CHART, CRUISING & SAFETY INFORMATION SOURCES
Charts of Various Waterways
Published by Office of Coast Survey (OCS), a unit of NOAA's National Ocean Service (NOS). See www.nauticalcharts.noaa.gov for all product and availability information. Available electronically from OCS. Also available from many local sales agents.
Inland Rivers and Tributaries Published by U.S. Army Corps of Engineers. See www.agc.army.mil/Missions/Echarts/Inland-Chart-Books for a list of inland-waters chart books available to download in pdf format, order as hard copy books from the District, or order from the Government Publishing Office Bookstore (bookstore.gpo.gov/agency/1784). The direct link for Inland Electronic Navigation Charts (IENCs) from the U.S. Army Corps of Engineers is www.agc.army.mil/Missions/Echarts/Product-Downloads.
Canadian Waters Coast pilots for Canadian waters were not available in early 2017.
Waters of Other Nations The National Geospatial-Intelligence Agency (NGA) publishes charts of many foreign areas. These are often based on charts of other nations, but increasingly this practice is being dropped in favor of direct use of the foreign charts. See msi.nga.mil/NGAPortal/MSI.portal for product and availability information. NGA charts are sold by retail sales agents.
Coast Pilots
U.S. Coastal Waters and Great Lakes Published by the Office of Coast Survey (OCS). See www.nauticalcharts.noaa.gov for product and availability information. Available electronically from OCS or as hard copy from retail sales agents.
Canadian Waters Published by Canadian Hydrographic Service. Information from Chart Distribution Office, CHS, Department of Fisheries and Oceans, www.charts.gc.ca; 613-998-4931; Fax: 613-998-1217; chsinfo@dfo.gc.ca. (info only; retail sales only via authorized dealers); www.charts.gc.ca. Titles are listed in chart catalogs.
Cruising Guides
Cruising Guide to the New York State Canal System N.Y. State Canal Corporation, 30 South Pearl St., Albany NY 12207, 518-449-6000; http://www.canals.ny.gov/index.shtml. Waterway Guide Regional editions provide annually updated information on the Intracoastal Waterway and adjacent waters. Northern: Maine to Chesapeake Bay and Delaware Canal; Champlain Waterway. Mid-Atlantic: Chesapeake Bay and Delaware Canal to Georgia/Florida border. Southern: Georgia/Florida border to Brownsville, Texas; and the Bahamas; 804-776-8999 or 800-233-3359; www.waterwayguide.com.
Quimby’s Cruising Guide Covers all navigable inland waterways with details of harbors, locks, dams, hazards, as well as onshore services, transportation, and attractions; provides sources of navigation charts and books. The Waterways Journal Weekly, 319 N. 4th Street, Suite 650, St. Louis, MO 63102-1994; 314-241-7354; fax 314-241-4207.
Guide for Cruising Maryland Waters Twenty fullcolor charts, with over 200 courses and distances plotted; includes marina and facility information: Department of Natural Resources, 580 Taylor Avenue, Annapolis, MD 21401; 1-877-620-8DNR (8367). See also dnr.maryland.gov/boating/Pages/default.aspx. (a Maryland boating course).
Ports Cruising Guides
Lake Ontario/Thousand Islands; Georgian Bay/North Channel/Lake Huron; Trent-Severn Waterway/Lake Simcoe: Ports Cruising Guides, 5046 Mainway, Unit #2, Burlington, ON L7L 5Z1. www.portsbooks.com
Yachtsman’s Guide to the Bahamas
Annually updated guide to the Bahamas: Tropical Island Publishers, Inc., P.O. Box 12, Adelphia, NJ 07710; 877-923-9653; Fax: 732-625-1206, www.yachtsmansguide.com.
Other Guides There are innumerable other cruising guides. To find one for your area of interest, visit www.bluewaterweb.com or other nautical bookstores.
Light Lists
U.S. Light Lists Published by U.S. Coast Guard: Available from Superintendent of Documents, U.S. Government Printing Office, 732 North Capitol St. NW, Washington, DC 20401-0001; 202-512-1800; Fax: 202-512-2104. The U.S. Government Printing Office Bookstore is at 710 North Capitol St. NW, Washington, DC, or send mail orders to U.S. Government Printing Office, P.O. Box 979050, St. Louis, MO 63197-9000. Online ordering now available at bookstore.gpo.gov. Available at GPO Regional Bookstores and some sales agents for charts. Each Light List volume may be accessed from www.navcen.uscg.gov. All or portions of the pdf files may be printed for use.
Navigation Rules
Navigation Rules and Regulations Handbook The latest edition of the Navigation Rules contains the International Regulations for Preventing Collisions at Sea, known as the 72 COLREGS, and the Inland Navigation Rules, which supersede the old Inland Rules, Western Rivers Rules, Great Lakes Rules, and other Pilot Rules. The book also includes sections on COLREGS demarcation lines, penalty provisions, alternative compliance, and the Vessel Bridge-to-Bridge Radiotelephone Regulations. Published by U.S. Coast Guard. Available from Superintendent of Documents, U.S. Government Printing Office; see contact information above.
Notices to Mariners
U.S. Notice to Mariners Weekly publication of the National Geospatial-Intelligence Agency, prepared jointly with the National Ocean Service and the U.S. Coast Guard. The email address for Notice to Mariners Corrections is MCDNtM@nga.mil. Website access is through http://msi.nga.mil/NGAPortal/MSI.portal.
Canadian Notices to Mariners (NOTMAR) Issued monthly. Available, in electronic form only, from the Canadian Coast Guard: www.notmar.gc.ca.
Local Notices to Mariners Issued weekly by Coast Guard District Commanders; no longer mailed, distributed only electronically. www.navcen.uscg.gov.
Publications of NGA (NIMA)
National Geospatial-Intelligence Agency (formerly National Mapping and Imagery Agency) publications are available from Superintendent of Documents, U.S. Government Printing Office, 732 North Capitol St. NW, Washington, DC 20401-0001; 202-512-1800; Fax: 202-512-2104; http://bookstore.gpo.gov. Send mail orders to U.S. Government Printing Office, P.O. Box 979050, St. Louis, MO 63197-9000. Also available at GPO regional bookstores and authorized sales agents for charts and publications. Many of the NGA publications listed below are no longer available from the government in hard-copy format but are available as downloadable files. Some publications may be available in printed form from commercial publishers.
Sailing Directions Books supplementing NGA charts containing descriptions of coastlines, harbors, dangers, aids, port facilities, and other data that cannot be shown conveniently on charts. Sailing Directions, Pilot Charts, and the numbered NGA publications listed below can be found at http://msi.nga.mil/NGAPortal/MSI.portal by clicking the “Publications” link. They all appear on a drop-down list at the top of the page and are available as downloadable.pdf files.
Pilot Charts Published at irregular intervals in “Atlas” format for major ocean areas; contains information on ocean currents and weather probabilities for various waters on a month-by-month basis. See on-line access path under Sailing Directions above.
List of Lights, Radio Aids, and Fog Signals For foreign waters, generally similar to U.S. Coast Guard Light Lists.
Miscellaneous NGA Publications (can be accessed on-line as with Sailing Directions above)
Pub. 9. American Practical Navigator, originally by Nathaniel Bowditch, 2002.
Pub. 102. International Code of Signals.
Pub. 117. Radio Navigational Aids. Information on Marine Direction-Finding Stations, Radio Beacons, Time Signals, Navigational Warnings, Distress Signals, Medical Advice and Quarantine Stations, and Loran and Regulations Covering the Use of Radio in Territorial Waters.
Pub. 150. World Port Index.
Pub. 151. Distances Between Ports.
Pub. 1310. Radar Navigation and Maneuvering Board Manual.
Safety Publications
Standards and Recommended Practices for Small Craft Available from ABYC, 613 Third Street, Suite 10, Annapolis, MD 21403; 410-990-4460; Fax: 410-990-4466; info@abycinc.org; www.abycinc.org.
NFPA 302: Fire Protection Standard for Pleasure and Commercial Motor Craft Available from NFPA, 1 Batterymarch Park, Quincy, MA 02169-7471; 800-344-3555 (U.S. & Canada), 617-770-3000 (International), 95-800-844-6058 (Mexico); Fax 800-593-NFPA (U.S. & Canada), 508-895-8301 (International); www.nfpa.org.
Tide & Current Tables
U.S. Tide Tables and Tidal Current Tables NOS data is made available in book format through private publishers and their distributors: NOS/NOAA also provides tide and current information at http://tidesandcurrents.noaa.gov.
Canadian Waters Available from Canadian Hydrographic Service at www.charts.gc.ca/index-eng.asp or at the Department of Fisheries and Oceans, 200 Kent Street, Station 12W090, Ottawa, ON K1A 0E6; 613-998-4931; Fax: 866-924-7742; email chsinfo@dfo-mpo.gc.ca. (Note: As of early 2017, the Department of Fisheries and Oceans was moving its services and information to Canada.ca.) Retail sales are only by authorized dealers.
U.S. Coast Guard Publications
A variety of materials on recreational boating safety are available at www.uscgboating.org.
A Boater’s Guide to the Federal Requirements for Recreational Boats and Safety Tips An operator booklet on U.S. laws, equipment requirements, and safety recommendations for recreational vessels. There are other equipment and considerations recommended for boat operator and passenger safety. Available at all Coast Guard offices and uscgboating.org/assets/1/AssetManager/Boaters-Guide-to-Federal-Requirments-for-Recreational-Boats.pdf.
Coast Guard Safety on the Internet The USCG provides a Web site that contains a wealth of infor-mation of interest to recreational boaters: www.uscgboating.org and www.navcen.uscg.gov.
Weather Publications
Worldwide Marine Weather Broadcasts Broadcast schedules of marine weather information from all areas of the world where such service is available. As of early 2017, this publication no longer seemed to be available.
Miscellaneous Publications
The American Nautical Almanac Compact publication from the United States Naval Observatory contains all ephemeris material essential to the solution of problems of navigational position; star chart is included. Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402; 202-512-1800; Fax: 202-512-2104; bookstore.gpo.gov. Send mail orders to Superintendent of Documents, P.O. Box 371954, Pittsburgh, PA 15250-7954. Available at GPO Regional Bookstores and some sales agents for charts.
Dutton’s Nautical Navigation by Thomas J. Cutler, 15th Edition, 2003. Customer Service, USNI Operations Center, 291 Wood Road, Annapolis, MD 21402; 410-268-6110 or 800-233-8764; Fax: 410-571-1703; customer@usni.org; www.usni.org. The Naval Institute Press publishes many other books of interest to boaters.
