expendable weight and casing assembly. When these 

 two assemblies are combined, the core barrel fits 

 loosely inside the casing. The device is dropped 

 over the side of the ship and allowed to fall free 

 to the bottom. A simple release-delay timer made 

 of magnesium releases the core barrel and its buoy- 

 ant float rises from the weight and casing assembly. 

 (35) 



MOORING BUOY . A buoy secured to the bottom by 

 permanent moorings and provided with means for moor- 

 ing a vessel by use of its anchor chain or mooring 

 lines. In its usual forrn a mooring buoy is equipped 

 with a ring. If it has an opening through which a 

 mooring pendant is passed, it is called a trunk 

 buoy. (17) 



w is the vertical velocity. With these simplifica- 

 tions, the equation of vertical motion is recognized 

 as the hydrostatic equation. 



The usual form for the scalar equations of 

 motion in Cartesian coordinates (x, y, z) , x taken 

 positive eastward, y northward, and z locally up- 

 ward, is as follows: 



iH+u |ii + v|ii+w|^= fv-2ncos *«- i 1^ + Fx; 



n. fi__ J.. jj^ p OX 



3t 



3x 



3y 

 av 



8v 3v "V •'. -. 

 3t ax 9y 3z 



P 



3w 3w 3w , 3w 



bT "" " 37 ■" ^ 37 " 5^ " ^"''°^ " 





3z 



g + Fz. 

 (14) 



MOORING SYSTEM . A mooring system is that arrange- 

 ment of components intended to locate the moored 

 object in a body of water such that its location 

 remains within pre-established boundaries for a 

 specified time. 



Mooring systems may be classified according 

 to: 



1. The nature of the moored object 



a. instrument skiffs 



b. instrument lines or pendants 



c. full sized vessels 



d. structures 



e. buoys 



2. the location of the moored object 



a. on the surface 



b. submerged 



3. the depth of water in which the mooring system 

 is located 



a. deep ocean 



(1) very deep 



(2) intermediate depths 



(3) deep sea mounts 



b. shallow water 



(1) bays, harbors 



(2) continental shelf 



(3) shallow sea mounts 



4. the type of moor 



a. taut-line 



b. slack line 



5. the configuration of the moor 



a. single leg, single catenary 



b. multi-leg, single catenary per leg 



c. multi-multi-leg, single catenary per leg 



d. those above but with compound (multi- 

 catenary) legs 



e. those above but with buoyant mooring lines. 

 (35) 



MOVING-COIL TRANSDUCER . A moving-coil transducer 

 is a moving-conductor transducer in which the 

 movable conductor is in the form of a coil. (1) 



MRI . Meteorological Research Institute. 



MSA . U. S. Navy ship designation for a Mine- 

 sweeper, Auxiliary. 



MSB. 



Maritime Safety Board. 



MSC . U. S. Navy ship designation for a Minesweeper, 

 Coastal (Nonmagnetic). 



MSC(O) . U. S. Navy ship designation for a Mine- 

 sweeper, Coastal (Old). 



MSF . U. S. Navy ship designation for a Minesweeper, 

 Fleet (Steel Hulled) . 



MSI . U. S. Navy ship designation for a Minesweeper, 

 Inshore. 



MSL . Mean Sea Level. 



MSO . U. S, Navy ship designation for a Minesweeper, 

 Ocean (Nonmagnetic) . 



MSS . U. S. Navy ship designation for a Minesweeper, 

 Special. 



MSTS . Military Sea Transport Service. 



OT. MEGATONS. The yield of a nuclear detonation 

 equivalent to 1,000,000 tons of TNT. 



MIL. 



Mean Tide Level. 



MOTION. EQUATIONS OF . A set of hydrodynamical 

 equations representing the applications of Newton's 

 second law of motion to a fluid system. The total 

 acceleration on an individual fluid particle is 

 equated to the sum of the forces acting on the par- 

 ticle within the fluid. 



Written for a unit mass of fluid in motion in 

 a coordinate system fixed at a point on the earth's 

 surface, the vector equation of motion for the at- 



mosphere is dv = - 2n xv - gk -i Vp + F, 



dt ^ p ^ 



where V is the three-dimensional velocity vector, 

 ^ the angular velocity of the earth, k a unit vec- 

 tor directed upward, perpendicular to the earth's 

 surface at the point in question, P the density, p 

 the pressure, g the acceleration of gravity, and F 

 the frictional force per unit mass. When applied 

 to the atmosphere's horizontal motion, the coriolis 

 acceleration terms 2S2xv are usually approximated 

 by the two horizontal components i2n sin 't'V , 

 and -j2 n sin •t'u , where i and j are the unit vec- 

 tors along the horizontal x and y axes, respective- 

 ly, while u and v are the velocity components along 

 these same axes. Here ^ is the magnitude of n , 

 and 't' is the geographical latitude. In the equa- 

 tion of vertical motion, the vertical component of 

 the coriolis force is frequently neglected and it 



is often assumed, in addition, that S^ =0, where 



Mrs . Marine Technology Society. A professional 

 membership, non profit society of the marine tech- 

 nological community. The society was founded and 

 incorporated in 1963 and has its headquarters in 

 Washington, D. C. 



MUD . Pelagic or terrigeneous detrital material con- 

 sisting of particles smaller than sand, that is, an 

 undifferentiated sediment made up of particles most- 

 ly within the silt-clay range smaller than 0.0025 

 inch (0.0625 millimeter). (16) 



"MUD FENETRATOR" . A continuous seismic profiling 

 system using electronically generated acoustic 

 pulses to determine the sub-bottom structure of 

 the sea floor in shallow water areas. 



MUD SNAPPER . The Mud Snapper is a small clamshell 

 type snapper which is about 11 inches long and 

 weighs 3 pounds . It is attached to the bottom of 

 a sounding lead by means of a hole drilled in the 

 lead. The jaws are cast bronze and are actuated 

 by a spring. The jaws are held open by engaging 

 two trigger pins within the jaws. The Mud Snapper 

 and sounding lead may be operated in shallow water 

 by hand lowering or by lowering from a BATHYTHER- 

 MOGRAPH or OCEANOGRAPHIC WINCH. (35) 



79 



