A production method for a headline sonar cable characterized by steps of:a. providing a first strength member (14)；b. coupling to strength member (14) a conductor (122)；c. forming a layer of polymeric material about the combination of strength member (14) and conductor (122) while ensuring that the conductor remains slack；d. forming a flow shield around the layer of polymeric material, thus forming an elongatable internally located conductive structure； ande. braiding a strength-member jacket layer (52) of polymeric material around the elongatable internally located conductive structure while ensuring that the conductor is slack when surrounded by the jacket layer (52).For another embodiment, an optical fibre is wrapped around the exterior of the layer of polymeric material within which is enclosed a braided conductor formed about the first strength member (14). Other embodiments employ further thermo-plastic layers and further sheaths and further conductors.
