The study of the hydrodynamic interaction of cables has become more important in recent years since umbilical cables of more than 3000 meters length have been used when photographing the wreck of the HMS Titanic or the Bismarck. Cable vibration can cause distorting of the digital signals being transmitted as well as premature fatigue failure of the cable conductors. The objective of the present study is to describe the hydrodynamic interaction of an element of such a rather vertical cable which is vibrating more or less crosswise in a constant current.