sheet pile— A pile mth a generalh flat cross section to be driven into the ground or seabed 

 and meshed or interlocked with like members to form a diaphragm, wall, or bulkhead. 



shingle— (1) Loosely and commonly, any beach material coarser than ordinary gravel, 

 especially any lia\ing flat or flattish pebbles. (2) Strictly and accurately, beach material 

 of smooth, w'ell-rounded pebbles that are roughly the same size. The spaces between 

 pebbles are not filled with finer materials. Shingle often gives out a musical note when 

 stepped on. 



shoal— (verb) (1) To become shallow gradualh . (2) To cause to become shallow. (3) To 

 proceed from a greater to a lesser depth of water. 



shoal— (noun) A detached elevation of the sea bottom comprised of any material except 

 rock or coral, and which may endanger surface navigation. 



significant wave height— The average height of the one -third highest waves of a given wave 

 group. Note that the composition of the highest waves depends upon the extent to which 

 the lower waves are considered. In wave record analysis, the average height of the highest 

 one-third of a selected number of waves, this number being determined by di\iding the 

 time of record by the significant period. 



slip— A berthing space between two finger piers. 



sonic probe— Investigation or exploration of depths by use of radio or sound pulse echos. 



spaUs— Small fragments or chips of stone. 



squat— The vertical downward displacement of a craft under power with respect to its 

 position in the water when not underway. 



stone— Quarried rock. v^Iso, any individual piece of rock broken away from its original mass. 



stringers— The relatively long, main, horizontal beams that support the deck of a fixed pier 

 or dock between bearing points. In a floating structure, tlie continuous beams (usually 

 along the sides) that join a series of floating modules. 



submarine canyon— A cut or gorge in the Continental Shelf. 



substrata— The layers of material beneath the surface soil. 



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