Definitions and Mnemonics for Sailors and Powerboaters

StudyWeb Award Navigate! award When one is first learning boating, there seems to be an endless confusion of terms, procedures, and rules to be memorized. Many of these are critical to safety, and over the years boaters have invented various little mnemonics to help them navigate the complexities. This Web page is a collection of such mnemonics, most time-honored, but a few invented by the author of the page (Geoff Kuenning) to fill in the gaps where none were available.

Disclaimer: Although every effort has been made to ensure the accuracy of these mnemonics, they are intended as memory aids, rather than as a substitute for other knowledge. In particular, the mnemonics for navigation lights and the "rules of the road" are simplifications and summaries, and the prudent mariner should not rely on them as a sole source of information. Study the rules first, and then use these mnemonics to help you remember them. Do not attempt to learn the rules by studying this Web page.

Note: this Web page was tested with Netscape Navigator 2.0 for Unix. If you see formatting that is obviously bogus, please e-mail me about it. Be sure to let me know what browser you use.

Formatting: definitions of terms are generally shown in emphasized text, unless they are also hypertext links. Mnemonics are shown in strongly emphasized text.

Copying: A number of people have asked permission to reproduce this page as handouts for use in boating classes. The short answer is "Yes, so long as I get credit and you don't make a profit." See the copyright notice at the end for a more legalistic phrasing. You don't even have to ask first, although I always appreciate getting e-mail letting me know, just because it makes me feel good to know that I'm helping the cause of boating.

Finally, a note for people who have questions about boating and terminology: I'm not an expert, I'm a beginner. I created this Web page to help myself. Please don't e-mail me with your questions, because I don't have the answers anyway. Thanks.

About the COLREGS

The word "COLREGS" is a common abbreviation for the International Regulations for Prevention of Collisions at Sea, which is the worldwide agreement on how boats should behave when in international waters. Most of these mnemonic are intended to help you remember important parts of the COLREGS, although some are specific to inland waterways in the United States (which have slightly different rules). When the mnemonics conflict with your interpretation of the COLREGS, remember that the COLREGS are the law and the mnemonics are only a memory aid!

Navigation Light Combinations

One of the most complex areas of boating is the light combinations used to indicate various types of ships at night. Luckily, there are also lots of standard mnemonics. Most of these were provided by Farnes Quinn and Steve Hodgson.

Running Lights

The most fundamental navigation lights are the running lights required on all boats over 5 meters. The basic running lights are white to the stern of the boat, red to port, and green to starboard. The colored lights are visible from forward of the boat as well as the sides. The three running lights may be mounted in a number of ways, separately or combined, high or low, but must always be masked so that you see the appropriate color from the each direction.

There are several useful mnemonics related to the color of the running lights. First, remember that port wine is red, so the red running light is on the left side of the boat. Second, you see stars in good weather, which is when you like to go out on the water, so green for go equals starboard (invented by Alistair Barclay). Third, stoplights (traffic signals) in most places show red when you should stop, green when you should go. The running lights and the right-of-way rules are arranged so that if you see another boat's port (red) running light and there is no other rule to tell you what to do, you should give way ("stop"), while if you see green, you should maintain course and speed ("go"). Red means stop, green means go.

A fourth mnemonic, suggested by Peter W. Meek, is Red Left Port. The image is of a red-headed sailor going to sea, where he belongs (not some nasty old port). This mnemonic has the advantage that it also serves for buoyage system "B" and for remembering that port is the left side of the boat.

In addition to the three-colored running lights used by all boats, a powerboat must show a white masthead light visible from the front. This light must be mounted higher than the running lights. Depending your angle relative to the powerboat, the masthead light might or might not appear to be in line with the visible running light, but it will always be higher. (From the stern, only the stern light is visible, regardless of the type of propulsion. This is because you aren't going to collide with a faster boat that's ahead of you, and if you're the faster one, you have to give way regardless of propulsion method. See the overtaken-wins rule in the right-of-way rules.)

To summarize, if you see a red light alone, you're looking at the port side of a sailboat. Similarly, green alone shows the starboard side of a sailing machine. White alone means you're seeing somebody's stern, but you don't know whether it's power or sail. White above red indicates the port side of a power vessel (note that the two lights won't necessarily be lined up as shown here). Finally, white above green means you're seeing the starboard side of a power boat.