Canadian Addresses
Canadian Coast Guard Transport Canada, Marine Safety Office of Boating Safety (AMSRO), Tower C, Place de Ville, 330 Sparks Street, Ottawa, Ontario K1A 0N8; 800-267-6687; Fax: 613-990-1866; obs-bsn@tc.gc.ca; www.tc.gc.ca/eng/marinesafety/debs-obs-menu-1362.htm.
Hydrographic Chart Distribution Office Department of Fisheries and Oceans (see contact information under “Canadian Waters” listings above).
Environment Canada Inquiry Centre, 10 Wellington, 23rd Floor, Gatineau, Quebec K1A 0H3; 819-997-2800; Fax: 819-994-1412; enviroinfo@ec.gc.ca; www.ec.gc.ca.
ASSOCIATIONS & ORGANIZATIONS
The American Boat & Yacht Council Inc. (ABYC) 613 Third Street, Suite 10, Annapolis, MD 21403; 410-990-4460; Fax: 410-990-4466; info@abycinc.org; www.abycinc.org.
American Boat Builders & Repairers Association Newport Shipyard, 1 Washington Street, Newport, RI 02840; 401-236-2466.
American Bureau of Shipping (ABS) 16855 Northchase Drive, Houston, TX 77060-6006; 281-877-6000; Fax 281-877-5943; Abs-Amer@eagle.org; ww2.eagle.org
American Power Boat Association (APBA) 17640 E. Nine Mile Road, P.O. Box 377, Eastpointe, MI 48021-0377; 586-773-9700; Fax: 586-773-6490; apbahq@apba.org; www.apba.org.
Boat Owners Association of the United States (BoatU.S.) 880 South Pickett Street, Alexandria, VA 22304-4606; 800-395-2628; Fax: 703-461-2845; BoatingSafety@BoatUS.com; www.boatus.com.
British Meteorological Office FitzRoy Road, Exeter, Devon EX1-3PB, UK; +44(0)1392 885680; Fax: +44(0)1392 885681; enquiries@metoffice.gov.uk; www.metoffice.gov.uk.
BUC International Corp. 1314 N.E. 17th Court, Fort Lauderdale, FL 33305; 800-327-6929; in Florida 954-565-6715; Fax: 954-561-3095; webmaster@buc.com; www.buc.com.
Canadian Power and Sail Squadrons 26 Golden Gate Court, Toronto, Ontario M1P 3A5; 416-293-2438 or 888-CPS-BOAT (277-2628); Fax 416-293-2445; www.cps-Eco.ca.
Cruising Club of America 298 Winslow Way West, Bainbridge Island, WA 98110; email: secretary@cruisingclub.org; www.cruisingclub.org.
International Organization for Standardization (ISO) BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland; Tel. +41-22-749-01-11; central@iso.org; www.iso.org.
Lloyds of London 1 Lime Street, London, EC3M 7HA; England; +44 (0)20 7327 1000; enquiries@lloyds.com; www.lloyds.com.
Marine Department of Underwriters Laboratories (UL) 12 Laboratory Drive, P.O. Box 13995, Research Triangle Park, NC 27709-3995; 919-549-1400; cec.us@us.ul.com; www.ul.com/marine.
National Association of State Boating Law Administrators (NASBLA) 1648 McGrathiana Parkway, Suite 360, Lexington, Kentucky 40511-1338; 859-225-9487; Fax: 859-231-6403; info@nasbla.org; www.nasbla.org.
National Boating Federation P.O. Box 4111, Annapolis, MD 21403-4111; Fax: 866-239-2070; www.n-b-f.org.
National Fire Protection Association (NFPA) 1 Batterymarch Park, Quincy, MA 02169-7471; 617-770-3000; Fax: 617-770-0700; www.nfpa.org.
National Marine Electronics Association 692 Ritchie Highway, Suite 104, Severna Park, MD 21146; 410-975-9425; Fax: 410-975-9450; info@nmea.org; www.nmea.org.
National Marine Manufacturers Association (NMMA) 231 S. LaSalle Street, Suite 2050, Chicago, IL 60604; 312-946-6200; Fax: 312-946-0388; www.nmma.org.
National Safe Boating Council 9500 Technology Drive, Suite 104, Manassas, VA 20110; 703-361-4294; Fax: 703-361-5294; www.safeboatingcouncil.org.
Sail Canada 53 Yonge Street, Kingston, Ontario K7M 6G4 Canada; 613-545-3044; Fax: 613-545-3045; sailcanada@sailing.ca; www.sailing.ca.
Society of Automotive Engineer (SAE) 400 Commonwealth Drive, Warrendale, PA, 15096; 877-606-7323 (U.S. And Canada) 724-776-4970 (outside U.S. and Canada); customerservice@sae.org; www.sae.org.
United Safe Boating Institute P.O. Box 30428, Raleigh, NC 27622-0428; 919-755-0092; Fax: 919-836-1813. For information on boating courses, call 1-800-336-BOAT; president@usbi.org; www.usbi.org.
United States Coast Guard Auxiliary National website and access to local flotilla information: www.cgaux.org.
United States Power Squadron 1504 Blue Ridge Road, Raleigh, NC 27607; 888-367-8777; contactme@HQ.USPS.org; www.usps.org.
United States Sailing Association (US SAILING) P.O. Box 1260, 15 Maritime Drive, Portsmouth, RI 02871-0907; 1-800-USSAIL 1 (1-800-877-2451); Fax: 401-683-0840; info@ussailing.org; www.ussailing.org.
USCG DISTRICT OFFICES
Contact the Recreational Boating Safety Specialist at the District Office with jurisdiction for your state or territory. (District boundaries are described in greater detail in Title 33 CFR Part 3.
First Coast Guard District
Maine, New Hampshire, Massachusetts, Vermont
(Lake Champlain), Rhode Island, Connecticut, portions of New York, and New Jersey (to
Shrewsbury River).
408 Atlantic Avenue
Boston, MA 02110-3350
617-223-8558; www.uscg.mil/d1/
Fifth Coast Guard District
Shrewsbury River, New Jersey to Delaware,
Pennsylvania east of 78°55'W, Maryland, Virginia,
District of Columbia, North Carolina.
Federal Building
431 Crawford Street
Portsmouth, VA 23704-5004
757-398-6486; www.uscg.mil/d5/
Seventh Coast Guard District
South Carolina, Georgia, Florida east of 83°50'W,
Panama Canal Zone, Puerto Rico and the Virgin Islands; U.S. naval reservations in the West Indies and on the north coast of South America.
Brickell Plaza Federal Building
909 SE First Avenue
Miami, FL 33131-3050
305-415-6752; www.uscg.mil/d7/
Eighth Coast Guard District
Florida west of 83°50'W, Alabama, Arkansas,
Colorado, Iowa, Kansas, Kentucky, Louisiana,
Mississippi, Missouri, Nebraska, New Mexico,
North Dakota, Oklahoma, South Dakota, Tennessee,
Texas, West Virginia, Wyoming, and portions of
Illinois, Indiana, Minnesota, Ohio, Pennsylvania, and Wisconsin.
Hale Boggs Federal Building
500 Poydras Street, Suite 1240
New Orleans, LA 70130-3310
504-589-6277; www.uscg.mil/d8
Ninth Coast Guard District
Michigan and portions of Illinois,
Indiana, Minnesota, New York,
Ohio, Pennsylvania, and
Wisconsin.
1240 East 9th Street
Cleveland, OH 44199-2060
216-902-6073; www.uscg.mil/d9/
Eleventh Coast Guard District
California, Arizona, Nevada, and Utah.
Coast Guard Island, Building 50-3
Alameda, CA 94501-5100
510-437-2970; www.uscg.mil/d11/
Thirteenth Coast Guard District
Oregon, Washington, Idaho, and Montana.
Jackson Federal Building
915 Second Avenue
Seattle, WA 98174-1067
206-220-7280; www.uscg.mil/d13/
Fourteenth Coast Guard District
Hawaii, Guam, American Samoa, Northern Mariana
Islands, and other U.S. islands in defined areas.
Prince Kalanianaole Federal Building
300 Ala Moana Boulevard, 9-216
Honolulu, HI 96850-4982
808-541-2316 (day), 808-842-2600 (night); www.uscg.mil/d14/
Seventeenth Coast Guard District
Alaska.
P.O. Box 25517
Juneau, AK 99802-5517
907-463-2269 (day), 907-463-2004 (night); www.uscg.mil/d17/
THE METRIC SYSTEM
The Metric Conversion Act of 1975 (amended by the Omnibus Trade and Competitiveness Act of 1988) declares, as the policy of the United States, that the metric system of measurement is the preferred system of weights and measures for U.S. trade and commerce. To date, little progress has been made in converting the everyday thinking of the general U.S. population, including boaters; most persons continue to use a system that is variously called “Customary,” “English,” or “Inch-Pound.” An understanding of the metric system, however, is becoming increasingly necessary as its use continues to expand—Navigation Rules, internal-combustion engines, liquor and wine, the nautical charts of other nations (and now some U.S. charts), etc.
The terms “metric system,” “SI,” “SI metric,” and “SI units” refer to units belonging to the International System of Units (abbreviated SI from the French Le Système International d’Unités). They include the SI units (together with their multiples and submultiples); three other metric units—the liter, hectare, and metric ton—that are accepted for use with the SI units because of their practical importance; and a small number of other metric units that are accepted because of their use in specialized fields. SI provides a logical and interrelated framework for measurements in science, industry, commerce, and other forms of human endeavor.
The modern metric system is based on a foundation of base units, with multiples and submultiples expressed in a decimal system using various prefixes.
The SI Units
The base units of most interest to boaters are length, weight, and time. These units and their symbols are:
| Length | meter (m)* |
| Mass (weight) | kilogram (kg)** |
| Time | second (s)*** |
Other base units of wide interest are temperature and electrical current:
| Temperature | Kelvin (K)**** |
| Electrical current | Ampere (A) |
* The international spelling is “metre,” but for United States usage “meter” has been adopted (the pronunciation is the same).
** The kilogram is the only base unit that integrally includes a multiplier (see below).
*** Although the base SI unit for time is the second, units of minute, hour, and day are accepted for use with SI.
**** For nonscientific use, the degree Celsius (C) is more commonly used. The size of the units is the same; the difference is in the zero degree temperature. Degree “Celsius” was formerly known as “centigrade” (also symbol “C”).
The symbols, shown in parentheses, are not abbreviations. Most are written in lowercase letters except for those units (such as Ampere and degrees Celsius and Kelvin) that are named after a person. Unit symbols are not changed for the plural form. In the statement of a quantity, a space is inserted between the numerical value and the symbol; a hyphen is normally used in the adjectival form (exception: no space is used between values of degrees, minutes, and seconds and the symbols). Periods are not used with any symbols (except at the end of a sentence).
