for use, the cup protrudes about half an inch from 

 the barrel and a hinged cover is held back by a 

 spring. Attachment to the light towing wire is by 

 means of a hinged arm that is folded down during 

 descent. When ready, the sampler is gently lowered 

 over the ship's side, but on striking the water the 

 brake is taken off the winch drum and the cable 

 rapidly run out. On striking bottom, a small sample 

 is taken into the cup which at the same time is 

 forced back into the tube. As this happens, the 

 spring holding back the lid is released and the 

 latter now comes over the end of the tube and pre- 

 vents any loss of sample during hoisting. Simul- 

 taneously a catch is sprung which frees the after 

 end of the towing arm so that during hoisting the 

 towing point of the sampler is brought nearer the 

 forward end, thus reducing drag. Although limited 

 as to the type and amount of sediment that can be 

 sampled this device has been very successfully used 

 to make rapid surveys in water of depth up to 100 

 fathoms . (35) 



SCOR . Scientific Committee on Oceanographic 

 Research. 



SCORIAE . Volcanic slag, pyroclastic ejecta; frag- 

 ments of scoriae between 0.16 and 1.26 inches 

 (4 and 32 millimeters) in size are essentially 

 equivalent to volcanic cinders. Scoriae are 

 classed as gravel on bottom sediment charts, 



SCUBA . Self Contained Underwater Breathing Appara- 

 tus. See OPEN CIRCUIT SCUBA, CLOSED CIRCUIT SCUBA, 

 and SEMI-CLOSED CIRCUIT SCUBA. 



SEA . 1. Same as ocean. 



2. A subdivision of an ocean. All seas 

 except "inland seas" are physically interconnec- 

 ted parts of the earth's total salt water system. 

 Two types are distinguished, mediterranean and ad- 

 jacent. Mediterraneans are groups of seas, col- 

 lectively separated from the major water body as 

 an individual sea. Adjacent seas are those con- 

 nected individually to the larger body. 



3. Same as state of the sea. (See SEA STATE) 



4. Sea-surface waves within their fetch; 

 opposed to SWELL. (24) 



SEA ACORNS . See BARNACLES. 



SEA ANCHOR . An object towed by a vessel, usually 

 a small one, to keep the vessel end-on to a heavy 

 sea or surf or to reduce the drift. In its usual 

 form it consists of a conical canvas bag with the 

 large end open. When towed with this end forward, 

 it offers considerable resistance. A small trip- 

 ping line attached to the pointed end is used for 

 hauling the sea anchor into the vessel. A sea 

 anchor is sometimes improvised by using a weighted 

 sail and spar, a bucket, a basket, a weight, or a 

 long line. Also called drag, drogue. (17) 



SEABEES . Civil Engineering Corps Division of 

 Bureau of Yards and Docks, BuDocks Building; 

 Washington, D. C. 



SEA BREEZE . A coastal local wind that blows from 

 sea to land, caused by the temperature difference 

 when the sea surface is colder than the adjacent 

 land. Therefore, it usually blows on relatively 

 calm, sunny, summer days; and alternates with the 

 oppositely directed, usually weaker, nighttime 

 land breeze. As the sea breeze regime progresses, 

 the wind develops a component parallel to the coast, 

 owing to the coriolis deflection. (Defant, F., 

 in Compendium of Meteorology, 1951, pp. 655-672) 

 (24) 



SEA BREEZE OF THE SECOND KIND . See COLD-FRONT-LIKE 

 SEA BREEZE. 



SEA BUOY . The outermost buoy marking the entrance 

 to a channel or harbor. Sometimes called farewell 



buoy, since it is the last buoy passed by a vessel 

 proceeding out to sea. (17) 



SEACHANNEL . A long, narrow, U-shaped or V-shaped 

 shallow depression of the sea floor, usually oc- 

 curring on a gently sloping PLAIN or FAN. (26) 



SEA FOG . A type of advection fog formed when air 

 that has been lying over a warm water surface is 

 transported over a colder water surface, resulting 

 in cooling of the lower layer of air below its dew 

 point. (24) 



SEAGOING PLATFORM FOR ACOUSTIC RESEARCH . See SPAR. 



SEA GRASS . Seed bearing marine plants, more highly 

 organized than algae, found in shallow waters both 

 brackish and marine, attaining lengths up to 8 feet. 

 (15) 



SEA ICE . All ice formed by the freezing of sea 

 water. It may be classified as FAST ICE if attached 

 in any way to the shore or to the bottom, FLOATING 

 ICE if unattached, or it may be classified accord- 

 ing to related features. (17) 



SEA ICE SHELF . Sea ice floating in the vicinity 

 of its formation and separated from fast ice, of 

 which it may have been a part, by a tide crack, or 

 a family of such cracks. (17) 



SEALAB I . An underwater laboratory used in July 

 1964 by 4 Navy divers who lived and worked in and 

 outside of this 192 foot deep laboratory placed at 

 the base of ARGUS IS. The work of these divers was 

 to participate in the Navy's first protracted 

 physiological-engineering test to determine how 

 men can work freely and for extended periods of 

 time at these (192') underwater depths, 



SEA LEVEL . The height or level of the sea surface 

 (without further technical definition) . It is used 

 loosely as a synonym for MEAN SEA LEVEL, STILL- 

 WATER LEVEL, or HALF-TIDE LEVEL. (24) 



SEA LEVEL DATUM . A determination of mean sea level 

 that has been adopted as a standard datum for 

 heights. The sea level is subject to some varia- 

 tions from year to year, but as the permanency of 

 any datiim is of prime importance in engineering 

 work, a sea level datum after adoption should in 

 general be maintained indefinitely even though 

 differing slightly from later determinations of 

 mean sea level based upon longer series of obser- 

 vations. The sea level datum now used for the U. S. 

 Coast and Geodetic Survey level net is officially 

 known as the Sea Level Datum of 1929, the year re- 

 ferring to the last general adjustment of the net. 

 The datum itself may be considered as an adjustment 

 based upon tide observations taken at various tide 

 stations along the coasts of the United States over 

 a number of years. See also MEAN SEA LEVEL, (27) 



SEAMOUNT . An elevation of the sea floor having a 

 nearly equidimensional plan less than 60 nautical 

 miles across the summit. (26) 



SEAMOUNT CHAIN . Three or more SEAMOUNTS in a line 

 with bases separated by a relatively flat sea floor. 

 (26) 



SEAMOUNT GROUP . Three or more SEAMOUNTS not in a 

 line and with bases separated by a relatively flat 

 sea floor. (26) 



SEAMOUNT RANGE . Three or more SEAMOUNTS having con- 

 nected bases and aligned along a RIDGE or RISE. 

 (26) 



SEA FUSS , A dangerous longshore current, a RIP 

 CURRENT, caused by return flow, loosely the sub- 

 merged channel or inlet through a BAR caused by 

 those currents. (11) 



lOU 



