The present invention provides an underwater cable arrangement includes an underwater cable having one or more external devices mounted on the cable. In one form of the invention, the external devices are powered primarily or entirely by inductive coupling between a coil disposed in the cable and a coil disposed in the external device. The invention also provides a variety of external devices capable of use with an underwater cable. The invention further provides a coil support arrangement for supporting a coil within an underwater cable in a manner protecting a core of the coil from damage.