Tsaacs—Faughn—-Schick—Sargent: Deep-Sea Moorings 287 
To compare the configuration of moorings using lines of different materials 
requires consideration of their weight in water. For taut-wire moorings of small 
inclination, the weight (or buoyaney) may be considered to act in the same direc- 
tion as the maximum allowable tension. Thus: 
T =1/k (s[7/4] t? — 62.4 [p- 1.024] L [1/4] [t?/144]) (5) 
where 
L =length of wire in feet 
p =Specifie gravity of wire 
1.024 =specifie gravity of sea water 
D~t (6) 
Hence if R’ is the tension/drag ratio 
R’ ~ st — 0.434 Lt (p — 1.024) (7) 
~ t(s— 0.484 L (p — 1.024) ) 
TABLE 1 
CoMPARISON OF CABLES 
Material Ce oa en ee ee 
Piano wire.............. 325,000 8 0.12 0.12 
IWITEPODE Me orc eyeefars ayscieus 125,000 8 0.39 1.20 
INA? Gila seanaoen en ammte ae 30,000 1 0.93 0.87 
* The wire rope used for this example is airplane control cable which is unsuitable on other counts besides its un 
favorable tension/drag ratio. 
Table 1 compares lines of different material and construction having the same 
tension/drag ratio, namely R’ = 32,000 for a length of 20,000 feet. Thus to have 
the same tension/drag ratio as %-inch piano wire, the airplane control cable 
would weigh 10 times as much in air, and the nylon line 7 times as much. 
It is apparent that the problem of high stresses in lowering could be ameliorated 
by use of a mooring line whose density is closer to unity. Some experimental instal- 
lations have been made with taut nylon rope (see Appendix). 
For this most critical component—the 2 to 3 miles of mooring wire—of deep- 
ocean taut-moored systems, two types of wire have been used: a solid electrolyti- 
cally galvanized steel wire and a stranded (1x7, long lay) electrolytically gal- 
vanized steel wire. The solid wire size varies from a 0.082-inch diameter to a 
0.120-inch diameter. The stranded wire size varies from a 0.123-inch diameter to a 
0.200-inch diameter. 
Stations using the special stranded wire with a tensile strength of 260,000 psi 
have been installed. Experience indicates that such stations have a life expectancy 
equal at least to that of stations using a solid wire. A few well-spaced butt welds 
may be used in fabricating the individual strands, for the loss in strength is re- 
duced by the number of strands. There are several advantages in using stranded 
wire. The stranded wire will take a smaller radius bend than the solid wire; it is 
simpler to unspool because of a reduced tendency to “‘cut in” to the underlying 
layers; it is possible to make the stranded wire in extremely long continuous 
