a T-bone steak.
Range
Distance, usually in nautical miles.
A GNSS device can be asked to provide the range and bearing from the unit to a waypoint. This fixes the position of the device.
The distance (in metres) between Low Water and High Water in a single tide. The range of the tide is greatest at the Spring tide and least at the Neap tide.
The distance to which a projectile may be fired from a gun.
Or, the location, such as Foulness Sand, over which test firing of guns is carried out.
Firing ranges are marked on nautical charts. The Notes on the chart will indicate the circumstances under which it is safe for a vessel to cross a firing range.
At one time, the amount of cable or rode flaked out along the deck in preparation for anchoring. See Scope.
In Falconer's time it was a large cleat, with two horns, in the waist of the ship, to which sheets and braces were belayed.
In the USA a transit is known as a range.
Rank
The relative situations which people hold with one another.
People of a higher rank may, in general, give instructions or advice to people of a lower rank.
Rasing
ng Marking the outline of (say) a timber or frame on a piece of wood by cutting or scratching a line around a pattern.
A rasing-knife, a small edged tool with a handle, is now known as a marking-knife.
Rattle down, to
vb To rattle down is to attach the ratlines firmly to the shrouds so that they don't slip down when the sailors step on them.
Reach
vb, n To sail with the wind before, on or abaft the beam, as in close reach, beam reach or broad reach.
n The reach of a river or estuary is a straight length between bends: a ship might sail the entire length of a reach without tacking, wearing or trimming sails.
Ready about
"Prepare to change the tack"
Rebate
A return of part of money paid for goods or services, perhaps when payment is made early.
See Rabbet.
Reciprocal
A heading or bearing plus or minus 180°.
Exactly the opposite direction.
Back-bearings to a buoy are usually the reciprocal of the course needed, but not necessarily of the heading needed.
Mathematically, the reciprocal of a number is 1 divided by the number.
Red duster
A nickname for the Red Ensign.
Red to red
Power-driven vessels approaching one another head-on are required to turn to starboard so as to pass one another port side to port side; their red navigation lights would then face one another; red to red.
IRPCS "Section II. Conduct of vessels in sight of one another" Rule 14 "Head-on situation" says
"(a) When two power-driven vessels are meeting on reciprocal . . courses so as to involve a risk of collision each shall alter her course to starboard so that each shall pass on the port side of the other."
Reef
n, v. To reduce the area of a sail by rolling and tying up a portion of it.
Also to shorten the bowsprit by hauling it inboard.
See Cringle, Pendant, Knot, Point, Nettle.
n a rock, sandbar, or other feature, usually coral, lying beneath the surface of the water (80 meters or less beneath low water).
Reef band
The reef points and cringles are placed within a stronger strip of canvas sewn across the sail.
Reef knot
Otherwise known as a square knot, it may be used for tying in reefs or for tying parcels (and almost nothing else).
Reef tackle
A line with two blocks and a tail to pull the reef down to the boom, especially when the sail is full of wind.
Reel
n A circular cylinder, usually with a hollow core, for coiling rope, line or small stuff.
Some ropes, especially of small diameter, are coiled onto reels; cotton is always on a reel.
Fishing reels may be complex arrangements with handles, brakes, ratchets and attachments for rods.
n A Scottish dance.
vb To walk irregularly, almost to fall, as when drunk or drugged.
Reeve
Reference port
The port to which the tidal diamonds on a chart are referenced.
In the table of tidal diamonds, the tidal hours are before and after the time of high water at the reference port. The reference port may, or may not, be on the same chart as the diamonds.
The port to which the dots (or commas) in a tidal stream atlas are referenced.
On the pages of the tidal stream atlas the tidal hours are often described as 'hours before' or 'hours after' rather than as tidal hours.
Not the same as a Standard Port, although a Reference Port may also be a Standard Port.
Regatta
Refit
n, vb The components of the ship are replaced or refurbished, and brought up-to-date.
Reflection
n What you see when you look in a mirror.
Light which falls on your face is reflected in all directions. Some of it falls on the mirror and is reflected from the silvering behind the glass into your eyes. You see a reflection of your face.
When you adjust the mirror of your sextant you see a reflection of the sun, or star. By changing the angle of the mirror you can move the reflection of the sun, or star, to coincide with the horizon.
During a rainstorm sunlight may be reflected (and refracted) from raindrops into your eye; the refracted light is perceived as a rainbow. If the sun (perhaps low in the morning or evening) is first reflected from the surface of the sea and then reflected and refracted by the raindrops a second rainbow will appear in a different position.
