PORT - A place vjhere vessels may discharge or receive cargo j may be 

 the entire liarbor including its approaches and anchorages or may 

 be the commercial part of a harbor « where the quays, wharves, 

 facilities for transfer of cargo, docks, repair shops, etc. are 

 situated, 



POTENTIAL ENERGY OF WAVES - In a progressive oscillatory wave, the energy 

 resulting from the elevation or depression of the water surface from 

 the undisturbed level » This energy advances with the wave formo 



PROFILE, BEACH ~ The intersection of the ground surface with a vertical 

 planej may extend from the top of the dune line to the seaward limit 

 of sand movement, (See Figure A-l) 



PROGRESSION - See ADVANCE, 



PROGRESSIVE WAVE - A wave which is manifested by the progressive move- 

 ment of the wave formo 



PROMONTORY - A high point of land projecting into a body of water j a 

 headlands 



PROPAGATION OF WAVES - The transmission of waves through water. 



PROTOTYPE - In laboratory usage^ the original structure, concept.^ or 



phenomenon used as a basis for constructing a scaie model or copy. 



QUAY (pronounced KEY) - A stretch of paved bank., or a solid artificial 



landing place parallel to the navigable waterway, for use in loading 

 and unloading vesselSo 



QUICKSAND = Loose^ yielding., wet sand which offers no support to heavy 



objects. The upward flow of the water has a velocity that eliminates 

 contact pressures between the sand grains^ and causes the sand-water 

 mass to behave like a fluid. 



RECESSION (OF A BEACH) - (l) A continuing landward movement of the shore 

 lineo (2) A net landward movement of the shore line over a specified 

 time. Also RETROGRESSION o 



REEF - A chain or range of rock or coral j, elevated above the surrounding 

 bottom of the sea, generally submerged and dangerous to surface 

 navigation. 



REEF, ATOLL - A ring-shaped;, coral reef,, often carrying low sand islands, 

 enclosing a body of water. 



REEF, BARRIER = A reef which roughly parallels land but is some distance 

 offshore, with deeper water intervening, 



A-2h 



