®-««vj 9.-9 



Figure 13(a).--Typlcal narrow-band Doppler from a small metal triplane at 10 yards (9.1 m.): no motion, large 

 spike at Doppler, horizontal scale 60 Hz/div, vertical scale relative; (b) motion of triplane toward hydrophone, 

 spike displaced to left; (c) motion away from hydrophone, spike displaced to right. 



16 



