288 Bulletin, Scripps Institution of Oceanography 
lengths without special processing; and it has satisfactory ratios of tension/drag 
and strength/weight. 
Sections of solid wire recovered from actual installations after five months of 
use, and a section of 0.123-inch, 1 x 7 strand wire recovered after three months of 
use, showed no visible signs of deterioration. Samples of wires fastened to a test 
board and not under stress were recovered after fifteen months. Here the sections 
of solid wire showed clearly visible signs of deterioration, rather severe in some 
instances, whereas the stranded-wire samples showed no visible signs of deteriora- 
tion. It is believed that some of the water-resistant lubricants used on stranded 
wire by manufacturers are of real value in retarding deterioration. The U.S. Navy 
Electronics Laboratory Materials Engineering Section has been helpful in recom- 
mending suitable lubricants. 
ANCHORS 
High-density anchors are desirable because their small dimensions for a given 
weight permit handling without excessively long booms or davits. Also their high 
rate of lowering in water allows a mooring to be laid in a short time, thus avoiding 
drifting off station. 
Various kinds of anchors have been used. Some have been solid steel cubes with 
pad eyes welded on top and bottom and some have been ordinary railroad-ear 
wheels. As moorings increase in size and complexity, a more sophisticated design 
of anchor will be required if the size of the mooring wire is to be kept at a mini- 
mum. For our installations, gravity anchors have been designed so that the net 
vertical reaction against the bottom is equal to at least 1.4 times the sum of the 
expected horizontal forces. Or, 
Wat Ww-B=1.4 Fu (fig. 8) (8) 
where 
Wa =weight in sea water of anchor 
Ww =weight in sea water of wire below submerged float 
B  =buoyancy of submerged float 
Fy =horizontal component of forces at the anchor 
= Fy, cos 6, where F'y is the tension on the mooring wire 
This has led to satisfactory performance on a relatively flat bottom. For a bottom 
with a slope ¢, the frictional foree F; required may be expressed as 
Fy=0.7 (W,-T) cos¢ (9) 
where 
Ce SIRS Worse siba @ 
For equilibrium the sum of forces F acting parallel to the slope must equal zero, or 
F =Tsin¢d— Wasin¢—Fy cos ¢+0.7 (Wa-—T) cosp=0 
W,-T=Fy/ (0.7-tan ¢) (11) 
With these assumptions a simple gravity anchor becomes impractical on bottoms 
with slopes exceeding about 20 degrees, and anchors with hooks, flukes, or grapnels 
must be used. Unless other considerations are overriding, it is best to anchor moor- 
ings in flat areas. Small-scale bottom features may be ignored to the extent that the 
