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 action of a deepwater wave on running into shoal 

 water and beginning to be influenced by the bottom. 



FETCH - Tlie area in which SEAS are generated by a wind having a rather 

 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, same as 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 hurri- 

 cane eye in mph or knots . 



A-13 



