282 Bulletin, Scripps Institution of Oceanography 
For surface floats at Seripps we have used glass-reinforeed plastic skiffs of 
various sizes up to 16 feet long, and catamarans (see Appendix). A 20-foot painter 
ending in a ring is secured to the stem of the skiff (fig. 4). This connects with the 
main pennant, as explained later. 
Spar Buoys 
A nonresponding spar buoy has many advantages, but it is not suitable for use 
with a long-lived taut-wire mooring. A nonresponding spar is one whose natural 
period of vertical oscillation is much longer than that of any expected wave of 
significant height. For a hydrometer-shaped float or a spar restrained by an 
elastic pennant, a damped spring-mass calculation must be made.* Resonance, 
which is obviously a condition to be avoided, will occur with a lightly restrained 
cylindrical spar whose submerged length is Lo/2z. If the pennant between the 
spar and the submerged float leads away horizontally at the surface, it will be 
subject to severe flexing and abrasion at the point of attachment to the spar. If it 
is vertical, then when it is slack during calm weather it will foul the submerged 
float. The principal difficulty with the spar buoy, however, is that its motion in a 
seaway is incompatible with that of any conventional craft that might try to 
handle it or come alongside. 
PENNANTS AND INSTRUMENT LINES 
The pennant is the member of the mooring assembly which connects the surface 
float to the submerged float. 
The surface pennant to a responding float (skiff) either must lead almost 
horizontally away from the float, or, if nearly vertical, must be highly elastic. 
This is because, when the float is subject to whitecaps or combers, its vertical 
downward accelerations approach that of gravity. Hence, any vertical string 
depending only upon gravity forces for tension will slack and jerk in a way that 
will greatly shorten its life, if, indeed, it survives at all. In addition, the skiff does 
not respond well to a vertical load near the bow. 
Both types of pennants are in use. A common pennant is a nylon float line that 
tends upward in a floating catenary. In slack weather this pennant (with a scope 
of about 2.0) floats forward of the surface float and greatly increases the possi- 
bility that the mooring will be run down by a passing vessel. This danger is 
intensified by the fact that in slack weather the visual and radar detection range 
of vessels is increased so that curious passing navigators are more likely to 
investigate. 
The instrument line can then be lowered independently over the stern of the 
float, utilizing a section of shock cord to provide elasticity. This system is limited 
to instrument lines that are shallower than the submerged float; to weather situa- 
tions that are constant, such as the trades; and to short-period installations. 
(Otherwise the pennant and the instrument line will foul.) 
Experimental vertically tending elastic pennants are now under test. The 
pennant is made of fabric-covered rubber shock cord with the instrument line 
* Tt should be kept in mind in this calculation that the “damping pot” (i.e., the sea water) 
is not fixed as in the usual model, but is oscillating. 
