The buoy contains two separate and electri- 
cally independent anchor release circuits pro- 
viding three modes of actuation. In normal 
operation, the main buoy clock/programmer actu- 
ates the acoustic command receiver circuits at 
the end of the timed measurement period. The 
acoustic command receiver circuit is energized 
for a period of approximately three days during 
which time reception of the correct acoustic 
code will fire the anchor release. The enable 
period is designed to be adjustable and can be 
set anywhere between 9 and 99 hours in incre- 
ments of 10 hours. If the proper acoustic code 
has not been received at the end of the enable 
period, the main buoy programmer will fire the 
anchor release. 
An additional separate timer powered from 
its own battery pack will also fire the re- 
lease mechanism through completely independent 
circuits, providing backup to the acoustic 
command receiver circuit in the event of a 
failure in the main battery or electrical con- 
trol system. The secondary timer will be set 
to fire after runout of the acoustic enable 
period has occurred. 
The acoustic command receiver function pro- 
vides two valuable features in the recovery 
system. In normal operation, the recovery 
ship is not required to be in a precise posi- 
tion at a precise time to insure that the buoy 
will surface relatively close at hand. There- 
fore, an allowance is made for the routing 
emergencies and delays which continually arise 
such as equipment breakdown or inclement 
weather conditions. Secondly, the relatively 
short acoustic command range provides a higher 
probability that the buoy will surface within 
visual sighting range. The backup circuit pro- 
vides for eventual buoy release and return to 
the surface in case of a failure in another 
part of the recovery system. 
The acoustic command receiver responds to 
a pair of accurately timed signals provided 
by small explosive charges (No. 6 blasting 
caps). This system was chosen because of the 
simplicity and inexpensiveness of the signal 
generator requirements. The recovery ship 
does not need a specialized transmitting trans- 
ducer and associated electronics. 
Provision is also made against actuation 
of the release mechanism by random background 
and/or ship noises. Decoder circuit, therefore, 
is incorporated in the receiver design to dis- 
criminate against background noise, reducing 
the probability of false triggering. 
24 
POWER SUPPLY 
Electrical power is supplied by a Yardney 
silver-cadmium battery assembled from 22 YSs-4o0 
units in a series connection. This combination 
supplies 960 watt-hours of electrical energy 
which is sufficient to make 1600 measurement 
cycles leaving a 20-percent battery charge in 
reserve. 