Derived Units
Other units in the metric system are derived from the base units. Typical of those expressed in combinations of base units and of interest to boaters are:
| Area | square meter (m2) |
| Volume | cubic meter (m3) |
| Speed, velocity | meter per second (m/s) kilometer per hour (km/h) |
| Frequency | Hertz (Hz) [cycles per second] |
| Energy, work | Joules (J) |
| Power | Watt (W) [Joules/s] |
Multiples & Submultiples
Units larger and smaller than the base units are formed by adding prefixes to make multiples and submultiples. The prefix symbol is added to the symbol for the base unit. Prefixes that are multiples or submultiples of 1,000 (kilo, centi, milli) are generally preferred as follows (there are others for larger and smaller multipliers, but such are of lesser interest):
| 1,000,000,000 | 109 | giga | G* |
| 1,000,000 | 106 | mega | M* |
| 1000 | 103 | kilo | k |
| 100 | 102 | hecto | h |
| 10 | 10 | deka | da* |
| 0.1 | 10-1 | deci | d |
| 0.01 | 10-2 | centi | c |
| 0.001 | 10-3 | milli | m |
| 0.000,001 | 10-6 | micro | µ (Greek letter ìmuî) |
| 0.000,000,000,001 | 10-12 | pico | p |
* Note the exception to the capitalization and single-letter rules for “G,” “M,” and “da” to prevent confusion with “g,” “m,” and “d.”
Retained Non-SI Units
Certain units that are not metric units are so widely used that they are accepted for use with the metric system.
Non-SI Units of Interest to Boaters
Of interest to boaters are degrees (°), minutes (‘), and seconds (“) as measurements of arc. (The radian is the metric measurement of plane angles, but its use has been limited to scientific applications.)
Other Non-SI Units
There are other non-SI units, the use of which continues for a limited time subject to future review. These include the nautical mile and knots as measurements of distance and speed. Also retained are the “bar” and “millibar” for atmospheric pressure.
The “liter” as a unit of volume is widely used—it is equal to 0.001 m3 or 1,000 cm3. The international symbol for liter is the lowercase letter “l”; but because of the similarity of this character with the numeral “1,” the uppercase letter, “L,” is commonly used in the United States.
The “metric ton”(t), 1,000 kilograms, is not strictly a part of SI but is widely used.
Conversion
Conversion factors are given below. These factors are rounded off for general use; in most cases these will yield quite acceptable practical results.
Metric System Conversion Factors
Customary Units to Metric Units
| Known | value | Multiply by | To find | |
| in | inches | 25.4 | millimeters | mm |
| ft | feet | 0.3048 | meters | m |
| yd | yards | 0.9144 | meters | m |
| mi | statute miles | 1.609 | kilometers | km |
| n mi | nautical miles | 1.852 | kilometers | km |
| oz | ounces (weight) | 28.35 | grams | g |
| lb | pounds | 0.4536 | kilograms | kg |
| oz | ounces (liquid) | 29.57 | milliliters | mL |
| qt | quarts | 0.9464 | liters | L |
| gal | gallons | 3.785 | liters | L |
| hp | horsepower | 0.746 | kilowatts | kW |
| °F | degrees Fahrenheit (temperature) | 5/9 (0.56) after subtracting 32 | degrees Celsius (temperature) | °C |
Metric Units to Customary Units
| Known | value | Multiply by | To find | |
| cm | centimeters | 0.3937 | inches | in |
| m | meters | 3.281 | feet | ft |
| m | meters | 1.094 | yards | yd |
| km | kilometers | 0.6214 | statute miles | mi |
| km | kilometers | 0.5400 | nautical miles | n mi |
| g | grams | 0.03527 | ounces (weight) | oz |
| kg | kilograms | 2.205 | pounds | lb |
| mL | milliliters | 0.03381 | ounces (liquid) | oz |
| L | liters | 1.057 | quarts | qt |
| L | liters | 0.2642 | gallons | gal |
| KW | kilowatts | 1.34 | horsepower | hp |
| °C | degrees Celsius (temperature) | 9/5 (1.8) then add 32 | degrees Fahrenheit (temperature) | °F |
When converting in either direction, care must be taken that multiplication does not result in a value implying a higher degree of precision (see Chapter 16) than the value in the original system. Rounding should be applied to the converted value to yield the same number of significant digits (do not round either the original value or the conversion factor).
Using the Internet Conversions in either direction for any unit or value are quickly, easily, and accurately made by using one of the several available Web sites on the Internet, such as: www.unitconversion.org; www.digitaldutch.com/unitconverter.
ABBREVIATIONS & ACRONYMS
ABYC American Boat and Yacht Council. (See also Glossary.)
AC Alternating Current.
ADF Automatic Direction Finder, an advanced version of radio direction finder.
AIS Automatic Identification System, a VHF radio system for automatic exchange of vessel position and navigation information.
AM Amplitude Modulation, a form of radio transmission, modulating the strength of the carrier wave in accordance with the strength of the audio signal.
AP Advanced Piloting, a course and a grade in the U.S. Power Squadrons.
ATON Coast Guard acronym for Aids to Navigation.
c metric prefix for 1/100.
C (1) Course, used in labeling chart plots; (2) Celsius, the metric temperature scale (formerly “centigrade”).
CE Center of Effort.
CB Citizens Band, a short-wave radio frequency service; compass bearing.
CLR Center of Lateral Resistance.
CMG Course Made Good.
CNG Compressed Natural Gas, a fuel sometimes used for cooking and heating.
CO Carbon monoxide, a poisonous gas.
CO2 Carbon dioxide; a type of fire extinguishing agent.
COLREGS USCG acronym for International Regulations for the Prevention of Collisions at Sea.
CPS Canadian Power and Sail Squadrons.
CQR A brand of plow anchor.
D (1) Direction; (2) Distance, used in labeling data on a chart plot.
DC Direct Current.
DF (1) Direction Finder. (2) Direction Finding.
DGPS Differential GPS (USCG corrections).
DR Dead Reckoning, a form of navigation.
E East, cardinal compass point.
EHF Extremely High Frequency (radar).
eLoran improved Loran system.
EP Estimated Position.
EPIRB Emergency Position Indicating Radiobeacon. (See also Glossary.)
ETA Estimated Time of Arrival.
ETD Estimated Time of Departure.
F Fahrenheit, usually shown as °F, a temperature scale.
FAA Federal Aviation Administration.
FBSA Federal Boat Safety Act (U.S.).
FCC Federal Communications Commission, the U.S. regulator and licenser of radio transmission facilities.
FM Frequency Modulation, a communications technology that changes the frequency of the transmitting radio wave in accordance with the information being transmitted.
FRP Fiberglass reinforced plastic, usually referred to simply as “fiberglass.”
G metric prefix for 1,000,000,000.
GMT Greenwich Mean Time; essentially the same as Universal Time Coordinated (UTC).
GPO Government Printing Office, a source of U.S. publications and documents.
GPS Global Positioning System, a radio navigation system using signals from satellites.
HF High Frequency (radio).
HIN Hull Identification Number.
hp Horsepower, a unit of power, equal to 746 watts.
Hz Hertz, a unit of frequency measurement, equivalent to cycles per second.
ICW Intracoastal Waterway.
JN Junior Navigator, a course and a grade in the U.S. Power Squadrons.
k metric prefix for 1,000.
kHz Kilohertz, unit of radio frequency equal to one thousand Hertz.
km Kilometer, one thousand meters, 0.62 statute mile, 0.54 nautical mile.
kn Knot, speed measurement, one nautical mile per hour (sometimes “kt”).
lat Latitude.
LF Low Frequency (Loran-C).
LNM Local Notice to Mariners.
LOA Length overall. (See also Glossary.)
long Longitude.
LOP Line of Position.
LORAN-C Long Range Navigation system using several timed radio pulses from different locations.
LPG Liquefied Petroleum Gas, a fuel.
LWL Length of a vessel on the waterline or load waterline. (See also Glossary.)
m (1) meter, unit of linear measurement. (2) metric prefix for 1/1,000.
M metric prefix for 1,000,000.
MF Medium Frequency (radio).
MHW Mean High Water, a tidal datum for heights.
MHz Megahertz, unit of radio frequency, one thousand kHz, or one million Hertz.
MLLW Mean lower low water, a tidal datum.
MLW Mean low water.
MSD Marine Sanitation Device.
N (1) North, cardinal compass point. (2) Navigator, a course and highest educational grade in the U.S. Power Squadrons.
NFPA National Fire Protection Association.
NGA National Geospatial-Intelligence Agency.
NIMA National Imagery and Mapping Agency.
NM Notice to Mariners.
NMMA National Marine Manufacturers Association.
NOAA National Oceanic and Atmospheric Administration.
NOS National Ocean Service, a unit of NOAA.
NWS National Weather Service, a unit of NOAA.
p pico, 10-12 P Piloting, a course and a grade in the U.S. Power Squadrons.
PFD Personal Floatation Device.
PPI Plan Position Indicator, a type of radar display.
Q flag (1) Yellow quarantine flag, so-called. (2) The International Signal Code is “My vessel is healthy and I request free practique.”
RACON A radar beacon that, when triggered by pulses from a vessel’s radar, transmits a reply.
RDF Radio Direction Finder. (See also Glossary.)
rpm Revolutions per minute.
S (1) South, cardinal compass point. (2) Seamanship, a course and grade in the U.S. Power Squadrons.
SAR Search and Rescue, Coast Guard and CG Auxiliary term.
SDGPS Satellite Differential GPS (FAA system).
SHF Super High Frequency (radar).
SN Senior Navigator, a U.S. Power Squadrons designation for a member who has completed all courses.
SOLAS Safety of Life at Sea Convention.
SOS Morse code signal of distress.
SSB Single Side Band, radio term for a shortwave communications technique.
T flag Transportation flag, signal flag hoisted as a signal requesting a tender or launch service.
UHF Ultra High Frequency (radio).
UL Underwriters Laboratories, a safety organization that conducts product tests.
USCG United States Coast Guard.
USCG Aux United States Coast Guard Auxiliary.
USN United States Navy.
USPS United States Power Squadrons.
UTC Universal Time Coordinated.
VHF Very High Frequency (radio).
VLF Very Low Frequency.
W West, cardinal compass direction.
WAAS Wide Area Augmentation System (FAA).
WWV Continuous broadcast time signal station, transmitting from Colorado.
WWVH 24-hour radio time signal station, Hawaii.
