Hi David,

[www.uboatwar.net]

[Primary use]
The forward Bow jumper wire was used as a short wave radio transmitter antenna (3 - 30 MHz), while the twin Stern wires were used for reception.

[Secondary]
The jumper wires were used for attaching life lines for crew working on deck in bad weather.

Regards,
Don_

"A man's got to know his limitations..."
Harry Callahan, SFPD