Mast Lights

Mast lights are shown in addition to running lights to identify vessels more precisely than simply "I'm a boat." If a boat has no mast light at all, it's a sailboat (see above). (Note that a three-colored running light, as described above, isn't a "mast light" even if it's mounted at the top of a sailboat's mast, nor is the white masthead light shown by all power boats. Confused enough?)

Other, more complex mast light combinations indicate the operational status of the boat. They are usually, though not always, shown all-around:

Red over Red
Red over Red
This boat is dead

(or "Captain's in bed" or "Captain's in the head," or "Captain's dead"). Two red lights in a vertical line indicate a vessel "not under command." In other words, when you see this combination, don't expect them to do anything to avoid you, regardless of what the right-of-way rules say. You should show these lights any time there is a circumstance, such as engine or steering failure, that prevents you from complying with the rules of the road. The preferred mnemonic was submitted by Dominick Orefice.

An alternative, submitted by Alistair Barclay and taken from A Small Boat Guide to the RULES OF THE ROAD by John Mellor, is Two reds equal too dangerous to command.

Red over Green
Red over Green
Sailing machine

(or "sailing is keen"). Note that this is the less-used of the two sailboat lighting combinations. Most sailboats identify themselves by the lackof a white masthead light visible to 22.5 degrees abaft the beam. Don't assume that lack of red-over-green means it's under power!

Red over White
Red over White
Fishing boat lights

If the fishing gear extends over 150 meters (492 feet) from the boat, an all-around white light must indicate the direction.

Andy Oliver has suggested another mnemonic for this: They are fishing for red salmon. A Small Boat Guide to the RULES OF THE ROAD by John Mellor has a third alternative, They are stopped over a white fish (submitted by Alistair Barclay).

Green over White
Green over White
Trawling tonight

Note that this is different from the general fishing lights.

Andy Oliver has suggested another mnemonic for this: They may trawl up a piece of green seaweed. A Small Boat Guide to the RULES OF THE ROAD by John Mellor has a third alternative, White fish under green sea (submitted by Alistair Barclay).

White over White
White over White
Short tug/tow in sight

A short tow is under 200 meters (656 feet).

White over White over White
White over White over White
Long tug/tow in sight

A long tow is over 200 meters (656 feet).

Red over Red over Red
Red over Red over Red
Rudder Rubbing Rocks

This refers to a vessel constrained by her draft. It applies only under the international rules.

White over Red
White over Red
Pilot ahead

A pilot boat, waiting for "customers," displays this combination so that boats needing a pilot will be able to find it. Pilot boats also display this combination when waiting to pick up a pilot who is finished with a customer. (The customer boat displays it normal running lights, as appropriate.) Thanks to John Browning for providing the correct information here.

An alternative mnemonic, submitted by Alistair Barclay and taken from A Small Boat Guide to the RULES OF THE ROAD by John Mellor, is White hat over red face. Dominick Orefice has suggested "Pilot in bed" as an alternative.

Red over White over Red
Red over White over Red
Red When Restricted

A vessel showing this combination is restricted in its ability to maneuver. Stay away! Examples include vessels servicing navigation marks, cables, pipelines; vessels dredging, surveying, or carrying out under water operations (such as dive boats); any vessel engaged in servicing, replenishing, or transferring cargo or persons; or any vessel launching or recovering aircraft.

This is from A Small Boat Guide to the RULES OF THE ROAD by John Mellor and was submitted by Alistair Barclay.

(Original) An alternative, invented by myself, is Red over White over Red / Rudder Might be Dead. This rhymes, but isn't quite accurate (a vessel with a truly dead rudder is Not Under Command, Red over Red).

Stern Lights

Boats can also show stern lights to help identify them. These are only visible when you are behind the boat. Some stern light combinations include:

Yellow over Yellow
Yellow over Yellow
A pushy inland fellow

This refers to the stern lights of a tug pushing a barge, under the inland rules only. Improved by Rod McFadden.

Yellow over White
Yellow over White
My towline is tight

This refers to the stern lights of a tug towing astern. (Improved by Jim Woodward.)

Control Lights

Lights are also used to control passage through bridges and locks. So far, I only have information for the European lock system, submitted by Ray Battersby. More will be added as time and knowledge permit.

European (International) Harbor Traffic Control Signal Lights

This entire section was written and submitted by Ray Battersby.