GLOSSARY OF SELECTED TERMS
The definitions that follow are for the nautical use of these terms; many will have additional definitions in other fields of interest. More specialized terms are defined in appropriate chapters throughout Chapman Piloting & Seamanship.
abaft (1)Behind. (2) Toward the stern.
abeam (1)To one side of a vessel. (2) At a right angle to the fore-and-aft line.
abovedeck On deck as opposed to within the boat; actually being above deck level is described as being aloft.
abreast (1)Even with. (2) By the side of. (3) Side by side.
ABYC American Boat and Yacht Council, Inc., the organization that sets voluntary safety and construction standards for small craft in the U.S.A.
admeasure To measure a vessel for the purpose of documentation.
admiralty law Law of the sea; a term for maritime law derived from the British.
aft, after Near or at the stern.
aground With the keel or bottom fast on the sea bottom.
aids to navigation Markers on land or sea that are established to enable navigators to avoid danger and fix their position; typically buoys, lights, daybeacons, and radiobeacons.
air draft Height of highest point on vessel above water.
aloft Above the deck, usually in the rigging.
allision Used by USCG to describe a vessel striking a fixed object such as a bridge or pier. (Collision is one vessel striking another vessel.)
AMVER (Automated Mutual-Assistance Vessel Rescue) The USCG’s unique, computer-based, and voluntary global ship reporting system used worldwide by search and rescue authorities to arrange for assistance to persons in distress at sea.
amidship (1) In the center. (2) The center portion of the vessel.
anchorage A customary, suitable, and (usually) designated harbor area in which vessels may anchor.
anchor bend A specific knot, generally used to fasten an anchor line to an anchor.
anchor light An all-round white light required by the Navigation Rules when a vessel is at anchor or moored; also called a riding light.
anchor rode A line or chain, used to hold a vessel fast to the anchor.
anchor watch Person or persons kept alert on deck while the vessel is at anchor or moored in order to cope with unexpected situations.
anemometer An instrument that measures wind velocity.
aneroid barometer A device to measure and indicate air pressure for meteorology, using a mechanical means, rather than a liquid such as mercury. The pressure is generally indicated as the equivalent of so many millibars, or as inches of mercury.
antifouling A type of paint, used on the bottoms of boats, that repels barnacles, marine grass and many other undesirable adhesions.
apparent wind The direction and force of the wind relative to a moving vessel, differing from true wind. The motion of a sailboat or powerboat underway makes the effective wind, acting on sails or hull, vary from the actual wind. Apparent wind can be indicated by a telltale or instruments.
astern (1) The direction toward the stern of a vessel. (2) Beyond the stern.
athwart At right angles to the centerline.
auxiliary A sailboat that has an engine.
aweigh Off the bottom, said of an anchor.
backdrafting A potentially dangerous condition caused by air movement over or around a boat, creating a low-pressure area at the stern that can increase CO levels on board.
backing (wind) Wind changing its direction, counterclockwise in the northern hemisphere, clockwise in the southern hemisphere; opposite of veering.
backsplice A splice in which the strands are reversed and interwoven, to make a neat end to a line.
backstay A stay supporting the mast, running from the masthead to the stern.
bar A sand, mud, or debris shoal, as across the mouth of a river or harbor.
batten down To close all openings, such as hatches, and fasten all loose gear, in heavy weather; wooden hatches used to be covered with a tarpaulin, and then fastened with battens and wedges.
battens Thin flexible strips of wood or plastic, used in batten pockets of a sail to support (stiffen to keep flat) the roach; battens are also used in awnings.
beam (1) One of the principal dimensions of a boat, the width. (2) The direction at right angles to the centerline of a vessel, as “the lighthouse is broad on the beam.”
beam reach A point of sailing with the apparent wind blowing at right angles to the boat’s fore-and-aft line.
bearing The direction of an object (vessel, buoy, etc.) from an observer; bearings can be visual, or by radio or radar.
bear off (1)To turn away from the wind. (2) To turn leeward; also “to bear away.”
beating Sailing against the wind, in alternate tacks.
Beaufort wind scale A scale indicating the force of the wind, invented by Admiral Beaufort in 1808; the original scale indicated the effect on a fullrigged frigate under sail; it has been extended to cover effects on shore as well as at sea, plus criteria that can now be measured, such as speed of the wind; the scale usually shows wind forces 0 through 12, but it has been expanded to 17. Each increase of force (number) means a doubling of the pressure (not velocity) of the wind.
becket (1) A loop or eye made in the end of rope or wire. (2) A rope handle.
bedding compound Caulking material used for mating two surfaces, rendering them watertight.
bend One of several types of knots, a combination of turns and tucks, used to fasten a line to a spar or another line; to fasten by means of a bend or knot.
berth (1) A position, as a place to sleep. (2) A place in which a vessel may be made fast.
bight (1) The middle part of a slack rope. (2) A loop. (3) An indentation in a shoreline.
bilge (1) The lowest point of a vessel’s interior hull. (2) The part of the exterior between the bottom and the topsides, the “turn of the bilge.”
binnacle A compass box or case, or a stand, usually illuminated at night.
binocular A telescopic instrument for the use of both eyes at once, having two tubes, each furnished with lenses and prisms to minimize the size.
bitt A strong post of wood or iron, similar to a samson post, on deck in the bow or the stern, to which anchor, mooring, and towing lines may be fastened.
bitter end (1) Inboard end of an anchor rode. (2) The extreme end of any line.
block-and-tackle Arrangement of blocks (pulleys) and line to gain a mechanical advantage.
boarding ladder A temporary set of steps placed over a vessel’s side.
boat (1) A small vessel, propelled by oars, sail, or power. Many consider a boat as being not over 65 feet in length. Another dividing point might be 20 meters (65.6 ft), as used in the Navigation Rules. (2) A vessel that can be carried on board a ship.
boathook A pole with a hook on one end, used for retrieving or picking up objects and for fending off.
bollard A strong vertical fitting, usually iron, on deck or on a pier or wharf, to which mooring lines may be fastened.
boom A spar used to extend the foot of a sail.
boom vang A system of and line to hold the boom down under some sailing conditions.
bosun A boatswain, a petty officer in charge of hull, rigging, and sail maintenance as well as deck operations; other spellings are bos’n, bo’s’n, bo’sun.
bosun’s chair A seat, sometimes a rigid plank or made of canvas, used to hoist a person aloft to repair rigging; pockets for tools are often included.
bow The forward part of a vessel.
bow & beam bearings A set of bearings on an object ashore or an aid to navigation whose position is known, used to determine distance off.
Bowditch A standard reference work on navigation, containing useful tables and reference text; it is named after Nathaniel Bowditch, the nineteenthcentury author of the first “Bowditch” (Publication No. 9 from NGA).
bowline The “king of knots,” used to make a loop in a line; this knot is simple, strong, virtually slipproof and is very easily untied.
bowsprit A fixed spar, projecting from the bow, to which forestays and/or the headstay are fastened; also useful for anchor handling.
braided line A modern configuration of rope (usually called “line” on board a boat or ship); it may be a single braid or double braid, one braid (core) inside another.
breast line Mooring or dock line, extending laterally from the vessel to a pier or float, as distinguished from a spring line, which controls fore and aft movement of the vessel.
bridge (1) The control station of a vessel. (2) The persons in charge of a vessel, or (by extension) of an organization, such as the U.S. Power Squadrons. (3) A structure over water to carry pedestrian, vehicular, or railroad traffic.
brightwork (1) Polished brass, bronze or stainless steel aboard a vessel. (2) Varnished wood as trim.
Bristol fashion Shipshape; clean, neat, orderly, and conforming to high standards of seamanship.
broach to, broaching The sudden, unplanned, and uncontrolled turning of a vessel so that the hull is broadside to the seas or to the wind.
broad on the beam At a right angle to a vessel’s fore-and-aft axis.
broad reach A point of sailing with the apparent wind broad just aft of the beam.
bulkhead A transverse wall in the hull; the interior compartmentalization of a vessel is created by bulkheads; in some cases bulkheads are watertight, adding to the safety in case of damage to the hull.
buntline hitch A simple, useful hitch for attaching a halyard to a shackle; strong, secure, easily undone.
buoy (1) A floating aid to navigation showing channels or otherwise indicating location, rocks and other obstructions, and prohibited areas on the water; turning points in races. (2) To buoy an anchor is to temporarily fasten the anchor line to a float, so that the anchor need not be raised when a vessel is leaving its anchorage.
burdened vessel Formerly under the Navigation Rules, the vessel that must “give way” to another vessel in a crossing or overtaking situation.
burgee A special flag flown on a vessel or on a flagstaff of a shore installation, indicating either the ownership of the vessel or the identity of a yacht club or similar organization.
camber (1) Curvature of either sail or keel. (2) The curvature of the deck usually being higher in the center so that the water can run off.
can A cylindrical buoy, generally green.
canvas (1) Firm, closely woven cloth (originally hemp, linen or cotton) used for sails and awnings. (2) A set of sails; today the word “sailcloth” is generally used for modern sailmaking fabrics such as polyester (Dacron) and nylon.
capstan A vertical winch on deck, used for hauling, such as the anchor line.
cardinal points The four principal compass points: North, East, South, and West.
carlins Fore and aft members of the deck frame; they support the coamings of the cockpit, the cabin trunk sides and the hatch coamings.
carry away To break loose, said of gear that is stressed beyond the strength of its fastenings.
cast off (1) To loose or unfasten. (2) To undo all mooring lines in preparation for departure.
catamaran A twin-hulled vessel, sail or power.
catboat A simple rig for a sailboat, with one mast and one sail, which may be either Marconi rig or with a gaff.
catenary In a rope or chain run between two points, the sag from a straight line due to the effect of gravity.
cavitate, cavitation Turbulence in the water caused by the overfast rotation of a propeller; causes wear on the propeller and a reduction in propeller efficiency.
ceiling (1) The inside lining of the hull. (2) The height of cloud cover.
celestial navigation Position determination (and the total process of navigation based on it) by reference to sun, stars, and moon. A sextant is used to measure the altitude of the observed heavenly body above the horizon, a highly accurate source of time information is used to determine the time of the sight, and tables and/or a calculator or computer are used to determine a position line; the place where two position lines cross is a fix.
centerboard A board or metal plate, moving vertically or pivoting up and down in a slot in the keel, which adds lateral resistance to the hull form of a sailboat; in effect the boat’s sideways motion through the water is thus controlled by increasing the area of the keel.
chafe (1) Abrasion. (2) Wear.
chafing gear Cloth, tape, or other material fastened around a line or other rigging to prevent wear.
chain locker Stowage space for anchor chain.
chainplates Fittings on the sides of the hull or the outer edges of the deck of a sailboat, to which the port and starboard rigging, shrouds, are fastened.
chandlery (1) Items of nautical gear. (2) A store where nautical gear is sold.
channel (1) The navigable portion of a waterway. (2) The marked and designated area where there is a known depth of water; boats may not normally anchor in a channel.