If you drop a stone into a pond ripples (small waves) move outward from the point at which the stone entered the water. When the ripples meet the wall at the edge of the pond they are reflected back into the pond.
The bow and stern waves of your boat are reflected from the sides of the canal, or harbour, back into the water of the canal or harbour.
A snooker ball which strikes the cushion, or another ball, is reflected away from the cushion or other ball.
When an 'object' is reflected the angle of incidence is always equal to the angle of reflection.
Refraction
Relative bearing
A bearing in a clockwise direction relative to the heading of the vessel.
A bearing must be expressed in True, Magnetic or (rarely) Compass; a relative bearing is none of these. A relative bearing is the bearing minus the heading.
If a vessel's heading is, say, 055°T, and the bearing to a lighthouse is, say, 175°T, then the relative bearing to the lighthouse is 120°, or about 3 points abaft the starboard beam. In the 'clock' notation this would be 5 o'clock.
Rhumb line
A line (drawn on a chart) which crosses all meridians of longitude at the same angle. A vessel on a constant heading, relative to True North, would follow a rhumb line. A straight line on a chart to Mercator's Projection is a rhumb line.
A continuation of a rhumb line will ultimately, unless it follows a parallel of latitude at right angles to a meridian, reach one or other of the poles.
The shortest distance between two points on the earth's surface is a great circle: a rhumb line is not a great circle, unless it follows the equator or a meridian.
RIB
A Rigid Inflatable Boat.
The hull, being made of GRP or a thermoplastic material, is rigid below the chine. Above the chine, the 'hull' consists of inflatable tubes.
Riding light
Colloquial term for an anchor light.
IRPCS Rule 30 "Anchored vessels . . . " says
(a) A vessel at anchor shall exhibit . . :
(i) in the fore part, an all-round white light . .;
(ii) at or near the stern and at a lower level than . . prescribed in . . (i), an all-round white light."
A riding light (anchor light) is not a masthead light, although the anchor lights of small vessels are usually at the top of the mast. Masthead lights are 'ahead of' the mast, not at the top.
Rig
The sails and rigging; the appearance of a boat from her sails and rigging.
Clothing worn by people associated with the sea.
Rigging
The standing rigging includes the shrouds and stays which hold up the masts.
The running rigging includes the ha’lyards, sheets, tacklines, kicking strap, lazyjacks, vangs.
Righting moment
The force tending to bring a heeled vessel upright. The centre of gravity, and the centre of buoyancy, and the horizontal distance between the two contribute to the righting moment.
'Moment' here has nothing to do with time. It is the product of a force and the perpendicular distance between the force and its fulcrum. See AVS.
Right of way
Before the amendments to the IRPCS of 1995 some vessels were given a right of way over others.
Since then no vessel has a right of way, unhindered, over another; the Rules specify which vessels should give way, and require the stand-on vessel to give way if the other does not. See IRPCS Rule 17.
Ring Bolt
Eye-bolts having a ring through the eye of the bolt.
Rip tide
A fast-flowing current of water, parallel to the shore between banks. Not, strictly, a tide, although it may arise from the channelling of a tidal stream.
River
Water flowing along a well-defined, more or less permanent path or bed from higher to lower ground and ultimately to the sea (or an inland lake).
The stream (current) of a river depends on rainfall; the set is more or less constant and predictable, while the drift may vary significantly: it has no tide. Where a river is connected to the sea and a tide becomes evident the river is an estuary.
Roach
Where the leech of a sail (especially a Bermudan mainsail) arcs outward and is held out by battens to increase the area of the sail.
Roadstead, road
An anchorage, usually deep water, outside a harbour.
Rock
n A solid aggregate of one or more minerals. In a sailing context, such an aggregate protrudes from the seabed or from the shore and presents a danger to vessels.
Rocks may be visible above sea level, or covered and uncovered by the tide, or always covered. They are represented on nautical charts by a variety of symbols.
vb To heel or list a boat one way and then the other repeatedly. Children love to frighten one another by rocking small boats.
See Roll.
An adult who 'rocks the boat' is acting against the authorised pattern of behaviour.
Rode
The line or chain between the boat and it’s anchor.
Rogue wave
An unusually large wave.
When the sea is disturbed by several wave patterns, perhaps from different directions, their frequencies are different. Often, the harmonics cancel out; occasionally they augment one another to create a 'rogue wave'.
Roll
A ship rolls when she heels or lists to one side and then the other.
Oscillations about a horizontal fore-and-aft axis.
Rolling is caused by the action of waves or swell, except when sailing downwind under Bermudan mainsail and jib, or jib alone; such rolling may increase progressively (a death roll) until the sail or boom touches the water.