Traffic-Light control signals are commonplace at the entrances to European ports. These are generally of the form, Red, White (Yellow) and Green, vertically arranged and often with other lamps in parallel. Because of the need to identify inbound and outbound traffic, they don't use a simple Red = Stop, White (yellow) = Prepare to Move and Green = Go (as for road traffic - that would be too simple and too easy to remember!) but a combination.

However, by studying the Silk Cut Almanac, I have found that the following rules apply:

NOTE: Although the above matches the official interpretation in terms of your own rights of passage, using this abbreviated interpretation, a sharp lookout for other shipping movements (especially from the opposite direction and from astern) is strongly advised.


Decorative picture of lighthouse There are two buoyage systems used in the world, named "A" and "B". Buoyage system "A" is used in Europe, Asia, and Australia, with the exception of Japan, Korea, and the Philippines. System "B" is used elsewhere, notably including all of the Americas. The two systems use opposite color codes.

In both systems, the buoys also have coded shapes, called cans and nuns. A can is a simple cylinder, like an oil can. A nun is conical, with the name being reminiscent of the pointed hats worn by some orders of nuns. In both systems, cans appear on the left when returning from sea to port, nuns on the right.

Buoyage Numbering

In both systems, green buoys are given odd numbers and red buoys are even. The numbering starts at "1" at the mouth of the harbor or river, and increases from there.

The following two mnemonics, submitted by David H. Shaffer, may help remember the numbering scheme in the IALA "B" system:

Buoy numbers DEcrease MOving DownStream.
You'll never see a nun 69
Nun (cone-shaped) buoys always have an even number.

Buoyage System "A"

The mnemonics given below are for buoyage system "A." Be sure to learn the right mnemonics for your area!

Barrels to Port
In IALA "A," red-colored buoys are cans, which are shaped like barrels. A sailor returning from a long trip looks forward to a barrel of port, so when coming into port, keep your port side closest to the red barrel and you will be on the way to the nearest tavern. This was invented by Alistair Barclay; many thanks to him for submitting it.
Bleeding Heart
In IALA "A," red-colored buoys are kept to the side of your heart (left) when returning to port. This was suggested on Yacht-L by Matthijs van Couwelaar.

Buoyage System "B"

The mnemonics given below are for buoyage system "B." Be sure to learn the right mnemonics for your area!

Red Right Returning
In IALA "B," red-colored buoys are nuns, which are kept to the right (starboard) side of the boat when returning from the ocean to port. There is a detailed convention for defining exactly what "returning" means in ambiguous situations (i.e., on canals and rivers), which will not be repeated here.
Green Going Out The complement to "Red right returning," indicating that green buoys are left to starboard when you are heading out to sea. Suggested by Paul Atterton.
Even Red Left Port
(Suggested by Peter W. Meek, improved by Jeremiah V. Donovan and Kathy Spahn). The image is of a day so perfect that even the old red-headed sailor left his rocking chair to go to sea, where he belongs (not that boring old port). This mnemonic has the advantage that it also serves for the colors of running lights, for remembering that port is the left side of the boat, and for recalling that red markers are even-numbered.

Sound Signals

There are many sound signals used in situations of limited visibility (i.e., fog), and when two ships need to agree on the maneuvers necessary to avoid collisions (see the right-of-way rules below). Most of these signals are quite hard to remember, and there didn't seem to be any mnemonics for them, so I invented some to help me out.

(Original) For collision avoidance, there are two systems. On inland waterways, intention/agreement signals are used. On international (offshore) waters, actual rudder actions are signaled. Fortunately, although at first glance the two systems differ, both actually use the same effective meanings for signals. So all you have to remember is that on an inland waterway, if somebody toots at you, you need to agree by repeating the same pattern back at them, and if you toot, don't change course until you get agreement. If you disagree, give the danger signal. Inland uses intention/agreement, offshore signals rudder operations.

In sound signals, a short blast has a duration of about 1 second; a prolonged blast is 4-6 seconds.

When you are approaching another boat head-on (more or less), the first two mnemonics below give the same information: turning to port will cause the other boat to pass on your starboard side. This simplifies things: since both mnemonics refer to a double blast, you can just memorize that fact, and know that the other direction is the single-blast case. Note: If you are exactly head-on, or very nearly so, the COLREGS prefer that you turn to starboard (single blast).

