280 Bulletin, Scripps Institution of Oceanography 
successful use for some time. The mooring utilizes a lower line that is buoyant 
(polypropylene), and an upper portion that is nonbuoyant (nylon). The entire 
mooring cable therefore assumes a shape like that shown in the accompanying 
illustration, thus avoiding many of the problems of slack mooring and permitting 
installation by streaming. 
In the taut-wire configuration the adjustment to increased horizontal force is 
an inclination of an initially taut wire. There is little increase in tension. Hence 
the major portion of the buoyancy in such a mooring may be submerged at some 
relatively constant depth where it is in the region of reduced currents and wave 
motion. 
A common requirement of deep moorings is station keeping. For this require- 
ment the taut-wire mooring is superior. The taut-wire mooring, however, requires 
much more rigorous design, handling, and installation procedures than the slack 
mooring; thus the latter may be preferred in some circumstances, particularly for 
installations from which only surface data are taken and for short-term installa- 
tions. 
TAUT-WIRE MOORING COMPONENTS 
SURFACE FLOATS 
Two general types of surface floats are feasible: (1) a surface-following float, such 
as a skiff or a nun buoy that tends to move with the waves, and (2) a stable float, 
such as a long-period spar or a “hydrometer-shaped” float whose vertical excur- 
sions in the presence of waves are small. Although each of these types has advan- 
tages, the present discussion will be limited to surface-following floats. 
A primary requirement of the surface float is that it possess sufficient displace- 
ment to support its instrument and power load. The float should also be designed 
to support the weight of the mooring wire and the submerged float, so as to pre- 
vent the loss of the entire mooring if the submerged float leaks and fills. It should 
also carry a radar reflector and a flashing light to aid in homing on it and to warn 
ships against running it down. Figure 4 shows one type of float made of a glass- 
reinforced plastic skiff. 
The responding surface float should be designed so that a comber does not load 
its frontal area instantly. Thus a conical or boatlike bow is preferred. The float 
will then reach the velocity of the comber very rapidly, but not impulsively. As it 
is temporarily shielded from the wind, its early velocity in respect to the comber 
will be the speed imparted by a towing force equal to the wind drag. That is to 
say, as soon as the float is shielded from the wind, the tension in the cable due to 
the wind will be available to move the float through the water. This initial velocity 