Charlie Noble A stovepipe fitting in a cabin top or deck, through which the metal “chimney” of a boat’s cooking or heating stove passes; usually equipped with a cooling rim of water and a partial cap to exclude rain and spray.
chart Seagoing map; most charts are issued by governmental sources, and their data are based on surveys of the land and underwater areas, showing depths as well as lights, buoys, and other aids to navigation; they are updated periodically.
Chartplotter Electronic display of navigation chart annotated with present position of vessel.
chine The intersection between the topsides and bottom of the hull of a vessel.
chock A rigging fitting, essentially shaped like a U or an O, normally mounted on deck or in the toe rail, to control a rigging or mooring line.
classes Organized groups of boats (essentially for racing), with either identical measurements and specifications, or variable measurements to fit a formula, designed to equalize boat performance to some degree and thus put a premium on skill and tactics.
cleat (1) A fitting to which mooring lines, sailcontrol lines such as sheets and halyards, and miscellaneous lines are temporarily attached. (2) To make fast a line to a cleat.
cleat hitch The distinctive crisscross or figure-eight hitch used to fasten (belay) a line to a cleat.
clevis pin A large pin that secures one fitting to another.
clew The lower, after corner of a sail, to which the sheet is attached.
close-hauled Hard on the wind, a point of sailing in which the sheets are hauled tight, enabling the boat to sail “against the wind.”
clove hitch A double-lock hitch, generally used around a piling or bollard; easily adjusted, but it can work loose.
club-footed Foot of sail, such as a jib or foresail, supported by a small boom.
coaming A raised edge, as around part or all of a cockpit, that prevents the seawater from entering the boat.
cockpit A space for the crew, lower than the deck and often watertight or self-draining.
cockpit sole The actual floor of a cockpit.
cold molding Process of bending multiple thin layers of wood in sequence with glue to achieve a total desired thickness as opposed to forming by steam bending or sawing.
colors (1) The national ensign. (2) Sometimes applied to all flags flown from a vessel. (3) The act or ceremony of raising the colors, including other flags.
COLREGS USCG term for the International Regulations for Preventing Collisions at Sea, also known as the International Navigation Rules.
come about (1) To tack. (2) To change direction relative to the wind.
companionway A hatch or entrance, from deck to cabin.
compass (1) Navigation instrument, either magnetic needles or bars attached, which floats or pivots in a bowl; older compasses used a system of graduated points while most modern ones use the 0 to 360 degree system. (2) A plotting tool used to draw circles or circular arcs.
cored construction The use of a core material sandwiched between an outer layer and inner layer, e.g. deck made of fiberglass inner and outer layers and balsa core.
Corinthian An amateur yachtsman or boater.
counter The portion of the hull, at the stern, above the waterline and extending aft.
course (1) The direction in which a vessel is to be steered (2) In racing, the present course or series of courses, often triangular, to be followed.
cowls (scoops) Direct the flow of air and vapors in or out of ducts.
cradle A frame used to support a vessel on land.
cringle A rope loop or circular eye, made on a metal or plastic thimble, used for fastening the corner of a sail, awning, or other canvas item.
critical value table A table prepared for each whole degree of deviation; opposite this is listed on one side the range of compass headings for which that value of deviation is applicable; on the other side is the range of magnetic headings which have that value of deviation.
crossing situation When two vessels meet, not head on or nearly head on but with each having the other forward of a direction 22.5 degrees abaft the beam; the vessel having the other on its starboard side is the give-way vessel and must keep clear.
cunningham A line controlling tension along a sail’s luff, invented by Briggs Cunningham.
current Horizontal movement of water, as from the normal flow of a river or when caused by the rise and fall of tides.
Dacron Trademark name for a type of polyester fiber, may be cloth or line.
daggerboard A centerboard that is retracted vertically rather than hinged.
danger angle A measured angle between the bearings of two points—such as buoys, landmarks, or rocks—indicates to the mariner an unsafe area for his/her vessel.
davit A swing-out device, a crane, used to hoist; a pair of davits, at the stern or at the side of the vessel, handles a dinghy or other small boat; a single davit at the bow is sometimes used to handle a heavy anchor.
dayboard A sign with a specified geometric shape and color atop a pile or dolphin as part of an aid to navigation; the combination of the dayboard and pile or dolphin if unlighted is a “daybeacon,” if lighted it is termed a “light.”
daysailer A boat without a cabin that is used for short sails or racing.
dayshape A special geometric marker, such as a black ball, cone, or cylinder hung aloft to indicate a vessel’s type, occupation or state; one black ball means “at anchor,” three means “aground.”
dead ahead, dead astern Direction exactly ahead of or behind a vessel.
deadlight (1) A fixed skylight, comparatively small, in a deck or cabin top, admitting light to the space below. (2) A non-opening port.
dead reckoning The navigation means used to determine position, calculated from the course steered and the speed through the water, without obtaining a fix; a dead reckoning position is indicated on a chart by marking a half circle with a dot on the track line; the time is placed at an angle to the horizontal and to the track line.
deadrise Height between the bottom of a vessel and its widest beam, also expressed as an angle.
departure, point of The last fix obtained by an outward bound vessel; it is marked on the chart as the beginning of the track until the next fix or estimated position. A vessel “takes departure” from such a position.
deviation The amount by which a ship’s magnetic compass needle points to one side or the other of magnetic north; iron, steel, magnets, and DC current in wires cause the compass to vary by different amounts on differing headings.
dinghy A small boat used as a tender; the term is also used for a small racing sailboat.
displacement The weight of the water displaced by a floating hull; the volume of water will vary depending on whether it is fresh water or seawater.
displacement hull A vessel supported by its own buoyancy while in motion; see planing hull.
distress signals Standardized or improvised signals, which may be visual, audible, or electronic, that are used on board a boat to indicate distress and seek assistance; various signals are listed in the Navigation Rules.
ditty bag A small bag for tools and personal items.
dock An enclosed or nearly enclosed water area; a place where vessels can make fast, as at a pier, wharf, or floating structure; frequently used incorrectly to refer to the pier or wharf itself.
dolphin (1) A small group of piles, in the water, tied together into a single structure, generally used for mooring or as part of an aid to navigation. (2) A species of marine mammal. (3) A species of fish.
dorade vent Specially designed deck box ventilation to keep water out with a baffle while letting air in below decks.
douse (1) To drop or lower a sail quickly. (2) To put out a lamp or a fire.
downhaul (1) A rigging line used to haul down. (2) To hold down a spar or sail.
draft (1) The vertical distance from the waterline to the lowest point of the hull or attachments such as propellers and rudders, thus the minimum depth of water in which a vessel will float; a vessel is said to “draw” a certain amount of water. (2) The curvature built into a sail.
dressing ship On national holidays, at regattas, and on other special occasions, yachts often “dress ship” with International Code signal flags; A vessel is dressed at 0800, and remains so dressed until the time of evening colors (while at anchor only, except for a vessel’s maiden and final voyages, and participation in a marine parade or other situation).
drift (1) Movement of a vessel through the water without propulsion. (2) Speed of a current.
drydock An enclosed dock from which the water can be pumped out, so a ship can have its lower hull cleaned or repaired.
dry rot Decay of wood timbers, as in a boat, actually occurring in moist conditions.
ease To let out a line under full control, gradually as with a sheet or a docking line.
ebb A tidal current flowing toward the sea.
eLoran Land based long-range hyperbolic navigation system; improved version of Loran-C.
ensign (1) The national flag. (2) The flag of an organization such as the Coast Guard Auxiliary or the U.S. Power Squadrons.
entry Forward-designed section of hull in the water; qualifies the type of hull in terms of efficiency and behavior in relation to wave action (for example, a sharper entry means faster hull speed for a racing hull).
estimated position (EP) A navigational point (less precise than a fix) based on course run, speed, and estimates of such factors as drift caused by wind or currents.
eye splice A fixed loop in the end of a line, made by intertwining strands of rope or by tucking an outer core of double-braid rope back into itself.
fairlead A rigging fitting designed to change the direction of a line, control the line and minimize friction.
fastening (1) Any of several methods of holding planks in a wooden boat to the frames. (2) Screws, nails, rivets. (3) A screw or bolt used to fasten rigging and plumbing fixtures.
fathom A nautical linear measurement, 6 feet, used primarily to measure depth and anchor rodes.
fathometer The formerly trademarked name for one brand (Raytheon) of electronic instrument for measuring depth of water; now used generically for electronic depth sounders.
fender A cushioning device hung between the boat and a float, pier, or another craft.
fetch (1) The distance across water over which the wind is or has been blowing. (2) To sail a course that will clear a buoy or shoal, also “lay.”
fid A tapered, pointed tool used to separate strands of rope, as in splicing.
figure-eight A knot, usually in the end of a line as a stopper, to prevent the end of the line from passing through a block or fairlead.
fin keel Keel shaped like the fin of a fish, shorter and deeper than a full-length keel.
fix The position of a vessel, determined by bearings, either visual or electronic, or by any other means believed to be acceptably accurate.
flare (1) A pyrotechnic signal that can indicate distress. (2) The outward curvature of the topsides.
flashing A lighted aid to navigation that is on less than it is off in a regular sequence of single flashes occurring less than 30 times in each minute.
flemish To coil a line spirally, laid flat on deck, either for appearance or to make a mat.
float plan A plan given to a responsible person on shore that tells where you intend to cruise and when you expect to make port again including a description of the boat; a form, not required, is available from many sources (do not attempt to file a plan with the USCG; they do not have the manpower to keep track of boats).
flood An incoming tidal current.
flotsam Wreckage debris floating on the water.
flying bridge A high steering position, usually above the normal wheelhouse of a power cruiser, also called a “fly bridge.”
following sea Waves from astern.
foot (1) The bottom edge of a sail; also. (2) To steer slightly lower than close-hauled in order to increase boat speed.
fore Located at the front, as of a vessel.
fore-and-aft From stem to stern, from front to back, oriented parallel to the keel.
forecast Formalized weather prediction.
forecastle The forward portion, below decks, of a vessel; the place where the crew is quartered. Pronounced and often spelled fo’c’sle.
foredeck The forward part of the main deck of a vessel.
