of an additional use of the sonobuoy . The sonobuoy would be placed on a 

 raft payed out from the ATLANTIS about 1000 ft. downwind. A sotmd pulse 

 would be released by a transducer on the ATLANTIS. The sonobuoy hydro- 

 phone would pick up the signal, which travels through water, convert it to 

 an electromagnetic signal and retransmit it through air, at a given f?:equency, 

 to be picked pp by a receiver on the ship. The echo-sounder would record 

 the time of one round trip. The trip through water takes about 0.2 seconds 

 (for 1000 ft), and the return through air takes 1.08 x 10" seconds. The 

 time of the return trip is considered negligible, and if the rate or propa- 

 gation of sound in water is known as a function of temperature and salinity, 



■I 



then the distance traveled by the signal can be computed. 



In July, ONR enlisted the interest of the Naval Air Development Unit 

 at the Naval Air Station, South Weymouth, Mass. where a pair of blim.ps 

 were available for the job. A request originated from ONR for the utilization 

 of the NADU resources. At the sam,e time, ONR ordered four cameras, two 

 gyrostabilizing mounts and an abundance of film. WHOI was directed to set 

 up and install the FM link, W, Marks (WHOI) was appointed field super- 

 visor of the project. 



As the pieces began to fall into place, certain difficulties became in- 

 creasingly apparejat. 



1. The m.easurem.ent of stereo-baseline had not been resolved, 



2, Since weather plays a prom.inant role in determining the desired 



*Sonobuoy Instruction Manual AN-SS Q2. 



22 



