magnet around the cable once or twice. This magnetic mark lasts several 

 months, is easily detected electrically and transduced to ring a bell as 

 each mark passes the sensor, obviating the need for measuring wheels 

 which are vulnerable to slippage. 



E-M cable used as structural members in submarine construction is 

 a recent development, probably dating from the late 1960's. The Navy 

 AUTEC range in the Tongue-of-the-Ocean, Bahamas, includes a tri-moor 

 platform from which is suspended an E-M cable to a submerged buoy. This 

 cable is a signal carrier and also supports sensors between the buoy and 

 the tri-moor platform. 



In 1969 the deployment of Pacific SEA SPIDER, a tri-moor E-M and 

 mechanical cable structure, was attempted. A cable release opened pre- 

 maturely, severely kinking the E-M cable, aborting the implantment. 



71 



