revetment— A facing of stone, concrete, or other material, built to protect a scarp, 

 embankment, or shore structure against erosion by wave action or currents. 



riprap— A layer, facing, or protective mound of stones randomly placed to prevent erosion, 

 scour, or sloughing of a structure or embankment. Also the stone so used. 



riser— A vertical pipe, post, or support extending above deck level to support utility outlets 

 and other facilities. 



roadstead— (Nautical) A sheltered area of water near shore where vessels may anchor in 

 relative safety. Also road. 



rock— Stone in the mass, as in a quarry or rock stratum. 



roll— The rotational oscillations of a craft about its longitudinal axis under wave excitation. 



rubble mound— A mound of random-shaped and random-placed stones protected with a 

 cover layer of selected stones or specially shaped concrete armor units. (Armor units in 

 primary cover layer may be placed in orderly manner or dumped at random.) 



rub strake— A longitudinal rib or protective strip running along the huU of a craft to 

 function as a bumper. 



scend— The sinkage of a craft in the trough of a wave. 



scour— Removal of underwater material by waves and currents, especially at the base or toe 

 of a shore structure. 



screw— A propeller on any type of craft. 



sea— (1) An ocean, or alternatively a large body of (usually) saltwater smaller than an ocean. 

 (2) Waves caused by wind at the place and time of observation. (3) State of the ocean or 

 lake surface in regard to waves. 



section modulus— A relative measure of the ability of a cross-sectional configuration to resist 

 bending forces. Technically, the maximum allowable bending movement of a homoge- 

 nous beam divided by its maximum allowable fiber stress. 



seiche— A standing wave oscillation of an enclosed water body that continues, pendulum 

 fashion, after the cessation of the originating force. 



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