Port Rudder Action
Blast twice short,
Turn to port

Leaving a Boat on Your Starboard Side
Double blast,
Starboard pass

A double blast always means that you are turning (COLREGS) or will turn (inland waters) to port. This means that you will pass the other boat on your starboard side.

Backing Down
Three in turn,
Power astern

This indicates a boat that is slowing or stopping to avoid risk of collision.

Danger Signal
Blast quick five
To stay alive

This is the danger signal, to be given if you think there is confusion or imminent danger of a collision.

Navigational Formulas

Decorative picture of compass rose Navigation often requires relatively complicated arithmetic. The most common is compass corrections: converting between true directions and a compass reading.

Timid Virgins Make Dull Company at Weddings
(Or "Add Whiskey.") This is the formula for converting true directions or courses to compass readings: True plus Variation equals Magnetic heading. Beyond that, add the Deviation to get the Compass heading. In all of these corrections, "at weddings" means Add Westerly variations and deviations as part of the calculation (and, by implication, subtract easterly ones).

There are a number of minor variations on this mnemonic, but the differences aren't important.

(Before you call me or anyone else sexist, note that virgins can be of either sex. If you think virgins make perfectly fine company, please remember that it's just a memory aid, not a politico-religious philosophy. In any case, I'm just quoting other people. Don't send me flames. Sheesh!)

Can Dead Men Vote Twice at Elections?
This is the formula for converting compass headings back to true ones: Compass plus Deviation equals Magnetic heading. Beyond that, add the Variation to get the True heading. In all of these corrections, "at elections" means Add Easterly deviations and variations as part of the calculation (and, by implication, subtract westerly ones).

(Original) Charter Boaters Detest Returning
This refers to the common mnemonic for predicting a collision: CBDR, for "Constant Bearing, Decreasing Range." If the bearing to another vessel does not change, and the range is getting less, you are going to bump. Note that this refers to the true or magnetic bearing, not the relative value. Submitted by Steven Hodgson.

Right-of-Way Rules

The rules for who has the right of way are complex. The basic rule, of course, is General Responsibility: notwithstanding any other rule, you're not supposed to run into other people or things. That ought to be obvious.

For recreational boaters, a commonly-observed practical corollary is "tonnage has the right of way": stay out of the way of big boats, because even if you're technically right, you're going to be the loser in a collision.

Nevertheless, there are rules about who goes first, and you ought to know them. Since they're complex and lengthy, I invented a mnemonic to help recall them.

(Note: I've tried to summarize the essence of the COLREGS here. If you think I've gotten things wrong, you're welcome to e-mail me and set me straight. I'll appreciate it if you do, and I'll correct this Web page as soon as possible after I'm corrected.)

However, note that this mnemonic is a simplification of the rules. I'm not trying to codify every word of the COLREGS, I'm just trying to help you remember the most important points. Please don't nitpick. On second thought, please do nitpick, because I care a lot about details, but please don't get upset if your particular nit never makes it into this Web page.

The mnemonic below doesn't cover the situation where two similar boats are approaching (nearly) head-on. In that case, it is preferred that you alter course to starboard, so that you pass port-to-port (red to red, so that both are the give-way vessel; thanks to Paul Atterton for pointing this out). "Stay to the right and you'll be right," but the general-responsibility rule still overrides everything else.

(Original) This mnemonic gives the "order of priority," with the most important first. To use it, find yourself and the other boat on the list. The boat which comes first has the right of way, and is the stand-on vessel. If you both fall in the same category, then either the category itself tells you what to do (e.g., sailboats beat powerboats), or you must continue down the list. The mnemonic is "Generally, anchoring our red tugboat diligently minimizes surge loads." It is interpreted as follows:

General responsibility. Above all else, don't have a collision. "I had the right of way" isn't a defense if there was something you could have done to avoid the other boat.
Anchored. Anchored, stopped, or moored boats must be avoided by all other vessels.
Overtaken. Boats being overtaken have the right of way over the overtaking vessel. (This is true even if the slower boat is power and the faster boat is sail.)
Restricted maneuverability. Boats with restricted maneuverability, whether due to fishing, draft, length, towing, or other causes, have the right of way over vessels not so restricted.
Traffic separation. Vessels participating in a traffic-separation scheme have the right of way over non-participating vessels. (If you must cross a traffic lane, try to do so at right angles.)
Downriver. On certain inland waters, powerboats proceeding downriver have the right of way over upriver and crossing vessels.
Man-powered beats sail beats motorboat beats seaplane. Human-powered boats (canoes and rowboats) have the right of way over sailboats, which in turn have the right of way over powerboats, and even they have the right of way over seaplanes. I think of this in terms of increasing technological sophistication: the fancier your equipment, the fewer rights you have (sort of a class reversal).

