FAIRWAY. The parts of a waterway that are open and unobstructed for naviga- 

 tion. The main traveled part of a waterway; a marine thoroughfare. 



FATHOM. A unit of measurement used for soundings equal to 1.83 meters (6 

 feet). 



FATHOMETER. The copyrighted trademark for a type of echo sounder. 



FEEDER BEACH. An artificially widened beach serving to nourish downdrift 

 beaches by natural littoral currents or forces. 



FEEDER CURRENT. See CURRENT, FEEDER. 



FEELING BOTTOM. The initial action of a deepwater wave, in reponse to the 

 bottom, upon running into shoal water. 



FETCH. The area in which SEAS are generated by a wind having a fairly 

 constant direction and speed. Sometimes used synonymously with FETCH 

 LENGTH. Also GENERATING AREA. 



FETCH LENGTH. The horizontal distance (in the direction of the wind) over 

 which a wind generates SEAS or creates a WIND SETUP. 



FIRTH. A narrow arm of the sea; also, the opening of a river into the sea. 



FIORD (FJORD). A narrow, deep, steep-walled inlet of the sea, usually 

 formed by entrance of the sea into a deep glacial trough. 



FLOOD CURRENT. The tidal current toward shore or up a tidal stream, usually 

 associated with the increase in the height of the tide. 



FLOOD TIDE. The period of tide between low water and the succeeding high 

 water; a rising tide. (See Figure A-10.) 



FOAM LINE. The front of a wave as it advances shoreward, after it has 

 broken. (See Figure A-4.) 



FOLLOWING WIND. Generally, the same as a tailwind; in wave forecasting, wind 

 blowing in the direction of ocean-wave advance. 



FOREDUNE. The front dune immediately behind the backshore. 



FORERUNNER. Low, long-period ocean SWELL which commonly precedes the main 

 swell from a distant storm, especially a tropical cyclone. 



FORESHORE. The part of the shore, lying between the crest of the seaward berm 

 (or upper limit of wave wash at high tide) and the ordinary low-water 

 mark, that is ordinarily traversed by the uprush and backrush of the waves 

 as the tides rise and fall. See BEACH FACE. (See Figure A-1.) 



FORWARD SPEED (hurricane). Rate of movement (propagation) of the hurricane 

 eye in meters per second, knots, or miles per hour. 



A-13 



