Isaacs—Faughn-Schick—-Sargent: Deep-Sea Moorings 311 
For a 300-foot pennant with scope 2.0 and ten equally spaced floats having a 
buoyancy of 4.5 pounds each, if the angle at the submerged buoy is 60 degrees, the 
total force in a horizontal direction is 
> F, = 48.3 & cos (Om-1— Y2A0) sin (On-1 — Y2A0) (23) 
= 43.3 x 3.2 = 138 pounds 
Fig. 14. Restoring forces on a pennant. 
The initial horizontal restoring velocity at the skiff may then be calculated, 
using the following assumed form drag areas. 
A half-inch pennant reaching to 150 feet (4%4 x 42x 150)... 6.3 sq. ft. 
FTC TG TL OA LS ee tan se shears eee Leen pate tne elie, avawslieue dene eliove Leuete’ coaretersssre 2.8 
A vertical instrument line with instruments.............. 3.0 
Equivalent form drag area of skiff (20 x 0.01)............ 0.2 
12.3 sq. ft. 
Vou V (2x 188)/(1.2 x 12.3 x 2) =3 ft. per second 
which exceeds the requirement of 2.5 feet per second set by a hypothetical storm 
wave 25 feet high. 
This result is not very sensitive to changes in the figure of the pennant except 
under two conditions. The first is the improbable condition that combers might 
occur when there is little wind or surface current. The second is that the pennant 
is stretched so that 6, at every float is less than 30°. In this instance, however, the 
elastic stretching of the pennant rapidly increases the restoring force, as already 
noted. When the skiff is being driven by the cascading comber, its bow is deep in 
the water and Cp = 1.0. When it surmounts or reaches the terminus of the comber, 
it floats higher, especially at the bow, and Cp = 0.01. There is thus a large effective 
force available to stretch the pennant, of which a small proportion is sufficient, 
when added to the buoyancy of the floats, to make up the required restoring force. 