This is an important one for sailors, of course, but note that there are a number of situations listed above where sailors must still give way.

Starboard boat or starboard tack wins. This actually represents two rules, depending on whether the meeting boats are both sail or both power. (If one is sail and one is power, the rule above applies.) For power boats, the boat approaching from starboard has the right of way. For sailboats, the boat that is on starboard tack has the right of way, regardless of from where it is approaching.
Leeward boat wins. When two sailboats meet on the same tack, the leeward boat has the right of way over the windward boat.

Alistair Barclay sent me a different mnemonic, taken from A Small Boat Guide to the RULES OF THE ROAD by John Mellor: The mnemonic is "Nuclear restrictions constrain fishing and sailing, people say." It is interpreted as follows:

Not Under Command. ("NUC" for "nuclear"). A vessel that is "not under command" in the technical sense has the right of way. This refers to anchored or unoccupied vessels as well as those that have lost the ability to maneuver (e.g., through loss of power or their rudder).
Restricted maneuverability. Boats with restricted maneuverability, whether due to fishing, draft, length, towing, or other causes, have the right of way over vessels not so restricted. (Note: Rod McFadden has pointed out that while it makes sense for NUC boats to have the right of way over those with restricted ability to maneuver, this is not explicitly mentioned in the COLREGS. He comments, "I've been unable to find any case where a NUC/RAM collision occurred; it's safe to say that if such a collision ever does occur, the Admiralty Bar will dine well for quite some time!")
Constrained by draft. Boats constrained to a narrow channel by their draft have the right of way. (This is really a special case of restricted maneuverability).
fishing and
Fishing vessels. Vessels engaged in fishing (this means towing nets, etc., not people with a pole off the back end) have the right of way. (Again, this is a special case of restricted maneuverability).
Sailing vessel underway. Sailboats have the right of way over powerboats.
Power-driven vessel underway. Powerboats are near the bottom, but have right of way over:
Seaplanes. Seaplanes must avoid everybody else.


There are lots of weather mnemonics to help you predict and analyze the weather. Unfortunately, my best source at the moment is copyrighted (Reed's Nautical Companion, which I highly recommend anyway, though I must admit a slight bias because the people there have been very nice to me). So I'm limited at the moment to a few things that I can be sure are in the public domain. I'll expand this as I can.

WARNING: Remember that most of these weather rhymes are rules of thumb, collected over the centuries before we had supercomputers to help with weather foreguessing (oops, forecasting). They are useful guides, but as in all areas of weather, there are no certainties. Don't complain to me if they are less than 100% accurate.

  • When the wind is at your back, the low is on your left. A formula for finding the center of a weather system. This works only for the Northern Hemisphere; in the South, it's reversed. Combined with a feeling for the direction weather moves, you can use this to make forecasts. Submitted by David H. Shaffer.
  • Red sky at morning,
    Sailors take warning.
    Red sky at night,
    Sailor's delight.
    One of many classics. I learned this when I was a kid. I don't recall the mechanisms that make it true, but a colorful dawn means bad weather, while a colorful sunset means that tomorrow will probably be great sailing. Here's to red sunsets!
  • Reading the Color of the Bottom

    Ways to guess the depth, based on water color. This is useful in the Caribbean, among other places. The mnemonic goes from shallowest to deepest. It was provided by Steve Hodgson.

    Brown brown, run aground,
    White white, you might,
    Green green, nice and clean,
    Blue blue, run right through.

    Chart Scale

    I don't think anybody has any trouble picking a chart of the appropriate scale out of a pile, since it's pretty obvious whether it covers just a harbor or the whole ocean. But a lot of us have trouble with naming the damned things. Here's a helpful mnemonic which I picked up from The Practical Pilot by Leonard Eyges: Small scale, small detail; large scale, large detail. So a large-scale chart is the one you'd ask for if you needed to enter a harbor.

