Abstract The limits of the operational area of a ROV (Remotely Operated Vehicle) are calculated when it is working at a certain water depth. The boundary of the operational area is called the footprint and is depending on the thrust which can be delivered by the submersible, the current velocity, the water depth and the cable parameters A method to calculate the thrust which can be delivered by a submersible is not given in the paper, but can be acquired according to Dewhurst1 He gives the influence of the current on the thrust of a single thruster in a nozzle. The influence of external parameters as current and water depth is given together with the influence of the cable parameters. Introduction Several means are available in order to reduce the drag of an umbilical cable exposed to a current. Besides neutral buoyant cables and cables with a normal weight are available. These factors mean that the owner of a"ROV has to make decisions about the type of cable he wants to use with respect to drag and weight. So the question with which he is confronted is: which cable, buoyant or not, with what length and which kind of fairing should be used in order to maintain a desired operational area at a certain water depth? When positioned in a current a drag force and a friction force are exerted on the umbilical cable. The cable itself has a certain weight and buoyancy. At the lower end of the cable the submersible exerts a force on it, depending on the available thrust and on the drag of the vehicle. A computer program has been developed which is in agreement with a method as described by P.I. Johansson for a finite element model for mooring cables.2 The position of the submersible with respect to the surface ship, with or without velocity, is calculated as a function of cable data, current data and effective thrust at the lower end of the cable. Besides the three dimensional position of the cable nodes, positioned at regular intervals along the cable, is estimated. A description of the program is given in the Appendix. Footprint Area - Variation Of Parameters A visual presentation of the general situation is given in fig. 1. The footprint area which can be covered by a submersible is a function of:Cddrag coefficient of the cable perpendicular to the cableDt= tangential friction coefficient of cableD= cable diameterY= mass of cable per meterL= cable lengthVscurrent velocity which may vary in magnitude and direction over the water depthHswater depthTs=delivered thrust by the propellers of the submersibleRsresistance of submersibleTs and Rs give the boundary condition at the lower end of the cable. A way to calculate the thrust of a propeller in a nozzle, taking into account the influence of the magnitude and direction of the current on the thrust, is given by Dewhurstl. The method will not be discussed in this paper. The tangential friction coefficient Ct is very small and the influence of this parameter has not been considered.