symmetrical and does not require orientation 
into the current. Current direction is sensed 
by a vane in the upper cage which will orient 
to within 10° of the current direction at .01l 
knot. The vane carries a magnet which couples 
through the end cap of the pressure case to a 
jewel bearing mounted magnet and seven level 
gray binary encoding disc. When a light is 
flashed behind this disc the light passing 
through the seven channels is "piped" to the 
field of view of the camera by small plexiglas 
light guides where it appears as seven spots 
on the film, either present or not present de- 
pending upon the orientation of the vane rela- 
tive to the pressure case. A similar seven 
level gray binary number is obtained at the 
same time from a compass mechanism which also 
carries an encoding disc. This encodes the 
Magnetic orientation of the instrument as a 
whole and the difference between the vane and 
compass readings is the direction of the 
current. These seven level binary numbers give 
directions individually accurate to about 2 1/2 
or current direction to 5° when they are sub- 
tracted. The current speed is sensed by a 
Savonius rotor the bearings of which permit it 
to start rotating at speeds of less than .Ol 
knot. The rotor is also magnetically coupled 
through its end cap to a jewel bearing mounted 
light chopper which provides one pulse of light 
for each rotation of the rotor. This pulse is 
"piped" to the field of view of the camera by 
a fiber optics light guide. The film is ad- 
vanced at a slow uniform rate by the camera 
motor (1/8 inch per minute) and the rotor 
pulses appear as a succession of spots on the 
film which can be counted photoelectrically. 
An illustration of the film format is shown in 
Figure 5. 
Tests of the mooring system were made in 
1500 fathoms off Bermuda during December and 
January 1960-61. Tension measurements were 
made which showed a maximum during this period 
of about 800 pounds under heavy storm conditions 
and a typical tension of 100 to 300 pounds. It 
thus appeared the design was reasonably con- 
servative for a moderate current environment 
and the instruments required for the line as 
shown in section in figure 2 were constructed 
during the spring of 1961. Statioms A, R, C 
and D (Figure 1) were set in early May. Fail- 
ures of the shallow stations A, R and C occurred 
after a week or two and this was traced to 
failure of the bails on the current meters 
caused by vibration. This fault was corrected 
and the rest of the line was set in early June. 
Station H failed and was recovered on a chance 
encounter of the surface float with R/V ATLANTIS. 
Failure was attributed to stress corrosion of 
the tie rods of the upper-most current meter, 
possibly caused by overstressing during assembly, 
and the entire moor was lost. Station G failed 
a few weeks later for the same reason, although 
evidence for this mode of failure was not avail- 
able soon enough to allow realization that this 
209 
was to be a serious problem. Stations I and J 
(the remaining Gulf Stream stations) were opera- 
tive for several weeks but were not found when 
the line was visited for recovery of records 
in late July. The surface float of station I, 
together with the upper-most current meter, was 
recovered by a freighter in October but was set 
adrift again without retaining the instrument. 
Thus a good set of Gulf Stream current measure- 
ments is still drifting around in the ocean. 
The surface float from station J has never been 
reported. Stations A, B, C, D, E, F, K, L and 
M have been maintained with reasonable success 
from May or June until late September. The 
visitations of Hurricanes Esther and Frances, 
the tracks of which are shown in Figure 6, 
caused considerable difficulty. The deep 
stations at D, E, F, K, L, and M which were 
in place at the time of the storms have sur- 
vived with only damage to their towers. The 
shallow stations A, B and C however, are now 
adrift, although it appears that C was on 
station some ten days after the passage of 
Frances. 
To summarize, we have been quite success- 
ful with deep stations except those in the 
Gulf Stream where we have had no success at 
all. The shallow stations (less than 100 
fathoms) have been reasonably successful 
during the summer months but have fallen 
victim to the fall storms. 
At the time of this writing the work of 
data reduction has just begun. Hopefully we 
will be able to report on this in the near 
future. 