forestay A stay, from high on the mast to the foredeck; the headstay runs from the top of the mast, or near there. to the bow and is the outermost stay.
forestaysail A sail attached to the forestay, similar to a jib, which is on the headstay.
foretriangle The area bounded by the mast, foredeck, and headstay.
forward On board a vessel, the direction to the front, toward the bow.
fractional rig A rig in which the jib of a sloop does not reach to the top of the mast, a three-quarter rig is an example of this rig.
frames Transverse structural members of a vessel, also called “ribs.”
freeboard The vertical distance between the waterline and the top of the deck.
fronts Boundaries between air masses that have different temperatures.
fully battened Sail with battens running full width of the sail horizontally.
furling Folding, rolling, or gathering a sail on its boom when it is not in use.
gaff (1) A spar holding the upper side (head) of a four-sided sail. (2) A device used to bring on board a large fish.
garboard strake The strake (plank) next to the keel.
genoa An overlapping jib.
geographic position Charted position.
give-way vessel The vessel that does not have the right of way in a crossing or overtaking situation; the vessel once called burdened.
grab rail A convenient grip, on a cabin top or along a companion ladder.
great circle A circle formed on a sphere, such as the earth, by the intersection of a plane passing through the center of the sphere. An arc of a great circle is the shortest distance on the surface between two points, hence a great circle route is the shortest route between the points.
grommet A ring or eyelet, as in a sail; a rope grommet is a circle made by unlaying the rope, then using one strand spirally, twisted onto itself, replacing the original strands.
gross tonnage The total interior space of a ship, including non-cargo space, computed at 40 cubic feet equals one ton; net tonnage is found by subtracting engine rooms, crew’s quarters, stores, and navigation space; displacement tonnage is the weight of the vessel, which is the same as the weight of the water displaced.
ground swells Swells that become shorter and steeper as they near the shore, because of the shoaling water.
ground tackle Anchor, anchor rode (line or chain), and the shackles and other gear used for attachment.
gunwale The upper edge of the side of a boat, usually a small projection above the deck; toe rail.
guy A rigging line for control, attached to the end of a movable spar.
hail A call to a ship or boat.
half-hitch The simplest knot, usually part of another knot, such as two half-hitches or a fisherman’s bend.
halyard A line used to hoist a spar or sail aloft.
hand lead A weight, attached to a line, lowered into the water to find out the depth.
handsomely Slowly and carefully, as to “ease a line handsomely,” in a proper manner.
handy-billy Block and tackle (movable).
hank Small snap hook securing the jib luff to the headstay.
hard over All the way in one direction, as a tiller or wheel can be put “hard over” to make an abrupt turn.
hauling (1) Hauling out is removing a boat from the water. (2) Pulling on an anchor line, halyard, or a rope or line is simply called hauling.
hauling part The part of a fall or tackle to which power is applied.
hawse hole An opening in the hull, through which mooring lines are run.
hawsepipes Fittings in the hawse holes through which dock or anchor lines may be run, and, in larger vessels, in which the upper part of the anchor may be stowed.
head (1) The bow or forward part of a vessel. (2) The upper end of a vertical part, such as the rudder head. (3) The upper corner of a triangular sail; the upper edge of a four-sided sail. (4) The toilet on board ship (fixture only or entire compartment).
heading The direction in which a vessel is pointed at any given moment.
headsail Any of several sails set forward of the mast (in the foretriangle).
head seas Waves coming from the direction in which a vessel is heading.
headstay (1) A stay from the bow to a point high on the mast. (2) The foremost stay.
headway Forward motion of a vessel through the water.
heave (1) To pull strongly on a line. (2) To throw a line.
heaving line A light line, coiled and thrown from vessel to vessel or between vessel and shore, to be used for pulling in a larger line, such as a dock line.
heaving to (1) Setting the sails so that a boat makes little headway, usually in a storm or a waiting situation. (2) In power-driven vessels, heading into the seas, or nearly so, and reducing speed to the minimum necessary to maintain control.
heel, heeling To tip, to lean to one side; heeling may result from uneven distribution of weight or the force of the wind; a list is a continuous; a roll is a repeated inclination, from side to side.
heeling error The additional or changing deviation in a compass caused by heeling, when the relative position of heavy iron (keel, engine) is changed so that the magnetic force varies.
helm The tiller, wheel, and other steering gear; a boat is said to have a weather helm if it tends to turn its bow to windward; lee helm if it tends to fall away to leeward.
high tide, high water The highest level reached as a result of tidal action.
hitch (1) A knot attaching a line to an object, such as a cleat, ring, spar. (2) The device used to connect a trailer to a towing vehicle.
horizontal angle An angle, usually measured with a sextant, between two landmarks, providing a line of position (the arc of a circle).
horseshoe buoy Personal Flotation Device (PFD), used in rescues, shaped like a U and mounted in a bracket at the rail; for man-overboard situations.
hydrofoil A type of boat with underwater foils that lifts the hull clear of the water when high speeds are reached.
hydrography The science of surveying the waters of the earth.
in irons Up in the wind and unable to pay off on either tack. A sailboat that loses headway (and therefore steerageway) when attempting to come about is said to be “in irons” or “in stays.”
inboard (1) More toward the center of a vessel. (2) Inside. (3) A motor fitted inside the boat.
inflatable boat A craft that has an inflatable structure; an inflatable boat with a rigid bottom is often referred to as a RIB.
Inland Rules Navigation Rules for vessel operations in certain harbors, rivers, lakes, and inland waterways of the United States.
Intracoastal Waterways (ICW) Bays, rivers, and canals along coasts (such as Atlantic and Gulf of Mexico coasts), connected so vessels may travel without entering the open sea.
isobars On a weather map, lines drawn connecting places of equal atmospheric pressure; isobars close together indicate a steeper gradient of pressure and stronger winds.
isogonic lines Lines, on a chart, connecting points of equal magnetic variation.
jetty A structure, usually masonry, projecting out from the shore; a jetty may protect a harbor entrance or the harbor itself.
jib A triangular sail, set on the headstay.
jibe To change direction, when sailing with the wind aft, so that the wind comes on a different quarter and the boom swings over to the opposite side; an accidental jibe can be dangerous.
keel The main structural member of a vessel, the backbone; the lateral area beneath the hull to provide steering stability and reduce leeway.
ketch A two-masted sailing rig; the after (mizzen) mast is shorter than the forward (main) mast and stepped forward of the rudder post, so the mizzen sail on a ketch is relatively larger than it might be on a yawl.
knot (1) Unit of speed, one nautical mile per hour. (2) A general term for a hitch or bend.
laid up Not in commission and ready for use.
latitude Geographic distance north or south of the equator, measured in degrees, minutes, and seconds or fractions of a minute.
launch (1) To move a boat into the water from land. (2) A powerboat used as a ferry between land and a moored boat; also “shore boat.”
laying-to Underway with little or no way on; an alternative to anchoring under certain circumstances.
lazarette A small storage compartment at the stern.
lead A shaped weight on a marked line, used to measure water depth and to pick up bottom samples (mud, clay, sand).
lead line, hand lead A weight, attached to a line, lowered into the water to find out the depth.
lee The direction toward which the wind blows, an object sheltered from the wind is “in the lee.” A lee shore is the coast lying in the direction toward which the wind is blowing.
leeboards Boards attached to the gunwale (in lieu of an external keel) to reduce leeway.
leech Trailing edge of a sail.
lee helm The tendency of a sailboat to turn the bow to leeward, as distinguished from weather helm, unless corrective rudder action is taken.
leeway Sideways drift of a boat, primarily caused by the wind or a current.
length on the waterline (LWL) The length of a vessel when measured at the line of flotation.
length overall (LOA) The distance between the tip of the bow and the end of the stern, excluding projecting spars or rudder.
lifelines Lines, usually of wire rope, often covered with plastic, at the sides of the boat’s deck to keep persons from falling overboard.
life preserver A flotation coat, vest, ring, cushion, or inflatable, formerly called Personal Flotation Device (PFD), now called life jacket by the USCG.
Light Lists A series of seven volumes published by the USCG for the coastal and inland waters that provide more complete information concerning aids to navigation than can be shown on charts; but they should not be used for navigation in lieu of charts and Coast Pilots.
lights Lighthouses or beacons; fixed aids to navigation that are equipped with light sources having certain prescribed characteristics.
line A rope in use aboard a vessel; laid line is formed by twisting three (sometimes four) strands; braided line may be single or braid over a core.
line of position (LOP) A line, straight or curved, along which an observer can be presumed to be located derived from observation or measurement by visual, electronic, or celestial sources; there are two lines: one “real,” one drawn on a chart.
linestoppers Also called jamcleats; they will keep the tension on a line while stopped or jammed.
list (1) A continuous leaning to one side, often caused by an imbalance in stowage or a leak into one compartment. (2) A Light List is a printed listing of aids to navigation, in geographical order.
locker A storage place, a closet.
log (1) A device for measuring distance run through the water. (2) A written record, usually in a book, including data on a vessel’s course, speed, weather encountered, as well as other details of navigation and maintenance.
long splice A splice joining two rope ends, made by untwisting strands, thinning and removing the ends, so that the final splice is no thicker than the original line; a long splice will thus go through a block without jamming.
lubber’s line The index mark, usually inside the compass, by which the course is read and the vessel is steered.
luff The forward part or leading edge of a sail.
magnetic bearing, course, heading A bearing, course, or heading named in relation to magnetic north; usually this is an intermediate step in converting a “compass” reading related to the direction of the north point of the compass to get a “true” reading related to the direction of true north.
magnetic meridian A line of horizontal magnetic force of the earth to which a compass, without local disturbances (deviation), aligns itself.
magnetic north The direction a compass needle points when there are no local disturbing influences (deviation).
mainsail The sail hoisted on the after side of the mainmast, pronounced “mains’l.”
make fast Action of attaching a line, such as making a boat fast to a pier or the shore.
marlinespike (1) A pointed steel tool for splicing line. (2) That portion of seamanship devoted to the use of lines, knots, and related matters.
masthead light A white light, at or near the masthead, used underway by a vessel under power at night; the range of visibility required varies with the size of the vessel; the arc of visibility is from dead ahead to 22.5 degrees abaft the beam, on both sides.
MAYDAY A radio-telephone distress call, from the French m’aidez (help me).
meridian A line passing through both poles and intersecting the equator at right angles, known as longitude. The prime meridian (0 degrees) passes through Greenwich, England, a part of Greater London.
messenger A light line used to carry another line such as a halyard or a larger hawser from a ship to the shore or to another vessel; see heaving line.
midships Location near the center of a vessel measured either from side to side or fore-and-aft.
mile The statute mile is 5280 feet; the nautical mile is 6076.12 feet (1852 meters exactly).
mizzen The aftermost mast in a ketch, yawl, or schooner with three or more; the mizzen sail is set on this mast.
moored Anchored, made fast to a pier, wharf, etc.
mooring (1) Permanent ground tackle. (2) A place where vessels are kept at anchor.
