As a result, many such radars would be required along the coast, and such 

 an approach would not ordinarily be recommended for complete surveillance 

 of the 200-nmi fishing zone. On the other hand, there may be specific 

 regions that require such coverage. 



For detection, both surface-wave and skywave OTH radars 

 make use of the velocity of the ship target relative to the radar loca- 

 tion; or, with a ship dead in the water, such radars make use of the 

 wave motion relative to the ship. Such considerations will need to be 

 taken into account when a ship-detection radar is being designed for 

 specific applications. Advantage should be taken of the fact that de- 

 tection can be provided on a continuous basis, thus allowing full-time 

 surveillance of very large areas so that the general population of 

 foreign and domestic fishing boats can be monitored. When such radars 

 become operational, performance of the system would be greatly enhanced 

 if transponders were required on all foreign vessels. 



If, for example, the United States required the use of a 

 transponder as part of the licensing arrangement, and included the costs 

 of furnishing, installing, and maintaining the transponders in the 

 licensing fee, the entire program would be under U.S. control. 



Because of the large number of vessels that would be 

 transponder-equipped, it would be desirable, if not necessary, to pro- 

 vide selective interrogation. A number of benefits would result from 

 this action. 



• Vessels could be interrogated on the basis of 

 type, size, or national origin, 



• Within any chosen group, transponder responses 

 could be coded to identify a particular vessel. 



• Should a vessel discontinue responding, its 

 activities would be suspect and an appro- 

 priate Coast Guard unit could be assigned to 

 investigate. (Such an arrangement seems 

 possible only if ownership of the trans- 

 ponders is vested in the United States). 



49 



