Tsaacs—F'aughn—Schick—Sargent: Deep-Sea Moorings 295 
D = (360L/27[y2—y1]) (sin y2—sin y:) —L (17) 
where 
D =dip 
L = length of wire between submerged float and anchor; 
and 
E = (360L/27[y2—y1]) (cos yi — cos y2) (18) 
where 
EK = excursion 
The excursion is somewhat overestimated by this procedure and the dip is some- 
what underestimated. 
6) If the estimates of dip and excursion are satisfactory, the design may proceed. 
If they are too large, buoyaney may be increased moderately, say by 10 per cent, or 
other adjustments may be made. If these measures do not suffice, the size or 
the strength of the wire selected must be increased and the calculation must be 
repeated. This increase may be judged by selecting a wire with a strength/drag 
ratio that is larger than the first trial by the ratio of the calculated excursion (H,) 
to the desired excursion (E,). That is, R2=R,(E,:/E.), where R, and R» are the 
strength/drag ratios, respectively, of the first and the second trial wires. As the 
recalculated float and other parameters will scale proportionally to R, this second 
trial should be adequate. Note that simply increasing the size of the wire in- 
creases R. 
7) The geometry of the mooring should now be analyzed with greater exactitude. 
This may be done by the graphic method illustrated in the Appendix. In this com- 
putation it may be advisable to include factors that have previously been neglected, 
such as 
Water drag on the mooring pennant 
Water and wind drag on auxiliary floats 
Water drag on any instrument strings 
Buoyancy of auxiliary floats 
Buoyancy of the surface float (instrument skiff, etc.) 
In connection with the above computations, the basic coefficients of flow and the 
development of simplified formulas are discussed in the Appendix. 
8) As soon as the design is satisfactory from the standpoint of excursion and 
dip, the minimum anchor weight is determined by the criteria previously dis- 
cussed. 
9) The pennant length and characteristics are now chosen to afford satisfactory 
performance in combers, as explained earlier. This is carried out by determining 
the geometry of the mooring under highest expected wind stress without current 
stress. Then, assuming that the submerged buoy remains fixed, the pennant is 
extended horizontally to 20 per cent of Lo of the critical wave. The force increase 
should be such that (Vi+ Vu)/2=C./12, where V; is the velocity of the surface 
float under a force equal to the wind stress, V. is the velocity of the surface float 
under the increased force of the extended pennant, and Cy is the phase velocity of 
the wave. 
10) The calculation in (9) above is repeated, using the configuration of the 