Morse code A communication code developed by Samuel Morse, originally for the land telegraph; the code, modified for radio use, uses dots and dashes for letters, numerals, and a few special signs.
motorboat A boat propelled by an internal-combustion engine; the U.S. Motor Boat Act divides motorboats into four classes based on length.
motorsailer An auxiliary sailboat with a larger than usual engine.
mouse, mousing Turns of twine, taken across a hook, to prevent accidental unhooking.
nautical mile 6076.12 feet (1852 m), an international standard; for practical purposes, equals one minute of latitude, but not one minute of longitude.
naval architect Architect specializing in marine design.
navigation The art and science of determining a vessel’s position and guiding it safely and efficiently to another position; coastal navigation, using visual (surface) reference points, is more usually called piloting; celestial navigation uses observations of heavenly bodies (usually with instruments) and tables or calculators; electronic navigation (radionavigation) is the technical term when electronic devices and systems are used.
navigation lights Lights shown by a vessel that indicate course, position, and status such as fishing or towing.
Navigation Rules The Rules of the Road in the U.S., governing navigation lights, rules for vessels meeting or passing, sound signals, and distress signals; the Rules for International and U.S. waters differ in only a few small details.
neap tide One occurring when the sun and moon are farthest from being in line (quarter and threequarter moons); neap tides have the least range (rise and fall). See spring tide.
net tonnage A vessel’s capacity, determined by measuring its hull interior and subtracting the volume of non-cargo spaces (engine room, crew quarters, etc.) See gross tonnage.
nylon A polyamide synthetic material with a long-chain molecule; nylon fibers are used for rope and some sailcloth, when elasticity is desirable; hard nylon is used for some rigging parts, such as sheaves.
oarlock A U-shaped, or sometimes O-shaped, pivoting device in which oars are set when rowing.
offshore (1) Out of sight of land. (2) From the land; toward the water.
off-soundings Waters deeper than where depths can normally be measured; usually assumed to 100 fathoms or 200 meters.
outboard (1) Outside or away from a vessel’s hull; opposite of inboard. (2 A propulsion unit for boats, attached at the transom; includes motor, driveshaft and propeller; fuel tank and battery may be integral or could be installed separately in the boat.
outdrive A propulsion system for boats, with an inboard motor operating an exterior drive, with driveshaft, gears, and propeller; also called stern drive and inboard/outboard (I/O).
overall length (LOA) The extreme length of a vessel, excluding spars or rigging fittings.
painter A towline or tie-up line for a small boat.
parallax error The error in reading an instrument such as a compass or gauge from off to one side, resulting from the distance between the needle or pointer and the numerical scale.
passage (1) One leg of a voyage. (2) A journey.
patent log A device, including rotor on a towline and counter, for measuring distance run and speed.
pay out To release line in a controlled manner, as with an anchor rode.
pelorus A sighting device, without a compass, used to determine relative bearings.
pennant (1) A small flag, typically a signal flag. (2) A short length of line or cable between a mooring chain and the boat, sometimes called a pendant.
PFD Personal flotation device; obsolete terminology for life preserver.
pier A structure, usually wood or masonry, extending into the water, used as a landing place for boats and ships.
pile, piling A vertical wooden, concrete, or metal pole, driven into the bottom; may be a support for a pier or floats or an aid to navigation; also used for mooring.
piloting Navigation using visual reference points (aids to navigation, landmarks, etc.) and water depths.
pitch (1) The alternating rise and fall of the bow of a vessel proceeding through waves. (2) The theoretical distance advanced by a propeller in one revolution. (3) tar and resin used for caulking between the planks of a wooden vessel.
planing hull A hull designed so that forward speed creates hydrodynamic lift, reducing friction and increasing speed.
planking Lengths of wood used for the external skin or the deck of a vessel.
Pleasure Vessel License A form of USCG documentation that does not allow commercial use.
plumb bow Hull with vertical bow shape.
Polyester Synthetic material (typical trade name, Dacron) used for fibers for rope and sailcloth; polyester is stronger and has less elasticity than nylon.
port (1) Left, as the port side of a boat, or a direction, as “to turn to port.” (2) An opening, for light and/or ventilation, in the side of a vessel. (3) General area of a shore establishment having facilities for landing and maintaining vessels.
port tack A sailing vessel with the wind coming from the left, or port, side is said to be on the port tack; such a vessel normally does not have the right of way when meeting a vessel on the starboard tack.
pram A small boat used as a tender; a dinghy in the U.S., usually with a squared-off bow.
prime meridian The meridian of longitude through Greenwich, England (0°).
privileged vessel A vessel that should maintain both course and speed when encountering another vessel; termed “stand-on vessel” in Navigation Rules.
psychrometer A weather instrument, usually two hygrometers, one dry and one with a wet bulb, to measure the moisture in the air.
pulpit The forward railing structure at the bow of a boat.
purchase (1) A mechanical device for lifting or pulling. (2) On board ship, the term is used specifically for a block and tackle.
Q flag A plain yellow flag—the letter “Q” of the International Code Flag set—must be hoisted by any vessel arriving in the port of a country from the waters of another country; it must be kept flying until the vessel is “cleared” by customs and immigration officials of the arrival port.
quarter The side of a vessel, port or starboard, from amidships to the stern.
quartering sea Waves coming toward the vessel’s quarter.
quay A structure, usually of masonry or stonework, parallel to the water’s edge, where vessels can make fast, and load and unload cargo; a wharf.
radar An electronic system using super highfrequency radio waves; when reflected they show on a screen the position, size and distance of an object; radar is used at night and in bad visibility for both collision avoidance and navigation.
radio bearing A direction determined by radio.
radio direction finder (RDF) A radio receiver with special antenna and circuitry used to determine the direction to a source of radio waves.
radionavigation (1) Electronic piloting. (2) The determination of a vessel’s position, course, and speed by various electronic devices and systems.
rafting, rafted The mooring procedure for two or more vessels, made fast side-by-side at a dock or on an anchor or mooring buoy.
rail (1) A protective edge on deck. (2) A solid bar on supports, similar to a lifeline.
raised deck Deck level arranged to be higher than the actual gunwale.
rake (1) The slant, fore and aft, of a mast. (2) The slant of a ship’s funnels, bow, or stern.
reach, reaching (1) To sail across the wind. (2) A channel between the mainland and an island.
reciprocal A direction precisely opposite another; differing by 180°.
reef (1) An underwater barrier, such as rock or coral. (2) To shorten sail by reducing the area exposed, by tying in reef points, or by rolling up the foot or luff.
reeving Leading a line through a block or fairlead as in setting up a purchase, or rigging a halyard.
registration The numbering or licensing of a boat.
relative bearing A direction in relation to the bow of a vessel, expressed in degrees.
reverse sheer The reverse of normal sheer. The sheerline rises above the straight line from stem to stern instead of curving below.
rhumb line A straight line on a Mercator chart; it intersects all meridians at the same angle; for short distances it provides an adequate course, but a great circle is actually the shorter distance.
ribs Another term for frames, the transverse members of a wooden hull to which the planks are fastened.
riding light The anchor light.
rig (rigs) (1) The spars, standing rigging, and sails; (2) To make a boat ready for sailing or to prepare a sail or piece of gear for use.
rigging The wire rope, rods, lines, hardware, and other equipment that support and control the spars and sails; standing rigging is semi-permanent once set up; running rigging is continually adjusted as the sails are hoisted, doused, trimmed, or reefed.
right-of-way In both normal boat operation and racing, certain stand-on vessels have priority in crossing or overtaking situations, or at turns in races; the other give-way vessel must yield to the boat that has the right-of-way in particular situation; the boat on starboard tack, or the vessel coming from the right in the case of power boats, will have the right-of-way under most conditions.
rode The anchor line, which may be line (fiber rope), chain, or a combination of line and chain.
roll The alternating motion of a boat, leaning alternately to port and starboard; the motion of a boat about its fore-and-aft axis.
roller furling The method of furling a sail by winding it on a stay, most used for jibs but used for mainsails on some cruising boats.
roller reefing Reduction of sail area by winding the sail on a rotating boom or stay.
rolling hitch A knot useful for attaching a line to another line or to a spar.
rope Cordage made of fiber or steel; rope may be braided or formed with twisted strands; when in use aboard vessels it is generally called line.
round turn A turn, of line, around an object or a line; part of a knot.
rub rail, strake, or guard An outer member on the side of a vessel’s hull, designed to absorb friction and pounding from contact with pilings, docks, etc.
rules of the road A general term for the regulations governing vessels, used to prevent collisions; in the U.S. the technical name is Navigation Rules; the rules vary slightly for inland and international waters, but are generally similar.
running fix A navigation fix obtained by using a line of position (LOP) taken at or near the current time together with another earlier LOP that has been “advanced” for the movement of the vessel between these two times.
running lights The required lights, called navigation lights, that a vessel shows at night or in poor visibility, to indicate position, course, and status.
running rigging The adjustable lines (and certain hardware items) for the control of spars and sails.
safety harness Harness with webbing used with a safety line to lessen chances of persons on deck falling overboard.
samson post In a small vessel, a single bitt forward used to fasten the anchor and dock lines.
satellite navigation Position finding using radio transmissions from satellites orbiting in space with sophisticated on-board automatic equipment.
scope 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.
screw A propeller; sometimes called a wheel.
scudding Running before the wind in a gale.
scuppers Drain holes on deck, in the toe rail, or in bulwarks, or (with drain pipes) in the deck itself.
scuttlebutt Gossip, rumors, so called because sailors used to gather around the scuttlebutt, a cask for drinking water.
sea anchor Canvas shaped like a parachute or a cone with an opening at the tip to keep a boat’s bow to the seas in open water and reduce drift to a minimum; not a means of anchoring to the bottom.
sea cock A valve placed on the inside of a throughhull fitting to regulate the flow of water from the outside into the hull.
seakindly Comfortable in rough seas, moving through the water without undue motion or strain; said of a vessel’s hull design.
seamanship All the arts and skills of boat handling, ranging from maintenance and repairs to steering, anchoring, docking, sail handling, marlinespike work, and rigging.
seiche An oscillation of the surface of a lake or landlocked sea that varies in period from a few minutes to several hours.
seizing Binding two lines together, or a rope to a spar, and so on, using light line.
