NAVIGATION ACTS

in English history, a series of laws designed to restrict England's carrying trade to English ships, effective chiefly in the 17th and 18th centuries. The measures, originally framed to encourage the development of English shipping so that adequate auxiliary vessels would be available in wartime, became a form of trade protectionism during an era of mercantilism. The first navigation act, passed in 1381, remained virtually a dead letter because of a shortage of ships. In the 16th century, various Tudor measures had to be repealed because they provoked retaliation from other countries. The system came into its own at the beginning of the colonial era, in the 17th century. The great Navigation Act passed by the Commonwealth government in 1651 was aimed at the Dutch, then England's greatest commercial rivals. It distinguished between goods imported from European countries, which could be brought in either English ships or ships of the country of origin, and goods brought from Asia, Africa, or America, which could travel to England, Ireland, or any English colony only in ships from England or the particular colony. Various fish imports and exports were entirely reserved to English shipping, as was the English coastal trade. The law was reenacted in 1660, and the practice was introduced of enumerating certain colonial products, which could be shipped directly only to England, Ireland, or another English colony. These included sugar (until 1739), indigo, and tobacco; rice and molasses were added during the 18th century. Nonenumerated goods could go in English ships from English colonies directly to foreign ports. From 1664 English colonies could receive European goods only via England. Scotland was treated as a foreign country until the Act of Union (1707) gave it equal privileges with England; Ireland was excluded from the benefits of the laws between 1670 and 1779. Although English tonnage and trade increased steadily from the late 17th century, critics of the navigation system argue that this would have occurred in any case and that the policy forced up freight prices, thus ultimately making English manufactured goods less competitive. At first, colonial merchants benefited from an assured market, but the tightening of the laws in 1764 contributed to the unrest leading to the rebellion of England's American colonies; their achievement of independence made the first serious breach in the navigation system, and from then on exceptions were increasingly made. Enumeration was abandoned in 1822, and the navigation laws were finally repealed in 1849 and 1854. Additional reading A history of navigation is provided in J.E.D. Williams, From Sails to Satellites: The Origin and Development of Navigational Science (1992). General works include Nathaniel Bowditch, American Practical Navigator, rev. ed. by the United States Defense Mapping Agency Hydrographic/Topographic Center (1984); Harold Gatty, Nature Is Your Guide (1958, reprinted as Finding Your Way on Land or Sea: Reading Nature's Maps, 1983); Alton B. Moody, Navigation Afloat: A Manual for the Seaman (1980); Malcolm C. Armstrong, Practical Ship-Handling (1980); Bruce Fraser, Weekend Navigator (1981), a good introduction; Tom Bottomley, Practical Piloting (1983), a useful training guide; Jeff Markell, Coastal Navigation for the Small Boat Sailor (1984), a manual for those with some sailing experience; Benjamin Dutton, Dutton's Navigation & Piloting, 14th ed. by Elbert S. Maloney (1985), a standard text; and Richard R. Hobbs, Marine Navigation: Piloting and Celestial and Electronic Navigation, 3rd ed. (1990), an introduction. Celestial navigation is treated in John S. Letcher, Jr., Self-Contained Celestial Navigation with H.O. 208 (1977); Mortimer Rogoff, Calculator Navigation (1979); Mary Blewitt, Celestial Navigation for Yachtsmen, 10th ed. (1990); and Charles H. Cotter, The Elements of Navigation and Nautical Astronomy, rev. 2nd ed. (1992).Works on guidance, including position finding and radar, are W. Denne, Magnetic Compass Deviation and Correction, 3rd ed. rev. by A.N. Cockcroft (1979); H.H. Shufeldt and G.D. Dunlap, Piloting & Dead Reckoning, 3rd ed. rev. by Bruce Allan Bauer (1991); K. Linkwitz and U. Hangleiter (eds.), High Precision Navigation: Integration of Navigational and Geodetic Methods (1989), workshop proceedings; F.J. Wylie (ed.), The Use of Radar at Sea, 5th rev. ed. (1978); Edward L. Safford, Jr., Modern Radar: Theory, Operation & Maintenance, 2nd ed. (1981); and Merrill I. Skolnik (ed.), Radar Handbook, 2nd ed. (1990). Also useful is the journal Guidance and Control (annual). A special issue of Navigation, vol. 25, no. 2 (1978), is dedicated solely to the NavStar global position system. The fundamentals of the timing technique, the basis of NavStar and of increasing importance in navigation systems, are introduced in Robert C. Dixon, Spread Spectrum Systems, 3rd ed. (1994). F.S. Stringer, The Development of Flight Deck Display, The Journal of Navigation, vol. 37, no. 2 (1984), is also of interest.Electronic navigation is examined in L. Tetley and D. Calcutt, Electronic Aids to Navigation (1986); S.F. Appleyard, R.S. Linford, and P.J. Yarwood, Marine Electronic Navigation, rev. ed. (1988), for use in the merchant shipping industry; and G.J. Sonnenberg, Radar and Electronic Navigation, 6th ed. (1988). Edward W. Anderson William Edward May John Lawrance Howard S.S.D. Jones The Editors of the Encyclopdia Britannica