Rope
On the reel or in a coil. When a length has been cut from the reel and put into use aboard the boat it becomes a line.
The two words, ‘rope’ and ‘line’ are generally interchangeable. All the lines on a boat (with the possible exceptions of the bell-rope, bolt-rope, foot-rope and man-ropes) have specific names, like sheet, ha’lyard, rode, painter, but it is possible that these names were originally adjectives describing the word ‘line’ (or even 'rope'): Joshua Slocum referred to Spray's sheets as 'sheet-ropes' (perhaps implying that 'sheet' might once have been slang for 'sail').
A coil of rope may be one of two kinds.
If the rope has been wound around a core of wood or plastic (a reel) it must be unrolled from the outside of the winding. The core usually has an axial hole which can be mounted on a pole to make unwinding the rope easier.
If the coil has no central core the rope must be drawn from the centre of the coil, not the outside, to prevent kinking and ravelling.
RO-RO
Roll-on-roll-off. A ferry which carries vehicles which drive on and off under their own power, usually without reversing.
Rose
A compass card, showing the points of the compass (now rare) or gradations of 360°.
Nautical charts have several compass roses.
Round up
To turn a sailing boat directly into the wind (so that the wind blows from the stem to the stern) in order to stop and, perhaps, drop anchor.
Row
Royal
An adjective describing the mast, sails, rigging and yards set above the topgallant mast.
An adjective describing members of the monarch's close family. Occasionally used, especially in the plural and by the 'tabloid' press, as a noun.
An adjectival noun used colloquially to describe a member of the Royal Marine Corps.
Rubrail
A sacrificial piece attached to the side of a boat to prevent damage to the rest of the boat when coming alongside.
Rubstrake
A rubrail consisting of a run of planking from stem to stern. See strake.
Rudder
The fore-and-aft underwater plate which steers the boat, and which contributes to reducing leeway.
The rudder may be operated by a tiller connected directly to the rudder, or by a wheel or whipstaff connected to the rudder by lines. In all cases there is a tiller (however small) or quadrant on the rudder head.
The rudder may be mounted on the transom, or it may be mounted under the after part of the boat and connected to its tiller by a tube.
Rule
n A straightedge, often with graduations in imperial or metric units, which may be used to rule straight lines but is most often used to measure distances.
Battens may be used as straightedges, but are more often used to draw fair curves, as when lofting the lines of a boat.
vb To draw a straight line with a graduated rule or simple straightedge.
n A standing instruction (such as the IRPCS).
vb To rule, to reign over, to control people and territory. A person who rules is a ruler.
Ruler
n A person who rules, such as a king or queen (or perhaps someone with a straightedge and pencil).
Rules of the Road
A colloquial term for the International Regulations for Preventing Collisions at Sea.
Local rules, such as for racing, or on inland waters, are usually modifications of the IRPCS which do not conflict.
Runabout
An archaic term for a small single-masted vessel, usually carrying a mainsail and a jib. The mainsail would have been a lugsail or, later, a gaffsail but not, in those days, a Bermudan sail. The jib would have been flown from a bowsprit or, perhaps, the stemhead.
What is now called a sloop.
Running
vb Sailing before the wind; with the wind over the stern: with the wind blowing from the stern to the stem: sailing downwind.
Possibly the most difficult and dangerous point of sail for a modern sloop. The mainsail, boomed out to the beam as far as possible, denies wind to the jib which is then often set on the other side of the stay (goosewinged). It takes a skilled helmsman to keep both main and jib full of wind. The mainsail of a Marconi-stayed boat cannot be boomed square to the centre line; with the wind from astern there is always the danger that a flaw of wind will back the mainsail and cause an unexpected gybe. In strong winds, and thereby high waves, there is a danger that the water on the forward face of a wave will move faster than the boat, stall the rudder and cause a broach.
The fastest and most convenient point of sail for a square-rigged vessel.
adj as in ‘running backstay’, which is an item of standing rigging which is readily and easily adjusted.
adj As in running rigging, lines which move (run) through blocks to control spars and sails.
Running backstay
On some boats the forestay (or one of them) is attached part way up the mast and not at the top. The effort of the staysail would tend to bend or buckle the mast at the point of attachment. This is prevented by a pair of backstays from the mast to points forward of the quarters. These backstays tend to interfere with the boom and so, on each tack, the leeward backstay can be eased and drawn forward.
Running lights
Navigation lights.
See IRPCS, Part C, Rules 20 to 31.
Running rigging
Lines which move (run) through blocks to control sails and spars.
See Rigging.
Running the gantlet
August 2020
If you disagree,
or can't find a word
please let me know.