    By the way, The Practical Pilot is the best book I've ever read on the subject of pleasure-boat navigation. Where Dutton's has advice on steering a battleship or tanker through a narrow channel (fascinating, but not something I ever expect to do), Eyges shows you how to tell whether that's one island or two on the horizon. My favorite coastal-navigation book!

    Boat Parts

    The most basic terms in boating are those used to describe parts and directions on the boat. Most of these don't have or need mnemonics. (Do you really want to learn 50-odd different little rhymes just so you remember that the back of the boat is called the stern?) But a few have some handy mnemonics.

    General Boat Parts

    The left-hand side of the boat when facing forward. Many people remember that "port and left both have four letters." Others use the mnemonic "I wonder if there's any red port wine left," which (as Rich Arimoto points out) is nice because it gets the color of the light into the mnemonic.

    A third option, suggested by Peter W. Meek, is Red Left Port. The image is of a red-headed sailor going to sea, where he belongs (not some nasty old port). This mnemonic has the advantage that it also serves for remembering the colors of running lights and the codes for buoyage system "B".

    The name "port" derives from the fact that steering was originally done from the right-hand side of the boat (see starboard, so the other side was put to the dock or "port".

    The right-hand side of the boat when facing forward. The easiest way to remember this is to learn where port is, and then recall that starboard is the opposite of port.

    Incidentally, the word starboard comes from steerboard, because originally the rudder was just a board held on the side of the boat, and most steersmen were right-handed.

    The direction towards the front of the boat.
    The direction towards the back of the boat.
    The forward end of the boat, usually the pointy end.
    The aft end of the boat, usually the blunt end.
    A handy device for connecting things together. There are many types, but most consist of a "U" of metal, together with a removable metal piece that closes the top of the "U" to make an "O". You pull out the moving part, stick it through or around something, and fasten the whole thing together to make it hold. Often used to attach sails to things and things to sails.

    Sailboat Parts

    A spar used to give shape to the bottom of any sail. If you don't watch out, it'll hit you in the head, and you'll hear a loud boom.
    The forwardmost, lowest part of a triangular sail. Just remember that the tack is where the sail is tacked (attached) to the boat, usually by some sort of shackle. Not to be confused with the other meaning of the word, which has to do with the relationship of the sailboat to the wind.
    (Original) The aftmost, lowest part of a triangular sail. Expert sailors make all sorts of adjustments to a sail, but beginners can adjust the clew to catch the wind even if they don't have a clue about the finer points of sail trim.
    The leading (forward) part of a sail, the part closest to the wind. If you adjust the sail improperly, it will flap, which is called luffing, and the luff is the part which luffs first. (Got that?)
    (Original) The trailing (aft) part of a sail, the part where the wind exits. When the sail is adjusted properly, the wind will cling to the aft edge like a leech.

    Andy Oliver also points out that "leech" is a corruption of "lee edge" (say it fast).

    Any structural member that supports a sail or helps to maintain a sail's shape (e.g., the mast or the boom).
    A vertical spar. Most modern sailboats have a single mast which supports two sails, but many boats have two or more masts.

    Powerboat Parts

    Do powerboats have parts? :-)

    These mnemonics were compiled, organized, and occasionally invented by Geoff Kuenning. If you have additions, or if you would like me to try to invent a mnemonic for a particular situation, please send me e-mail about it.

    Copyright 1996, 1997 Geoff Kuenning. All rights reserved. Mnemonics not marked "original" are not covered by this copyright, although the descriptions of such mnemonics are still covered. Permission is granted to reproduce and/or disseminate this material in any form when used for non-profit or educational purposes, so long as authorship is properly credited and this copyright notice is maintained intact.

    Other Links for Learning About Boating

    The following links lead to Web sites and commercial products that are designed to help people learn about boating. I will only list sites and products here that I personally believe are useful. The decision on whether to list rests with me entirely, and is not conditional on payment or on whether the listed site chooses to list me. In other words, you can't buy a listing here, although I'm always happy to receive a pointer if you think I might be interested in what you have (but don't phrase it like an advertisement, or I'll think it's just spam and ignore it).

  • If you want to learn to tie basic knots, there is no better site than this one, which has animated color GIFs that show you exactly how the two lines intertwine.
  • Diederik Willemsen offers a free online coastal-navigation course that also has some useful (for planning, not for navigation) charts of Greece.

  • Geoff Kuenning's home page.

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    Geoff Kuenning.