sentinel Weight suspended from an anchor rode to help keep the pull on the anchor as horizontal as possible to prevent dragging in rough weather; also called a “kellet.”
serving Covering and protecting a portion of a line, to prevent wear; a serving may be as simple as a whipping (small stuff wrapped around) or more elaborate, with worming, parceling, and the addition of waterproofing.
set (1) To raise a sail. (2) The direction of a current.
shackle A metal link fitting with a pin across the throat, used to connect lines to an anchor, fasten blocks to a spar in rigging, or a line to a sail.
sheave A grooved wheel or pulley over which rope or rigging wire runs, used to change the direction of force; often sheaves are parts of blocks.
sheer (1) The curvature of the deck, fore and aft, as seen from the side. (2) A turn off course, from poor helmsmanship or difficult steering. (3) A swing, as on a moored boat.
sheet A line used to control a sail’s lateral movement, either directly or by limiting the movement of a boom or other spar.
sheet bend A knot useful for bending a line to an eye or to join two lines of different sizes.
ship (1) A large seagoing vessel. (2) A three-mastered sailing vessel with square sails, called “fullrigged,” on each mast. (3) To take something aboard, as water in rough seas. (4) To place gear in place, as to ship a rudder or to ship oars, bringing them inboard when not in use.
shipshape In good order, in good condition, properly rigged and ready.
shrouds Fixed rigging on either side of the mast.
sidelights Red and green navigation lights, visible from forward or on the beam. See running lights.
signal halyard Halyard for hoisting the signal flags and pennants.
slack (1) Not moving. (2) Loose. (3) To ease.
slack water The period of little or no water movement between flood and ebb tidal currents.
slip (1) A berth for a boat between two piers or floats or piles. (2) The percentage difference between the theoretical and the actual distance that a propeller advances when turning in water under load.
small stuff Cordage in small sizes, such as marline, spun yarn, sail twine; primarily used for whippings and servings.
snub a line To check a running rope quickly, usually by tension around a bitt or cleat.
sole The cabin or cockpit deck.
soundings Measurements of water depth as shown on a chart; a vessel is “off soundings” if in water too deep to use a long (deep sea) lead line; inside the 100 fathom line is usually “on soundings.”
spinnaker A three-cornered sail of light cloth, usually nylon, used in downwind sailing.
splice To join two lines, or make an eye, by tucking strands or otherwise interweaving parts of rope; braided rope that has a core and a cover is usually spliced by tucking one inside the other.
spring line One of the standard dock lines, used to control fore and aft motion of a boat made fast in to a pier or float.
squall A sudden and violent windstorm often accompanied by rain; a line squall or line of squalls quite often accompanies an advancing cold front.
square knot Another name for the reef knot, useful for tying two ends of a line together, as around an object; not a suitable knot to use when fastening two lines where the strain will be intermittent.
square rigged Vessel rigged with sails that are hung laterally and of square shape.
stanchion A metal post, used to hold lifelines along a deck.
standing part (1) The portion of a line not used in making a knot, or the part of the line around which the knot may be tied. (2) In a block and tackle, the part of the purchase that does not move when power is applied to the hauling part.
standing rigging The permanent stays and shrouds, as well as some other rigging parts, used mainly to hold up the mast and take the strain of the sails; although necessarily somewhat adjustable the standing rigging is not continually changed as is the running rigging.
stand-on vessel The boat that has the right of way in a crossing or overtaking situation; formerly the privileged vessel. See give-way vessel.
starboard (1) The right side of a vessel as related to facing the bow; the starboard side remains starboard no matter what the orientation of a person on board. (2) The right bank of a river as you face in the direction that the river flows is called its “starboard” bank, thus related to the river’s flow downstream, not to the vessel herself.
starboard tack A vessel sailing with the wind coming over the starboard side is on the starboard tack and generally has the right-of-way over a boat on the port tack.
stays Rigging, generally wire or roods, used to support the masts in a fore- and-aft direction and to carry certain sails.
staysail An additional sail that is set between the mast and the jib, or between masts.
steadying sail Sail hoisted more for steadying effect of the wind on it than for propulsion.
steerageway Sufficient motion through the water to enable a vessel to respond to its rudder.
stem The forward member of the hull, or the corresponding portion of the hull in composite construction.
step (1) At the base of the mast, the special part of the boat in which the heel of the mast is set. (2) To raise the mast and put it in place.
stern The after portion of the boat.
stern drive An inboard/outboard propulsion system with the engine inside the hull; steering is done by turning the outboard (propeller) unit.
stern line The dock or mooring line that runs from the stern of a vessel to the pier, float, or pile.
sternway Opposite of headway; having a reverse motion through the water.
stow To put in the proper place.
strakes Lines of planking, as from stem to stern.
See sheer strake and garboard strake.
stuffing box A through-hull fitting for the drive shaft or rudder post, also called a gland.
suit of sails The full complement of a boat’s sails.
superstructure Cabins and other structures above deck.
survey Inspection of a vessel for any reason by a qualified professional (marine surveyor).
swamp To fill with water, not from a leak but from water coming over the deck and gunwales.
swell A long, large wave that does not crest; swells come from such a distance that the wind causing them is not apparent locally.
swim platform Low platform installed at the transom for ease of boarding.
tack (1) The forward bottom corner of a sail, or either bottom corner of a square sail. (2) Each leg of a zigzag course sailed to windward or downwind.
tackle A purchase, a block and tackle, a combination rig of one or more blocks with lines to obtain mechanical advantage.
telltale A wind-direction indicator, mounted on the rigging, sail, or mast.
tender (1) A small boat accompanying a yacht or other recreational vessel, used to transport persons, gear, and supplies; a dinghy. (2) A vessel is said to be tender if it is relatively unstable.
tensile strength The load, in pounds of “pull,” at which a rope, chain, or other item would break.
thimble Metal fitting used in rigging, forming a reinforced place of attachment.
throat The forward upper corner of a four-sided fore-and-aft sail; the point where the throat halyard attaches.
thwart A crossways seat, usually contributing to structural strength in a rowboat or other small open boat.
tides The vertical rise and fall of ocean water, and waters affected by the ocean, caused by the gravitational forces of the moon and the sun.
tiller An arm or lever attached to the top of a rudder post for the purpose of controlling the position of the rudder and so steering the craft.
toe rail The low bulwark on a small decked boat.
topping lift A running rigging line to control a spar; typically an adjustable topping lift would run over a sheave or through a block at the top of the mast down to the end of a boom or spinnaker pole.
topsides (1) The sides of a vessel above the waterline. (2) On deck as opposed to below deck.
track (1) Metal or plastic rigging fitting, used to control spars, blocks and other rigging parts.
(2) The path, normally shown on a chart, between one position and another, as a dead reckoning track.
Traffic Separation Scheme (TSS) A plan, generally internationally agreed on, by which vessels in congested areas use one-way lanes to lessen the danger of collisions.
transom The transverse part of the stern.
trim, trimmed (1) The way in which a vessel floats, on an even keel, or trimmed by the head (bow) or stern, for example; adjustable by shifting ballast. (2) To set sails, to adjust by means of sheets and certain other rigging lines.
trip line A line fast to the crown of an anchor by means of which the anchor can be hauled out when dug in too deeply or fouled; a similar line used on a sea anchor to bring it aboard.
true course A course corrected for variation and deviation; one that is referenced to geographic north.
true north Geographic north.
true wind The actual direction and force of the wind, as distinct from apparent wind as felt by a person on board or indicated by a telltale, which varies with the speed and direction of the vessel.
tumblehome The inward curving of the topsides, above the waterline.
tune (1) To adjust the rigging and sails for maximum efficiency. (2) To adjust an engine for optimum efficiency.
tunnel hull Hull with tunnels shaped for the propeller to reduce draft.
turnbuckle A threaded, adjustable rigging fitting, used for stays, lifelines, and sometimes other rigging.
twine Small stuff, light line used for whippings or servings; sail twine is also used for sewing.
two-blocked Fully closed up, raised as far as the gear permits, as when both blocks in a purchase are drawn completely together.
two half-hitches A useful knot, in which the hitches are made upon the standing part of the line and then drawn up (tightened).
underway A vessel not at anchor or aground or made fast to the shore.
Underwriters Laboratories One of the principal testing organizations involved in setting safety standards in the United States.
upwind To the windward of.
V-drive Mechanism used with an engine installation that has the normally aft-facing end of the engine facing forward.
V-hull Hull shaped in a V, as contrasted with a rounded hull.
vector A line drawn to represent magnitude and direction, such as leeway a boat makes in a given time period as a result of wind or water current.
veer (1) To change direction, to swerve. (2) To veer out is to let out rope, as an anchor line. (3) When the wind veers it changes direction clockwise, as opposed to backing (counterclockwise).
VHF radio A Very High Frequency electronic communications system.
voyage A complete trip, as distinguished from a passage.
wake The track in the water of a moving vessel; commonly used for the disturbance of the water (waves) resulting from the passage of the vessel’s hull.
wash The loose or broken water left behind a vessel as it moves along; the surging action of waves.
weather helm The tendency of a vessel to turn to windward, requiring a slight amount of helm to keep it on course; normally this is considered a sailboat safety element.
weather shore The coast lying in the direction from which the wind is blowing, as opposed to a lee shore. See lee.
weather side Side of a boat upon which the wind is blowing.
well-found With adequate equipment and stores, well supplied and fitted out.
wetted surface The area of the wetted part of a hull (including rudder) in the water, affecting speed.
wharf A structure, parallel to the shore, for docking vessels.
wheel (1) The steering wheel. (2) A propeller.
whipping Twine wound around a line, as on the end or at an eye splice, to add strength and prevent fraying or abrasion.
Wide Area Augmentation System (WAAS) An FAA radionavigation system that transmits corrections to basic GPS signals to improve position accuracy.
wide berth To pass well clear of another vessel or an object.
winch A device, on deck, on a spar, or otherwise mounted, which is used to haul on a line; if geared or used with a handle (lever) it provides a mechanical advantage.
windage Wind resistance.
windlass A special form of winch, a rotating drum device for hauling a line or chain.
windward The direction from which the wind is blowing.
working sails The sails used in normal winds, as distinguished from light weather sails or storm sails.
worm To fill in the spaces in laid rope, as part of the procedure known as worm-and-parcel.
yard (1) A spar, crossing the mast, on which square sails are fitted. (2) A place where boats are stored, constructed, or repaired.
yaw To swing or steer off course, as when running with a quartering sea.
yawl A rig for two-masted sailboats, in which there is a mainmast and a smaller mizzen mast, stepped aft of the rudder post.